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Does ankle cryotherapy affect dynamic stability of healthy subjects?

University of Florida Institutional Repository

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DOES ANKLE CRYOTHERAPY AFFECT DYNAMIC STABILITY OF HEALTHY SUBJECTS? By SUSAN E. MINIELLO A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLOR IDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN EXERCISE AND SPORT SCIENCES UNIVERSITY OF FLORIDA 2003

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Copyright 2003 by Susan E. Miniello

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TABLE OF CONTENTS page LIST OF TABLES.............................................................................................................vi LIST OF FIGURES..........................................................................................................vii ABSTRACT.....................................................................................................................viii CHAPTER 1 INTRODUCTION........................................................................................................1 Statement of the Problem..............................................................................................1 Hypothesis....................................................................................................................2 Definition of Terms......................................................................................................2 Assumptions.................................................................................................................2 Limitations....................................................................................................................3 Significance of the Study..............................................................................................3 2 REVIEW OF LITERATURE.......................................................................................4 Ankle Anatomy.............................................................................................................4 Proprioception...............................................................................................................7 Measurement of Proprioception...................................................................................9 Threshold to Detection of Passive Motion..........................................................10 Joint Position Sense.............................................................................................10 Muscle Latency...................................................................................................10 Postural Stability.................................................................................................11 Proprioception Training..............................................................................................12 Cryotherapy................................................................................................................13 Ice or Injection Induced Anesthesia and Ankle Proprioception.................................17 3 METHODS.................................................................................................................20 Subjects.......................................................................................................................20 Instrumentation...........................................................................................................20 Vertec Vertical Jump Stand.................................................................................20 Force Plate...........................................................................................................21 Electromyography (EMG)...................................................................................21 Measurements.............................................................................................................21 Vertical Jump Height...........................................................................................21 iii

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Time to Stabilization...........................................................................................22 Muscle Activity...................................................................................................22 Treatment.............................................................................................................24 Procedures...................................................................................................................24 Study Design and Data Analysis................................................................................25 4 RESULTS...................................................................................................................27 Subject Demographics................................................................................................27 Normalized EMG Activity.........................................................................................28 Tibialis Anterior..................................................................................................28 Peroneous Longus...............................................................................................28 Time to Stabilization...................................................................................................29 Vertical Ground Reaction Force Time to Stabilization.......................................29 Medial/Lateral Ground Reaction Force Time to Stabilization............................30 Anterior/Posterior Ground Reaction Force Time to Stabilization.......................30 5 DISCUSSION.............................................................................................................32 Muscle Activity..........................................................................................................32 Time to Stabilization...................................................................................................40 Suggestions for Future Research................................................................................44 Conclusions.................................................................................................................45 APPENDIX A INSTITUTIONAL REVIEW BOARD......................................................................46 B INFORMED CONSENT............................................................................................49 C QUESTIONNAIRE FOR INCLUSION IN THE STUDY........................................51 D DATA COLLECTION FORM...................................................................................52 E ANOVA TABLE OF PERONEOUS LONGUS PREPARATORY ACTIVITY......53 F ANOVA TABLE OF PERONEOUS LONGUS REACTIVE ACTIVITY...............57 G ANOVA TABLE OF TIBIALIS ANTERIOR PREPARATORY ACTIVITY.........61 H ANOVA TABLE OF TIBIALIS ANTERIOR REACTIVE ACTIVITY..................65 I ANOVA TABLE OF VERTICAL GROUND REACTION FORCE TIME TO STABILIZATION......................................................................................................69 iv

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J ANOVA TABLE OF MEDIAL/ LATERAL GROUND REACTION FORCE TIME TO STABILIZATION.....................................................................................73 K ANOVA TABLE OF ANTERIOR/ POSTERIOR GROUND REACTION FORCE TIME TO STABILIZATION.....................................................................................77 LIST OF REFERENCES...................................................................................................81 BIOGRAPHICAL SKETCH.............................................................................................84 v

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LIST OF TABLES Table page 1 Normalized preparatory EMG activity of the tibialis anterior (% of MVIC)..........28 2 Normalized reactive EMG activity of tibialis anterior (% of MVIC)......................28 3 Normalized preparatory EMG activity of peroneous longus (% of MVIC)............29 4 Normalized reactive EMG activity of peroneous longus (% of MVIC)..................29 5 Vertical ground reaction force time to stabilization (in msec).................................30 6 Medial/lateral ground reaction force time to stabilization (in msec).......................30 7 Anterior/posterior ground reaction force time to stabilization (in msec).................31 vi

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LIST OF FIGURES Figure page 1 Tibialis Anterior Preparatory Activity.....................................................................33 2 Peroneous Longus Preparatory Activity..................................................................33 3 Increase in Muscle Activity after Cryotherapy........................................................34 4 Tibialis Anterior Reactive Activity..........................................................................35 5 Peroneous Longus Reactive Activity.......................................................................35 6 Temperature Decrease after Cryotherapy ................................................................38 7 Vertical Ground Reaction Force Time to Stabilization............................................40 8 Medial/Lateral Ground Reaction Force Time to Stabilization.................................41 9 Anterior/Posterior Ground Reaction Force Time to Stabilization...........................41 10 Comparison of Time to Stabilization.......................................................................43 vii

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Abstract of Thesis Presented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Master of Science in Exercise and Sport Sciences DOES ANKLE CRYOTHERAPY AFFECT DYNAMIC STABILITY OF HEALTHY SUBJECTS? By Susan E. Miniello August 2003 Chair: Michael E. Powers Major Department: Exercise and Sport Sciences The purpose of this study was to investigate the effects of lower leg cold immersion therapy on dynamic stability of the ankle complex as measured by time to stabilization. The subjects that volunteered to participate in this research were tested once under the control condition and once under cold immersion condition. The subjects were screened prior to participation for any history of the following conditions: acute or chronic lower extremity injury, decreased sensation or circulation, and hypersensitivity to cold. The subjects were asked to perform a jumping and landing task once before and twice after the treatment. During this task, EMG activity was measured on the tibialis anterior and peroneous longus muscles both before and after landing on the force plate. In addition time to stabilization measurements for the ground reaction force, anterior/ posterior sway, and medial/ lateral sway were also recorded. The results were analyzed using a 3 X 2 repeated measures ANOVA and indicated that cold immersion therapy had no effect on dynamic stability as measured by time to stabilization. The results did indicate that viii

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preparatory muscle activity was increased at the first posttest for the ice immersion condition. This muscle activity was most likely responsible for helping the body compensate for any detrimental effects of cryotherapy and allowing time to stabilization to remain unchanged. Therefore, it appears from the results of this study that immediate sports activity after a cryotherapy treatment is probably not contraindicated. ix

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CHAPTER 1 INTRODUCTION Statement of the Problem The lateral ankle sprain is one of the most common injuries suffered by todays athletic population. These injuries are even more prevalent in cutting and jumping sports such as volleyball, football, soccer, and basketball. Cryotherapy is commonly used in the management of pain and inflammation following ankle trauma. These modalities are also incorporated into rehabilitation protocols and are often continued before and after practices and games once the athlete has returned to competition. Although the systemic and local effects of cryotherapy have been widely studied, its effects on joint function, and more specifically, dynamic stability, are not completely understood. Cryotherapy has been shown to cause anesthesia, decreased nerve transmission, and increased tissue and joint stiffness, all of which may affect joint function. 25 It is possible that a decrease in nerve transmission can alter the bodys response to changes in joint position. It is also possible that this would adversely affect balance and dynamic stability, both of which are necessary for proper function in athletic competition. Because of this, it is possible that cold treatments may potentially predispose an individual to injury if the neuromuscular response to perturbation has been slowed. Thus, the purpose of this study was to investigate the effects of lower leg cold immersion therapy on dynamic stability of the ankle as measured by time to stabilization. Although relatively new to athletic training research, time to stabilization has become an accepted and reliable measure of dynamic stability. 4 1

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2 Hypothesis The following hypotheses were investigated in this study. 1. A twenty minute cold immersion treatment to the lower leg will significantly increase time to stabilization as compared to the control condition. 2. A twenty minute cold immersion treatment to the lower leg will significantly increase muscle activity of the tibialis anterior and peroneous longus muscles during the preparatory phase of activity. 3. A twenty minute cold immersion treatment to the lower leg will significantly increase muscle activity of the tibialis anterior and peroneous longus muscles during the reactive phase of activity. Definition of Terms The following terms had specialized meanings for the purpose of this study. Cold immersion--the treatment that the subject received of placing their lower leg in a bucket of water and ice maintained at a temperature of 13-16C. 19 Dynamic stability-the ability to maintain balance after moving the center of gravity. 4 Electromyography--the measurement of muscle activity using surface electrodes placed over the origins of the tibialis anterior and peroneous longus muscles. 7 Proprioception--the awareness of joint position as sensed by the central nervous system. 24 Time to stabilization--the time that it took for a subject to stop swaying on a triaxial force plate after a jump landing on a single leg. 4 Assumptions The following assumptions were made in order to carry out this research. 1. It was assumed that all subjects truthfully answered all questions about their medical history. 2. It was also assumed that all subjects completed all the tasks necessary for the study to the best of their ability.

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3 Limitations There were a few limitations in this research which are listed below. 1. Only the lower leg was treated. 2. Since all the subjects in this study were college students, it was difficult to generalize the results of this study to other age groups. 3. Only healthy subjects, with respect to the lower leg, were used. 4. There may have been variability in the jumps of individual subjects between trials. Significance of the Study This study is important to the field of athletic training because it may have an effect on current practices. Presently, the accepted practice is to place an injured athletes limb in ice immediately after the injury and then return the athlete to play once they are feeling better and the athletic trainer has determined it is safe to do so. However, there is little research to support this as a safe practice. Previous research on this practice has been conducted with measures of static joint function, which does not simulate dynamic activities like time to stabilization does. These researchers measured static balance as an indicator of joint function instead of dynamic activities which more closely mimic sports skills. The results of the present research may impact the future practices of athletic trainers and others who care for injured athletes.

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CHAPTER 2 REVIEW OF LITERATURE The purpose of this chapter is to discuss the literature pertaining to the effects of cryotherapy on ankle proprioception. This chapter contains a discussion of the following topics: ankle anatomy, proprioception, and cryotherapy. Ankle Anatomy The ankle joint is essential to everyday function. It is a system of bones, ligaments, tendons and muscles that allows movement of the feet. It also allows us to stand upright, move our body through space, adapt to uneven ground, and absorb shock. The ankle complex consists of a primary joint and an accessory joint. Four different bones meet together to form these two articulations: the tibia, fibula, talus, and calcaneous. 29 The tibia, the main bone of the lower leg, is responsible for bearing body weight in this region. The fibula, located lateral to the tibia, does not bear weight, but serves as a site for muscle attachment. The talus is the bridge between the lower leg and the foot. It rests on top of the calcaneous and sits between the distal ends of the tibia and fibula. The calcaneous makes up the posterior portion of the foot and transmits weight from the talus to the ground. 29 The talocrural joint, considered the true ankle joint, is created by the distal portions of the tibia and fibula and the superior portion of the talus. These bones articulate at three different points within the joint: the articular facet of the tibia and the trochlea of the talus, the medial malleolus of the tibia and the medial trochlea of the talus, and the lateral malleolus of the fibula and the lateral trochlea of the talus. 1 The bony alignment 4

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5 creates a socket between the tibia and fibula in which the talus can fit termed the ankle mortise. 29 The talocrural joint is classified as a synovial hinge joint based on the movements of plantarflexion and dorsiflexion it allows. 29 The subtalar joint (STJ) is the accessory joint that aids in ankle movement by allowing inversion and eversion and stability through its medial, lateral, and posterior ligaments. The STJ is formed by the articulation of the talus and the calcaneous. The STJ is a synovial joint that allows inversion and eversion. 29 The motions that occur at the ankle are actually a combination of the movements allowed at the subtalar and talocrural joints. The motions allowed are dorsiflexion and plantarflexion, inversion and eversion, and the rotational movements of adduction and abduction. These motions occur in the sagittal, frontal, and transverse planes, respectively. There are several muscles in the lower leg that create movement at the ankle complex. These muscles mainly act as dorsiflexors or plantarflexors, but they may also act as invertors or evertors. The dorsiflexors are located on the anterior portion of the lower leg, and include the extensor hallucis longus, extensor digitorum longus, peroneous tertius, and tibialis anterior. 1 The muscles that plantarflex are located on the posterior portion of the lower leg. These muscles include the gastrocnemius, soleus, tibialis posterior, flexor digitorum longus, flexor hallucis longus, and peroneus longus. 1 The invertors include the tibialis anterior and tibialis posterior, while the peroneous longus, brevis, and tertius are responsible for eversion. 29 The ankle complex contains a set of ligaments that add to the stability of the joint. These ligaments are located in three areas: the medial ankle, the lateral ankle, and

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6 between the tibia and fibula. The ligaments add to the stability of the ankle by reinforcing unstable areas created by the fibrous capsule. 29 The medial ankle ligaments are collectively known as the deltoid ligament, which consists of four parts: the tibiocalcaneal (TCL), the anterior tibiotalar (ATL), the intermediate tibiotalar (ITL), and posterior tibiotalar ligaments (PTL). The TCL makes up the superficial portion of the deltoid system and runs from the medial malleolus to the medial aspect of the calcaneous. This ligament is not very thick, and therefore does not withstand high forces during activity. 15 The three tibiotalar ligaments run from the medial malleolus to the talus. These ligaments are much stronger and thicker than the tibiocalcaneal ligament and are able to withstand substantial force. 15 The deltoid ligament as a unit acts as the primary restraint to eversion. 15 The lateral ankle ligaments create stability at the ankle complex by minimizing rotation. The lateral ankle ligaments include the anterior talofibular (ATF), the posterior talofibular (PTF), calcaneofibular (CF), and lateral talocalcaneal ligaments (LTC). The ATF is located on the anterior portion of the lateral ankle where it blends with the joint capsule. The ATF specifically runs from the anterior aspect of the fibula, near the articular cartilage of the lateral malleolus, to the neck of the talus. 3 In addition to this anterior band of the ATF, it is not uncommon to see a distinct inferior band in some people. The ATF is taut during plantarflexion and limits talar tilt, especially inversion. 3,15 The PTF, which blends with the joint capsule and runs from the medial portion of the lateral malleolus to the posterior talus, reduces talar tilt when the ankle is dorsiflexed. 15 The calcaneofibular ligament originates at the anterior aspect of the distal fibula and inserts on the calcaneous. 3 Because of its location, the CF covers both the talocrural and

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7 subtalar joints. Therefore, it is designed so as not to restrict motion at either the talocrural or subtalar joint. 15 The CF has an important function in dorsiflexion where it is most taut and best able to resist talar tilt, especially inversion. The structure of the LTC depends on the individual. Most often, the LTC covers the subtalar joint and is similar in location to the calcaneofibular ligament. The LTC acts as a back up to the CF. Collectively, the lateral ankle ligaments are important for keeping the ankle joint stable during inversion movements. 15 The ligaments located between the tibia and fibula are the anterior inferior and posterior inferior tibiofibular ligaments and the interosseous ligament. These ligaments act to prevent widening of the ankle mortise in order to maintain stability of the talocrural joint. The interosseous ligament is the main connection between the tibia and the fibula. The posterior inferior tibiofibular ligament holds the malleoli of the tibia and fibula together. 29 The neurovascular supply of the ankle and foot includes the tibial, deep peroneal, and superficial peroneal nerves. The muscles of the anterior compartment (dorsiflexors) are innervated by the deep peroneal nerve, while the tibial and superficial peroneal nerves supply the muscles of the posterior and lateral compartments respectively. 34 The anterior tibial, posterior tibial, and peroneal arteries, which branch off the femoral artery, give the ankle joint its blood supply. Proprioception Proprioception can be defined as the awareness of joint position as sensed by the central nervous system. 24 Proprioception is essential to joint function, as it allows a person to know how and where a body part is moving in space. This information allows the central nervous system to make adjustments in joint position consciously or

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8 subconsciously. 30 The three systems that relay proprioceptive information are the somatosensory, vestibular, and visual systems. 30 The visual system processes stimuli we receive with our eyes, while the vestibular system receives information from the semicircular canals of the ear. 24 The somatosensory system receives stimuli from mechanoreceptors in the periphery of the body. Mechanoreceptors are specialized receptors throughout the body that convert a physical stimulus into a neurological signal. These signals are then sent to the somatosensory system, which signals a response to joint position and movement. 21 The central nervous system is able to compare the actual to the intended movement and correct any discrepancies. 21 Mechanoreceptors, found in the skin, muscles, joints, tendons, and ligaments, are able to send information about pain, pressure, and joint movement, even without visual input. 12 The ability to maintain standing balance on one or two legs depends on the integrity of the visual, vestibular, and nervous systems. 17 There are two different systems for classifying these mechanoreceptors, or proprioceptors. The first system classifies a receptor as either quick adapting (QA) or slow adapting (SA). Quick adapting receptors decrease the rate at which they fire very quickly after being presented with a stimulus. 24 An example of a QA receptor is a Pacinian corpusle, which senses pressure. Quick adapting receptors help in sensing joint motion because they are able to detect even minimal changes in joint position. Slow adapting receptors continue to fire at the same rate in response to continuous stimuli. 24 An example of an SA receptor is a Golgi tendon organ. Golgi tendon organs protect the muscle and tendon from excessive tension. Golgi tendon organs are large, fusiform shaped, and stimulated at the extreme angles of joint displacement. 22 Slow adapting

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9 receptors also play a role in sensation of joint position because they are maximally stimulated at specific joint angles. Mechanoreceptors can also be classified as Type I, II, III, or IV. 28 Type I receptors are located in ligaments in low numbers and are spherical shaped. It is thought that these receptors are important in providing postural awareness information. 28 Type I receptors can also be classified as SA receptors. Type II receptors have a thick capsule and are cone shaped. These are also located in ligaments and their primary function is proprioception. 28 Type II receptors were the most common mechanoreceptor type found in ankle ligaments and can also be classified as QA receptors. Type III mechanoreceptors are fusiform in shape and are also found in high numbers in ankle ligaments. These receptors provide information when the joint is at the extremes of movement. These mechanoreceptors can also be classified as SA receptors. Finally, type IV receptors are free nerve endings and are found in the ankle joint capsule and at the end of the tibial, sural, and deep peroneal nerves. 28 The information received by the three systems is processed by the spinal cord, brain stem, and higher brain center. 24 The spinal cord is responsible for dynamic muscle stabilization and reflex responses. The brain stem is responsible for maintaining posture and balance and coordinating information from all three areas. The higher brain centers program musculoskeletal motion and provide for conscious and unconscious awareness of joint position and the ability to stabilize joints. 23 Measurement of Proprioception Methods to measure proprioception include joint position sense, muscle latency, postural sway, the modified Rhomberg test, stabilometry, and time to stabilization.

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10 Threshold to Detection of Passive Motion A subjects ability to sense joint motion can be measured rating the subjects ability to sense passive joint movement while blindfolded. This passive test primarily assesses proprioception of the joint receptors, as receptors within the muscle are not active. 24 Joint Position Sense Joint position sense incorporates both joint and muscle receptors by having a subject replicate active and passive joint angles as accurately as possible in the absence of visual stimuli. 24 Muscle Latency Another dynamic measure of proprioception includes using EMG muscle latency times to quantify reflex muscle stabilization around a particular joint in response to an involuntary perturbation. The electromyograph reading from this test will provide information about the muscles ability to fire in the correct sequence. 7,24 Some researchers support the idea that the reflex time of a muscle is an important indicator for determining if the joint is able to maintain dynamic stability. 8 EMG signals may also indicate the number of motor units that are being recruited within a particular muscle. 11 EMG is commonly used to measure muscle activation, force produced by the muscle, and fatigue that occurs within the muscle. 7 Variables computed from surface EMG signals include average rectified and root mean square values, and mean and median spectral frequencies. 7,11 The root mean square and average rectified values are used to measure signal amplitude. 7 In order to collect the EMG data, bipolar electrodes are placed on the skin over the muscle bellies at least 2 centimeters away from the nearest electrode. 2 The electrodes should also be placed on the skin so that they are perpendicularly intersecting with the orientation of the muscle fibers they are measuring. 7 In order to receive

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11 meaningful data from the EMG electrodes, they must be stationary, and not subject to movement artifacts. 7 Postural Stability Additional measures of proprioception include: postural sway, the modified Rhomberg test, and stabilometry. These three measures assess the combined function of the peripheral, vestibular, and visual systems in neuromuscular control. Postural sway and stabilometry quantify equilibrium. The instruments used to measure postural sway and stabilometry are able to assess proprioception fairly accurately. 24 Time to stabilization measures how long it takes a subject to stabilize their lower limb after a step or hop down with a single leg onto a force plate. 4 Research using both healthy and anterior cruciate ligament deficient subjects indicated that this measure is reliable for determining functional status. 4 A disruption in proprioception following soft tissue injury can be attributed to a number of factors: joint trauma, damaged nervous tissue, edema, and muscle weakness. Injury to a joint will cause a disruption of sensory nerves, joint capsule, and muscles that all play a role in proprioception. 21,23,30 DeCarlo and Talbot suggested that partial articular deafferentiation occurs in response to joint trauma secondary to the tearing of nerve fibers that possess less tensile strength than collagen present in ligaments. 6 Ruptured nerve fibers will result in decreased sensory input from peripheral receptors potentially leading to faulty ankle joint positioning and an increased chance for reinjury. 12 Any damage to the muscle spindles, Golgi tendon organs, or joint receptors will impact function and dynamic joint stability. 21,23 Increased pressure at the joint as a result of swelling further impedes feedback sent to the central nervous system because of the increased pressure negatively affecting proprioception. 21 A final possible contributor to

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12 proprioceptive loss is muscle weakness due to disuse. Research indicates that evertor strength can remain below normal up to one year after ankle injury. 13 A decreased ability to maintain balance on one leg, one measure of proprioception, has been found after an ankle injury. 13 If a person displays poor postural control during a static balance task, they may have even more trouble with balance when they are engaging in dynamic activity. 13 This decreased proprioception can lead to further injury when a person returns to normal activity. 13 This chance for reinjury may be because a person with a proprioceptive deficit is unable to control their body over a narrow base of support during high-speed activity. 13 Because of this instability, it is important that balance training be a part of a patients rehabilitation program. Proprioception training will help the patient in maintaining balance, posture, and joint position sense. 24 Proprioception Training Proprioception programs should be used to promote dynamic joint and functional stability because proprioception can be improved with training. 24 The proprioceptive program should include exercises that use both conscious and unconscious control of proprioception. Consciously mediated exercises should be performed at slower speeds to train specific muscles to stabilize the joint. Unconsciously mediated exercises should be performed to train the muscles to respond quickly to sudden changes in position that could cause injury. 21 One legged stands are useful in improving proprioception after injury. Standing on one leg improves postural steadiness and pronator strength in a program as short as ten weeks. 13 It has been reported that patients who did rocker board exercises during rehabilitation after ankle injury demonstrated lower rates of reinjury. 13 The study indicated that a program of eight weeks provided the maximum amount of ankle stability. In a study by Goldie et al. 13 the results suggested that those who did

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13 balance exercises after an ankle sprain had better postural control than those who did not do balance exercises as part of their rehabilitation. The exercises in a proprioception program should emphasize closed kinetic chain activities in order to more closely simulate sports activities and retrain disrupted proprioceptive pathways. 21 The proprioceptive program should finish with sports specific activities in order to enhance the retrained proprioceptive pathways. Adequate proprioception should be required of all athletes returning to participation. 24 Cryotherapy Cryotherapy is defined as the application of cold to living tissues that results in a lower temperature. 19 The practice of applying cold to tissue is common in the treatment of both acute and chronic injuries. Ice has been used as a treatment for thousands of years. Hippocrates used ice to decrease pain, decrease swelling, and produce numbness. 25,27 Since then, ice has been used in the medical world because of its beneficial effects of healing and anesthesia. As a result, a great deal of research has been conducted to document the physiological effects of ice. Cold can have effects on the body as a whole. These effects include overall decreased body temperature, general vasoconstriction in response to the cooling of the hypothalamus, decreased respiratory and heart rates, shivering, and increased muscle tone. 35 However, the application of cold is used primarily for its local tissue effects. One of the well documented effects of ice application, pain relief, occurs for a number of reasons. Ice has the ability to relieve muscle tension and disrupt the pain spasm cycle. 16,25 Ice also increases the firing threshold of the peripheral nerve endings. 25,38 Research has indicated that nerve conduction is blocked at deep temperatures of 50 degrees Fahrenheit and sensory nerve fibers are the first to be blocked. 38 Furthermore,

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14 ice reduces pain due to the counter irritant effect, whereby ice blocks painful stimuli associated with the injury. 25 Another effect of ice application is the reduction of muscle spasm. Muscle tension is relieved and nerve conduction is decreased when tissue temperature is lowered. 16,25 Ice contributes to tissue and joint stiffness because decreased temperatures increase collagen stiffness. 19 Ice also causes decreased dexterity because cold increases tissue viscosity. 25,27 Recently, it has been reported that cryotherapy decreases muscle velocity and power, thereby reducing muscle performance. 37 Stimulation from the autonomic nervous system in response to tissue cooling causes vasoconstriction when ice is applied. 39 This vasoconstriction leads to decreased edema and hemorrhage in the area. 18 Edema also decreases because less histamine and similar substances are released in response to tissue damage. 16 Cold also decreases blood flow and inflammation by decreasing cellular metabolism. This is an important effect of cold, because decreased cellular metabolism will reduce secondary hypoxic injury. 18 All together, the effects of cold aim to decrease edema and inflammation in order to decrease the amount of secondary hypoxic injury. There are several ways to apply cryotherapy to tissues. These methods are able to cool tissues by conduction, direct contact with the surface, or convection, movement of air or water over the surface to be cooled. The most common methods of cold application include ice bags, manufactured ice packs, ice massage, cold whirlpool, cold sprays, and ice immersion. Ice bags consist of putting crushed or cubed ice in plastic bags to place on the injury site. These are both practical and economical. Research involving various methods of cooling suggests that ice bags were the most effective in decreasing tissue temperature in the adult canine thigh over a 60 minute ice application. 26

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15 Commercial ice packs contain a gel that cools when placed in a freezer or special ice pack unit. They must be placed on a towel and never directly on the skin for cooling. 35 A potential drawback to manufactured ice packs is the cost. Ice massage involves ice cups applied to a specific area of the body. This involves the direct application of the ice to the skin and is useful for icing a localized area of pain. 35 Cold whirlpools are used for larger areas of pain such as knees or elbows. The whirlpool is filled with water maintained at a temperature of 13-16C. The whirlpool is filled high enough to cover the entire affected area. Range of motion exercises can be performed when a patient is in the cold whirlpool. Ice immersion is a cryotherapy method similar to cold whirlpool. A bucket or cooler is filled with ice and water and the injured body part is placed in the bucket. Ice immersion is indicated in the treatment of joint restrictions, muscle spasms, and in cases of acute pain. 38 Unlike the cold whirlpool, the water does not move over the joint in order to lower tissue temperature through convection. Cold sprays are used on the field and in the clinic to facilitate stretching exercises, also termed cryostretch. Cold sprays are able to lower skin temperature rapidly by evaporation. 35 Length of treatment is also a factor in the application of cryotherapy. Different amounts of time are used for different cryotherapy methods and with different patient goals in mind. When selecting treatment times, it is important to know that it takes ten minutes to cool superficial tissues and twenty to thirty minutes to cool deep tissues. 25 Cutaneous hypoalgesia can be achieved in as little as two to five minutes, but ice is left on longer to achieve cooling benefits in muscle and joint tissue. 25 Generally, a cold application method is left on until the area is numb, but care must also be given not to leave the cold on too long. Ice bags, cold packs, and cold whirlpool are generally used

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16 for twenty minutes because these methods take longer to cool the tissues. 25,37 Faster cooling methods, such as ice immersion and ice massage, are only applied for seven to ten minutes. 35 Cryotherapy induced analgesia can last anywhere from thirty minutes to three hours. 38 Cryotherapy is indicated mainly in two situations: the acute phase of injury or in conjunction with rehabilitation. 25 Ice is applied in the first twenty four to thirty six hours after an injury in order to decrease inflammation and edema. By reducing inflammation and edema, the tissue is allowed to heal faster. Cooling the tissues reduces the initial inflammatory response to trauma and removes the factors that hinder wound healing, allowing normal tissue repair. 14,27 This process will decrease the amount of secondary injury that may occur. Ice also aids in decreasing pain that is present in the initial injury phase. Ice, in conjunction with rest, elevation, and compression, provides the best environment for healing. Ice can also be used in conjunction with rehabilitation. Ice may be applied before rehabilitation to reduce pain and spasm so the patient is able to perform their exercises. The use of ice before rehabilitation exercises also allows a patient to achieve an increased range of motion during activity. 14 Ice application after exercise is also beneficial because it reduces pain and inflammation that are present once the patient has completed their rehabilitation program. 18 Cold application after exercise reduces vasodilatation and blood flow to prevent recurrent edema. 14 There are some occasions when ice should absolutely not be used to treat any injury. These occasions include when the patient has severe cold allergy, Raynauds phenomenon, rheumatoid conditions, cryoglobunemia, paroxysmal cold hemoglobinuria, and pheochromocytoma. 25,32 Even though cold application may be indicated in other

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17 situations, one should always be careful and monitor a patient who is undergoing cold treatment because there is always the risk of frostbite and tissue damage if the cold is left on the skin too long. Ice or Injection Induced Anesthesia and Ankle Proprioception A number of researchers have used either cryotherapy or injection induced anesthesia to examine the effects of altered nerve function on proprioception. 6,10,12,20,36 The majority of the research indicates that ice or anesthesia have no effect on proprioception. 10,12,20,36 However, one study suggested proprioception may be improved with anesthesia. 6 DeCarlo and Talbot 6 investigated a subjects ability to balance on one leg after they anesthetized the anterior talofibular ligament with Xylocaine. It was hypothesized that anesthesia of the anterior talofibular ligament would decrease the amount of proprioceptive input from the ankle to the central nervous system. Proprioception was then measured on a multiaxial balance evaluator. The results indicated that balance ability was improved after the ligament was anesthetized. The increase in balance ability was unexpected and may have been due to the learning effect. There have been several studies conducted that fail to report changes in proprioception after a joint is iced or anesthetized. Feuerbach et al. 12 anesthetized one or two ankle ligaments in healthy subjects and found no change in the subjects ability to match reference ankle joint positions while blindfolded. The authors concluded that the ligament receptors must play a small role in proprioception, and that receptors in the skin and muscle are adequate to accurately match reference angles. Konradsen et al. 20 observed that active joint position sense, postural sway, and peroneal reaction time were unaffected by anesthesia of the ankle and foot. However, they did find that anesthesia

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18 significantly impaired passive joint position sense. Thieme et al. 36 reported no change in proprioception in a study in which the knee was iced and the subjects ability to actively reproduce knee joint angles was tested. No significant differences were reported between the ice and control conditions. Agility was unchanged after ice immersion of the ankle in a study conducted by Evans et al. 10 in 1995. They measured agility by testing the carioca maneuver, the cocontraction test, and the shuttle run. The subjects performed similarly with or without ice immersion. All of these studies support the idea that proprioception is not affected by ice or anesthesia of the ankle, even though it has been reported that ice and anesthesia decrease the rate at which a neuron fires. 25 Elleys 9 study in 1994 produced results that made it difficult to draw conclusions about how ice application affects ankle proprioception. The study involved the application of an ice pack to the ankle followed by a measurement of postural sway during a one legged stance on a force plate. The results indicated that almost 60% of the subjects demonstrated a poorer ability to balance and almost 40% significantly improved. The author called for replication of this research in order to establish whether or not icing the ankle has a significant effect on postural sway. The present study attempted to add to the current body of knowledge on the topic of ice application and ankle proprioception, specifically dynamic stability. The study was different from the previous studies a force plate and the measure of time to stabilization was used to measure dynamic stability. This method is becoming common in the literature at this time. Another difference is that cold immersion was used to decrease the temperature of the tissue in and around the ankle joint. This is not the usual method of cryotherapy used in the literature, and it may be helpful to report what effects this method

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19 of cold application has on dynamic stability. The goal of the study was to investigate if ice immersion detrimentally affects dynamic stability at the ankle as measured by time to stabilization.

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CHAPTER 3 METHODS Subjects Twenty healthy male and female volunteers from the general university population were recruited to participate in this investigation. Subjects were excluded from participation if they have previously suffered an injury to the lower extremity, head, or spine that might influence the neuromuscular response characteristics of the ankle. Subjects were also excluded if they suffered from or have suffered from any of the contraindications for cryotherapy, which include areas of decreased sensation, areas of decreased circulation, Raynauds Syndrome, previous cold allergy, or previous cold injury. Additional exclusionary criteria included anyone currently suffering an illness, anyone taking medications that could influence body equilibrium, and anyone regularly undergoing cold treatments. Before participating in the investigation, each subject read a description of the study and signed an informed consent form approved by the university Institutional Review Board. Instrumentation Vertec Vertical Jump Stand Maximum vertical jump height was assessed using a Vertec (Sports Imports, Columbus, OH) vertical jump stand. The Vertec is a telescoping upright stand with plastic vanes spaced 1.27 cm apart. The maximum vertical jump height was determined by subtracting standing reach height from the height of the highest vane touched when jumping. 20

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21 Force Plate Time to stabilization (TTS) and ground reaction forces (GRF) were measured at a frequency of 1000-Hz using a triaxial force plate (Bertec Corporation, Columbus, OH). The force plate data went through an analogue to digital conversion and was stored on a PC-type computer using the DATAPAC 2000 (Run Technologies, Laguna Hills, CA) analog data acquisition, processing, and analysis system. Electromyography (EMG) A Myopac EMG system (Run Technologies, Laguna Hills, CA) was used to collect the raw EMG signal. The unit specifications for the EMG included an amplifier gain of 1-mV/V, a frequency bandwidth of 10-1000 Hz, CMRR 110 dB, input resistance of 1 M, and a sampling rate of 1000 Hz. Following sampling, the EMG data was transformed from analogue to digital conversion and was stored on a PC-type computer using the DATAPAC 2000 (Run Technologies, Laguna Hills, CA) analog data acquisition, processing, and analysis system. Measurements Vertical Jump Height Maximum vertical jump height was determined using the Vertec vertical jump stand. Subjects were instructed to stand on their toes next to the Vertec and reach as high as possible. The standing reach height was determined from the height of the highest vane the subject was able to touch. Each subject then jumped off both legs as high as possible while reaching up to touch the vanes. This was performed three times and the height of the highest vane touched was recorded. Maximum vertical jump was determined as the difference between the maximum jump height and the standing reach height.

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22 Time to Stabilization Each subject performed three stabilization maneuvers during a test session, requsiring them to perform a two-legged jump at 50% of their maximum jump height to the center of a force plate placed 70-cm from the starting position. All the jumping maneuvers were done with the subject in athletic shoes. To control for and standardize this height, the Vertec jump stand was set at the target height and placed between the subject and the force plate. The subject was instructed to jump the minimum height necessary to reach the Vertec. The subjects were also instructed to land on one leg with their hands on their hips and stabilize quickly while maintaining balance with a single leg stance for 20-sec. Each subject was allowed three practice trials to familiarize themselves with the jumping, landing, and stabilizing procedure before the data was collected. The subjects then underwent three pre-treatment test trials. The time to stabilization (TTS) was determined as the time needed to reduce the variation of a given ground reaction force (GRF) component to the range of variation of a GRF component in a stabilized position. The range of variation of a GRF component in a stabilized position was determined in a 5-sec window at the end of the 20-sec data collection period. The same procedure was used to determine TTS in the frontal and sagittal planes. After the subject received the treatment condition, they immediately participated in three post-treatment test trials. They rested for a period of five minutes and another three trials were done in the same manner. Muscle Activity Anticipatory and reactive muscle activity were assessed before and immediately after the jump landing. Each subject first had the skin over the tibialis anterior (TA) and peroneus longus (PL) muscles prepared by shaving and cleaning with isopropyl alcohol

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23 to reduce skin impedance. Bipolar 1-mm x 10-mm Ag/AgCl surface electrodes with an interdetection surface distance of 1.5-cm were then placed in parallel with the muscle fibers of the TA and PL muscles at a midpoint between the motor point and the musculotendinous junction. All electrode placements were confirmed with manual muscle testing and checked for cross-talk with real time oscilloscope displays. The acquired raw signals were digitally processed using, a symmetric root mean square (RMS) algorithm, with a 10-msec time constant. Anticipatory muscle activity was determined during the 50-msec time period immediately before foot contact on the force plate. The muscle reactive activity was measured during the 100-msec time period immediately following foot contact on the force plate. The mean muscle activity of both the tibialis anterior and peroneous longus during each phase of the three jumps was calculated and the mean of the three jumps at each testing time (pretest vs. posttest 1 vs. posttest 2) was recorded. All EMG data was reported relative to the muscle activity during a maximum voluntary isometric contraction (MVIC), which was performed before the jump trials using standard manual muscle testing protocols. Each muscle was tested by having the subject sitting with the lower leg hanging off the table and performing the primary action of the muscle against stationary resistance. The tibialis anterior was tested in a dorsiflexed and slightly inverted position against resistance from the researcher, and the peroneous longus was tested in an everted position against resistance. The electrodes had been placed on the muscles to measure the activity during this testing using the Myopac EMG system. Each muscle was tested against resistance for 5 seconds and this data was collected using the Myopac and DATAPAC 2000.

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24 Treatment Each subject took part in both a cold immersion treatment and a control condition. The cold immersion treatment consisted of the subject sitting and placing their lower leg in a bucket of water and ice up to the level of the tibial tuberosity. The water was maintained between 13 and 16C and the subject remained in the treatment position for twenty minutes. During the control condition, each subject sat in the same position used during the cold immersion treatment for 20 minutes, however, the bucket was empty and no treatment was applied. The subject had the weight of their leg supported during the control condition to control for any changes in blood flow that might occur while the leg was hanging down off the end of the chair since the water would support the weight of the leg in the treatment condition. Each subject had the height of the bucket adjusted so that their foot rested comfortably on the floor of the bucket whether or not there was water in the bucket. Procedures Each subject reported to the Biomechanics Research Laboratory on two separate occasions. Upon arrival on the first occasion, each subject completed a medical history questionnaire that included questions regarding recent or recurrent leg, head, or spine injuries, stability problems, current illness, medications, and cold contraindications. These questions determined if the volunteer was eligible to safely participate in the investigation. Each subject was tested under two conditions; control and cold immersion treatment. The order of these treatments was randomized and counterbalanced with a minimum of one week separating the two conditions. To begin the session, the subject had his or her maximum vertical jump height determined. The subject was then prepared

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25 for electrode placement and had an MVIC taken according to standard manual muscle testing procedures. The researcher checked for correct placement of the surface electrodes by performing manual muscle tests on the tibialis anterior and peroneous longus muscles. The tests were performed with the subjects sitting with their lower leg hanging off the table. The researcher then checked electrode placement by resisting the primary motion of each muscle. The electrodes on TA were checked by resisting active dorsiflexion, and the electrodes on PL were checked by resisting active eversion. They were then assessed for their TTS after a single leg landing from a jump equivalent to 50% of their maximum jump height. The subject was asked to perform the jump a total of three times. In addition to the measurement of time to stabilization, anticipatory and reactive muscle activity was recorded using surface EMG. Immediately following the three jumping and landing trials, the subject completed one of the two treatment conditions. Once the treatment time was completed, each subject was once again tested for TTS and EMG activity using a procedure identical to the one used during pre-testing. The subject was asked to perform three jumping and landing trials immediately after the treatment and three more five minutes later. All subjects were asked to return to the lab on a second occasion, at which time an identical protocol was completed and they received the remaining treatment condition. There was a minimum of seven days between the two treatment conditions. The subjects were encouraged to use the same means of transportation both times they came in to participate in testing. Study Design and Data Analysis A one pretest two posttest within subjects design was used for this investigation and a 3x2 repeated measures ANOVA was used to analyze the data. The independent variables were testing time (pre-treatment vs. post treatment I vs. post treatment II) and

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26 condition (treatment vs. control). The dependent variables were GRF TTS in the vertical, anterior/ posterior, and medial/lateral directions, as well as mean preparatory and reactive activity levels (as a percent of the MVIC) of the tibials anterior and peroneous longus muscles. Significant interactions were further analyzed using the Tukey Honestly Significant Difference (HSD) post hoc testing procedure. For all statistical analyses the level of significance was set at p < .05.

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CHAPTER 4 RESULTS The purpose of this study was to investigate the effects of an ice immersion treatment on dynamic stability following a jump landing. Using force plate data, we assessed the ability of healthy subjects to stabilize their center of gravity after landing from a height equivalent to fifty percent of their maximum vertical jump height. We also used EMG to assess the preparatory and reactive muscle activity of the peroneus longus and tibialis anterior immediately before and immediately following the landing. Seven 3x2 ANOVAs were used to analyze the normalized EMG data from the peroneus longus and tibialis anterior before and after landing and time to stabilization. The independent variables were treatment (ice immersion vs control) and testing time (pretest vs. posttest 1 vs. posttest 2). Subject Demographics Twenty healthy subjects without recent or chronic history of lower extremity injury, allergies to cold, circulation deficiencies, conditions or medications that would affect balance and regular cold treatments volunteered to participate in this study. Seventeen of the subjects were female and three were male. They had a mean age of 20.8 .01 years, mean height of 168.7 .9 cm, and a mean mass of 67.8 .6 kg. Sixteen subjects chose the right leg as their landing leg, and four of them chose the left. The average height that each subject jumped (50% of the maximum vertical jump) was 17.6 .1 cm. The average target height that each of the subjects reached for in performing the jumping and landing trials was 255.1 .2 cm. 27

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28 Normalized EMG Activity Tibialis Anterior Normalized preparatory EMG activity of the tibialis anterior is presented in Table 1. No significant treatment [F(1,19)=.968, p=.338] or time [F(1,19)=.307, p=.586] main effects were observed. However, a significant treatment time interaction [F(1,19)=7.34, p=.014] was observed for the tibialis anterior activity immediately before the landing. Table 1. Normalized preparatory EMG activity of the tibialis anterior (% of MVIC) Treatment Pre-test Post-test 1 Post-test 2 Ice Immersion 43.7 .5 50.8 .3 48.5 .9 Control 49.4 .6* 39.4 .6 42.4 .3 *Significantly greater than control condition post-test 1 (p<.05) Significantly greater than control condition post-test 1 (p<.05) Normalized reactive EMG activity of the tibialis anterior is presented in Table 2. A significant treatment main effect [F(1,19)=11.04, p=.004] was observed for the tibialis anterior, as the EMG activity during the ice immersion (92.2 .4%) session was significantly greater than during the control (71.9 .5%) session. However, neither the time main effect nor the treatment x time interaction was significant. Table 2. Normalized reactive EMG activity of tibialis anterior (% of MVIC) Treatment Pre-test Post-test 1 Post-test 2 Ice Immersion 83.6 7.1 97.9 7.7 95.3 7.9 Control 72.0 6.3 70.7 6.3 73.0 5.5 Peroneous Longus Normalized preparatory EMG activity of the peroneous longus muscle is presented in Table 3. No significant treatment [F(1,19)=.679, p=.420] or time [F(1, 19)=.335,

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29 p=.569] main effects were observed. A significant treatment time interaction [F(1, 19)=7.377, p=.014] was observed for the peroneous longus immediately before landing. Table 3. Normalized preparatory EMG activity of peroneous longus (% of MVIC) Treatment Pre-test Post-test 1 Post-test 2 Ice Immersion 113.8 .0 124.6 13.8 125.5 13.4 Control 122.9 14.1* 105.7 13.6 109.3 12.8 *Significantly greater than control condition post-test 1 (p<.05) Significantly greater than control condition post-test 1 (p<.05) Significantly greater than control condition post-test 1 (p<.05) Normalized reactive EMG activity for the peroneous longus is presented in Table 4. No significant main effects for treatment [F(1,19)=1.958, p=.178] or time [F(1,19)=.855, p=.367] were observed, and no significant interaction [F(1,19)=2.517, p=.129] between time and treatment was observed. Table 4. Normalized reactive EMG activity of peroneous longus (% of MVIC) Treatment Pre-test Post-test 1 Post-test 2 Ice Immersion 142.2 .2 163.2 12.5 145.1 .4 Control 135.7 15.9 127.4 18.5 129.7 15.9 Time to Stabilization The amount of time that it took each subject to stabilize the ground reaction forces after landing within a given variation during a quiet stance was measured in milliseconds. This data was collected for medial/lateral and anterior/posterior ground reaction forces. Vertical Ground Reaction Force Time to Stabilization The time in milliseconds for each subject to stabilize within 5% of their body weight is reported in Table 5. A significant main effect was observed for time [F(1,19), p=.014], as the mean TTS were significantly different between the pretest (1639.5 .1 ms), post-test 1 (1756.7 .6 ms), and post-test 2 (1494.8 .1 ms). No significant

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30 main effect for treatment [F(1,19)=.006, p=.940] or significant interaction [F(1,19)=.257, p=.618] between treatment and time were observed for vertical ground reaction force time to stabilization. Table 5. Vertical ground reaction force time to stabilization (in msec) Treatment Pre-test Post-test 1 Post-test 2 Ice Immersion 1644.48 .51 1730.67 71.46 1507.94 .22 Control 1634.47 77.26 1782.75 87.98 1481.64 82.66 Medial/Lateral Ground Reaction Force Time to Stabilization The time in milliseconds for each subject to sequential average to stabilize within plus or minus .25 standard deviations of the mean of the 3-sec collection period is reported in Table 6. No significant main effects for time [F(1,19)=.312, p=.583] or treatment [F(1,19)=.809, p=.380] were observed for medial/lateral ground reaction force time to stabilization and no significant interaction [F(1,19)=.946, p=.343] between treatment and time was observed either. Table 6. Medial/lateral ground reaction force time to stabilization (in msec) Treatment Pre-test Post-test 1 Post-test 2 Ice Immersion 1568.32 .24 1443.70 67.71 1455.73 .53 Control 1511.45 65.78 1572.65 73.56 1542.96 85.02 Anterior/Posterior Ground Reaction Force Time to Stabilization The time to milliseconds for each subject to stabilize to within plus or minus .25 standard deviations is reported in Table 7. No significant main effects for treatment [F(1,19)=3.234, p=.088] or time [F(1,19)=.879, p=.360] were observed for anterior/ posterior GRF TTS. There was no significant interaction observed [F(1,19)=.211, p=.651] between treatment and time.

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31 Table 7. Anterior/posterior ground reaction force time to stabilization (in msec) Treatment Pre-test Post-test 1 Post-test 2 Ice Immersion 1470.60 .13 1493.72 115.01 1373.94 .74 Control 1377.00 81.74 1292.88 108.59 1261.51 84.50

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CHAPTER 5 DISCUSSION The purpose of this study was to determine the effects of an ice immersion treatment on dynamic stability during a jumping and landing task. Using a triaxial force plate, the amount of time to stabilize the vertical, anterior/posterior, and medial/lateral ground reaction forces following a jump landing were used as the measures of dynamic stability. Preparatory and reactive activity of the tibialis anterior and peroneous longus muscles were also assessed using EMG analyses immediately before and immediately following the landing. Muscle Activity We hypothesized that the mean activity level of both the tibialis anterior and peroneous longus would be significantly higher following the immersion treatment as compared to the control condition. This was partially supported, as the preparatory activity level of both the tibialis anterior and peroneous longus was greater at the first posttest measurement following ice immersion as compared to the first posttest measurement during the control condition. The graphs below depict muscle activity in the preparatory phase for both the tibialis anterior and peroneous longus. The mean muscle activity during the 50 msec time frame was recorded and the mean of the 3 trials for each subject was reported and analyzed. 32

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33 *0102030405060PretestPostest 1Postest 2Testing Time% MVIC Ice Immersion Control* Figure 1. Tibialis Anterior Preparatory Activity *Significantly higher muscle activity as compared to control condition posttest 1 ***020406080100120140160PrestestPosttest 1Posttest 2Testing Time% MVIC Ice Immersion Control Figure 2. Peroneous Longus Preparatory Activity *Significantly higher muscle activity as compared to control condition posttest 1

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34 This finding is in agreement with previous research involving EMG activity of the gastrocnemius and soleus muscles. 33 In that study, it was reported that a 60-min cold whirlpool treatment resulted in a 45% increase in gastrocnemius activity and a 22% increase in soleus activity. 33 The muscle activity was measured during a drop jump exercise. In the present investigation we observed a 19% increase in tibialis anterior activity and a 27% increase in peroneous longus activity immediately following the immersion treatment. These changes in muscle activity are compared in the graph below. Increase in Muscle Activity after CryotherapyTAGastrocnemiusPLSoleus05101520253035404550OksaPresent StudyStudy% Increase in Muscle Activity Figure 3. Increase in Muscle Activity after Cryotherapy Similar observations were made when examining the reactive muscle activity of the tibialis anterior. The reactive activity was higher following the immersion treatment when compared to post testing during the control condition. No differences were observed for the peroneus longus.

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35 020406080100120Pretest Posttest 1Posttest 2Testing Time% MVIC Ice Immersion Control Figure 4. Tibialis Anterior Reactive Activity 020406080100120140160180200Pretest Posttest 1Posttest 2Testing Time% MVIC Ice Immersion Control Figure 5. Peroneous Longus Reactive Activity

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36 It must be noted that the activity of the tibialis anterior prior to the treatment was also greater when compared to the same measurement time during the control condition. This was unexpected and difficult to explain. The order of treatment was randomly assigned and counter balanced. Thus, a learning or practice effect would not provide an explanation. The change in activity level may have been due to psychological factors. The subject may have been expecting to perform worse on the jumping and landing task because of their own expectations of the situation and the treatment they were about to receive. Because of these expectations, the subject then worked harder to compensate for the perceived increased difficulty of the task. The higher post treatment activity levels observed in the preparatory phase for both the tibialis anterior and peroneous longus may be due to the physiological changes cold induces within the body, including the mechanoreceptors. Cryotherapy causes stiffness as well as increased fluid viscosity, which may cause the muscles that move the ankle to work harder against this resistance after cold immersion. 10 The muscles may also be working harder in order to make up for a lack of power that has been reported after cryotherapy. 10,33 It is also possible that the muscles were compensating for any deficits in proprioception caused by the decrease in tissue temperature. Feuerbach et al. 12 agreed that mechanoreceptors in the skin, muscles, and other parts of the joint capsule were able to compensate for the ligament receptors that were anesthetized in their study. They reported that ligament anesthesia had no effect on a subjects ability to reproduce joint positions. Another researcher hypothesized that different mechanoreceptors are activated at different points within the range of motion. 36 It is believed that the muscles play a greater role in proprioceptive tasks at the midranges of joint motion. 36 The jumping and

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37 landing task involved in the current study focuses more on the midranges of motion. It seems that muscular mechanoreceptors can compensate for a lack of activation of other receptors when a subject performs proprioceptive tasks such as joint repositioning and jumping and landing tasks. Although we did not assess skin or intramuscular temperature, we feel confident that our treatment did provide sufficient cooling. Temperature changes during and following cryotherapy treatments have been well documented. 27 In one study, 30-min of ice immersion at a temperature of 10C lowered skin and intramuscular temperature 16.3 and 9.3C respectively. 27 In another study, 20-min of ice immersion at a temperature of 10C lowered the intramuscular temperature 5.1C and the subcutaneous temperature 13.8C. 31 A comparison of these values is presented in Figure 2. It was surprising that the mean activity level during the immersion condition at the second post-test was only significantly greater than the control. There were significant differences in the preparatory muscle activity of the peroneous longus. Muscle activity was slightly greater in the other conditions, but not to the level of significance. This was most likely due to a re-warming of the lower leg that occurred during the 5-min rest between the two post-tests. Previous studies have reported re-warming rates of the lower leg after treatment in a 10C whirlpool. 31 Intramuscular temperature decreased 5.1 .8C following the 20-min treatment. However, the temperature increased over a 5-min post treatment period so that it was only .8 .4C lower than the pretreatment temperature. With respect to subcutaneous temperature, the temperature had decreased 13.8 .0C following treatment, but was only 2.6 .4C lower than pretreatment after the 5-min recovery period. From this data it can be noted that there is a re-warming trend that occurs

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38 immediately after the treatment is concluded. Therefore, if muscle activity were to increase in response to temperature changes, it would be expected that the activity levels would be higher immediately after treatment as compared to the 5-min post-treatment when re-warming has occurred. Thus, after a 5-min recovery period the muscles are not working as hard against stiffness and increased viscosity because the temperature has returned to pre-treatment levels. This finding has significant clinical implications. If stability is not hindered by cold application, then a clinician can be confident in asking an athlete to perform sports specific skills after as little as 5-min of warm-up, as long as the muscles are functioning properly. Temperature Decrease after Cryotherapy024681012141618Meeusen and LevensMyrer et alStudyTemperature Decrease (Celcius) Subcutaneous Temperature Intramuscular Temperature Figure 6: Temperature Decrease after Cryotherapy

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39 It was also interesting to note that the changes in muscle activity were more pronounced in the tibialis anterior as compared to the peroneous longus. This may indicate that the tibialis anterior plays more of a role in the stabilization of the lower leg just before and after landing than the peroneous longus muscle. The tibialis anterior is important in creating dorsiflexion and acting to control plantarflexion, as well as assisting with inversion. 5 Results from a previous study investigating ankle brace use and muscle activity suggest that the tibialis anterior may aid in maintaining the position of the foot relative to the ground at initial contact. 5 This may explain why the immersion treatment had a greater effect on the tibialis anterior as compared to the peroneous longus. It is also of note that the significant findings with respect to muscle activity were found in the preparatory phase instead of the reactive phase. This may be a compensatory effect from the lack of sensation and the subjects feeling unsure of the lower legs landing ability. It also must be noted that the control condition pretest mean was significantly higher than the control condition post-test 1 mean. In contrast, the ice immersion pretest mean was not significantly different from the post-test means for preparatory muscle activity for both the tibialis anterior and peroneous longus. It was not expected that the pretest mean would ever be significantly higher than a post-test mean. In the control condition, it was thought that the three means would not be significantly different, because no treatment was administered to the subject. In the immersion condition, it was expected that the post-test means would be significantly higher than the pretest mean because of the physiological effects of the cold treatment. The results were unexpected, but may have been due to the subject being unfamiliar with the testing protocol. Why it was significant in only one of the conditions is unknown. The order of the treatments, ice

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40 immersion and control, was randomized so it is not understood why the control condition would produce higher mean activity levels during a pre-test measurement. Time to Stabilization Time to stabilization for the vertical, medial/lateral, and anterior/posterior ground reaction forces was not significantly affected by the ice immersion treatment. A trend of increasing or decreasing times after treatment was not observed either. The data did not support our hypothesis that a 20-min cold immersion treatment to the lower leg would significantly change time to stabilization as compared to the control condition. 0200400600800100012001400160018002000Pretest Posttest 1Posttest 2 Testing TimeTime to Stabilization (in ms) Ice Immersion Control Figure 7. Vertical Ground Reaction Force Time to Stabilization

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41 130013501400145015001550160016501700PretestPosttest 1Posttest 2Testing TimeTime to Stabilization (in ms) Ice Immersion Control Figure 8. Medial/Lateral Ground Reaction Force Time to Stabilization 020040060080010001200140016001800Pretest Posttest 1Posttest 2Testing TimeTime to Stabilization (in ms) Ice Immersion Control Figure 9. Anterior/Posterior Ground Reaction Force Time to Stabilization

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42 To our knowledge, the only other study reporting times to stabilization compared subjects with a previous ACL reconstruction to control subjects after a step down from a height of 19-cm. 4 The ACL reconstruction group had a time to stabilization of 1527 msec, while the control subjects had a time to stabilization of 892 msec. This was a significant difference. In the current study, the time to stabilization for the ground reaction force was also measured. The time to stabilization after ice immersion was 1644 msec, while it was 1635 msec after the control condition. A comparison of these two studies is presented in Figure 3. These values are much higher than those reported in the previous study, however, they used a step down test from a predetermined height as opposed to a jumping and landing task such as the one used in the current study. The step down test involved having subjects drop down onto a force plate from a height of 19-cm. This drop down height was the same for every subject and did not take into account the subjects height or jumping ability. It is expected that the jumping and landing task used in the current study would produce longer times to stabilization because the subject is asked to jump instead of step down. A jumping activity would produce greater ground reaction forces and longer stabilization times. 4 The jumping task involved in this study also required the subjects to jump to a height equivalent to 50% of their maximum jump height. This was incorporated to make it more functional and individualized to each subject. Future research should focus on using similar measures and similar protocols so that results can be directly compared.

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43 Comparison of Time to Stabilization*020040060080010001200140016001800Colby StudyPresent StudyStudyVertical GRF TTS (in msec) Treatment Control Figure 10. Comparison of Time to Stabilization TTS significantly longer for treatment subjects as compared to control subjects It was not completely unexpected that the immersion condition produced no significant differences in time to stabilization. Most previous literature has reported no change in proprioceptive measures as a result of a cryotherapy treatment. In a study by Feuerbach et al. 12 it was suggested that anesthetizing the lateral ankle ligaments has no effect on a subjects ability to accurately match ankle joint angles. In this study, it appears that other mechanoreceptors can make up for a lack of ligament receptors in order to maintain proper joint proprioception. Another study found that icing the knee did not affect a subjects ability to actively reproduce passive movements. 36 The knee may not function exactly as the ankle does, but it does have muscles, tendons, ligaments, and joint capsule which all contain mechanoreceptors necessary for proper functioning proprioception. It is also possible that the 20 minute cold treatment does not allow for deep enough cooling to affect the function of mechanoreceptors. In a study that involved

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44 anesthetization of the ankle and foot, it was found that active joint position sense, peroneal reaction time, and postural sway were unchanged by the treatment. 20 Based on the results from this research, it is believed that receptors in the muscles and tendons can compensate for the mechanoreceptors in the ligaments and provide an accurate sense of position of the ankle complex. It was also suggested that reactions to perturbations remain functional despite a regional block of the ankle and foot with a local anesthetic. Again, this task is probably mediated by information from the receptors within muscles and tendons. The only study to examine sports related measures of proprioception after cryotherapy treatment also found no differences in the ability of a subject to perform based on the treatment they had received. 10 Times to complete the carioca maneuver, the cocontraction test, and the shuttle run did not change after immersion treatment. The immersion treatment involved 20 minutes of cryotherapy in 1C water to the dominant foot and ankle. The subjects for these agility tests were all athletic male college students. It was found that the local changes brought about by cold application do not seem to affect receptors that are responsible for fine, coordinated movements associated with agility tests. This finding was further supported by the current study reporting no significant differences in time to stabilization based on the treatment the subject received. The current study agrees with previous research that demonstrated that ice immersion and ligament anesthesia does not affect dynamic stability. Suggestions for Future Research This study was designed to minimize as many confounding variables as possible. But not all confounding variables could be controlled and there were also several limitations to this study. Future research should include equal numbers of males and females so that the findings can be more readily generalized to both male and female

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45 populations. A limitation of the study is that the results are applicable to healthy individuals and not injured ones. In the future, it would be clinically useful to test these same methods on injured or unstable ankles. If these subjects were tested, the findings could then be generalized to a larger population. In the future, it would also be useful to get a baseline on athletes during a season in order to test if there were deficits in proprioception post-injury. It would be helpful also to test these athletes throughout a season to see what effects intense in-season training and fatigue might have on their dynamic stability. Finally, future research should also include different age groups, such as high school and professional athletes. Future research should note if the findings from college aged populations are similar or different from the findings with other age populations. Conclusions As stated in previous research, it appears that cryotherapy has little effect on dynamic stability. Cyrotherapy to the lower leg produced no significant effects on time to stabilization. Its significant effects were on the muscles that were preparing to stabilize the lower leg in a jumping and landing task. The increased activity of these muscles appears to be sufficient to stabilize a healthy subject after the jumping and landing task. Thus, a return to activity following cryotherapy is most likely not contraindicated. This is especially true since there was only one significant difference found at the second post-test (five minutes post-treatment). Therefore, it appears that a re-warming period as short as five minutes is sufficient for mechanoreceptors and muscles to function normally. It appears that after cold application, mechanoreceptors outside of the muscles are able to function as well as they would without cold application.

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APPENDIX A INSTITUTIONAL REVIEW BOARD 1. TITLE OF PROTOCOL: Does ankle cryotherapy affect dynamic stability of healthy subjects? 2. PRINCIPAL INVESTIGATOR(s): Susan Miniello, ATC/L Graduate Assistant Athletic Trainer Department of Exercise and Sport Sciences 2777 SW Archer Rd Apt P73 (352) 384-0353 miniells@ufl.edu 3. SUPERVISOR (IF PI IS STUDENT): Michael E. Powers, PhD, ATC, CSCS Director of Athletic Training Education Assistant Professor Department of Exercise and Sport Sciences 144 Florida Gym Box 118205 University of Florida Office phone number (352) 392-0584 x1332 Fax number (352) 392-5262 mpowers@hhp.ufl.edu 4. DATES OF PROPOSED PROTOCOL: From September 1, 2002 to May 1, 2003 5. SOURCE OF FUNDING FOR THE PROTOCOL: (As indicated to the Office of Research, Technology and Graduate Education) None 6. SCIENTIFIC PURPOSE OF THE INVESTIGATION: The purpose of this study is to determine the effects of a cold water immersion (a common therapeutic treatment for athletic injuries) on dynamic stability of the ankle complex as measured by time to stabilization. 7. DESCRIBE THE RESEARCH METHODOLOGY IN NON-TECHNICAL LANGUAGE. The UFIRB needs to know what will be done with or to the research participant(s). Each research participant will be asked to participate in testing at two different times. Before the first testing session, each participant will be asked to read and 46

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47 complete an informed consent and a medical history questionnaire. Responses to the medical history questionnaire will be used to include or exclude possible participants. Each participant will undergo both the control and experimental conditions. The order of these treatments will be randomized and counterbalanced with a minimum of one week separating the two testing sessions. To begin data collection, each participant will have his/her maximum vertical jump height assessed. The participant will be asked to stand and reach the highest point possible on a Vertec vertical jump stand (a device designed for measuring vertical jump height). They will then be asked to jump and reach the highest point possible. This will be performed three times. The maximum vertical jump height will be calculated as the difference between the maximum height reached while jumping and the maximum height reached while standing. The subjects will then be tested on their time to stabilization following a single leg landing on a force plate from a height equal to one half of their maximum vertical jump height. To begin this measure, self-adhesive surface EMG electrodes will be affixed to the lower leg musculature (peroneus longus, tibialis anterior, gastrocnemius, and tibialis posterior muscles). The EMG data will allow for the analysis of preparation and reaction patterns of the muscles around the ankle during the landing task. After they land, the subjects will be asked to keep their hands on their hips and maintain balance for twenty seconds. When this is completed, each subject will then receive either the experimental or control condition. Immediately following the 20-min treatment period, the subject will again be measured for time to stabilization using identical methods as those used during pre-testing. The subject will be tested for time to stabilization immediately after the treatment and again five minutes after completion of the three post treatment trials. The subjects will then be asked to return one week later to complete the final session. Experimental Condition The experimental condition will involve the participant placing their lower leg in a bucket of ice and water maintained between 55 and 60 F for 20-min. The leg will be submerged so that the water is at the level of the midpoint of the tibia. Control Condition The control condition will involve the participant maintaining the same seated position as the one used in the experimental condition. However, the bucket will be empty during the entire 20-min period. 8. POTENTIAL BENEFITS AND ANTICIPATED RISK. (If risk of physical, psychological or economic harm may be involved, describe the steps taken to protect participant.) There will be no direct benefits to the subjects for taking part in this study. As with any type of exercise such as jumping, there is a slight risk muscle injury. A National Athletic Trainers Association licensed athletic trainer (ATC/L) who will assess and treat any injuries that may occur will be present for all exercise and testing sessions.

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48 9. DESCRIBE HOW PARTICIPANT(S) WILL BE RECRUITED, THE NUMBER AND AGE OF THE PARTICIPANTS, AND PROPOSED COMPENSATION (if any): Participants will be recruited from courses taught within the College of Health and Human Performance. The principle investigator will asked the instructors permission before recruiting subjects. No student will be recruited from any class taught by the principal investigator, or any supervisor. All subjects will be informed by the principal investigator as to what the study is investigating. A total of 20 voluntary subjects will be recruited. Subjects will range in age from 18-30 years. There will be no direct compensation for any subject. 10. DESCRIBE THE INFORMED CONSENT PROCESS. INCLUDE A COPY OF THE INFORMED CONSENT DOCUMENT (if applicable). Each subject will be asked to read and sign an informed consent form providing them with all the information about the study. This document will present an overview of the study and instructions on what will be done, as well as associated risks and benefits for participation. Please use attachments sparingly. __________________________ Principal Investigator's Signature _________________________ Supervisor's Signature I approve this protocol for submission to the UFIRB: ____________________________ Dept. Chair/Center Director Date

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APPENDIX B INFORMED CONSENT Protocol Title: Does ankle cryotherapy affect dynamic stability of healthy subjects? Please read this document carefully before you decide to participate in this research study. Purpose of the investigation: The purpose of this research study is to investigate the effects of placing the lower leg in a bucket of ice and water (this a common treatment used for ankle sprains) on balance after jumping and landing on one leg. What you will be asked to do in the research study: You will be asked to report to the Athletic Training Research Laboratory located in Florida Gymnasium (105D FLG) on two different occasions to perform similar routines. First, you will be asked to complete a medical history questionnaire. The purpose of this form is to determine if you are eligible to complete the study. If eligible, your maximum vertical leap (how high you can jump) will be determined. To do this, we will first measure how high you can reach while standing on your toes. You will then be asked to jump as high as possible and touch markers supported on a stand. Based on the number of markers you touch, the height of your jump is determined. We will have you do this two more times to assure that we get an accurate measure. Your non-dominant leg (the foot you would NOT normally use to kick a ball) will then be prepped and nine (9) adhesive electrodes will be placed on the skin of your lower leg. If necessary a small area of skin will be shaved to allow for electrode placement and the skin will be cleaned with alcohol. These electrodes allow us to measure the muscle activity (how much it contracts) when you jump and land. They only collect or read the electrical activity of the muscle, thus they do not transmit an electrical current into your body. You will then be asked to jump so that you reach a height equivalent to half of how high you jumped previously and land on a platform 28 away. After you land on the platform you will be asked to balance yourself on one leg while your hands remain on your hips for a period of 20 seconds. After the 20 second period you will be asked to return to the starting position and repeat the measurement. This will be done one more time for a total of three trials. After the balance measurements are completed, you will be asked to complete one of two treatment sessions. Which method you do will be randomly determined by a coin toss. If you are assigned to the cold immersion session, you will be asked to place your lower leg in a bucket filled with water and ice for 20 minutes. When this is done, you will then do three more trials of jumping down from the platform, landing on one leg, and attempting to get as steady as possible as quickly as you can. You will then rest for five minutes in a sitting position. After the five minutes is up, you will complete three final trials of jumping, landing, and stabilizing yourself on the platform. You will be asked to return 49

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50 one week later and repeat the protocol, however, you will complete the remaining treatment session. Time required: 2 hours1 hour each on two different days Risks: As with any type of exercise, there is a slight risk of musculoskeletal injury such as a sprain or a muscle pull. A certified athletic trainer will be present to evaluate and treat any such injuries should they occur. Benefits and Compensation: There are no direct benefits to you for participating. Confidentiality: Data will be kept confidential to the extent provided by the law. Your information will be assigned a code number. The list connecting your name to this number will be kept in a locked file. When the study is completed and the data have been analyzed, the list will be destroyed. Your name will not be used in any report. Voluntary participation: Y Your participation is completely voluntary. There is no penalty for not participating and you have the right to withdraw at anytime without any consequences. Whom to contact if you have questions about the study: Susan Miniello, ATC, Graduate Assistant Athletic Trainer, Department of Exercise and Sport Sciences, 2777 SW Archer Rd Apt P73, 384-0353 Dr. Michael Powers, PhD, ATC, CSCS, Department of Exercise and Sport Sciences, 144 Florida Gym, 392-0584 Whom to contact about your rights as a research participant in the study: UFIRB Office, Box 112250, University of Florida, Gainesville, FL 32611-2250, 392-0433 Agreement: I have read the procedure described above. I voluntarily agree to participate in the procedure and I have received a copy of this description. Participant:_____________________________________________ Date:___________ Principal Investigator:_____________________________________ Date:___________

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APPENDIX C QUESTIONNAIRE FOR INCLUSION IN THE STUDY Please circle YES or NO after each of the following questions and please answer truthfully. 1. Has a medical doctor (MD), physical therapist (PT), YES NO or certified athletic trained (ATC) diagnosed you with an ankle sprain in the last six months? 2. Has an MD, PT, or ATC diagnosed you with three YES NO or more ankle sprains in the last three years? 3. Do you experience episodes of ankle instability or YES NO feelings that your ankle is giving out on you more than once a month? 4. Have you ever experienced an allergy or YES NO hypersensitivity to cold? 5. Do you have a history of inner ear infection, vertigo, YES NO or other balance problem? 6. Do you currently suffer from circulatory insufficiency YES NO or decreased circulation? 7. Do you have any anesthetic areas or areas of numbness YES NO or decreased sensation in your lower leg? 8. Have you consumed alcohol in the last 24 hours? YES NO 9. Are you currently suffering from an illness? YES NO 10. Are you currently taking any medications that YES NO affect balance/ equilibrium? 11. Have you regularly received cold treatments any YES NO time in the last three months? 51

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APPENDIX D DATA COLLECTION FORM Subject No._________ Height: _________________ Weight: _________________ Sex: ____________________ Age: ____________________ __________________________________________________________________ Standing reach height: ____________________ Maximum vertical jump height: _____________ 50% of jump: ____________ Landing leg: _____________ Control condition date: _____________ Immersion condition date: ___________ 52

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APPENDIX E ANOVA TABLE OF PERONEOUS LONGUS PREPARATORY ACTIVITY General Linear Model Within-Subjects Factors Measure: MEASURE_1 CPRE CPOST1 CPOST2 IPRE IPOST1 IPOST2 TIME 1 2 3 1 2 3 TX 1 2 DependentVariable Descriptive Statistics 1.2292 .62878 20 1.0571 .60800 20 1.0931 .57328 20 1.1382 .53763 20 1.2458 .61627 20 1.2545 .59918 20 CPRE CPOST1 CPOST2 IPRE IPOST1 IPOST2 Mean Std. Deviation N 53

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54 Multivariate Testsb .035 .679a 1.000 19.000 .420 .965 .679a 1.000 19.000 .420 .036 .679a 1.000 19.000 .420 .036 .679a 1.000 19.000 .420 .033 .310a 2.000 18.000 .737 .967 .310a 2.000 18.000 .737 .034 .310a 2.000 18.000 .737 .034 .310a 2.000 18.000 .737 .527 10.015a 2.000 18.000 .001 .473 10.015a 2.000 18.000 .001 1.113 10.015a 2.000 18.000 .001 1.113 10.015a 2.000 18.000 .001 Pillai's Trace Wilks' Lambda Hotelling's Trace Roy's Largest Root Pillai's Trace Wilks' Lambda Hotelling's Trace Roy's Largest Root Pillai's Trace Wilks' Lambda Hotelling's Trace Roy's Largest Root Effect TX TIME TX TIME Value F Hypothesis df Error df Sig. Exact statistica. Design: Intercept Within Subjects Design: TX+TIME+TX*TIMEb. Mauchly's Test of Sphericityb Measure: MEASURE_1 1.000 .000 0 1.000 1.000 1.000 .998 .027 2 .986 .998 1.000 .500 .901 1.872 2 .392 .910 1.000 .500 Within Subjects Effect TX TIME TX TIME Mauchly's W Approx.Chi-Square df Sig. Greenhouse-Geisser Huynh-Feldt Lower-bound Epsilona Tests the null hypothesis that the error covariance matrix of the orthonormalized transformed dependent variables isproportional to an identity matrix. May be used to adjust the degrees of freedom for the averaged tests of significance. Corrected tests are displayed in theTests of Within-Subjects Effects table.a. Design: Intercept Within Subjects Design: TX+TIME+TX*TIMEb.

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55 Tests of Within-Subjects Effects Measure: MEASURE_1 .224 1 .224 .679 .420 .224 1.000 .224 .679 .420 .224 1.000 .224 .679 .420 .224 1.000 .224 .679 .420 6.260 19 .329 6.260 19.000 .329 6.260 19.000 .329 6.260 19.000 .329 2.183E-02 2 1.092E-02 .335 .717 2.183E-02 1.997 1.093E-02 .335 .717 2.183E-02 2.000 1.092E-02 .335 .717 2.183E-02 1.000 2.183E-02 .335 .569 1.238 38 3.257E-02 1.238 37.942 3.262E-02 1.238 38.000 3.257E-02 1.238 19.000 6.515E-02 .476 2 .238 7.377 .002 .476 1.820 .261 7.377 .003 .476 2.000 .238 7.377 .002 .476 1.000 .476 7.377 .014 1.225 38 3.224E-02 1.225 34.584 3.542E-02 1.225 38.000 3.224E-02 1.225 19.000 6.448E-02 Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Source TX Error(TX) TIME Error(TIME) TX TIME Error(TX*TIME) Type III Sumof Squares df Mean Square F Sig. Tests of Within-Subjects Contrasts Measure: MEASURE_1 .224 1 .224 .679 .420 6.260 19 .329 1.955E-03 1 1.955E-03 .062 .805 1.988E-02 1 1.988E-02 .588 .453 .596 19 3.134E-02 .642 19 3.381E-02 .319 1 .319 12.508 .002 .157 1 .157 4.025 .059 .484 19 2.548E-02 .741 19 3.900E-02 TIME Linear Quadratic Linear Quadratic Linear Quadratic Linear Quadratic TX Linear Linear Linear Linear Source TX Error(TX) TIME Error(TIME) TX TIME Error(TX*TIME) Type III Sumof Squares df Mean Square F Sig.

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56 Tests of Between-Subjects Effects Measure: MEASURE_1 Transformed Variable: Average 164.168 1 164.168 98.752 .000 31.586 19 1.662 Source Intercept Error Type III Sumof Squares df Mean Square F Sig. Estimated Marginal Means 1. Grand Mean Measure: MEASURE_1 1.170 .118 .923 1.416 Mean Std. Error Lower Bound Upper Bound 95% Confidence Interval 2. TX Measure: MEASURE_1 1.126 .131 .851 1.402 1.213 .126 .949 1.477 TX 1 2 Mean Std. Error Lower Bound Upper Bound 95% Confidence Interval 3. TIME Measure: MEASURE_1 1.184 .119 .934 1.433 1.151 .121 .899 1.404 1.174 .120 .922 1.426 TIME 1 2 3 Mean Std. Error Lower Bound Upper Bound 95% Confidence Interval 4. TX TIME Measure: MEASURE_1 1.229 .141 .935 1.523 1.057 .136 .773 1.342 1.093 .128 .825 1.361 1.138 .120 .887 1.390 1.246 .138 .957 1.534 1.255 .134 .974 1.535 TIME 1 2 3 1 2 3 TX 1 2 Mean Std. Error Lower Bound Upper Bound 95% Confidence Interval

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APPENDIX F ANOVA TABLE OF PERONEOUS LONGUS REACTIVE ACTIVITY General Linear Model Within-Subjects Factors Measure: MEASURE_1 CPRE CPOST1 CPOST2 IPRE IPOST1 IPOST2 TIME 1 2 3 1 2 3 TX 1 2 DependentVariable Descriptive Statistics 1.3570 .71323 20 1.2742 .82568 20 1.2970 .71266 20 1.4216 .68006 20 1.6318 .55845 20 1.4512 .77852 20 CPRE CPOST1 CPOST2 IPRE IPOST1 IPOST2 Mean Std. Deviation N 57

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58 Multivariate Testsb .093 1.958a 1.000 19.000 .178 .907 1.958a 1.000 19.000 .178 .103 1.958a 1.000 19.000 .178 .103 1.958a 1.000 19.000 .178 .064 .618a 2.000 18.000 .550 .936 .618a 2.000 18.000 .550 .069 .618a 2.000 18.000 .550 .069 .618a 2.000 18.000 .550 .251 3.020a 2.000 18.000 .074 .749 3.020a 2.000 18.000 .074 .336 3.020a 2.000 18.000 .074 .336 3.020a 2.000 18.000 .074 Pillai's Trace Wilks' Lambda Hotelling's Trace Roy's Largest Root Pillai's Trace Wilks' Lambda Hotelling's Trace Roy's Largest Root Pillai's Trace Wilks' Lambda Hotelling's Trace Roy's Largest Root Effect TX TIME TX TIME Value F Hypothesis df Error df Sig. Exact statistica. Design: Intercept Within Subjects Design: TX+TIME+TX*TIMEb. Mauchly's Test of Sphericityb Measure: MEASURE_1 1.000 .000 0 1.000 1.000 1.000 .900 1.889 2 .389 .909 1.000 .500 .886 2.179 2 .336 .898 .985 .500 Within Subjects Effect TX TIME TX TIME Mauchly's W Approx.Chi-Square df Sig. Greenhouse-Geisser Huynh-Feldt Lower-bound Epsilona Tests the null hypothesis that the error covariance matrix of the orthonormalized transformed dependent variables isproportional to an identity matrix. May be used to adjust the degrees of freedom for the averaged tests of significance. Corrected tests are displayed in theTests of Within-Subjects Effects table.a. Design: Intercept Within Subjects Design: TX+TIME+TX*TIMEb.

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59 Tests of Within-Subjects Effects Measure: MEASURE_1 1.107 1 1.107 1.958 .178 1.107 1.000 1.107 1.958 .178 1.107 1.000 1.107 1.958 .178 1.107 1.000 1.107 1.958 .178 10.744 19 .565 10.744 19.000 .565 10.744 19.000 .565 10.744 19.000 .565 .140 2 7.007E-02 .855 .433 .140 1.819 7.705E-02 .855 .425 .140 2.000 7.007E-02 .855 .433 .140 1.000 .140 .855 .367 3.116 38 8.199E-02 3.116 34.557 9.016E-02 3.116 38.000 8.199E-02 3.116 19.000 .164 .451 2 .225 2.517 .094 .451 1.795 .251 2.517 .101 .451 1.971 .229 2.517 .095 .451 1.000 .451 2.517 .129 3.405 38 8.960E-02 3.405 34.112 9.981E-02 3.405 37.445 9.092E-02 3.405 19.000 .179 Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Source TX Error(TX) TIME Error(TIME) TX TIME Error(TX*TIME) Type III Sumof Squares df Mean Square F Sig. Tests of Within-Subjects Contrasts Measure: MEASURE_1 1.107 1 1.107 1.958 .178 10.744 19 .565 4.637E-03 1 4.637E-03 .078 .783 .135 1 .135 1.295 .269 1.128 19 5.937E-02 1.988 19 .105 4.011E-02 1 4.011E-02 .486 .494 .411 1 .411 4.251 .053 1.568 19 8.254E-02 1.836 19 9.665E-02 TIME Linear Quadratic Linear Quadratic Linear Quadratic Linear Quadratic TX Linear Linear Linear Linear Source TX Error(TX) TIME Error(TIME) TX TIME Error(TX*TIME) Type III Sumof Squares df Mean Square F Sig.

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60 Tests of Between-Subjects Effects Measure: MEASURE_1 Transformed Variable: Average 237.041 1 237.041 109.229 .000 41.233 19 2.170 Source Intercept Error Type III Sumof Squares df Mean Square F Sig. Estimated Marginal Means 1. Grand Mean Measure: MEASURE_1 1.405 .134 1.124 1.687 Mean Std. Error Lower Bound Upper Bound 95% Confidence Interval 2. TX Measure: MEASURE_1 1.309 .164 .965 1.653 1.502 .136 1.216 1.787 TX 1 2 Mean Std. Error Lower Bound Upper Bound 95% Confidence Interval 3. TIME Measure: MEASURE_1 1.389 .138 1.101 1.677 1.453 .142 1.155 1.751 1.374 .139 1.084 1.664 TIME 1 2 3 Mean Std. Error Lower Bound Upper Bound 95% Confidence Interval 4. TX TIME Measure: MEASURE_1 1.357 .159 1.023 1.691 1.274 .185 .888 1.661 1.297 .159 .963 1.631 1.422 .152 1.103 1.740 1.632 .125 1.370 1.893 1.451 .174 1.087 1.816 TIME 1 2 3 1 2 3 TX 1 2 Mean Std. Error Lower Bound Upper Bound 95% Confidence Interval

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APPENDIX G ANOVA TABLE OF TIBIALIS ANTERIOR PREPARATORY ACTIVITY General Linear Model Within-Subjects Factors Measure: MEASURE_1 CPRE CPOST1 CPOST2 IPRE IPOST1 IPOST2 TIME 1 2 3 1 2 3 TX 1 2 DependentVariable Descriptive Statistics .4942 .25070 20 .3940 .20765 20 .4239 .19310 20 .4365 .20225 20 .5081 .23806 20 .4847 .22091 20 CPRE CPOST1 CPOST2 IPRE IPOST1 IPOST2 Mean Std. Deviation N 61

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62 Multivariate Testsb .048 .968a 1.000 19.000 .338 .952 .968a 1.000 19.000 .338 .051 .968a 1.000 19.000 .338 .051 .968a 1.000 19.000 .338 .049 .463a 2.000 18.000 .637 .951 .463a 2.000 18.000 .637 .051 .463a 2.000 18.000 .637 .051 .463a 2.000 18.000 .637 .445 7.222a 2.000 18.000 .005 .555 7.222a 2.000 18.000 .005 .802 7.222a 2.000 18.000 .005 .802 7.222a 2.000 18.000 .005 Pillai's Trace Wilks' Lambda Hotelling's Trace Roy's Largest Root Pillai's Trace Wilks' Lambda Hotelling's Trace Roy's Largest Root Pillai's Trace Wilks' Lambda Hotelling's Trace Roy's Largest Root Effect TX TIME TX TIME Value F Hypothesis df Error df Sig. Exact statistica. Design: Intercept Within Subjects Design: TX+TIME+TX*TIMEb. Mauchly's Test of Sphericityb Measure: MEASURE_1 1.000 .000 0 1.000 1.000 1.000 .862 2.676 2 .262 .879 .961 .500 .946 1.003 2 .606 .949 1.000 .500 Within Subjects Effec t TX TIME TX TIME Mauchly's W Approx.Chi-Square df Sig. Greenhouse-Geisser Huynh-Feldt Lower-bound Epsilona Tests the null hypothesis that the error covariance matrix of the orthonormalized transformed dependent variables isproportional to an identity matrix. May be used to adjust the degrees of freedom for the averaged tests of significance. Corrected tests are displayed Tests of Within-Subjects Effects table.a. Design: Intercept Within Subjects Design: TX+TIME+TX*TIMEb.

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63 Tests of Within-Subjects Effects Measure: MEASURE_1 4.587E-02 1 4.587E-02 .968 .338 4.587E-02 1.000 4.587E-02 .968 .338 4.587E-02 1.000 4.587E-02 .968 .338 4.587E-02 1.000 4.587E-02 .968 .338 .900 19 4.739E-02 .900 19.000 4.739E-02 .900 19.000 4.739E-02 .900 19.000 4.739E-02 4.502E-03 2 2.251E-03 .307 .737 4.502E-03 1.757 2.562E-03 .307 .710 4.502E-03 1.922 2.342E-03 .307 .729 4.502E-03 1.000 4.502E-03 .307 .586 .279 38 7.332E-03 .279 33.387 8.346E-03 .279 36.522 7.629E-03 .279 19.000 1.466E-02 .154 2 7.724E-02 7.340 .002 .154 1.897 8.143E-02 7.340 .002 .154 2.000 7.724E-02 7.340 .002 .154 1.000 .154 7.340 .014 .400 38 1.052E-02 .400 36.047 1.109E-02 .400 38.000 1.052E-02 .400 19.000 2.105E-02 Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Source TX Error(TX) TIME Error(TIME) TX TIME Error(TX*TIME) Type III Sumof Squares df Mean Square F Sig. Tests of Within-Subjects Contrasts Measure: MEASURE_1 4.587E-02 1 4.587E-02 .968 .338 .900 19 4.739E-02 2.428E-03 1 2.428E-03 .341 .566 2.074E-03 1 2.074E-03 .275 .606 .135 19 7.126E-03 .143 19 7.539E-03 7.012E-02 1 7.012E-02 5.420 .031 8.436E-02 1 8.436E-02 10.404 .004 .246 19 1.294E-02 .154 19 8.109E-03 TIME Linear Quadratic Linear Quadratic Linear Quadratic Linear Quadratic TX Linear Linear Linear Linear Source TX Error(TX) TIME Error(TIME) TX TIME Error(TX*TIME) Type III Sumof Squares df Mean Square F Sig.

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64 Tests of Between-Subjects Effects Measure: MEASURE_1 Transformed Variable: Average 25.051 1 25.051 121.288 .000 3.924 19 .207 Source Intercept Error Type III Sumof Squares df Mean Square F Sig. Estimated Marginal Means 1. Grand Mean Measure: MEASURE_1 .457 .041 .370 .544 Mean Std. Error Lower Bound Upper Bound 95% Confidence Interval 2. TX Measure: MEASURE_1 .437 .045 .343 .531 .476 .047 .378 .575 TX 1 2 Mean Std. Error Lower Bound Upper Bound 95% Confidence Interval 3. TIME Measure: MEASURE_1 .465 .045 .372 .559 .451 .043 .362 .540 .454 .042 .367 .541 TIME 1 2 3 Mean Std. Error Lower Bound Upper Bound 95% Confidence Interval 4. TX TIME Measure: MEASURE_1 .494 .056 .377 .611 .394 .046 .297 .491 .424 .043 .334 .514 .437 .045 .342 .531 .508 .053 .397 .619 .485 .049 .381 .588 TIME 1 2 3 1 2 3 TX 1 2 Mean Std. Error Lower Bound Upper Bound 95% Confidence Interval

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APPENDIX H ANOVA TABLE OF TIBIALIS ANTERIOR REACTIVE ACTIVITY General Linear Model Within-Subjects Factors Measure: MEASURE_1 CPRE CPOST1 CPOST2 IPRE IPOST1 IPOST2 TIME 1 2 3 1 2 3 TX 1 2 DependentVariable Descriptive Statistics .7201 .28099 20 .7067 .28298 20 .7298 .24489 20 .8363 .31669 20 .9785 .34515 20 .9526 .35162 20 CPRE CPOST1 CPOST2 IPRE IPOST1 IPOST2 Mean Std. Deviation N 65

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66 Multivariate Testsb .368 11.040a 1.000 19.000 .004 .632 11.040a 1.000 19.000 .004 .581 11.040a 1.000 19.000 .004 .581 11.040a 1.000 19.000 .004 .109 1.102a 2.000 18.000 .354 .891 1.102a 2.000 18.000 .354 .122 1.102a 2.000 18.000 .354 .122 1.102a 2.000 18.000 .354 .169 1.835a 2.000 18.000 .188 .831 1.835a 2.000 18.000 .188 .204 1.835a 2.000 18.000 .188 .204 1.835a 2.000 18.000 .188 Pillai's Trace Wilks' Lambda Hotelling's Trace Roy's Largest Root Pillai's Trace Wilks' Lambda Hotelling's Trace Roy's Largest Root Pillai's Trace Wilks' Lambda Hotelling's Trace Roy's Largest Root Effect TX TIME TX TIME Value F Hypothesis df Error df Sig. Exact statistica. Design: Intercept Within Subjects Design: TX+TIME+TX*TIMEb. Mauchly's Test of Sphericityb Measure: MEASURE_1 1.000 .000 0 1.000 1.000 1.000 .896 1.972 2 .373 .906 .996 .500 .917 1.561 2 .458 .923 1.000 .500 Within Subjects Effe c TX TIME TX TIME Mauchly's W Approx.Chi-Square df Sig. Greenhouse-Geisser Huynh-Feldt Lower-bound Epsilona Tests the null hypothesis that the error covariance matrix of the orthonormalized transformed dependent variables i s proportional to an identity matrix. May be used to adjust the degrees of freedom for the averaged tests of significance. Corrected tests are displ a Tests of Within-Subjects Effects table.a. Design: Intercept Within Subjects Design: TX+TIME+TX*TIMEb.

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67 Tests of Within-Subjects Effects Measure: MEASURE_1 1.244 1 1.244 11.040 .004 1.244 1.000 1.244 11.040 .004 1.244 1.000 1.244 11.040 .004 1.244 1.000 1.244 11.040 .004 2.140 19 .113 2.140 19.000 .113 2.140 19.000 .113 2.140 19.000 .113 .108 2 5.414E-02 1.530 .230 .108 1.812 5.976E-02 1.530 .231 .108 1.992 5.436E-02 1.530 .230 .108 1.000 .108 1.530 .231 1.345 38 3.539E-02 1.345 34.428 3.906E-02 1.345 37.850 3.553E-02 1.345 19.000 7.078E-02 .127 2 6.328E-02 1.896 .164 .127 1.847 6.854E-02 1.896 .168 .127 2.000 6.328E-02 1.896 .164 .127 1.000 .127 1.896 .185 1.268 38 3.338E-02 1.268 35.085 3.615E-02 1.268 38.000 3.338E-02 1.268 19.000 6.675E-02 Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Source TX Error(TX) TIME Error(TIME) TX TIME Error(TX*TIME) Type III Sumof Squares df Mean Square F Sig. Tests of Within-Subjects Contrasts Measure: MEASURE_1 1.244 1 1.244 11.040 .004 2.140 19 .113 7.940E-02 1 7.940E-02 1.886 .186 2.889E-02 1 2.889E-02 1.007 .328 .800 19 4.210E-02 .545 19 2.868E-02 5.683E-02 1 5.683E-02 2.385 .139 6.973E-02 1 6.973E-02 1.624 .218 .453 19 2.382E-02 .816 19 4.293E-02 TIME Linear Quadratic Linear Quadratic Linear Quadratic Linear Quadratic TX Linear Linear Linear Linear Source TX Error(TX) TIME Error(TIME) TX TIME Error(TX*TIME) Type III Sumof Squares df Mean Square F Sig.

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68 Tests of Between-Subjects Effects Measure: MEASURE_1 Transformed Variable: Average 80.823 1 80.823 259.148 .000 5.926 19 .312 Source Intercept Error Type III Sumof Squares df Mean Square F Sig. Estimated Marginal Means 1. Grand Mean Measure: MEASURE_1 .821 .051 .714 .927 Mean Std. Error Lower Bound Upper Bound 95% Confidence Interval 2. TX Measure: MEASURE_1 .719 .055 .604 .833 .922 .064 .789 1.056 TX 1 2 Mean Std. Error Lower Bound Upper Bound 95% Confidence Interval 3. TIME Measure: MEASURE_1 .778 .053 .667 .889 .843 .058 .721 .964 .841 .058 .720 .962 TIME 1 2 3 Mean Std. Error Lower Bound Upper Bound 95% Confidence Interval 4. TX TIME Measure: MEASURE_1 .720 .063 .589 .852 .707 .063 .574 .839 .730 .055 .615 .844 .836 .071 .688 .985 .979 .077 .817 1.140 .953 .079 .788 1.117 TIME 1 2 3 1 2 3 TX 1 2 Mean Std. Error Lower Bound Upper Bound 95% Confidence Interval

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APPENDIX I ANOVA TABLE OF VERTICAL GROUND REACTION FORCE TIME TO STABILIZATION General Linear Model Within-Subjects Factors Measure: MEASURE_1 IXPRE IXPST1 IXPST2 CXPRE CXPST1 CXPST2 TIME 1 2 3 1 2 3 TX 1 2 DependentVariable Descriptive Statistics 1644.4750 275.10047 20 1730.6667 319.58007 20 1507.9417 273.80864 20 1634.4720 345.54176 20 1782.7478 393.46474 20 1481.6350 369.64539 20 IXPRE IXPST1 IXPST2 CXPRE CXPST1 CXPST2 Mean Std. Deviation N 69

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Multivariate Testsb .000 .006a 1.000 19.000 .940 1.000 .006a 1.000 19.000 .940 .000 .006a 1.000 19.000 .940 .000 .006a 1.000 19.000 .940 .469 7.953a 2.000 18.000 .003 .531 7.953a 2.000 18.000 .003 .884 7.953a 2.000 18.000 .003 .884 7.953a 2.000 18.000 .003 .037 .344a 2.000 18.000 .714 .963 .344a 2.000 18.000 .714 .038 .344a 2.000 18.000 .714 .038 .344a 2.000 18.000 .714 Pillai's Trace Wilks' Lambda Hotelling's Trace Roy's Largest Root Pillai's Trace Wilks' Lambda Hotelling's Trace Roy's Largest Root Pillai's Trace Wilks' Lambda Hotelling's Trace Roy's Largest Root Effect TX TIME TX TIME Value F Hypothesis df Error df Sig. Exact statistica. Design: Intercept Within Subjects Design: TX+TIME+TX*TIMEb. Mauchly's Test of Sphericityb Measure: MEASURE_1 1.000 .000 0 1.000 1.000 1.000 .759 4.974 2 .083 .806 .869 .500 .717 5.978 2 .050 .780 .837 .500 Within Subjects Effe c TX TIME TX TIME Mauchly's W Approx.Chi-Square df Sig. Greenhouse-Geisser Huynh-Feldt Lower-bound Epsilona Tests the null hypothesis that the error covariance matrix of the orthonormalized transformed dependent variables i s proportional to an identity matrix. May be used to adjust the degrees of freedom for the averaged tests of significance. Corrected tests are displ a Tests of Within-Subjects Effects table.a. Design: Intercept Within Subjects Design: TX+TIME+TX*TIMEb.

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Tests of Within-Subjects Effects Measure: MEASURE_1 829.134 1 829.134 .006 .940 829.134 1.000 829.134 .006 .940 829.134 1.000 829.134 .006 .940 829.134 1.000 829.134 .006 .940 2709177.198 19 142588.274 2709177.198 19.000 142588.274 2709177.198 19.000 142588.274 2709177.198 19.000 142588.274 1377054.247 2 688527.123 7.774 .001 1377054.247 1.611 854762.346 7.774 .003 1377054.247 1.738 792354.378 7.774 .003 1377054.247 1.000 1377054.247 7.774 .012 3365451.054 38 88564.501 3365451.054 30.610 109947.159 3365451.054 33.021 101919.689 3365451.054 19.000 177129.003 34216.352 2 17108.176 .257 .774 34216.352 1.559 21943.089 .257 .720 34216.352 1.673 20446.350 .257 .735 34216.352 1.000 34216.352 .257 .618 2526913.990 38 66497.737 2526913.990 29.627 85290.550 2526913.990 31.796 79472.877 2526913.990 19.000 132995.473 Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Source TX Error(TX) TIME Error(TIME) TX TIME Error(TX*TIME) Type III Sumof Squares df Mean Square F Sig. Tests of Within-Subjects Contrasts Measure: MEASURE_1 829.134 1 829.134 .006 .940 2709177.198 19 142588.274 418675.949 1 418675.949 3.503 .077 958378.298 1 958378.298 16.633 .001 2270674.574 19 119509.188 1094776.480 19 57619.815 1329.048 1 1329.048 .025 .876 32887.305 1 32887.305 .414 .528 1016918.940 19 53522.049 1509995.051 19 79473.424 TIME Linear Quadratic Linear Quadratic Linear Quadratic Linear Quadratic TX Linear Linear Linear Linear Source TX Error(TX) TIME Error(TIME) TX TIME Error(TX*TIME) Type III Sumof Squares df Mean Square F Sig.

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Tests of Between-Subjects Effects Measure: MEASURE_1 Transformed Variable: Average 318954381 1 318954381.0 1512.195 .000 4007507.195 19 210921.431 Source Intercept Error Type III Sumof Squares df Mean Square F Sig. Estimated Marginal Means 1. Grand Mean Measure: MEASURE_1 1630.323 41.925 1542.574 1718.072 Mean Std. Error Lower Bound Upper Bound 95% Confidence Interval 2. TX Measure: MEASURE_1 1627.694 42.886 1537.934 1717.455 1632.952 63.660 1499.709 1766.194 TX 1 2 Mean Std. Error Lower Bound Upper Bound 95% Confidence Interval 3. TIME Measure: MEASURE_1 1639.474 49.083 1536.743 1742.204 1756.707 58.593 1634.071 1879.343 1494.788 62.121 1364.767 1624.810 TIME 1 2 3 Mean Std. Error Lower Bound Upper Bound 95% Confidence Interval 4. TX TIME Measure: MEASURE_1 1644.475 61.514 1515.724 1773.226 1730.667 71.460 1581.099 1880.235 1507.942 61.225 1379.795 1636.088 1634.472 77.265 1472.753 1796.191 1782.748 87.981 1598.601 1966.895 1481.635 82.655 1308.636 1654.634 TIME 1 2 3 1 2 3 TX 1 2 Mean Std. Error Lower Bound Upper Bound 95% Confidence Interval

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APPENDIX J ANOVA TABLE OF MEDIAL/ LATERAL GROUND REACTION FORCE TIME TO STABILIZATION General Linear Model Within-Subjects Factors Measure: MEASURE_1 IYPRE IYPST1 IYPST2 CYPRE CYPST1 CYPST2 TIME 1 2 3 1 2 3 TX 1 2 DependentVariable Descriptive Statistics 1568.3167 412.49609 20 1443.7000 302.80833 20 1455.7333 315.42072 20 1511.4522 294.18949 20 1572.6517 328.96142 20 1542.9613 380.23033 20 IYPRE IYPST1 IYPST2 CYPRE CYPST1 CYPST2 Mean Std. Deviation N 73

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Multivariate Testsb .041 .809a 1.000 19.000 .380 .959 .809a 1.000 19.000 .380 .043 .809a 1.000 19.000 .380 .043 .809a 1.000 19.000 .380 .044 .414a 2.000 18.000 .667 .956 .414a 2.000 18.000 .667 .046 .414a 2.000 18.000 .667 .046 .414a 2.000 18.000 .667 .079 .775a 2.000 18.000 .475 .921 .775a 2.000 18.000 .475 .086 .775a 2.000 18.000 .475 .086 .775a 2.000 18.000 .475 Pillai's Trace Wilks' Lambda Hotelling's Trace Roy's Largest Root Pillai's Trace Wilks' Lambda Hotelling's Trace Roy's Largest Root Pillai's Trace Wilks' Lambda Hotelling's Trace Roy's Largest Root Effect TX TIME TX TIME Value F Hypothesis df Error df Sig. Exact statistica. Design: Intercept Within Subjects Design: TX+TIME+TX*TIMEb. Mauchly's Test of Sphericityb Measure: MEASURE_1 1.000 .000 0 1.000 1.000 1.000 .901 1.876 2 .391 .910 1.000 .500 .965 .635 2 .728 .966 1.000 .500 Within Subjects Ef f TX TIME TX TIME M auchly's W Approx.Chi-Square df Sig. Greenhouse-Geisser Huynh-Feldt L ower-bound Epsilona Tests the null hypothesis that the error covariance matrix of the orthonormalized transformed depende n proportional to an identity matrix. May be used to adjust the degrees of freedom for the averaged tests of significance. Corrected tes t Tests of Within-Subjects Effects table.a. Design: Intercept Within Subjects Design: TX+TIME+TX*TIMEb.

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Tests of Within-Subjects Effects Measure: MEASURE_1 84604.408 1 84604.408 .809 .380 84604.408 1.000 84604.408 .809 .380 84604.408 1.000 84604.408 .809 .380 84604.408 1.000 84604.408 .809 .380 1987548.720 19 104607.827 1987548.720 19.000 104607.827 1987548.720 19.000 104607.827 1987548.720 19.000 104607.827 36355.091 2 18177.545 .312 .734 36355.091 1.820 19976.840 .312 .713 36355.091 2.000 18177.545 .312 .734 36355.091 1.000 36355.091 .312 .583 2211538.143 38 58198.372 2211538.143 34.577 63959.107 2211538.143 38.000 58198.372 2211538.143 19.000 116396.744 190103.869 2 95051.935 .946 .397 190103.869 1.933 98346.846 .946 .395 190103.869 2.000 95051.935 .946 .397 190103.869 1.000 190103.869 .946 .343 3819214.026 38 100505.632 3819214.026 36.727 103989.593 3819214.026 38.000 100505.632 3819214.026 19.000 201011.265 Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Source TX Error(TX) TIME Error(TIME) TX TIME Error(TX*TIME) Type III Sumof Squares df Mean Square F Sig. Tests of Within-Subjects Contrasts Measure: MEASURE_1 84604.408 1 84604.408 .809 .380 1987548.720 19 104607.827 32865.103 1 32865.103 .632 .436 3489.988 1 3489.988 .054 .818 988218.114 19 52011.480 1223320.028 19 64385.265 103813.243 1 103813.243 1.111 .305 86290.626 1 86290.626 .802 .382 1774786.346 19 93409.808 2044427.680 19 107601.457 TIME Linear Quadratic Linear Quadratic Linear Quadratic Linear Quadratic TX Linear Linear Linear Linear Source TX Error(TX) TIME Error(TIME) TX TIME Error(TX*TIME) Type III Sumof Squares df Mean Square F Sig.

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Tests of Between-Subjects Effects Measure: MEASURE_1 Transformed Variable: Average 275718876 1 275718876.4 989.451 .000 5294511.118 19 278658.480 Source Intercept Error Type III Sumof Squares df Mean Square F Sig. Estimated Marginal Means 1. Grand Mean Measure: MEASURE_1 1515.803 48.189 1414.942 1616.663 Mean Std. Error Lower Bound Upper Bound 95% Confidence Interval 2. TX Measure: MEASURE_1 1489.250 62.652 1358.119 1620.381 1542.355 49.624 1438.490 1646.220 TX 1 2 Mean Std. Error Lower Bound Upper Bound 95% Confidence Interval 3. TIME Measure: MEASURE_1 1539.884 54.186 1426.471 1653.298 1508.176 49.538 1404.491 1611.860 1499.347 66.979 1359.158 1639.536 TIME 1 2 3 Mean Std. Error Lower Bound Upper Bound 95% Confidence Interval 4. TX TIME Measure: MEASURE_1 1568.317 92.237 1375.263 1761.371 1443.700 67.710 1301.981 1585.419 1455.733 70.530 1308.112 1603.355 1511.452 65.783 1373.767 1649.137 1572.652 73.558 1418.693 1726.610 1542.961 85.022 1365.008 1720.915 TIME 1 2 3 1 2 3 TX 1 2 Mean Std. Error Lower Bound Upper Bound 95% Confidence Interval

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APPENDIX K ANOVA TABLE OF ANTERIOR/ POSTERIOR GROUND REACTION FORCE TIME TO STABILIZATION General Linear Model Within-Subjects Factors Measure: MEASURE_1 IZPRE IZPST1 IZPST2 CZPRE CZPST1 CZPST2 TIME 1 2 3 1 2 3 TX 1 2 DependentVariable Descriptive Statistics 1470.6000 452.24995 20 1493.7250 514.36296 20 1373.9375 508.64178 20 1367.9990 365.53430 20 1292.8760 485.62623 20 1261.5093 377.91127 20 IZPRE IZPST1 IZPST2 CZPRE CZPST1 CZPST2 Mean Std. Deviation N 77

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78 Multivariate Testsb .145 3.234a 1.000 19.000 .088 .855 3.234a 1.000 19.000 .088 .170 3.234a 1.000 19.000 .088 .170 3.234a 1.000 19.000 .088 .100 .997a 2.000 18.000 .389 .900 .997a 2.000 18.000 .389 .111 .997a 2.000 18.000 .389 .111 .997a 2.000 18.000 .389 .026 .244a 2.000 18.000 .786 .974 .244a 2.000 18.000 .786 .027 .244a 2.000 18.000 .786 .027 .244a 2.000 18.000 .786 Pillai's Trace Wilks' Lambda Hotelling's Trace Roy's Largest Root Pillai's Trace Wilks' Lambda Hotelling's Trace Roy's Largest Root Pillai's Trace Wilks' Lambda Hotelling's Trace Roy's Largest Root Effect TX TIME TX TIME Value F Hypothesis df Error df Sig. Exact statistica. Design: Intercept Within Subjects Design: TX+TIME+TX*TIMEb. Mauchly's Test of Sphericityb Measure: MEASURE_1 1.000 .000 0 1.000 1.000 1.000 .842 3.102 2 .212 .863 .942 .500 .824 3.488 2 .175 .850 .925 .500 Within Subjects Eff e TX TIME TX TIME Mauchly's W Approx.Chi-Square df Sig. Greenhouse-Geisser Huynh-Feldt Lower-bound Epsilona Tests the null hypothesis that the error covariance matrix of the orthonormalized transformed dependent va r proportional to an identity matrix. May be used to adjust the degrees of freedom for the averaged tests of significance. Corrected tests a r Tests of Within-Subjects Effects table.a. Design: Intercept Within Subjects Design: TX+TIME+TX*TIMEb.

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79 Tests of Within-Subjects Effects Measure: MEASURE_1 576515.498 1 576515.498 3.234 .088 576515.498 1.000 576515.498 3.234 .088 576515.498 1.000 576515.498 3.234 .088 576515.498 1.000 576515.498 3.234 .088 3386796.731 19 178252.460 3386796.731 19.000 178252.460 3386796.731 19.000 178252.460 3386796.731 19.000 178252.460 222740.590 2 111370.295 .879 .424 222740.590 1.727 128998.968 .879 .411 222740.590 1.883 118261.010 .879 .418 222740.590 1.000 222740.590 .879 .360 4815765.937 38 126730.683 4815765.937 32.807 146790.733 4815765.937 35.786 134571.777 4815765.937 19.000 253461.365 58558.288 2 29279.144 .211 .811 58558.288 1.700 34436.943 .211 .775 58558.288 1.850 31648.357 .211 .794 58558.288 1.000 58558.288 .211 .651 5269998.290 38 138684.166 5269998.290 32.309 163114.698 5269998.290 35.155 149906.228 5269998.290 19.000 277368.331 Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound Source TX Error(TX) TIME Error(TIME) TX TIME Error(TX*TIME) Type III Sumof Squares df Mean Square F Sig. Tests of Within-Subjects Contrasts Measure: MEASURE_1 576515.498 1 576515.498 3.234 .088 3386796.731 19 178252.460 206354.014 1 206354.014 1.355 .259 16386.576 1 16386.576 .162 .692 2892596.448 19 152241.918 1923169.488 19 101219.447 482.866 1 482.866 .004 .952 58075.422 1 58075.422 .391 .539 2446773.143 19 128777.534 2823225.148 19 148590.797 TIME Linear Quadratic Linear Quadratic Linear Quadratic Linear Quadratic TX Linear Linear Linear Linear Source TX Error(TX) TIME Error(TIME) TX TIME Error(TX*TIME) Type III Sumof Squares df Mean Square F Sig.

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80 Tests of Between-Subjects Effects Measure: MEASURE_1 Transformed Variable: Average 227460954 1 227460953.7 428.364 .000 10088974.8 19 530998.672 Source Intercept Error Type III Sumof Squares df Mean Square F Sig. Estimated Marginal Means 1. Grand Mean Measure: MEASURE_1 1376.774 66.521 1237.545 1516.004 Mean Std. Error Lower Bound Upper Bound 95% Confidence Interval 2. TX Measure: MEASURE_1 1446.088 81.153 1276.232 1615.943 1307.461 72.353 1156.024 1458.899 TX 1 2 Mean Std. Error Lower Bound Upper Bound 95% Confidence Interval 3. TIME Measure: MEASURE_1 1419.300 72.373 1267.822 1570.777 1393.301 85.087 1215.212 1571.389 1317.723 84.463 1140.941 1494.506 TIME 1 2 3 Mean Std. Error Lower Bound Upper Bound 95% Confidence Interval 4. TX TIME Measure: MEASURE_1 1470.600 101.126 1258.941 1682.259 1493.725 115.015 1252.996 1734.454 1373.938 113.736 1135.886 1611.989 1367.999 81.736 1196.924 1539.074 1292.876 108.589 1065.596 1520.156 1261.509 84.504 1084.641 1438.377 TIME 1 2 3 1 2 3 TX 1 2 Mean Std. Error Lower Bound Upper Bound 95% Confidence Interval

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26. McMaster WC, Liddle S, Waugh TR. Laboratory evaluation of various cold therapy modalities. The American Journal of Sports Medicine. 1978;6:291-294. 27. Meeusen R, Lievens P. The use of cryotherapy in sports injuries. Sports Medicine. 1986;3:398-414. 28. Michelson JD, Hutchins C. Mechanoreceptors in human ankle ligaments. The Journal of Bone and Joint Surgery. 1995;77-B:219-224. 29. Moore KL, Dalley AF. Clinically Orientated Anatomy. 4th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 1999. 30. Mulloy Forkin D, Koczar C, Battle R, Newton RA. Evaluation of kinesthetic deficits indicative of balance control in gymnasts with unilateral chronic ankle sprains. Journal of Orthopaedic and Sports Physical Therapy. 1996;23:245-250. 31. Myrer JW, Measom G, Fellingham GW. Temperature changes in the human leg during and after two methods of cryotherapy. Journal of Athletic Training. 1998;33:25-29. 32. Nanneman D. Thermal modalities: Heat and cold. AAOHN Journal. 1991;39:70-75. 33. Oksa J, Rintamaki H, Rissanen S. Muscle performance and electromyogram activity of the lower leg muscles with different levels of cold exposure. European Journal of Applied Physiology. 1997;75:484-490. 34. Spence, AP. Basic Human Anatomy. 3rd ed. Redwood City, CA: The Benjamin/ Cummings Publishing Company, Inc.; 1990. 35. Starkey, C. Therapeutic Modalties. 2nd ed. Philadelphia, PA: F.A. Davis Company; 1999. 36. Thieme HA, Ingersoll CD, Knight KL, Ozmun JC. Cooling does not affect knee proprioception. Journal of Athletic Training. 1996;31:8-11. 37. Verducci F. Interval cryotherapy and fatigue in university baseball pitchers. Research Quarterly for Exercise and Sport. 2001;72:280-287. 38. Waylonis G. The physiologic effects of ice massage. Archives of Physical Medicine and Rehabilitation. 1967;48:37-42. 39. Zemke JE, Anderson JC, Guion WK, McMillan J, Joyner AB. Intramuscular temperature responses in the human leg to two forms of cryotherapy: Ice massage and ice bag. Journal of Orthopaedic and Sports Physical Therapy. 1998;27:301-307.

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BIOGRAPHICAL SKETCH I, Susan Miniello, am originally from Strongsville, OH, a suburb of Cleveland. I grew up there and graduated from Strongsville High School. I went on to attend Marietta College in Marietta, OH, where I majored in sports medicine. I then decided to attend the University of Florida to pursue a masters degree in athletic training/sports medicine. After UF, I plan to work as an athletic trainer and instructor at a small college. 84


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Title: Does ankle cryotherapy affect dynamic stability of healthy subjects?
Physical Description: Mixed Material
Creator: Miniello, Susan E. ( Author, Primary )
Publication Date: 2003
Copyright Date: 2003

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DOES ANKLE CRYOTHERAPY AFFECT DYNAMIC STABILITY OF HEALTHY
SUBJECTS?


















By

SUSAN E. MINIELLO


A THESIS PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
MASTER OF SCIENCE IN EXERCISE AND SPORT SCIENCES

UNIVERSITY OF FLORIDA


2003

































Copyright 2003

by

Susan E. Miniello
















TABLE OF CONTENTS
page

L IST O F T A B L E S ........ .. ...... .. ............ ...................................................... vi

L IST O F F IG U R E S .... ...... ................................................ .. .. ..... .............. vii

A B S T R A C T .......................................... .................................................. v iii

CHAPTER

1 IN TR OD U CTION ............................................... .. ......................... ..

State ent of the P problem .................................................................................. 1
H hypothesis ......................................................................... . 2
D definition of T erm s ....................................................... 2
A ssum options ................................................................. 2
L im itatio n s ................................................................................. 3
Significance of the Study ........................................................................... .......

2 REVIEW OF LITERA TURE .................................................................................. .... 4

A nkle A natom y ................................................................... ............................. . 4
Proprioception ..................................................................................................... 7
Measurement of Proprioception ........................... ......... ................9......
Threshold to Detection of Passive Motion ........... ........................ 10
Joint P position Sense ......... ......... ......... ........... ............... ............... 10
M uscle Latency ..................... ......... .... .. ..... ............... 10
P ostural Stability .......................................................................... 11
Proprioception Training ...... ...................................................... ............... 12
C ry o th erap y ................... ..... .......... ...........................................13
Ice or Injection Induced Anesthesia and Ankle Proprioception .............. .............. 17

3 M E T H O D S ........................................................................................... .. .. ..2 0

S u objects ............................... ..........................................2 0
In strum entation ............... ... ...... ........................ ......... ......................................20
V ertec V ertical Jum p Stand ........................................................... ......................20
Force Plate ............... ....... ............ .......................21
Electrom yography (EM G ) ............................ ..... .............................. 21
M easu rem ents ......... ....... ....................... ......... .......................................2 1
V ertical Jum p H eight................................................. .............................. 21









T im e to Stabilization ..................... .. ...................... ... .... .. ........... 22
M uscle A activity ................................... .. ... ..... ...............22
Treatment .......................... ..................... 24
Procedures ......... ........ .. .................................................................. 24
Study D esign and D ata A analysis ........................................ .......................... 25

4 R E S U L T S .............................................................................2 7

Subject Demographics ...... ........ ...... ................. .. ........ ............... 27
N orm alized E M G A activity .............................................................. .....................28
T ibialis A interior ...................... ........ ............ ................. .... ....... 28
P eroneou s L ongu s .............................. ...... .................... .. ........ .... ............2 8
Tim e to Stabilization ...................................................... ... .... ...... ... 29
Vertical Ground Reaction Force Time to Stabilization.................. ............29
Medial/Lateral Ground Reaction Force Time to Stabilization............................30
Anterior/Posterior Ground Reaction Force Time to Stabilization......................30

5 D ISC U SSIO N ......... ...... ... ............................................. ........................... 32

M u scle A ctiv ity ................................................................32
Tim e to Stabilization......................................................... ... .... .... 40
Suggestions for Future R research ........................................ .......................... 44
C o n c lu sio n s........................................................................................................... 4 5

APPENDIX

A INSTITUTIONAL REVIEW BOARD ........................................... ............... 46

B IN F O R M E D C O N SE N T ............. .........................................................................49

C QUESTIONNAIRE FOR INCLUSION IN THE STUDY .......................................51

D D A TA CO LLECTION FO RM ..................................................................................52

E ANOVA TABLE OF PERONEOUS LONGUS PREPARATORY ACTIVITY ......53

F ANOVA TABLE OF PERONEOUS LONGUS REACTIVE ACTIVITY ..............57

G ANOVA TABLE OF TIBIALIS ANTERIOR PREPARATORY ACTIVITY .........61

H ANOVA TABLE OF TIBIALIS ANTERIOR REACTIVE ACTIVITY ..................65

I ANOVA TABLE OF VERTICAL GROUND REACTION FORCE TIME TO
ST A B IL IZ A T IO N ................................................................... 69









J ANOVA TABLE OF MEDIAL/ LATERAL GROUND REACTION FORCE
TIM E TO STA B IL IZ A TIO N ......................................................... .....................73

K ANOVA TABLE OF ANTERIOR/ POSTERIOR GROUND REACTION FORCE
TIME TO STABILIZATION ........... ...... ........... ........................ 77

LIST OF REFEREN CES ........ ......................................................... ............... 81

BIOGRAPH ICAL SKETCH ..................................................... 84
















LIST OF TABLES


Table page

1 Normalized preparatory EMG activity of the tibialis anterior (% of MVIC) ..........28

2 Normalized reactive EMG activity of tibialis anterior (% of MVIC)...................28

3 Normalized preparatory EMG activity of peroneous longus (% of MVIC) ...........29

4 Normalized reactive EMG activity of peroneous longus (% of MVIC) ..................29

5 Vertical ground reaction force time to stabilization (in msec)..............................30

6 Medial/lateral ground reaction force time to stabilization (in msec) .....................30

7 Anterior/posterior ground reaction force time to stabilization (in msec) ...............31
















LIST OF FIGURES


Figure p

1 Tibialis Anterior Preparatory Activity .......................................... ............... 33

2 Peroneous Longus Preparatory Activity ...................................... ............... 33

3 Increase in M uscle Activity after Cryotherapy ................................ ............... 34

4 Tibialis Anterior Reactive Activity .................................... ............ ......... ...... 35

5 Peroneous Longus Reactive Activity ............................................ ............... 35

6 Temperature Decrease after Cryotherapy ..................................... .................38

7 Vertical Ground Reaction Force Time to Stabilization................ .............. ....40

8 Medial/Lateral Ground Reaction Force Time to Stabilization..............................41

9 Anterior/Posterior Ground Reaction Force Time to Stabilization .........................41

10 Com prison of Tim e to Stabilization ............................................ ............... 43















Abstract of Thesis Presented to the Graduate School
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Master of Science in Exercise and Sport Sciences

DOES ANKLE CRYOTHERAPY AFFECT DYNAMIC STABILITY OF HEALTHY
SUBJECTS?

By

Susan E. Miniello

August 2003

Chair: Michael E. Powers
Major Department: Exercise and Sport Sciences

The purpose of this study was to investigate the effects of lower leg cold immersion

therapy on dynamic stability of the ankle complex as measured by time to stabilization.

The subjects that volunteered to participate in this research were tested once under the

control condition and once under cold immersion condition. The subjects were screened

prior to participation for any history of the following conditions: acute or chronic lower

extremity injury, decreased sensation or circulation, and hypersensitivity to cold. The

subjects were asked to perform a jumping and landing task once before and twice after

the treatment. During this task, EMG activity was measured on the tibialis anterior and

peroneous longus muscles both before and after landing on the force plate. In addition

time to stabilization measurements for the ground reaction force, anterior/ posterior sway,

and medial/ lateral sway were also recorded. The results were analyzed using a 3 X 2

repeated measures ANOVA and indicated that cold immersion therapy had no effect on

dynamic stability as measured by time to stabilization. The results did indicate that









preparatory muscle activity was increased at the first posttest for the ice immersion

condition. This muscle activity was most likely responsible for helping the body

compensate for any detrimental effects of cryotherapy and allowing time to stabilization

to remain unchanged. Therefore, it appears from the results of this study that immediate

sports activity after a cryotherapy treatment is probably not contraindicated.














CHAPTER 1
INTRODUCTION

Statement of the Problem

The lateral ankle sprain is one of the most common injuries suffered by today's

athletic population. These injuries are even more prevalent in cutting and jumping sports

such as volleyball, football, soccer, and basketball. Cryotherapy is commonly used in the

management of pain and inflammation following ankle trauma. These modalities are also

incorporated into rehabilitation protocols and are often continued before and after

practices and games once the athlete has returned to competition. Although the systemic

and local effects of cryotherapy have been widely studied, its effects on joint function,

and more specifically, dynamic stability, are not completely understood. Cryotherapy has

been shown to cause anesthesia, decreased nerve transmission, and increased tissue and

joint stiffness, all of which may affect joint function.25 It is possible that a decrease in

nerve transmission can alter the body's response to changes in joint position. It is also

possible that this would adversely affect balance and dynamic stability, both of which are

necessary for proper function in athletic competition. Because of this, it is possible that

cold treatments may potentially predispose an individual to injury if the neuromuscular

response to perturbation has been slowed. Thus, the purpose of this study was to

investigate the effects of lower leg cold immersion therapy on dynamic stability of the

ankle as measured by time to stabilization. Although relatively new to athletic training

research, time to stabilization has become an accepted and reliable measure of dynamic

stability.4









Hypothesis

The following hypotheses were investigated in this study.

1. A twenty minute cold immersion treatment to the lower leg will significantly
increase time to stabilization as compared to the control condition.

2. A twenty minute cold immersion treatment to the lower leg will significantly
increase muscle activity of the tibialis anterior and peroneous longus muscles during the
preparatory phase of activity.

3. A twenty minute cold immersion treatment to the lower leg will significantly
increase muscle activity of the tibialis anterior and peroneous longus muscles during the
reactive phase of activity.


Definition of Terms

The following terms had specialized meanings for the purpose of this study.

Cold immersion--the treatment that the subject received of placing their lower leg
in a bucket of water and ice maintained at a temperature of 13-160C.19

Dynamic stability-- the ability to maintain balance after moving the center of
gravity.4

Electromyography--the measurement of muscle activity using surface electrodes
placed over the origins of the tibialis anterior and peroneous longus muscles.7

Proprioception--the awareness of joint position as sensed by the central nervous
system.24

Time to tlalilirLati,,--the time that it took for a subject to stop swaying on a triaxial
force plate after a jump landing on a single leg.4


Assumptions

The following assumptions were made in order to carry out this research.

1. It was assumed that all subjects truthfully answered all questions about their
medical history.

2. It was also assumed that all subjects completed all the tasks necessary for the study
to the best of their ability.











Limitations

There were a few limitations in this research which are listed below.

1. Only the lower leg was treated.

2. Since all the subjects in this study were college students, it was difficult to
generalize the results of this study to other age groups.

3. Only healthy subjects, with respect to the lower leg, were used.

4. There may have been variability in the jumps of individual subjects between trials.


Significance of the Study

This study is important to the field of athletic training because it may have an effect

on current practices. Presently, the accepted practice is to place an injured athlete's limb

in ice immediately after the injury and then return the athlete to play once they are feeling

better and the athletic trainer has determined it is safe to do so. However, there is little

research to support this as a safe practice. Previous research on this practice has been

conducted with measures of static joint function, which does not simulate dynamic

activities like time to stabilization does. These researchers measured static balance as an

indicator of joint function instead of dynamic activities which more closely mimic sports

skills. The results of the present research may impact the future practices of athletic

trainers and others who care for injured athletes.














CHAPTER 2
REVIEW OF LITERATURE

The purpose of this chapter is to discuss the literature pertaining to the effects of

cryotherapy on ankle proprioception. This chapter contains a discussion of the following

topics: ankle anatomy, proprioception, and cryotherapy.

Ankle Anatomy

The ankle joint is essential to everyday function. It is a system of bones, ligaments,

tendons and muscles that allows movement of the feet. It also allows us to stand upright,

move our body through space, adapt to uneven ground, and absorb shock. The ankle

complex consists of a primary joint and an accessory joint. Four different bones meet

together to form these two articulations: the tibia, fibula, talus, and calcaneous.29 The

tibia, the main bone of the lower leg, is responsible for bearing body weight in this

region. The fibula, located lateral to the tibia, does not bear weight, but serves as a site

for muscle attachment. The talus is the bridge between the lower leg and the foot. It

rests on top of the calcaneous and sits between the distal ends of the tibia and fibula. The

calcaneous makes up the posterior portion of the foot and transmits weight from the talus

to the ground.29

The talocrural joint, considered the true ankle joint, is created by the distal portions

of the tibia and fibula and the superior portion of the talus. These bones articulate at

three different points within the joint: the articular facet of the tibia and the trochlea of

the talus, the medial malleolus of the tibia and the medial trochlea of the talus, and the

lateral malleolus of the fibula and the lateral trochlea of the talus.1 The bony alignment









creates a socket between the tibia and fibula in which the talus can fit termed the ankle

mortise.29 The talocrural joint is classified as a synovial hinge joint based on the

movements of plantarflexion and dorsiflexion it allows.29 The subtalar joint (STJ) is the

accessory joint that aids in ankle movement by allowing inversion and version and

stability through its medial, lateral, and posterior ligaments. The STJ is formed by the

articulation of the talus and the calcaneous. The STJ is a synovial joint that allows

inversion and versionn.9 The motions that occur at the ankle are actually a combination

of the movements allowed at the subtalar and talocrural joints. The motions allowed are

dorsiflexion and plantarflexion, inversion and version, and the rotational movements of

adduction and abduction. These motions occur in the sagittal, frontal, and transverse

planes, respectively.

There are several muscles in the lower leg that create movement at the ankle

complex. These muscles mainly act as dorsiflexors or plantarflexors, but they may also

act as investors or evertors. The dorsiflexors are located on the anterior portion of the

lower leg, and include the extensor hallucis longus, extensor digitorum longus, peroneous

tertius, and tibialis anterior.1 The muscles that plantarflex are located on the posterior

portion of the lower leg. These muscles include the gastrocnemius, soleus, tibialis

posterior, flexor digitorum longus, flexor hallucis longus, and peroneus longus.1 The

investors include the tibialis anterior and tibialis posterior, while the peroneous longus,

brevis, and tertius are responsible for versionn2

The ankle complex contains a set of ligaments that add to the stability of the joint.

These ligaments are located in three areas: the medial ankle, the lateral ankle, and









between the tibia and fibula. The ligaments add to the stability of the ankle by

reinforcing unstable areas created by the fibrous capsule.29

The medial ankle ligaments are collectively known as the deltoid ligament, which

consists of four parts: the tibiocalcaneal (TCL), the anterior tibiotalar (ATL), the

intermediate tibiotalar (ITL), and posterior tibiotalar ligaments (PTL). The TCL makes

up the superficial portion of the deltoid system and runs from the medial malleolus to the

medial aspect of the calcaneous. This ligament is not very thick, and therefore does not

withstand high forces during activity.15 The three tibiotalar ligaments run from the

medial malleolus to the talus. These ligaments are much stronger and thicker than the

tibiocalcaneal ligament and are able to withstand substantial force.15 The deltoid

ligament as a unit acts as the primary restraint to versionn.5

The lateral ankle ligaments create stability at the ankle complex by minimizing

rotation. The lateral ankle ligaments include the anterior talofibular (ATF), the posterior

talofibular (PTF), calcaneofibular (CF), and lateral talocalcaneal ligaments (LTC). The

ATF is located on the anterior portion of the lateral ankle where it blends with the joint

capsule. The ATF specifically runs from the anterior aspect of the fibula, near the

articular cartilage of the lateral malleolus, to the neck of the talus.3 In addition to this

anterior band of the ATF, it is not uncommon to see a distinct inferior band in some

people. The ATF is taut during plantarflexion and limits talar tilt, especially inversion.3'15

The PTF, which blends with the joint capsule and runs from the medial portion of the

lateral malleolus to the posterior talus, reduces talar tilt when the ankle is dorsiflexed.15

The calcaneofibular ligament originates at the anterior aspect of the distal fibula and

inserts on the calcaneous.3 Because of its location, the CF covers both the talocrural and









subtalarjoints. Therefore, it is designed so as not to restrict motion at either the

talocrural or subtalarjoint.15 The CF has an important function in dorsiflexion where it is

most taut and best able to resist talar tilt, especially inversion. The structure of the LTC

depends on the individual. Most often, the LTC covers the subtalarjoint and is similar in

location to the calcaneofibular ligament. The LTC acts as a back up to the CF.

Collectively, the lateral ankle ligaments are important for keeping the ankle joint stable

during inversion movements.15

The ligaments located between the tibia and fibula are the anterior inferior and

posterior inferior tibiofibular ligaments and the interosseous ligament. These ligaments

act to prevent widening of the ankle mortise in order to maintain stability of the talocrural

joint. The interosseous ligament is the main connection between the tibia and the fibula.

The posterior inferior tibiofibular ligament holds the malleoli of the tibia and fibula

together.29

The neurovascular supply of the ankle and foot includes the tibial, deep peroneal,

and superficial peroneal nerves. The muscles of the anterior compartment (dorsiflexors)

are innervated by the deep peroneal nerve, while the tibial and superficial peroneal nerves

supply the muscles of the posterior and lateral compartments respectively.34 The anterior

tibial, posterior tibial, and peroneal arteries, which branch off the femoral artery, give the

ankle joint its blood supply.

Proprioception

Proprioception can be defined as the awareness of joint position as sensed by the

central nervous system.24 Proprioception is essential to joint function, as it allows a

person to know how and where a body part is moving in space. This information allows

the central nervous system to make adjustments in joint position consciously or









subconsciously.30 The three systems that relay proprioceptive information are the

somatosensory, vestibular, and visual systems.30 The visual system processes stimuli we

receive with our eyes, while the vestibular system receives information from the

semicircular canals of the ear.24 The somatosensory system receives stimuli from

mechanoreceptors in the periphery of the body. Mechanoreceptors are specialized

receptors throughout the body that convert a physical stimulus into a neurological signal.

These signals are then sent to the somatosensory system, which signals a response to joint

position and movement.21 The central nervous system is able to compare the actual to the

intended movement and correct any discrepancies.21 Mechanoreceptors, found in the

skin, muscles, joints, tendons, and ligaments, are able to send information about pain,

pressure, and joint movement, even without visual input.12 The ability to maintain

standing balance on one or two legs depends on the integrity of the visual, vestibular, and

nervous systems.17

There are two different systems for classifying these mechanoreceptors, or

proprioceptors. The first system classifies a receptor as either quick adapting (QA) or

slow adapting (SA). Quick adapting receptors decrease the rate at which they fire very

quickly after being presented with a stimulus.24 An example of a QA receptor is a

Pacinian corpusle, which senses pressure. Quick adapting receptors help in sensing joint

motion because they are able to detect even minimal changes in joint position. Slow

adapting receptors continue to fire at the same rate in response to continuous stimuli.24

An example of an SA receptor is a Golgi tendon organ. Golgi tendon organs protect the

muscle and tendon from excessive tension. Golgi tendon organs are large, fusiform

shaped, and stimulated at the extreme angles of joint displacement.22 Slow adapting









receptors also play a role in sensation of joint position because they are maximally

stimulated at specific joint angles.

Mechanoreceptors can also be classified as Type I, II, III, or IV.28 Type I receptors

are located in ligaments in low numbers and are spherical shaped. It is thought that these

receptors are important in providing postural awareness information.28 Type I receptors

can also be classified as SA receptors. Type II receptors have a thick capsule and are

cone shaped. These are also located in ligaments and their primary function is

proprioception.28 Type II receptors were the most common mechanoreceptor type found

in ankle ligaments and can also be classified as QA receptors. Type III

mechanoreceptors are fusiform in shape and are also found in high numbers in ankle

ligaments. These receptors provide information when the joint is at the extremes of

movement. These mechanoreceptors can also be classified as SA receptors. Finally, type

IV receptors are free nerve endings and are found in the ankle joint capsule and at the end

of the tibial, sural, and deep peroneal nerves.28

The information received by the three systems is processed by the spinal cord,

brain stem, and higher brain center.24 The spinal cord is responsible for dynamic muscle

stabilization and reflex responses. The brain stem is responsible for maintaining posture

and balance and coordinating information from all three areas. The higher brain centers

program musculoskeletal motion and provide for conscious and unconscious awareness

of joint position and the ability to stabilize joints.23

Measurement of Proprioception

Methods to measure proprioception include joint position sense, muscle latency,

postural sway, the modified Rhomberg test, stabilometry, and time to stabilization.









Threshold to Detection of Passive Motion

A subject's ability to sense joint motion can be measured rating the subject's ability

to sense passive joint movement while blindfolded. This passive test primarily assesses

proprioception of the joint receptors, as receptors within the muscle are not active.24

Joint Position Sense

Joint position sense incorporates both joint and muscle receptors by having a

subject replicate active and passive joint angles as accurately as possible in the absence of

visual stimuli.24

Muscle Latency

Another dynamic measure of proprioception includes using EMG muscle latency

times to quantify reflex muscle stabilization around a particular joint in response to an

involuntary perturbation. The electromyograph reading from this test will provide

information about the muscles' ability to fire in the correct sequence.7'24 Some

researchers support the idea that the reflex time of a muscle is an important indicator for

determining if the joint is able to maintain dynamic stability.8 EMG signals may also

indicate the number of motor units that are being recruited within a particular muscle."

EMG is commonly used to measure muscle activation, force produced by the muscle, and

fatigue that occurs within the muscle.7 Variables computed from surface EMG signals

include average rectified and root mean square values, and mean and median spectral

frequencies.7'1 The root mean square and average rectified values are used to measure

signal amplitude.7 In order to collect the EMG data, bipolar electrodes are placed on the

skin over the muscle bellies at least 2 centimeters away from the nearest electrode.2 The

electrodes should also be placed on the skin so that they are perpendicularly intersecting

with the orientation of the muscle fibers they are measuring.7 In order to receive









meaningful data from the EMG electrodes, they must be stationary, and not subject to

movement artifacts.7

Postural Stability

Additional measures of proprioception include: postural sway, the modified

Rhomberg test, and stabilometry. These three measures assess the combined function of

the peripheral, vestibular, and visual systems in neuromuscular control. Postural sway

and stabilometry quantify equilibrium. The instruments used to measure postural sway

and stabilometry are able to assess proprioception fairly accurately.24 Time to

stabilization measures how long it takes a subject to stabilize their lower limb after a step

or hop down with a single leg onto a force plate.4 Research using both healthy and

anterior cruciate ligament deficient subjects indicated that this measure is reliable for

determining functional status.4

A disruption in proprioception following soft tissue injury can be attributed to a

number of factors: joint trauma, damaged nervous tissue, edema, and muscle weakness.

Injury to a joint will cause a disruption of sensory nerves, joint capsule, and muscles that

all play a role in proprioception.21,23,30 DeCarlo and Talbot suggested that partial articular

deafferentiation occurs in response to joint trauma secondary to the tearing of nerve

fibers that possess less tensile strength than collagen present in ligaments.6 Ruptured

nerve fibers will result in decreased sensory input from peripheral receptors potentially

leading to faulty ankle joint positioning and an increased chance for reinjury.12 Any

damage to the muscle spindles, Golgi tendon organs, or joint receptors will impact

function and dynamic joint stability.21,23 Increased pressure at the joint as a result of

swelling further impedes feedback sent to the central nervous system because of the

increased pressure negatively affecting proprioception.21 A final possible contributor to









proprioceptive loss is muscle weakness due to disuse. Research indicates that evertor

strength can remain below normal up to one year after ankle injury.13

A decreased ability to maintain balance on one leg, one measure of proprioception,

has been found after an ankle injury.13 If a person displays poor postural control during a

static balance task, they may have even more trouble with balance when they are

engaging in dynamic activity.13 This decreased proprioception can lead to further injury

when a person returns to normal activity.13 This chance for reinjury may be because a

person with a proprioceptive deficit is unable to control their body over a narrow base of

support during high-speed activity.13 Because of this instability, it is important that

balance training be a part of a patient's rehabilitation program. Proprioception training

will help the patient in maintaining balance, posture, and joint position sense.24

Proprioception Training

Proprioception programs should be used to promote dynamic joint and functional

stability because proprioception can be improved with training.24 The proprioceptive

program should include exercises that use both conscious and unconscious control of

proprioception. Consciously mediated exercises should be performed at slower speeds to

train specific muscles to stabilize the joint. Unconsciously mediated exercises should be

performed to train the muscles to respond quickly to sudden changes in position that

could cause injury.21 One legged stands are useful in improving proprioception after

injury. Standing on one leg improves postural steadiness and pronator strength in a

program as short as ten weeks.13 It has been reported that patients who did rocker board

exercises during rehabilitation after ankle injury demonstrated lower rates of reinjury.13

The study indicated that a program of eight weeks provided the maximum amount of

ankle stability. In a study by Goldie et al.13 the results suggested that those who did









balance exercises after an ankle sprain had better postural control than those who did not

do balance exercises as part of their rehabilitation. The exercises in a proprioception

program should emphasize closed kinetic chain activities in order to more closely

simulate sports activities and retrain disrupted proprioceptive pathways.21 The

proprioceptive program should finish with sports specific activities in order to enhance

the retrained proprioceptive pathways. Adequate proprioception should be required of all

athletes returning to participation.24

Cryotherapy

Cryotherapy is defined as the application of cold to living tissues that results in a

lower temperature.19 The practice of applying cold to tissue is common in the treatment

of both acute and chronic injuries. Ice has been used as a treatment for thousands of

years. Hippocrates used ice to decrease pain, decrease swelling, and produce

numbness.25'27 Since then, ice has been used in the medical world because of its

beneficial effects of healing and anesthesia. As a result, a great deal of research has been

conducted to document the physiological effects of ice.

Cold can have effects on the body as a whole. These effects include overall

decreased body temperature, general vasoconstriction in response to the cooling of the

hypothalamus, decreased respiratory and heart rates, shivering, and increased muscle

tone.35 However, the application of cold is used primarily for its local tissue effects. One

of the well documented effects of ice application, pain relief, occurs for a number of

reasons. Ice has the ability to relieve muscle tension and disrupt the pain spasm

cycle.16'25 Ice also increases the firing threshold of the peripheral nerve endings.25'38

Research has indicated that nerve conduction is blocked at deep temperatures of 50

degrees Fahrenheit and sensory nerve fibers are the first to be blocked.38 Furthermore,









ice reduces pain due to the counter irritant effect, whereby ice blocks painful stimuli

associated with the injury.25 Another effect of ice application is the reduction of muscle

spasm. Muscle tension is relieved and nerve conduction is decreased when tissue

temperature is lowered.16,25 Ice contributes to tissue and joint stiffness because decreased

temperatures increase collagen stiffness.19 Ice also causes decreased dexterity because

cold increases tissue viscosity.25,27 Recently, it has been reported that cryotherapy

decreases muscle velocity and power, thereby reducing muscle performance.37

Stimulation from the autonomic nervous system in response to tissue cooling causes

vasoconstriction when ice is applied.39 This vasoconstriction leads to decreased edema

and hemorrhage in the area.18 Edema also decreases because less histamine and similar

substances are released in response to tissue damage.16 Cold also decreases blood flow

and inflammation by decreasing cellular metabolism. This is an important effect of cold,

because decreased cellular metabolism will reduce secondary hypoxic injury.18 All

together, the effects of cold aim to decrease edema and inflammation in order to decrease

the amount of secondary hypoxic injury.

There are several ways to apply cryotherapy to tissues. These methods are able to

cool tissues by conduction, direct contact with the surface, or convection, movement of

air or water over the surface to be cooled. The most common methods of cold

application include ice bags, manufactured ice packs, ice massage, cold whirlpool, cold

sprays, and ice immersion. Ice bags consist of putting crushed or cubed ice in plastic

bags to place on the injury site. These are both practical and economical. Research

involving various methods of cooling suggests that ice bags were the most effective in

decreasing tissue temperature in the adult canine thigh over a 60 minute ice application.26









Commercial ice packs contain a gel that cools when placed in a freezer or special ice

pack unit. They must be placed on a towel and never directly on the skin for cooling.35

A potential drawback to manufactured ice packs is the cost. Ice massage involves ice

cups applied to a specific area of the body. This involves the direct application of the ice

to the skin and is useful for icing a localized area of pain.35 Cold whirlpools are used for

larger areas of pain such as knees or elbows. The whirlpool is filled with water

maintained at a temperature of 13-16C. The whirlpool is filled high enough to cover the

entire affected area. Range of motion exercises can be performed when a patient is in the

cold whirlpool. Ice immersion is a cryotherapy method similar to cold whirlpool. A

bucket or cooler is filled with ice and water and the injured body part is placed in the

bucket. Ice immersion is indicated in the treatment of joint restrictions, muscle spasms,

and in cases of acute pain.38 Unlike the cold whirlpool, the water does not move over the

joint in order to lower tissue temperature through convection. Cold sprays are used on

the field and in the clinic to facilitate stretching exercises, also termed "cryostretch."

Cold sprays are able to lower skin temperature rapidly by evaporation.35

Length of treatment is also a factor in the application of cryotherapy. Different

amounts of time are used for different cryotherapy methods and with different patient

goals in mind. When selecting treatment times, it is important to know that it takes ten

minutes to cool superficial tissues and twenty to thirty minutes to cool deep tissues.25

Cutaneous hypoalgesia can be achieved in as little as two to five minutes, but ice is left

on longer to achieve cooling benefits in muscle and joint tissue.25 Generally, a cold

application method is left on until the area is numb, but care must also be given not to

leave the cold on too long. Ice bags, cold packs, and cold whirlpool are generally used









for twenty minutes because these methods take longer to cool the tissues.25'37 Faster

cooling methods, such as ice immersion and ice massage, are only applied for seven to

ten minutes.35 Cryotherapy induced analgesia can last anywhere from thirty minutes to

three hours.38

Cryotherapy is indicated mainly in two situations: the acute phase of injury or in

conjunction with rehabilitation.25 Ice is applied in the first twenty four to thirty six hours

after an injury in order to decrease inflammation and edema. By reducing inflammation

and edema, the tissue is allowed to heal faster. Cooling the tissues reduces the initial

inflammatory response to trauma and removes the factors that hinder wound healing,

allowing normal tissue repair.14'27 This process will decrease the amount of secondary

injury that may occur. Ice also aids in decreasing pain that is present in the initial injury

phase. Ice, in conjunction with rest, elevation, and compression, provides the best

environment for healing. Ice can also be used in conjunction with rehabilitation. Ice may

be applied before rehabilitation to reduce pain and spasm so the patient is able to perform

their exercises. The use of ice before rehabilitation exercises also allows a patient to

achieve an increased range of motion during activity.14 Ice application after exercise is

also beneficial because it reduces pain and inflammation that are present once the patient

has completed their rehabilitation program.18 Cold application after exercise reduces

vasodilatation and blood flow to prevent recurrent edema.14

There are some occasions when ice should absolutely not be used to treat any

injury. These occasions include when the patient has severe cold allergy, Raynaud's

phenomenon, rheumatoid conditions, cryoglobunemia, paroxysmal cold hemoglobinuria,

and pheochromocytoma.25'32 Even though cold application may be indicated in other









situations, one should always be careful and monitor a patient who is undergoing cold

treatment because there is always the risk of frostbite and tissue damage if the cold is left

on the skin too long.

Ice or Injection Induced Anesthesia and Ankle Proprioception

A number of researchers have used either cryotherapy or injection induced

anesthesia to examine the effects of altered nerve function on proprioception.6'10'12'20'36

The majority of the research indicates that ice or anesthesia have no effect on

proprioception.10,12,20,36 However, one study suggested proprioception may be improved

-6
with anesthesia.6

DeCarlo and Talbot6 investigated a subject's ability to balance on one leg after they

anesthetized the anterior talofibular ligament with Xylocaine. It was hypothesized that

anesthesia of the anterior talofibular ligament would decrease the amount of

proprioceptive input from the ankle to the central nervous system. Proprioception was

then measured on a multiaxial balance evaluator. The results indicated that balance

ability was improved after the ligament was anesthetized. The increase in balance ability

was unexpected and may have been due to the learning effect.

There have been several studies conducted that fail to report changes in

proprioception after a joint is iced or anesthetized. Feuerbach et al.12 anesthetized one or

two ankle ligaments in healthy subjects and found no change in the subject's ability to

match reference ankle joint positions while blindfolded. The authors concluded that the

ligament receptors must play a small role in proprioception, and that receptors in the skin

and muscle are adequate to accurately match reference angles. Konradsen et al.20

observed that active joint position sense, postural sway, and peroneal reaction time were

unaffected by anesthesia of the ankle and foot. However, they did find that anesthesia









significantly impaired passive joint position sense. Thieme et al.36 reported no change in

proprioception in a study in which the knee was iced and the subject's ability to actively

reproduce knee joint angles was tested. No significant differences were reported between

the ice and control conditions. Agility was unchanged after ice immersion of the ankle in

a study conducted by Evans et al.10 in 1995. They measured agility by testing the carioca

maneuver, the cocontraction test, and the shuttle run. The subjects performed similarly

with or without ice immersion. All of these studies support the idea that proprioception is

not affected by ice or anesthesia of the ankle, even though it has been reported that ice

and anesthesia decrease the rate at which a neuron fires.25

Elley's9 study in 1994 produced results that made it difficult to draw conclusions

about how ice application affects ankle proprioception. The study involved the

application of an ice pack to the ankle followed by a measurement of postural sway

during a one legged stance on a force plate. The results indicated that almost 60% of the

subjects demonstrated a poorer ability to balance and almost 40% significantly improved.

The author called for replication of this research in order to establish whether or not icing

the ankle has a significant effect on postural sway.

The present study attempted to add to the current body of knowledge on the topic

of ice application and ankle proprioception, specifically dynamic stability. The study was

different from the previous studies a force plate and the measure of time to stabilization

was used to measure dynamic stability. This method is becoming common in the

literature at this time. Another difference is that cold immersion was used to decrease the

temperature of the tissue in and around the ankle joint. This is not the usual method of

cryotherapy used in the literature, and it may be helpful to report what effects this method






19


of cold application has on dynamic stability. The goal of the study was to investigate if

ice immersion detrimentally affects dynamic stability at the ankle as measured by time to

stabilization.














CHAPTER 3
METHODS

Subjects

Twenty healthy male and female volunteers from the general university population

were recruited to participate in this investigation. Subjects were excluded from

participation if they have previously suffered an injury to the lower extremity, head, or

spine that might influence the neuromuscular response characteristics of the ankle.

Subjects were also excluded if they suffered from or have suffered from any of the

contraindications for cryotherapy, which include areas of decreased sensation, areas of

decreased circulation, Raynaud's Syndrome, previous cold allergy, or previous cold

injury. Additional exclusionary criteria included anyone currently suffering an illness,

anyone taking medications that could influence body equilibrium, and anyone regularly

undergoing cold treatments. Before participating in the investigation, each subject read a

description of the study and signed an informed consent form approved by the university

Institutional Review Board.

Instrumentation

Vertec Vertical Jump Stand

Maximum vertical jump height was assessed using a VertecTM (Sports Imports,

Columbus, OH) vertical jump stand. The Vertec is a telescoping upright stand with

plastic vanes spaced 1.27 cm apart. The maximum vertical jump height was determined

by subtracting standing reach height from the height of the highest vane touched when

jumping.









Force Plate

Time to stabilization (TTS) and ground reaction forces (GRF) were measured at a

frequency of 1000-Hz using a triaxial force plate (Bertec Corporation, Columbus, OH).

The force plate data went through an analogue to digital conversion and was stored on a

PC-type computer using the DATAPAC 2000 (Run Technologies, Laguna Hills, CA)

analog data acquisition, processing, and analysis system.

Electromyography (EMG)

A Myopac EMG system (Run Technologies, Laguna Hills, CA) was used to collect

the raw EMG signal. The unit specifications for the EMG included an amplifier gain of

1-mV/V, a frequency bandwidth of 10-1000 Hz, CMRR 110 dB, input resistance of 1

MQ, and a sampling rate of 1000 Hz. Following sampling, the EMG data was

transformed from analogue to digital conversion and was stored on a PC-type computer

using the DATAPAC 2000 (Run Technologies, Laguna Hills, CA) analog data

acquisition, processing, and analysis system.

Measurements

Vertical Jump Height

Maximum vertical jump height was determined using the Vertec vertical jump

stand. Subjects were instructed to stand on their toes next to the Vertec and reach as high

as possible. The standing reach height was determined from the height of the highest

vane the subject was able to touch. Each subject then jumped off both legs as high as

possible while reaching up to touch the vanes. This was performed three times and the

height of the highest vane touched was recorded. Maximum vertical jump was

determined as the difference between the maximum jump height and the standing reach

height.









Time to Stabilization

Each subject performed three stabilization maneuvers during a test session,

requiring them to perform a two-legged jump at 50% of their maximum jump height to

the center of a force plate placed 70-cm from the starting position. All the jumping

maneuvers were done with the subject in athletic shoes. To control for and standardize

this height, the Vertec jump stand was set at the target height and placed between the

subject and the force plate. The subject was instructed to jump the minimum height

necessary to reach the Vertec. The subjects were also instructed to land on one leg with

their hands on their hips and stabilize quickly while maintaining balance with a single leg

stance for 20-sec. Each subject was allowed three practice trials to familiarize

themselves with the jumping, landing, and stabilizing procedure before the data was

collected. The subjects then underwent three pre-treatment test trials. The time to

stabilization (TTS) was determined as the time needed to reduce the variation of a given

ground reaction force (GRF) component to the range of variation of a GRF component in

a stabilized position. The range of variation of a GRF component in a stabilized position

was determined in a 5-sec window at the end of the 20-sec data collection period. The

same procedure was used to determine TTS in the frontal and sagittal planes. After the

subject received the treatment condition, they immediately participated in three post-

treatment test trials. They rested for a period of five minutes and another three trials were

done in the same manner.

Muscle Activity

Anticipatory and reactive muscle activity were assessed before and immediately

after the jump landing. Each subject first had the skin over the tibialis anterior (TA) and

peroneus longus (PL) muscles prepared by shaving and cleaning with isopropyl alcohol









to reduce skin impedance. Bipolar 1-mm x 10-mm Ag/AgCl surface electrodes with an

interdetection surface distance of 1.5-cm were then placed in parallel with the muscle

fibers of the TA and PL muscles at a midpoint between the motor point and the

musculotendinous junction. All electrode placements were confirmed with manual

muscle testing and checked for cross-talk with real time oscilloscope displays.

The acquired raw signals were digitally processed using, a symmetric root mean

square (RMS) algorithm, with a 10-msec time constant. Anticipatory muscle activity was

determined during the 50-msec time period immediately before foot contact on the force

plate. The muscle reactive activity was measured during the 100-msec time period

immediately following foot contact on the force plate. The mean muscle activity of both

the tibialis anterior and peroneous longus during each phase of the three jumps was

calculated and the mean of the three jumps at each testing time pretestt vs. posttest 1 vs.

posttest 2) was recorded. All EMG data was reported relative to the muscle activity

during a maximum voluntary isometric contraction (MVIC), which was performed before

the jump trials using standard manual muscle testing protocols. Each muscle was tested

by having the subject sitting with the lower leg hanging off the table and performing the

primary action of the muscle against stationary resistance. The tibialis anterior was tested

in a dorsiflexed and slightly inverted position against resistance from the researcher, and

the peroneous longus was tested in an everted position against resistance. The electrodes

had been placed on the muscles to measure the activity during this testing using the

Myopac EMG system. Each muscle was tested against resistance for 5 seconds and this

data was collected using the Myopac and DATAPAC 2000.









Treatment

Each subject took part in both a cold immersion treatment and a control condition.

The cold immersion treatment consisted of the subject sitting and placing their lower leg

in a bucket of water and ice up to the level of the tibial tuberosity. The water was

maintained between 13 and 160C and the subject remained in the treatment position for

twenty minutes. During the control condition, each subject sat in the same position used

during the cold immersion treatment for 20 minutes, however, the bucket was empty and

no treatment was applied. The subject had the weight of their leg supported during the

control condition to control for any changes in blood flow that might occur while the leg

was hanging down off the end of the chair since the water would support the weight of

the leg in the treatment condition. Each subject had the height of the bucket adjusted so

that their foot rested comfortably on the floor of the bucket whether or not there was

water in the bucket.

Procedures

Each subject reported to the Biomechanics Research Laboratory on two separate

occasions. Upon arrival on the first occasion, each subject completed a medical history

questionnaire that included questions regarding recent or recurrent leg, head, or spine

injuries, stability problems, current illness, medications, and cold contraindications.

These questions determined if the volunteer was eligible to safely participate in the

investigation.

Each subject was tested under two conditions; control and cold immersion

treatment. The order of these treatments was randomized and counterbalanced with a

minimum of one week separating the two conditions. To begin the session, the subject

had his or her maximum vertical jump height determined. The subject was then prepared









for electrode placement and had an MVIC taken according to standard manual muscle

testing procedures. The researcher checked for correct placement of the surface

electrodes by performing manual muscle tests on the tibialis anterior and peroneous

longus muscles. The tests were performed with the subjects sitting with their lower leg

hanging off the table. The researcher then checked electrode placement by resisting the

primary motion of each muscle. The electrodes on TA were checked by resisting active

dorsiflexion, and the electrodes on PL were checked by resisting active version. They

were then assessed for their TTS after a single leg landing from a jump equivalent to 50%

of their maximum jump height. The subject was asked to perform the jump a total of

three times. In addition to the measurement of time to stabilization, anticipatory and

reactive muscle activity was recorded using surface EMG. Immediately following the

three jumping and landing trials, the subject completed one of the two treatment

conditions. Once the treatment time was completed, each subject was once again tested

for TTS and EMG activity using a procedure identical to the one used during pre-testing.

The subject was asked to perform three jumping and landing trials immediately after the

treatment and three more five minutes later. All subjects were asked to return to the lab

on a second occasion, at which time an identical protocol was completed and they

received the remaining treatment condition. There was a minimum of seven days

between the two treatment conditions. The subjects were encouraged to use the same

means of transportation both times they came in to participate in testing.

Study Design and Data Analysis

A one pretest two posttest within subjects design was used for this investigation

and a 3x2 repeated measures ANOVA was used to analyze the data. The independent

variables were testing time (pre-treatment vs. post treatment I vs. post treatment II) and






26


condition (treatment vs. control). The dependent variables were GRF TTS in the vertical,

anterior/ posterior, and medial/lateral directions, as well as mean preparatory and reactive

activity levels (as a percent of the MVIC) of the tibials anterior and peroneous longus

muscles. Significant interactions were further analyzed using the Tukey Honestly

Significant Difference (HSD) post hoc testing procedure. For all statistical analyses the

level of significance was set at p < .05.














CHAPTER 4
RESULTS

The purpose of this study was to investigate the effects of an ice immersion

treatment on dynamic stability following a jump landing. Using force plate data, we

assessed the ability of healthy subjects to stabilize their center of gravity after landing

from a height equivalent to fifty percent of their maximum vertical jump height. We also

used EMG to assess the preparatory and reactive muscle activity of the peroneus longus

and tibialis anterior immediately before and immediately following the landing.

Seven 3x2 ANOVAs were used to analyze the normalized EMG data from the

peroneus longus and tibialis anterior before and after landing and time to stabilization.

The independent variables were treatment (ice immersion vs control) and testing time

pretestt vs. posttest 1 vs. posttest 2).

Subject Demographics

Twenty healthy subjects without recent or chronic history of lower extremity

injury, allergies to cold, circulation deficiencies, conditions or medications that would

affect balance and regular cold treatments volunteered to participate in this study.

Seventeen of the subjects were female and three were male. They had a mean age of 20.8

1.01 years, mean height of 168.7 8.9 cm, and a mean mass of 67.8 13.6 kg. Sixteen

subjects chose the right leg as their landing leg, and four of them chose the left. The

average height that each subject jumped (50% of the maximum vertical jump) was 17.6

7.1 cm. The average target height that each of the subjects reached for in performing

the jumping and landing trials was 255.1 17.2 cm.









Normalized EMG Activity

Tibialis Anterior

Normalized preparatory EMG activity of the tibialis anterior is presented in Table

1. No significant treatment [F(1,19)=.968, p=.338] or time [F(1,19)=.307, p=.586] main

effects were observed. However, a significant treatment time interaction [F(1,19)=7.34,

p=.014] was observed for the tibialis anterior activity immediately before the landing.

Table 1. Normalized preparatory EMG activity of the tibialis anterior (% of MVIC)

Treatment Pre-test Post-test 1 Post-test 2
Ice Immersion 43.7 4.5 50.8 5.3t 48.5 4.9
Control 49.4 5.6* 39.4 4.6 42.4 4.3
*Significantly greater than control condition post-test 1 (p<.05)
tSignificantly greater than control condition post-test 1 (p<.05)

Normalized reactive EMG activity of the tibialis anterior is presented in Table 2. A

significant treatment main effect [F(1,19)= 11.04, p=.004] was observed for the tibialis

anterior, as the EMG activity during the ice immersion (92.2 6.4%) session was

significantly greater than during the control (71.9 5.5%) session. However, neither the

time main effect nor the treatment x time interaction was significant.

Table 2. Normalized reactive EMG activity of tibialis anterior (% of MVIC)
Treatment Pre-test Post-test 1 Post-test 2
Ice Immersion 83.6 7.1 97.9 7.7 95.3 7.9
Control 72.0 6.3 70.7 6.3 73.0 5.5

Peroneous Longus

Normalized preparatory EMG activity of the peroneous longus muscle is presented

in Table 3. No significant treatment [F(1,19)=.679, p=.420] or time [F(1, 19)=.335,









p=.569] main effects were observed. A significant treatment time interaction [F(1,

19)=7.377, p=.014] was observed for the peroneous longus immediately before landing.

Table 3. Normalized preparatory EMG activity of peroneous longus (% of MVIC)
Treatment Pre-test Post-test 1 Post-test 2
Ice Immersion 113.8 +12.0 124.6 13.8t 125.5 13.4
Control 122.9 14.1* 105.7 13.6 109.3 12.8
*Significantly greater than control condition post-test 1 (p<.05)
tSignificantly greater than control condition post-test 1 (p<.05)
Significantly greater than control condition post-test 1 (p<.05)

Normalized reactive EMG activity for the peroneous longus is presented in Table 4.

No significant main effects for treatment [F(1,19)=1.958, p=.178] or time [F(1,19)=.855,

p=.367] were observed, and no significant interaction [F(1,19)=2.517, p=. 129] between

time and treatment was observed.

Table 4. Normalized reactive EMG activity of peroneous longus (% of MVIC)
Treatment Pre-test Post-test 1 Post-test 2
Ice Immersion 142.2 15.2 163.2 12.5 145.1 17.4
Control 135.7 15.9 127.4 18.5 129.7 15.9

Time to Stabilization

The amount of time that it took each subject to stabilize the ground reaction forces

after landing within a given variation during a quiet stance was measured in milliseconds.

This data was collected for medial/lateral and anterior/posterior ground reaction forces.

Vertical Ground Reaction Force Time to Stabilization

The time in milliseconds for each subject to stabilize within 5% of their body

weight is reported in Table 5. A significant main effect was observed for time [F(1,19),

p=.014], as the mean TTS were significantly different between the pretest (1639.5 49.1

ms), post-test 1 (1756.7 58.6 ms), and post-test 2 (1494.8 62.1 ms). No significant









main effect for treatment [F(1,19)=.006, p=.940] or significant interaction [F(1,19)=.257,

p=.618] between treatment and time were observed for vertical ground reaction force

time to stabilization.

Table 5. Vertical ground reaction force time to stabilization (in msec)

Treatment Pre-test Post-test 1 Post-test 2
Ice Immersion 1644.48 61.51 1730.67 71.46 1507.94 61.22
Control 1634.47 77.26 1782.75 87.98 1481.64 82.66

Medial/Lateral Ground Reaction Force Time to Stabilization

The time in milliseconds for each subject to sequential average to stabilize within

plus or minus .25 standard deviations of the mean of the 3-sec collection period is

reported in Table 6. No significant main effects for time [F(1,19)=.312, p=.583] or

treatment [F(1,19)=.809, p=.380] were observed for medial/lateral ground reaction force

time to stabilization and no significant interaction [F(1,19)=.946, p=.343] between

treatment and time was observed either.

Table 6. Medial/lateral ground reaction force time to stabilization (in msec)

Treatment Pre-test Post-test 1 Post-test 2
Ice Immersion 1568.32 92.24 1443.70 67.71 1455.73 70.53
Control 1511.45 65.78 1572.65 73.56 1542.96 85.02

Anterior/Posterior Ground Reaction Force Time to Stabilization

The time to milliseconds for each subject to stabilize to within plus or minus .25

standard deviations is reported in Table 7. No significant main effects for treatment

[F(1,19)=3.234, p=.088] or time [F(1,19)=.879, p=.360] were observed for anterior/

posterior GRF TTS. There was no significant interaction observed [F(1,19)=.211,

p=.651] between treatment and time.






31


Table 7. Anterior/posterior ground reaction force time to stabilization (in msec)

Treatment Pre-test Post-test 1 Post-test 2

Ice Immersion 1470.60 101.13 1493.72 115.01 1373.94 113.74

Control 1377.00 81.74 1292.88 108.59 1261.51 84.50














CHAPTER 5
DISCUSSION

The purpose of this study was to determine the effects of an ice immersion

treatment on dynamic stability during a jumping and landing task. Using a triaxial force

plate, the amount of time to stabilize the vertical, anterior/posterior, and medial/lateral

ground reaction forces following a jump landing were used as the measures of dynamic

stability. Preparatory and reactive activity of the tibialis anterior and peroneous longus

muscles were also assessed using EMG analyses immediately before and immediately

following the landing.

Muscle Activity

We hypothesized that the mean activity level of both the tibialis anterior and

peroneous longus would be significantly higher following the immersion treatment as

compared to the control condition. This was partially supported, as the preparatory

activity level of both the tibialis anterior and peroneous longus was greater at the first

posttest measurement following ice immersion as compared to the first posttest

measurement during the control condition. The graphs below depict muscle activity in

the preparatory phase for both the tibialis anterior and peroneous longus. The mean

muscle activity during the 50 msec time frame was recorded and the mean of the 3 trials

for each subject was reported and analyzed.


























EIce Immersion
SControl


Pretest


Postest 1
Testing Time


Figure 1. Tibialis Anterior Preparatory Activity
*Significantly higher muscle activity as compared to control co


160


140


120


100


Prestest


Postest 2


ndition posttest 1
















E Ice Immersion
SControl


Posttest 1 Posttest 2
Testing Time


Figure 2. Peroneous Longus Preparatory Activity
*Significantly higher muscle activity as compared to control condition posttest 1










This finding is in agreement with previous research involving EMG activity of the

gastrocnemius and soleus muscles.33 In that study, it was reported that a 60-min cold

whirlpool treatment resulted in a 45% increase in gastrocnemius activity and a 22%

increase in soleus activity.33 The muscle activity was measured during a drop jump

exercise. In the present investigation we observed a 19% increase in tibialis anterior

activity and a 27% increase in peroneous longus activity immediately following the

immersion treatment. These changes in muscle activity are compared in the graph below.


Increase in Muscle Activity after Cryotherapy

50
Gastrocnemius
45

40

35



25 Soleus
TA
20 -

u 15

S10

5

0
Oksa Present Study
Study

Figure 3. Increase in Muscle Activity after Cryotherapy

Similar observations were made when examining the reactive muscle activity of the

tibialis anterior. The reactive activity was higher following the immersion treatment

when compared to post testing during the control condition. No differences were

observed for the peroneus longus.












































Pretest


Posttest 1 Posttest 2
Testing Time


Tibialis Anterior Reactive Activity


LT


Pretest Posttest 1
Testing Time


Figure 5. Peroneous Longus Reactive Activity


SIce Immersion
SControl


40




20




0





Figure 4.


200 -


180


160


140


120


S100


80


60


40


20


0


SIce Immersion
SControl


Posttest 2









It must be noted that the activity of the tibialis anterior prior to the treatment was

also greater when compared to the same measurement time during the control condition.

This was unexpected and difficult to explain. The order of treatment was randomly

assigned and counter balanced. Thus, a learning or practice effect would not provide an

explanation. The change in activity level may have been due to psychological factors.

The subject may have been expecting to perform worse on the jumping and landing task

because of their own expectations of the situation and the treatment they were about to

receive. Because of these expectations, the subject then worked harder to compensate for

the perceived increased difficulty of the task.

The higher post treatment activity levels observed in the preparatory phase for both

the tibialis anterior and peroneous longus may be due to the physiological changes cold

induces within the body, including the mechanoreceptors. Cryotherapy causes stiffness

as well as increased fluid viscosity, which may cause the muscles that move the ankle to

work harder against this resistance after cold immersion.10 The muscles may also be

working harder in order to make up for a lack of power that has been reported after

cryotherapy.10,33 It is also possible that the muscles were compensating for any deficits in

proprioception caused by the decrease in tissue temperature. Feuerbach et al.12 agreed

that mechanoreceptors in the skin, muscles, and other parts of the joint capsule were able

to compensate for the ligament receptors that were anesthetized in their study. They

reported that ligament anesthesia had no effect on a subject's ability to reproduce joint

positions. Another researcher hypothesized that different mechanoreceptors are activated

at different points within the range of motion.36 It is believed that the muscles play a

greater role in proprioceptive tasks at the midranges of joint motion.36 The jumping and









landing task involved in the current study focuses more on the midranges of motion. It

seems that muscular mechanoreceptors can compensate for a lack of activation of other

receptors when a subject performs proprioceptive tasks such as joint repositioning and

jumping and landing tasks.

Although we did not assess skin or intramuscular temperature, we feel confident

that our treatment did provide sufficient cooling. Temperature changes during and

following cryotherapy treatments have been well documented.27 In one study, 30-min of

ice immersion at a temperature of 100C lowered skin and intramuscular temperature 16.3

and 9.30C respectively.27 In another study, 20-min of ice immersion at a temperature of

100C lowered the intramuscular temperature 5.1 C and the subcutaneous temperature

13.80C.31 A comparison of these values is presented in Figure 2. It was surprising that

the mean activity level during the immersion condition at the second post-test was only

significantly greater than the control. There were significant differences in the

preparatory muscle activity of the peroneous longus. Muscle activity was slightly greater

in the other conditions, but not to the level of significance. This was most likely due to a

re-warming of the lower leg that occurred during the 5-min rest between the two post-

tests. Previous studies have reported re-warming rates of the lower leg after treatment in

a 100C whirlpool.31 Intramuscular temperature decreased 5.1 +1.80C following the 20-

min treatment. However, the temperature increased over a 5-min post treatment period

so that it was only .8 .40C lower than the pretreatment temperature. With respect to

subcutaneous temperature, the temperature had decreased 13.8 +3.0C following

treatment, but was only 2.6 .40C lower than pretreatment after the 5-min recovery

period. From this data it can be noted that there is a re-warming trend that occurs










immediately after the treatment is concluded. Therefore, if muscle activity were to

increase in response to temperature changes, it would be expected that the activity levels

would be higher immediately after treatment as compared to the 5-min post-treatment

when re-warming has occurred. Thus, after a 5-min recovery period the muscles are not

working as hard against stiffness and increased viscosity because the temperature has

returned to pre-treatment levels. This finding has significant clinical implications. If

stability is not hindered by cold application, then a clinician can be confident in asking an

athlete to perform sports specific skills after as little as 5-min of warm-up, as long as the

muscles are functioning properly.


Temperature Decrease after Cryotherapy


18

16

S14

O 12

10 -
Sa Subcutaneous Temperature





Study
8 Fig Intramuscular Temperature


I-
6-



2

0
Meeusen and Levens Myrer et al
Study

Figure 6: Temperature Decrease after Cryotherapy









It was also interesting to note that the changes in muscle activity were more

pronounced in the tibialis anterior as compared to the peroneous longus. This may

indicate that the tibialis anterior plays more of a role in the stabilization of the lower leg

just before and after landing than the peroneous longus muscle. The tibialis anterior is

important in creating dorsiflexion and acting to control plantarflexion, as well as assisting

with inversion.5 Results from a previous study investigating ankle brace use and muscle

activity suggest that the tibialis anterior may aid in maintaining the position of the foot

relative to the ground at initial contact.5 This may explain why the immersion treatment

had a greater effect on the tibialis anterior as compared to the peroneous longus. It is also

of note that the significant findings with respect to muscle activity were found in the

preparatory phase instead of the reactive phase. This may be a compensatory effect from

the lack of sensation and the subjects feeling unsure of the lower leg's landing ability.

It also must be noted that the control condition pretest mean was significantly

higher than the control condition post-test 1 mean. In contrast, the ice immersion pretest

mean was not significantly different from the post-test means for preparatory muscle

activity for both the tibialis anterior and peroneous longus. It was not expected that the

pretest mean would ever be significantly higher than a post-test mean. In the control

condition, it was thought that the three means would not be significantly different,

because no treatment was administered to the subject. In the immersion condition, it was

expected that the post-test means would be significantly higher than the pretest mean

because of the physiological effects of the cold treatment. The results were unexpected,

but may have been due to the subject being unfamiliar with the testing protocol. Why it

was significant in only one of the conditions is unknown. The order of the treatments, ice







40


immersion and control, was randomized so it is not understood why the control condition

would produce higher mean activity levels during a pre-test measurement.

Time to Stabilization

Time to stabilization for the vertical, medial/lateral, and anterior/posterior ground

reaction forces was not significantly affected by the ice immersion treatment. A trend of

increasing or decreasing times after treatment was not observed either. The data did not

support our hypothesis that a 20-min cold immersion treatment to the lower leg would

significantly change time to stabilization as compared to the control condition.


T T


T T


nIce Immersion
SControl


Pretest Posttest 1 Posttest 2
Testing Time

Figure 7. Vertical Ground Reaction Force Time to Stabilization






















































Figure 8.



1800 -



1600



1400



S1200
E
.E
1000
.N

800


i= 600



400



200



0


Pretest Posttest 1 Posttest 2
Testing Time


Medial/Lateral Ground Reaction Force Time to Stabilization


mice Immersion
SControl










































mice Immersion
mControl


Pretest Posttest 1 Posttest 2
Testing Time


Figure 9. Anterior/Posterior Ground Reaction Force Time to Stabilization









To our knowledge, the only other study reporting times to stabilization compared

subjects with a previous ACL reconstruction to control subjects after a step down from a

height of 19-cm.4 The ACL reconstruction group had a time to stabilization of 1527

216 msec, while the control subjects had a time to stabilization of 892 +498 msec. This

was a significant difference. In the current study, the time to stabilization for the ground

reaction force was also measured. The time to stabilization after ice immersion was 1644

62 msec, while it was 1635 77 msec after the control condition. A comparison of these

two studies is presented in Figure 3. These values are much higher than those reported in

the previous study, however, they used a step down test from a predetermined height as

opposed to a jumping and landing task such as the one used in the current study. The

step down test involved having subjects drop down onto a force plate from a height of 19-

cm. This drop down height was the same for every subject and did not take into account

the subject's height or jumping ability. It is expected that the jumping and landing task

used in the current study would produce longer times to stabilization because the subject

is asked to jump instead of step down. A jumping activity would produce greater ground

reaction forces and longer stabilization times.4 The jumping task involved in this study

also required the subject's to jump to a height equivalent to 50% of their maximum jump

height. This was incorporated to make it more functional and individualized to each

subject. Future research should focus on using similar measures and similar protocols so

that results can be directly compared.







43



Comparison of Time to Stabilization

1800

1600

1400

E 1200

( 1000- m Treatment
SControl
L 800

600

> 400

200

0
Colby Study Present Study
Study

Figure 10. Comparison of Time to Stabilization
* TTS significantly longer for treatment subjects as compared to control subjects

It was not completely unexpected that the immersion condition produced no

significant differences in time to stabilization. Most previous literature has reported no

change in proprioceptive measures as a result of a cryotherapy treatment. In a study by

Feuerbach et al.12 it was suggested that anesthetizing the lateral ankle ligaments has no

effect on a subject's ability to accurately match ankle joint angles. In this study, it

appears that other mechanoreceptors can make up for a lack of ligament receptors in

order to maintain proper joint proprioception. Another study found that icing the knee

did not affect a subject's ability to actively reproduce passive movements.36 The knee

may not function exactly as the ankle does, but it does have muscles, tendons, ligaments,

and joint capsule which all contain mechanoreceptors necessary for proper functioning

proprioception. It is also possible that the 20 minute cold treatment does not allow for

deep enough cooling to affect the function of mechanoreceptors. In a study that involved









anesthetization of the ankle and foot, it was found that active joint position sense,

peroneal reaction time, and postural sway were unchanged by the treatment.20 Based on

the results from this research, it is believed that receptors in the muscles and tendons can

compensate for the mechanoreceptors in the ligaments and provide an accurate sense of

position of the ankle complex. It was also suggested that reactions to perturbations

remain functional despite a regional block of the ankle and foot with a local anesthetic.

Again, this task is probably mediated by information from the receptors within muscles

and tendons. The only study to examine sports related measures of proprioception after

cryotherapy treatment also found no differences in the ability of a subject to perform

based on the treatment they had received.10 Times to complete the carioca maneuver, the

cocontraction test, and the shuttle run did not change after immersion treatment. The

immersion treatment involved 20 minutes of cryotherapy in 1C water to the dominant

foot and ankle. The subjects for these agility tests were all athletic male college students.

It was found that the local changes brought about by cold application do not seem to

affect receptors that are responsible for fine, coordinated movements associated with

agility tests. This finding was further supported by the current study reporting no

significant differences in time to stabilization based on the treatment the subject received.

The current study agrees with previous research that demonstrated that ice immersion and

ligament anesthesia does not affect dynamic stability.

Suggestions for Future Research

This study was designed to minimize as many confounding variables as possible.

But not all confounding variables could be controlled and there were also several

limitations to this study. Future research should include equal numbers of males and

females so that the findings can be more readily generalized to both male and female









populations. A limitation of the study is that the results are applicable to healthy

individuals and not injured ones. In the future, it would be clinically useful to test these

same methods on injured or unstable ankles. If these subjects were tested, the findings

could then be generalized to a larger population. In the future, it would also be useful to

get a baseline on athletes during a season in order to test if there were deficits in

proprioception post-injury. It would be helpful also to test these athletes throughout a

season to see what effects intense in-season training and fatigue might have on their

dynamic stability. Finally, future research should also include different age groups, such

as high school and professional athletes. Future research should note if the findings from

college aged populations are similar or different from the findings with other age

populations.

Conclusions

As stated in previous research, it appears that cryotherapy has little effect on

dynamic stability. Cyrotherapy to the lower leg produced no significant effects on time

to stabilization. Its significant effects were on the muscles that were preparing to

stabilize the lower leg in a jumping and landing task. The increased activity of these

muscles appears to be sufficient to stabilize a healthy subject after the jumping and

landing task. Thus, a return to activity following cryotherapy is most likely not

contraindicated. This is especially true since there was only one significant difference

found at the second post-test (five minutes post-treatment). Therefore, it appears that a

re-warming period as short as five minutes is sufficient for mechanoreceptors and

muscles to function normally. It appears that after cold application, mechanoreceptors

outside of the muscles are able to function as well as they would without cold application.














APPENDIX A
INSTITUTIONAL REVIEW BOARD

1. TITLE OF PROTOCOL: Does ankle cryotherapy affect dynamic stability of healthy
subj ects?

2. PRINCIPAL INVESTIGATOR(s):
Susan Miniello, ATC/L
Graduate Assistant Athletic Trainer
Department of Exercise and Sport Sciences
2777 SW Archer Rd Apt P73
(352) 384-0353
miniells@ufl.edu

3. SUPERVISOR (IF PI IS STUDENT):
Michael E. Powers, PhD, ATC, CSCS
Director of Athletic Training Education
Assistant Professor
Department of Exercise and Sport Sciences
144 Florida Gym
Box 118205
University of Florida
Office phone number (352) 392-0584 x1332
Fax number (352) 392-5262
mpowers@hhp.ufl.edu

4. DATES OF PROPOSED PROTOCOL: From September 1, 2002 to May 1, 2003

5. SOURCE OF FUNDING FOR THE PROTOCOL:
(As indicated to the Office of Research, Technology and Graduate Education)
None

6. SCIENTIFIC PURPOSE OF THE INVESTIGATION:
The purpose of this study is to determine the effects of a cold water immersion (a
common therapeutic treatment for athletic injuries) on dynamic stability of the ankle
complex as measured by time to stabilization.

7. DESCRIBE THE RESEARCH METHODOLOGY IN NON-TECHNICAL
LANGUAGE. The UFIRB needs to know what will be done with or to the research
participantss.
Each research participant will be asked to participate in testing at two different
times. Before the first testing session, each participant will be asked to read and









complete an informed consent and a medical history questionnaire. Responses to the
medical history questionnaire will be used to include or exclude possible participants.
Each participant will undergo both the control and experimental conditions. The order of
these treatments will be randomized and counterbalanced with a minimum of one week
separating the two testing sessions.
To begin data collection, each participant will have his/her maximum vertical
jump height assessed. The participant will be asked to stand and reach the highest point
possible on a Vertec vertical jump stand (a device designed for measuring vertical jump
height). They will then be asked to jump and reach the highest point possible. This will
be performed three times. The maximum vertical jump height will be calculated as the
difference between the maximum height reached while jumping and the maximum height
reached while standing. The subjects will then be tested on their time to stabilization
following a single leg landing on a force plate from a height equal to one half of their
maximum vertical jump height. To begin this measure, self-adhesive surface EMG
electrodes will be affixed to the lower leg musculature peroneuss longus, tibialis anterior,
gastrocnemius, and tibialis posterior muscles). The EMG data will allow for the analysis
of preparation and reaction patterns of the muscles around the ankle during the landing
task. After they land, the subjects will be asked to keep their hands on their hips and
maintain balance for twenty seconds. When this is completed, each subject will then
receive either the experimental or control condition. Immediately following the 20-min
treatment period, the subject will again be measured for time to stabilization using
identical methods as those used during pre-testing. The subject will be tested for time to
stabilization immediately after the treatment and again five minutes after completion of
the three post treatment trials. The subjects will then be asked to return one week later to
complete the final session.


Experimental Condition The experimental condition will involve the participant placing
their lower leg in a bucket of ice and water maintained between 55 and 600 F for 20-min.
The leg will be submerged so that the water is at the level of the midpoint of the tibia.


Control Condition The control condition will involve the participant maintaining the
same seated position as the one used in the experimental condition. However, the bucket
will be empty during the entire 20-min period.

8. POTENTIAL BENEFITS AND ANTICIPATED RISK. (If risk of physical,
psychological or economic harm may be involved, describe the steps taken to protect
participant.)
There will be no direct benefits to the subjects for taking part in this study. As
with any type of exercise such as jumping, there is a slight risk muscle injury. A
National Athletic Trainers Association licensed athletic trainer (ATC/L) who will assess
and treat any injuries that may occur will be present for all exercise and testing sessions.









9. DESCRIBE HOW PARTICIPANTS) WILL BE RECRUITED, THE NUMBER
AND AGE OF THE PARTICIPANTS, AND PROPOSED COMPENSATION (if
any):
Participants will be recruited from courses taught within the College of Health
and Human Performance. The principle investigator will asked the instructors permission
before recruiting subjects. No student will be recruited from any class taught by the
principal investigator, or any supervisor. All subjects will be informed by the principal
investigator as to what the study is investigating. A total of 20 voluntary subjects will be
recruited. Subjects will range in age from 18-30 years. There will be no direct
compensation for any subject.


10. DESCRIBE THE INFORMED CONSENT PROCESS. INCLUDE A COPY OF
THE INFORMED CONSENT DOCUMENT (if applicable).
Each subject will be asked to read and sign an informed consent form providing
them with all the information about the study. This document will present an overview of
the study and instructions on what will be done, as well as associated risks and benefits
for participation.



Please use attachments sparingly.


Principal Investigator's Signature


Supervisor's Signature

I approve this protocol for submission to the UFIRB:


Dept. Chair/Center Director Date














APPENDIX B
INFORMED CONSENT

Protocol Title: Does ankle cryotherapy affect dynamic stability of healthy subjects?

Please read this document carefully before you decide to participate in this research
study.

Purpose of the investigation: The purpose of this research study is to investigate the
effects of placing the lower leg in a bucket of ice and water (this a common treatment
used for ankle sprains) on balance after jumping and landing on one leg.

What you will be asked to do in the research study: You will be asked to report to the
Athletic Training Research Laboratory located in Florida Gymnasium (105D FLG) on
two different occasions to perform similar routines. First, you will be asked to complete
a medical history questionnaire. The purpose of this form is to determine if you are
eligible to complete the study. If eligible, your maximum vertical leap (how high you
can jump) will be determined. To do this, we will first measure how high you can reach
while standing on your toes. You will then be asked to jump as high as possible and
touch markers supported on a stand. Based on the number of markers you touch, the
height of your jump is determined. We will have you do this two more times to assure
that we get an accurate measure. Your non-dominant leg (the foot you would NOT
normally use to kick a ball) will then be prepped and nine (9) adhesive electrodes will be
placed on the skin of your lower leg. If necessary a small area of skin will be shaved to
allow for electrode placement and the skin will be cleaned with alcohol. These electrodes
allow us to measure the muscle activity (how much it contracts) when you jump and land.
They only collect or read the electrical activity of the muscle, thus they do not transmit an
electrical current into your body. You will then be asked to jump so that you reach a
height equivalent to half of how high you jumped previously and land on a platform 28"
away. After you land on the platform you will be asked to balance yourself on one leg
while your hands remain on your hips for a period of 20 seconds. After the 20 second
period you will be asked to return to the starting position and repeat the measurement.
This will be done one more time for a total of three trials. After the balance
measurements are completed, you will be asked to complete one of two treatment
sessions. Which method you do will be randomly determined by a coin toss. If you are
assigned to the cold immersion session, you will be asked to place your lower leg in a
bucket filled with water and ice for 20 minutes. When this is done, you will then do three
more trials of jumping down from the platform, landing on one leg, and attempting to get
as steady as possible as quickly as you can. You will then rest for five minutes in a
sitting position. After the five minutes is up, you will complete three final trials of
jumping, landing, and stabilizing yourself on the platform. You will be asked to return









one week later and repeat the protocol, however, you will complete the remaining
treatment session.

Time required:
2 hours- 1 hour each on two different days

Risks:
As with any type of exercise, there is a slight risk of musculoskeletal injury such as a
sprain or a muscle pull. A certified athletic trainer will be present to evaluate and treat
any such injuries should they occur.

Benefits and Compensation:
There are no direct benefits to you for participating.

Confidentiality:
Data will be kept confidential to the extent provided by the law. Your information will
be assigned a code number. The list connecting your name to this number will be kept in
a locked file. When the study is completed and the data have been analyzed, the list will
be destroyed. Your name will not be used in any report.

Voluntary participation: Y
Your participation is completely voluntary. There is no penalty for not participating and
you have the right to withdraw at anytime without any consequences.

Whom to contact if you have questions about the study:
Susan Miniello, ATC, Graduate Assistant Athletic Trainer, Department of Exercise and
Sport Sciences, 2777 SW Archer Rd Apt P73, 384-0353

Dr. Michael Powers, PhD, ATC, CSCS, Department of Exercise and Sport Sciences, 144
Florida Gym, 392-0584

Whom to contact about your rights as a research participant in the study:
UFIRB Office, Box 112250, University of Florida, Gainesville, FL 32611-2250, 392-
0433

Agreement:
I have read the procedure described above. I voluntarily agree to participate in the
procedure and I have received a copy of this description.


Participant: Date:


Principal Investigator:


Date:














APPENDIX C
QUESTIONNAIRE FOR INCLUSION IN THE STUDY

Please circle YES or NO after each of the following questions and please answer
truthfully.

1. Has a medical doctor (MD), physical therapist (PT), YES NO
or certified athletic trained (ATC) diagnosed you
with an ankle sprain in the last six months?

2. Has an MD, PT, or ATC diagnosed you with three YES NO
or more ankle sprains in the last three years?

3. Do you experience episodes of ankle instability or YES NO
feelings that your ankle is giving out on you more
than once a month?

4. Have you ever experienced an allergy or YES NO
hypersensitivity to cold?

5. Do you have a history of inner ear infection, vertigo, YES NO
or other balance problem?

6. Do you currently suffer from circulatory insufficiency YES NO
or decreased circulation?

7. Do you have any anesthetic areas or areas of numbness YES NO
or decreased sensation in your lower leg?

8. Have you consumed alcohol in the last 24 hours? YES NO

9. Are you currently suffering from an illness? YES NO

10. Are you currently taking any medications that YES NO
affect balance/ equilibrium?

11. Have you regularly received cold treatments any YES NO
time in the last three months?















APPENDIX D
DATA COLLECTION FORM


Subject No.


Height:

Weight:

Sex:

Age:



Standing reach height:

Maximum vertical jump height:

50% of jump:

Landing leg:

Control condition date:

Immersion condition date:

















APPENDIX E
ANOVA TABLE OF PERONEOUS LONGUS PREPARATORY ACTIVITY

General Linear Model

Within-Subjects Factors

Measure: MEASURE 1
Dependent
TX TIME Variable
1 1 CPRE
2 CPOST1
3 CPOST2
2 1 IPRE
2 IPOST1
3 IPOST2


Descriptive Statistics

Mean Std. Deviation N
CPRE 1.2292 .62878 20
CPOST1 1.0571 .60800 20
CPOST2 1.0931 .57328 20
IPRE 1.1382 .53763 20
IPOST1 1.2458 .61627 20
IPOST2 1.2545 .59918 20








54



Multivariate Testsb

Effect Value F Hypothesis df Error df Sig.
TX Pillai's Trace .035 .679a 1.000 19.000 .420
Wilks' Lambda .965 .679a 1.000 19.000 .420
Hotelling's Trace .036 .679a 1.000 19.000 .420
Roy's Largest Root .036 .679a 1.000 19.000 .420
TIME Pillai's Trace .033 .310a 2.000 18.000 .737
Wilks' Lambda .967 .310a 2.000 18.000 .737
Hotelling's Trace .034 .310a 2.000 18.000 .737
Roy's Largest Root .034 .310a 2.000 18.000 .737
TX* TIME Pillai's Trace .527 10.015a 2.000 18.000 .001
Wilks' Lambda .473 10.015a 2.000 18.000 .001
Hotelling's Trace 1.113 10.015a 2.000 18.000 .001
Roy's Largest Root 1.113 10.015a 2.000 18.000 .001
a. Exact statistic
b.
Design: Intercept
Within Subjects Design: TX+TIME+TX*TIME

Mauchly's Test of Sphericity
Measure: MEASURE 1

Epsilona
Approx. Greenhous
Within Subjects Effect Mauchly's W Chi-Square df Sig. e-Geisser Huynh-Feldt Lower-bound
TX 1.000 .000 0 1.000 1.000 1.000
TIME .998 .027 2 .986 .998 1.000 .500
TX TIME .901 1.872 2 .392 .910 1.000 .500
Tests the null hypothesis that the error covariance matrix of the orthonormalized transformed dependent variables is
proportional to an identity matrix.
a. May be used to adjust the degrees of freedom for the averaged tests of significance. Corrected tests are displayed in the
Tests of Within-Subjects Effects table.
b.
Design: Intercept
Within Subjects Design: TX+TIME+TX*TIME












Tests of Within-Subjects Effects

Measure: MEASURE 1
Type III Sum
Source of Squares df Mean Square F Sig.
TX Sphericity Assumed .224 1 .224 .679 .420
Greenhouse-Geisser .224 1.000 .224 .679 .420
Huynh-Feldt .224 1.000 .224 .679 .420
Lower-bound .224 1.000 .224 .679 .420
Error(TX) Sphericity Assumed 6.260 19 .329
Greenhouse-Geisser 6.260 19.000 .329
Huynh-Feldt 6.260 19.000 .329
Lower-bound 6.260 19.000 .329
TIME Sphericity Assumed 2.183E-02 2 1.092E-02 .335 .717
Greenhouse-Geisser 2.183E-02 1.997 1.093E-02 .335 .717
Huynh-Feldt 2.183E-02 2.000 1.092E-02 .335 .717
Lower-bound 2.183E-02 1.000 2.183E-02 .335 .569
Error(TIME) Sphericity Assumed 1.238 38 3.257E-02
Greenhouse-Geisser 1.238 37.942 3.262E-02
Huynh-Feldt 1.238 38.000 3.257E-02
Lower-bound 1.238 19.000 6.515E-02
TX TIME Sphericity Assumed .476 2 .238 7.377 .002
Greenhouse-Geisser .476 1.820 .261 7.377 .003
Huynh-Feldt .476 2.000 .238 7.377 .002
Lower-bound .476 1.000 .476 7.377 .014
Error(TX*TIME) Sphericity Assumed 1.225 38 3.224E-02
Greenhouse-Geisser 1.225 34.584 3.542E-02
Huynh-Feldt 1.225 38.000 3.224E-02
Lower-bound 1.225 19.000 6.448E-02


Tests of Within-Subjects Contrasts

Measure: MEASURE 1
Type III Sum
Source TX TIME of Squares df Mean Square F Sig.
TX Linear .224 1 .224 .679 .420
Error(TX) Linear 6.260 19 .329
TIME Linear 1.955E-03 1 1.955E-03 .062 .805
Quadratic 1.988E-02 1 1.988E-02 .588 .453
Error(TIME) Linear .596 19 3.134E-02
Quadratic .642 19 3.381E-02
TX*TIME Linear Linear .319 1 .319 12.508 .002
Quadratic .157 1 .157 4.025 .059
Error(TX*TIME) Linear Linear .484 19 2.548E-02
Quadratic .741 19 3.900E-02











Tests of Between-Subjects Effects


Measure: MEASURE 1
Transformed Variable: Average
Type III Sum
Source of Squares df Mean Square F Sig.
Intercept 164.168 1 164.168 98.752 .000
Error 31.586 19 1.662

Estimated Marginal Means

1. Grand Mean


95% Confidence Interval
Mean Std. Error Lower Bound Upper Bound
1.170 .118 .923 1.416


2. TX


Measure: MEASURE 1
95% Confidence Interval
TX Mean Std. Error Lower Bound Upper Bound
1 1.126 .131 .851 1.402
2 1.213 .126 .949 1.477


3. TIME

Measure: MEASURE 1
95% Confidence Interval
TIME Mean Std. Error Lower Bound Upper Bound
1 1.184 .119 .934 1.433
2 1.151 .121 .899 1.404
3 1.174 .120 .922 1.426


4. TX TIME


Measure: MEASURE 1
95% Confidence Interval
TX TIME Mean Std. Error Lower Bound Upper Bound
1 1 1.229 .141 .935 1.523
2 1.057 .136 .773 1.342
3 1.093 .128 .825 1.361
2 1 1.138 .120 .887 1.390
2 1.246 .138 .957 1.534
3 1.255 .134 .974 1.535

















APPENDIX F
ANOVA TABLE OF PERONEOUS LONGUS REACTIVE ACTIVITY



General Linear Model

Within-Subjects Factors


Measure: MEASURE 1
Dependent
TX TIME Variable
1 1 CPRE
2 CPOST1
3 CPOST2
2 1 IPRE
2 IPOST1
3 IPOST2


Descriptive Statistics

Mean Std. Deviation N
CPRE 1.3570 .71323 20
CPOST1 1.2742 .82568 20
CPOST2 1.2970 .71266 20
IPRE 1.4216 .68006 20
IPOST1 1.6318 .55845 20
IPOST2 1.4512 .77852 20








58



Multivariate Testsb

Effect Value F Hypothesis df Error df Sig.
TX Pillai's Trace .093 1.958a 1.000 19.000 .178
Wilks' Lambda .907 1.958a 1.000 19.000 .178
Hotelling's Trace .103 1.958a 1.000 19.000 .178
Roy's Largest Root .103 1.958a 1.000 19.000 .178
TIME Pillai's Trace .064 .618a 2.000 18.000 .550
Wilks' Lambda .936 .618a 2.000 18.000 .550
Hotelling's Trace .069 .618a 2.000 18.000 .550
Roy's Largest Root .069 .618a 2.000 18.000 .550
TX* TIME Pillai's Trace .251 3.020a 2.000 18.000 .074
Wilks' Lambda .749 3.020a 2.000 18.000 .074
Hotelling's Trace .336 3.020a 2.000 18.000 .074
Roy's Largest Root .336 3.020a 2.000 18.000 .074

a. Exact statistic
b.
Design: Intercept
Within Subjects Design: TX+TIME+TX*TIME

Mauchly's Test of Sphericity
Measure: MEASURE 1

Epsilona
Approx. Greenhous
Within Subjects Effect Mauchly's W Chi-Square df Sig. e-Geisser Huynh-Feldt Lower-bound
TX 1.000 .000 0 1.000 1.000 1.000
TIME .900 1.889 2 .389 .909 1.000 .500
TX* TIME .886 2.179 2 .336 .898 .985 .500
Tests the null hypothesis that the error covariance matrix of the orthonormalized transformed dependent variables is
proportional to an identity matrix.
a. May be used to adjust the degrees of freedom for the averaged tests of significance. Corrected tests are displayed in the
Tests of Within-Subjects Effects table.
b.
Design: Intercept
Within Subjects Design: TX+TIME+TX*TIME








59



Tests of Within-Subjects Effects

Measure: MEASURE 1
Type III Sum
Source of Squares df Mean Square F Sig.
TX Sphericity Assumed 1.107 1 1.107 1.958 .178
Greenhouse-Geisser 1.107 1.000 1.107 1.958 .178
Huynh-Feldt 1.107 1.000 1.107 1.958 .178
Lower-bound 1.107 1.000 1.107 1.958 .178
Error(TX) Sphericity Assumed 10.744 19 .565
Greenhouse-Geisser 10.744 19.000 .565
Huynh-Feldt 10.744 19.000 .565
Lower-bound 10.744 19.000 .565
TIME Sphericity Assumed .140 2 7.007E-02 .855 .433
Greenhouse-Geisser .140 1.819 7.705E-02 .855 .425
Huynh-Feldt .140 2.000 7.007E-02 .855 .433
Lower-bound .140 1.000 .140 .855 .367
Error(TIME) Sphericity Assumed 3.116 38 8.199E-02
Greenhouse-Geisser 3.116 34.557 9.016E-02
Huynh-Feldt 3.116 38.000 8.199E-02
Lower-bound 3.116 19.000 .164
TX TIME Sphericity Assumed .451 2 .225 2.517 .094
Greenhouse-Geisser .451 1.795 .251 2.517 .101
Huynh-Feldt .451 1.971 .229 2.517 .095
Lower-bound .451 1.000 .451 2.517 .129
Error(TX*TIME) Sphericity Assumed 3.405 38 8.960E-02
Greenhouse-Geisser 3.405 34.112 9.981 E-02
Huynh-Feldt 3.405 37.445 9.092E-02
Lower-bound 3.405 19.000 .179


Tests of Within-Subjects Contrasts

Measure: MEASURE 1
Type III Sum
Source TX TIME of Squares df Mean Square F Sig.
TX Linear 1.107 1 1.107 1.958 .178
Error(TX) Linear 10.744 19 .565
TIME Linear 4.637E-03 1 4.637E-03 .078 .783
Quadratic .135 1 .135 1.295 .269
Error(TIME) Linear 1.128 19 5.937E-02
Quadratic 1.988 19 .105
TX*TIME Linear Linear 4.011E-02 1 4.011E-02 .486 .494
Quadratic .411 1 .411 4.251 .053
Error(TX*TIME) Linear Linear 1.568 19 8.254E-02
Quadratic 1.836 19 9.665E-02











Tests of Between-Subjects Effects


Measure: MEASURE 1
Transformed Variable: Average
Type III Sum
Source of Squares df Mean Square F Sig.
Intercept 237.041 1 237.041 109.229 .000
Error 41.233 19 2.170

Estimated Marginal Means

1. Grand Mean


95% Confidence Interval
Mean Std. Error Lower Bound Upper Bound
1.405 .134 1.124 1.687


2. TX


Measure: MEASURE 1
95% Confidence Interval
TX Mean Std. Error Lower Bound Upper Bound
1 1.309 .164 .965 1.653
2 1.502 .136 1.216 1.787


3. TIME

Measure: MEASURE 1
95% Confidence Interval
TIME Mean Std. Error Lower Bound Upper Bound
1 1.389 .138 1.101 1.677
2 1.453 .142 1.155 1.751
3 1.374 .139 1.084 1.664


4. TX TIME


Measure: MEASURE 1
95% Confidence Interval
TX TIME Mean Std. Error Lower Bound Upper Bound
1 1 1.357 .159 1.023 1.691
2 1.274 .185 .888 1.661
3 1.297 .159 .963 1.631
2 1 1.422 .152 1.103 1.740
2 1.632 .125 1.370 1.893
3 1.451 .174 1.087 1.816

















APPENDIX G
ANOVA TABLE OF TIBIALIS ANTERIOR PREPARATORY ACTIVITY

General Linear Model

Within-Subjects Factors

Measure: MEASURE 1
Dependent
TX TIME Variable
1 1 CPRE
2 CPOST1
3 CPOST2
2 1 IPRE
2 IPOST1
3 IPOST2


Descriptive Statistics

Mean Std. Deviation N
CPRE .4942 .25070 20
CPOST1 .3940 .20765 20
CPOST2 .4239 .19310 20
IPRE .4365 .20225 20
IPOST1 .5081 .23806 20
IPOST2 .4847 .22091 20












Multivariate Testsb

Effect Value F Hypothesis df Error df Sig.
TX Pillai's Trace .048 .968a 1.000 19.000 .338
Wilks' Lambda .952 .968a 1.000 19.000 .338
Hotelling's Trace .051 .968a 1.000 19.000 .338
Roy's Largest Root .051 .968a 1.000 19.000 .338
TIME Pillai's Trace .049 .463a 2.000 18.000 .637
Wilks' Lambda .951 .463a 2.000 18.000 .637
Hotelling's Trace .051 .463a 2.000 18.000 .637
Roy's Largest Root .051 .463a 2.000 18.000 .637
TX* TIME Pillai's Trace .445 7.222a 2.000 18.000 .005
Wilks' Lambda .555 7.222a 2.000 18.000 .005
Hotelling's Trace .802 7.222a 2.000 18.000 .005
Roy's Largest Root .802 7.222a 2.000 18.000 .005
a. Exact statistic
b.
Design: Intercept
Within Subjects Design: TX+TIME+TX*TIME

Mauchly's Test of Sphericif,
Measure: MEASURE 1

Epsilona
Approx. Greenhous
Within Subjects Effec Mauchly'sW Chi-Square df Sig. e-Geisser Huynh-Feldt Lower-bound
TX 1.000 .000 0 1.000 1.000 1.000
TIME .862 2.676 2 .262 .879 .961 .500
TX* TIME .946 1.003 2 .606 .949 1.000 .500
Tests the null hypothesis that the error covariance matrix of the orthonormalized transformed dependent variables is
proportional to an identity matrix.
a. May be used to adjust the degrees of freedom for the averaged tests of significance. Corrected tests are displayed
Tests of Within-Subjects Effects table.
b.
Design: Intercept
Within Subjects Design: TX+TIME+TX*TIME












Tests of Within-Subjects Effects

Measure: MEASURE 1
Type III Sum
Source of Squares df Mean Square F Sig.
TX Sphericity Assumed 4.587E-02 1 4.587E-02 .968 .338
Greenhouse-Geisser 4.587E-02 1.000 4.587E-02 .968 .338
Huynh-Feldt 4.587E-02 1.000 4.587E-02 .968 .338
Lower-bound 4.587E-02 1.000 4.587E-02 .968 .338
Error(TX) Sphericity Assumed .900 19 4.739E-02
Greenhouse-Geisser .900 19.000 4.739E-02
Huynh-Feldt .900 19.000 4.739E-02
Lower-bound .900 19.000 4.739E-02
TIME Sphericity Assumed 4.502E-03 2 2.251 E-03 .307 .737
Greenhouse-Geisser 4.502E-03 1.757 2.562E-03 .307 .710
Huynh-Feldt 4.502E-03 1.922 2.342E-03 .307 .729
Lower-bound 4.502E-03 1.000 4.502E-03 .307 .586
Error(TIME) Sphericity Assumed .279 38 7.332E-03
Greenhouse-Geisser .279 33.387 8.346E-03
Huynh-Feldt .279 36.522 7.629E-03
Lower-bound .279 19.000 1.466E-02
TX TIME Sphericity Assumed .154 2 7.724E-02 7.340 .002
Greenhouse-Geisser .154 1.897 8.143E-02 7.340 .002
Huynh-Feldt .154 2.000 7.724E-02 7.340 .002
Lower-bound .154 1.000 .154 7.340 .014
Error(TX*TIME) Sphericity Assumed .400 38 1.052E-02
Greenhouse-Geisser .400 36.047 1.109E-02
Huynh-Feldt .400 38.000 1.052E-02
Lower-bound .400 19.000 2.105E-02


Tests of Within-Subjects Contrasts

Measure: MEASURE_1
Type III Sum
Source TX TIME of Squares df Mean Square F Sig.
TX Linear 4.587E-02 1 4.587E-02 .968 .338
Error(TX) Linear .900 19 4.739E-02
TIME Linear 2.428E-03 1 2.428E-03 .341 .566
Quadratic 2.074E-03 1 2.074E-03 .275 .606
Error(TIME) Linear .135 19 7.126E-03
Quadratic .143 19 7.539E-03
TX*TIME Linear Linear 7.012E-02 1 7.012E-02 5.420 .031
Quadratic 8.436E-02 1 8.436E-02 10.404 .004
Error(TX*TIME) Linear Linear .246 19 1.294E-02
Quadratic .154 19 8.109E-03











Tests of Between-Subjects Effects


Measure: MEASURE 1
Transformed Variable: Average
Type III Sum
Source of Squares df Mean Square F Sig.
Intercept 25.051 1 25.051 121.288 .000
Error 3.924 19 .207

Estimated Marginal Means

1. Grand Mean


Measure: MEASURE 1
95% Confidence Interval
Mean Std. Error Lower Bound Upper Bound
.457 .041 .370 .544


2. TX


Measure: MEASURE 1
95% Confidence Interval
TX Mean Std. Error Lower Bound Upper Bound
1 .437 .045 .343 .531
2 .476 .047 .378 .575


3. TIME

Measure: MEASURE 1
95% Confidence Interval
TIME Mean Std. Error Lower Bound Upper Bound
1 .465 .045 .372 .559
2 .451 .043 .362 .540
3 .454 .042 .367 .541


4. TX TIME


Measure: MEASURE 1
95% Confidence Interval
TX TIME Mean Std. Error Lower Bound Upper Bound
1 1 .494 .056 .377 .611
2 .394 .046 .297 .491
3 .424 .043 .334 .514
2 1 .437 .045 .342 .531
2 .508 .053 .397 .619
3 .485 .049 .381 .588

















APPENDIX H
ANOVA TABLE OF TIBIALIS ANTERIOR REACTIVE ACTIVITY

General Linear Model

Within-Subjects Factors

Measure: MEASURE 1
Dependent
TX TIME Variable
1 1 CPRE
2 CPOST1
3 CPOST2
2 1 IPRE
2 IPOST1
3 IPOST2


Descriptive Statistics

Mean Std. Deviation N
CPRE .7201 .28099 20
CPOST1 .7067 .28298 20
CPOST2 .7298 .24489 20
IPRE .8363 .31669 20
IPOST1 .9785 .34515 20
IPOST2 .9526 .35162 20












Multivariate Testsb

Effect Value F Hypothesis df Error df Sig.
TX Pillai's Trace .368 11.040a 1.000 19.000 .004
Wilks' Lambda .632 11.040a 1.000 19.000 .004
Hotelling's Trace .581 11.040a 1.000 19.000 .004
Roy's Largest Root .581 11.040a 1.000 19.000 .004
TIME Pillai's Trace .109 1.102a 2.000 18.000 .354
Wilks' Lambda .891 1.102a 2.000 18.000 .354
Hotelling's Trace .122 1.102a 2.000 18.000 .354
Roy's Largest Root .122 1.102a 2.000 18.000 .354
TX*TIME Pillai's Trace .169 1.835a 2.000 18.000 .188
Wilks' Lambda .831 1.835a 2.000 18.000 .188
Hotelling's Trace .204 1.835a 2.000 18.000 .188
Roy's Largest Root .204 1.835a 2.000 18.000 .188
a. Exact statistic
b.
Design: Intercept
Within Subjects Design: TX+TIME+TX*TIME

Mauchly's Test of Sphericity

Measure: MEASURE 1

Epsilona
Approx. Greenhous
Within Subjects Effe Mauchly's W Chi-Square df Sig. e-Geisser Huynh-Feldt Lower-bound
TX 1.000 .000 0 1.000 1.000 1.000
TIME .896 1.972 2 .373 .906 .996 .500
TX* TIME .917 1.561 2 .458 .923 1.000 .500
Tests the null hypothesis that the error covariance matrix of the orthonormalized transformed dependent variables il
proportional to an identity matrix.
a. May be used to adjust the degrees of freedom for the averaged tests of significance. Corrected tests are displz
Tests of Within-Subjects Effects table.
b.
Design: Intercept
Within Subjects Design: TX+TIME+TX*TIME












Tests of Within-Subjects Effects

Measure: MEASURE 1
Type III Sum
Source of Squares df Mean Square F Sig.
TX Sphericity Assumed 1.244 1 1.244 11.040 .004
Greenhouse-Geisser 1.244 1.000 1.244 11.040 .004
Huynh-Feldt 1.244 1.000 1.244 11.040 .004
Lower-bound 1.244 1.000 1.244 11.040 .004
Error(TX) Sphericity Assumed 2.140 19 .113
Greenhouse-Geisser 2.140 19.000 .113
Huynh-Feldt 2.140 19.000 .113
Lower-bound 2.140 19.000 .113
TIME Sphericity Assumed .108 2 5.414E-02 1.530 .230
Greenhouse-Geisser .108 1.812 5.976E-02 1.530 .231
Huynh-Feldt .108 1.992 5.436E-02 1.530 .230
Lower-bound .108 1.000 .108 1.530 .231
Error(TIME) Sphericity Assumed 1.345 38 3.539E-02
Greenhouse-Geisser 1.345 34.428 3.906E-02
Huynh-Feldt 1.345 37.850 3.553E-02
Lower-bound 1.345 19.000 7.078E-02
TX TIME Sphericity Assumed .127 2 6.328E-02 1.896 .164
Greenhouse-Geisser .127 1.847 6.854E-02 1.896 .168
Huynh-Feldt .127 2.000 6.328E-02 1.896 .164
Lower-bound .127 1.000 .127 1.896 .185
Error(TX*TIME) Sphericity Assumed 1.268 38 3.338E-02
Greenhouse-Geisser 1.268 35.085 3.615E-02
Huynh-Feldt 1.268 38.000 3.338E-02
Lower-bound 1.268 19.000 6.675E-02


Tests of Within-Subjects Contrasts

Measure: MEASURE 1
Type III Sum
Source TX TIME of Squares df Mean Square F Sig.
TX Linear 1.244 1 1.244 11.040 .004
Error(TX) Linear 2.140 19 .113
TIME Linear 7.940E-02 1 7.940E-02 1.886 .186
Quadratic 2.889E-02 1 2.889E-02 1.007 .328
Error(TIME) Linear .800 19 4.210E-02
Quadratic .545 19 2.868E-02
TX TIME Linear Linear 5.683E-02 1 5.683E-02 2.385 .139
Quadratic 6.973E-02 1 6.973E-02 1.624 .218
Error(TX*TIME) Linear Linear .453 19 2.382E-02
Quadratic .816 19 4.293E-02











Tests of Between-Subjects Effects


Measure: MEASURE 1
Transformed Variable: Average
Type III Sum
Source of Squares df Mean Square F Sig.
Intercept 80.823 1 80.823 259.148 .000
Error 5.926 19 .312

Estimated Marginal Means

1. Grand Mean


Measure: MEASURE 1
95% Confidence Interval
Mean Std. Error Lower Bound Upper Bound
.821 .051 .714 .927


2. TX


Measure: MEASURE 1
95% Confidence Interval
TX Mean Std. Error Lower Bound Upper Bound
1 .719 .055 .604 .833
2 .922 .064 .789 1.056


3. TIME

Measure: MEASURE 1
95% Confidence Interval
TIME Mean Std. Error Lower Bound Upper Bound
1 .778 .053 .667 .889
2 .843 .058 .721 .964
3 .841 .058 .720 .962


4. TX TIME


Measure: MEASURE 1
95% Confidence Interval
TX TIME Mean Std. Error Lower Bound Upper Bound
1 1 .720 .063 .589 .852
2 .707 .063 .574 .839
3 .730 .055 .615 .844
2 1 .836 .071 .688 .985
2 .979 .077 .817 1.140
3 .953 .079 .788 1.117
















APPENDIX I
ANOVA TABLE OF VERTICAL GROUND REACTION FORCE TIME TO
STABILIZATION

General Linear Model

Within-Subjects Factors


Measure: MEASURE 1
Dependent
TX TIME Variable
1 1 IXPRE
2 IXPST1
3 IXPST2
2 1 CXPRE
2 CXPST1
3 CXPST2


Descriptive Statistics

Mean Std. Deviation N
IXPRE 1644.4750 275.10047 20
IXPST1 1730.6667 319.58007 20
IXPST2 1507.9417 273.80864 20
CXPRE 1634.4720 345.54176 20
CXPST1 1782.7478 393.46474 20
CXPST2 1481.6350 369.64539 20












Multivariate Testsb

Effect Value F Hypothesis df Error df Sig.
TX Pillai's Trace .000 .006a 1.000 19.000 .940
Wilks' Lambda 1.000 .006a 1.000 19.000 .940
Hotelling's Trace .000 .006a 1.000 19.000 .940
Roy's Largest Root .000 .006a 1.000 19.000 .940
TIME Pillai's Trace .469 7.953a 2.000 18.000 .003
Wilks' Lambda .531 7.953a 2.000 18.000 .003
Hotelling's Trace .884 7.953a 2.000 18.000 .003
Roy's Largest Root .884 7.953a 2.000 18.000 .003
TX* TIME Pillai's Trace .037 .344a 2.000 18.000 .714
Wilks' Lambda .963 .344a 2.000 18.000 .714
Hotelling's Trace .038 .344a 2.000 18.000 .714
Roy's Largest Root .038 .344a 2.000 18.000 .714
a. Exact statistic
b.
Design: Intercept
Within Subjects Design: TX+TIME+TX*TIME

Mauchly's Test of Sphericity

Measure: MEASURE 1

Epsilona
Approx. Greenhous
Within Subjects Effe Mauchly's W Chi-Square df Sig. e-Geisser Huynh-Feldt Lower-bound
TX 1.000 .000 0 1.000 1.000 1.000
TIME .759 4.974 2 .083 .806 .869 .500
TX* TIME .717 5.978 2 .050 .780 .837 .500
Tests the null hypothesis that the error covariance matrix of the orthonormalized transformed dependent variables il
proportional to an identity matrix.
a. May be used to adjust the degrees of freedom for the averaged tests of significance. Corrected tests are displz
Tests of Within-Subjects Effects table.
b.
Design: Intercept
Within Subjects Design: TX+TIME+TX*TIME












Tests of Within-Subjects Effects

Measure: MEASURE 1
Type III Sum
Source of Squares df Mean Square F Sig.
TX Sphericity Assumed 829.134 1 829.134 .006 .940
Greenhouse-Geisser 829.134 1.000 829.134 .006 .940
Huynh-Feldt 829.134 1.000 829.134 .006 .940
Lower-bound 829.134 1.000 829.134 .006 .940
Error(TX) Sphericity Assumed 2709177.198 19 142588.274
Greenhouse-Geisser 2709177.198 19.000 142588.274
Huynh-Feldt 2709177.198 19.000 142588.274
Lower-bound 2709177.198 19.000 142588.274
TIME Sphericity Assumed 1377054.247 2 688527.123 7.774 .001
Greenhouse-Geisser 1377054.247 1.611 854762.346 7.774 .003
Huynh-Feldt 1377054.247 1.738 792354.378 7.774 .003
Lower-bound 1377054.247 1.000 1377054.247 7.774 .012
Error(TIME) Sphericity Assumed 3365451.054 38 88564.501
Greenhouse-Geisser 3365451.054 30.610 109947.159
Huynh-Feldt 3365451.054 33.021 101919.689
Lower-bound 3365451.054 19.000 177129.003
TX* TIME Sphericity Assumed 34216.352 2 17108.176 .257 .774
Greenhouse-Geisser 34216.352 1.559 21943.089 .257 .720
Huynh-Feldt 34216.352 1.673 20446.350 .257 .735
Lower-bound 34216.352 1.000 34216.352 .257 .618
Error(TX*TIME) Sphericity Assumed 2526913.990 38 66497.737
Greenhouse-Geisser 2526913.990 29.627 85290.550
Huynh-Feldt 2526913.990 31.796 79472.877
Lower-bound 2526913.990 19.000 132995.473


Tests of Within-Subjects Contrasts

Measure: MEASURE_1
Type III Sum
Source TX TIME of Squares df Mean Square F Sig.
TX Linear 829.134 1 829.134 .006 .940
Error(TX) Linear 2709177.198 19 142588.274
TIME Linear 418675.949 1 418675.949 3.503 .077
Quadratic 958378.298 1 958378.298 16.633 .001
Error(TIME) Linear 2270674.574 19 119509.188
Quadratic 1094776.480 19 57619.815
TX*TIME Linear Linear 1329.048 1 1329.048 .025 .876
Quadratic 32887.305 1 32887.305 .414 .528
Error(TX*TIME) Linear Linear 1016918.940 19 53522.049
Quadratic 1509995.051 19 79473.424











Tests of Between-Subjects Effects


Measure: MEASURE 1
Transformed Variable: Average
Type III Sum
Source of Squares df Mean Square F Sig.
Intercept 318954381 1 318954381.0 1512.195 .000
Error 4007507.195 19 210921.431

Estimated Marginal Means

1. Grand Mean


Measure: MEASURE 1
95% Confidence Interval
Mean Std. Error Lower Bound Upper Bound
1630.323 41.925 1542.574 1718.072


2. TX


Measure: MEASURE 1
95% Confidence Interval
TX Mean Std. Error Lower Bound Upper Bound
1 1627.694 42.886 1537.934 1717.455
2 1632.952 63.660 1499.709 1766.194


3. TIME

Measure: MEASURE 1
95% Confidence Interval
TIME Mean Std. Error Lower Bound Upper Bound
1 1639.474 49.083 1536.743 1742.204
2 1756.707 58.593 1634.071 1879.343
3 1494.788 62.121 1364.767 1624.810


4. TX TIME


Measure: MEASURE 1
95% Confidence Interval
TX TIME Mean Std. Error Lower Bound Upper Bound
1 1 1644.475 61.514 1515.724 1773.226
2 1730.667 71.460 1581.099 1880.235
3 1507.942 61.225 1379.795 1636.088
2 1 1634.472 77.265 1472.753 1796.191
2 1782.748 87.981 1598.601 1966.895
3 1481.635 82.655 1308.636 1654.634


















ANOVA TABLE OF MEDIAL/



General Linear Model

Within-Subjects Factors

Measure: MEASURE 1
Dependent
TX TIME Variable
1 1 IYPRE
2 IYPST1
3 IYPST2
2 1 CYPRE
2 CYPST1
3 CYPST2


APPENDIX J
LATERAL GROUND REACTION FORCE TIME TO
STABILIZATION


Descriptive Statistics

Mean Std. Deviation N
IYPRE 1568.3167 412.49609 20
IYPST1 1443.7000 302.80833 20
IYPST2 1455.7333 315.42072 20
CYPRE 1511.4522 294.18949 20
CYPST1 1572.6517 328.96142 20
CYPST2 1542.9613 380.23033 20












Multivariate Testsb

Effect Value F Hypothesis df Error df Sig.
TX Pillai's Trace .041 .809a 1.000 19.000 .380
Wilks' Lambda .959 .809a 1.000 19.000 .380
Hotelling's Trace .043 .809a 1.000 19.000 .380
Roy's Largest Root .043 .809a 1.000 19.000 .380
TIME Pillai's Trace .044 .414a 2.000 18.000 .667
Wilks' Lambda .956 .414a 2.000 18.000 .667
Hotelling's Trace .046 .414a 2.000 18.000 .667
Roy's Largest Root .046 .414a 2.000 18.000 .667
TX*TIME Pillai's Trace .079 .775a 2.000 18.000 .475
Wilks' Lambda .921 .775a 2.000 18.000 .475
Hotelling's Trace .086 .775a 2.000 18.000 .475
Roy's Largest Root .086 .775a 2.000 18.000 .475
a. Exact statistic
b.
Design: Intercept
Within Subjects Design: TX+TIME+TX*TIME


Mauchly's Test of SpheriCity

Measure: MEASURE 1

Epsilona
Approx. Greenhous
Within Subjects Ef lauchly's W Chi-Square df Sig. e-Geisser -luynh-Feldt-ower-bound
TX 1.000 .000 0 1.000 1.000 1.000
TIME .901 1.876 2 .391 .910 1.000 .500
TX TIME .965 .635 2 .728 .966 1.000 .500
Tests the null hypothesis that the error covariance matrix of the orthonormalized transformed defender
proportional to an identity matrix.
a. May be used to adjust the degrees of freedom for the averaged tests of significance. Corrected tes
Tests of Within-Subjects Effects table.
b.
Design: Intercept
Within Subjects Design: TX+TIME+TX*TIME












Tests of Within-Subjects Effects

Measure: MEASURE 1
Type III Sum
Source of Squares df Mean Square F Sig.
TX Sphericity Assumed 84604.408 1 84604.408 .809 .380
Greenhouse-Geisser 84604.408 1.000 84604.408 .809 .380
Huynh-Feldt 84604.408 1.000 84604.408 .809 .380
Lower-bound 84604.408 1.000 84604.408 .809 .380
Error(TX) Sphericity Assumed 1987548.720 19 104607.827
Greenhouse-Geisser 1987548.720 19.000 104607.827
Huynh-Feldt 1987548.720 19.000 104607.827
Lower-bound 1987548.720 19.000 104607.827
TIME Sphericity Assumed 36355.091 2 18177.545 .312 .734
Greenhouse-Geisser 36355.091 1.820 19976.840 .312 .713
Huynh-Feldt 36355.091 2.000 18177.545 .312 .734
Lower-bound 36355.091 1.000 36355.091 .312 .583
Error(TIME) Sphericity Assumed 2211538.143 38 58198.372
Greenhouse-Geisser 2211538.143 34.577 63959.107
Huynh-Feldt 2211538.143 38.000 58198.372
Lower-bound 2211538.143 19.000 116396.744
TX TIME Sphericity Assumed 190103.869 2 95051.935 .946 .397
Greenhouse-Geisser 190103.869 1.933 98346.846 .946 .395
Huynh-Feldt 190103.869 2.000 95051.935 .946 .397
Lower-bound 190103.869 1.000 190103.869 .946 .343
Error(TX*TIME) Sphericity Assumed 3819214.026 38 100505.632
Greenhouse-Geisser 3819214.026 36.727 103989.593
Huynh-Feldt 3819214.026 38.000 100505.632
Lower-bound 3819214.026 19.000 201011.265


Tests of Within-Subjects Contrasts

Measure: MEASURE_1
Type III Sum
Source TX TIME of Squares df Mean Square F Sig.
TX Linear 84604.408 1 84604.408 .809 .380
Error(TX) Linear 1987548.720 19 104607.827
TIME Linear 32865.103 1 32865.103 .632 .436
Quadratic 3489.988 1 3489.988 .054 .818
Error(TIME) Linear 988218.114 19 52011.480
Quadratic 1223320.028 19 64385.265
TX*TIME Linear Linear 103813.243 1 103813.243 1.111 .305
Quadratic 86290.626 1 86290.626 .802 .382
Error(TX*TIME) Linear Linear 1774786.346 19 93409.808
Quadratic 2044427.680 19 107601.457











Tests of Between-Subjects Effects


Measure: MEASURE 1
Transformed Variable: Average
Type III Sum
Source of Squares df Mean Square F Sig.
Intercept 275718876 1 275718876.4 989.451 .000
Error 5294511.118 19 278658.480

Estimated Marginal Means

1. Grand Mean


Measure: MEASURE 1
95% Confidence Interval
Mean Std. Error Lower Bound Upper Bound
1515.803 48.189 1414.942 1616.663


2. TX


Measure: MEASURE 1
95% Confidence Interval
TX Mean Std. Error Lower Bound Upper Bound
1 1489.250 62.652 1358.119 1620.381
2 1542.355 49.624 1438.490 1646.220


3. TIME

Measure: MEASURE 1
95% Confidence Interval
TIME Mean Std. Error Lower Bound Upper Bound
1 1539.884 54.186 1426.471 1653.298
2 1508.176 49.538 1404.491 1611.860
3 1499.347 66.979 1359.158 1639.536


4. TX TIME


Measure: MEASURE 1
95% Confidence Interval
TX TIME Mean Std. Error Lower Bound Upper Bound
1 1 1568.317 92.237 1375.263 1761.371
2 1443.700 67.710 1301.981 1585.419
3 1455.733 70.530 1308.112 1603.355
2 1 1511.452 65.783 1373.767 1649.137
2 1572.652 73.558 1418.693 1726.610
3 1542.961 85.022 1365.008 1720.915
















APPENDIX K
ANOVA TABLE OF ANTERIOR/ POSTERIOR GROUND REACTION FORCE TIME
TO STABILIZATION

General Linear Model

Within-Subjects Factors


Measure: MEASURE 1
Dependent
TX TIME Variable
1 1 IZPRE
2 IZPST1
3 IZPST2
2 1 CZPRE
2 CZPST1
3 CZPST2


Descriptive Statistics

Mean Std. Deviation N
IZPRE 1470.6000 452.24995 20
IZPST1 1493.7250 514.36296 20
IZPST2 1373.9375 508.64178 20
CZPRE 1367.9990 365.53430 20
CZPST1 1292.8760 485.62623 20
CZPST2 1261.5093 377.91127 20












Multivariate Testsb

Effect Value F Hypothesis df Error df Sig.
TX Pillai's Trace .145 3.234a 1.000 19.000 .088
Wilks' Lambda .855 3.234a 1.000 19.000 .088
Hotelling's Trace .170 3.234a 1.000 19.000 .088
Roy's Largest Root .170 3.234a 1.000 19.000 .088
TIME Pillai's Trace .100 .997a 2.000 18.000 .389
Wilks' Lambda .900 .997a 2.000 18.000 .389
Hotelling's Trace .111 .997a 2.000 18.000 .389
Roy's Largest Root .111 .997a 2.000 18.000 .389
TX*TIME Pillai's Trace .026 .244a 2.000 18.000 .786
Wilks' Lambda .974 .244a 2.000 18.000 .786
Hotelling's Trace .027 .244a 2.000 18.000 .786
Roy's Largest Root .027 .244a 2.000 18.000 .786
a. Exact statistic
b.
Design: Intercept
Within Subjects Design: TX+TIME+TX*TIME


Mauchly's Test of Spheridty

Measure: MEASURE 1

Epsilona
Approx. Greenhous
Within Subjects Eff VIauchly's W Chi-Square df Sig. e-Geisser Huynh-Feldt Lower-bound
TX 1.000 .000 0 1.000 1.000 1.000
TIME .842 3.102 2 .212 .863 .942 .500
TX* TIME .824 3.488 2 .175 .850 .925 .500
Tests the null hypothesis that the error covariance matrix of the orthonormalized transformed dependent var
proportional to an identity matrix.
a. May be used to adjust the degrees of freedom for the averaged tests of significance. Corrected tests ar
Tests of Within-Subjects Effects table.
b.
Design: Intercept
Within Subjects Design: TX+TIME+TX*TIME












Tests of Within-Subjects Effects

Measure: MEASURE 1
Type III Sum
Source of Squares df Mean Square F Sig.
TX Sphericity Assumed 576515.498 1 576515.498 3.234 .088
Greenhouse-Geisser 576515.498 1.000 576515.498 3.234 .088
Huynh-Feldt 576515.498 1.000 576515.498 3.234 .088
Lower-bound 576515.498 1.000 576515.498 3.234 .088
Error(TX) Sphericity Assumed 3386796.731 19 178252.460
Greenhouse-Geisser 3386796.731 19.000 178252.460
Huynh-Feldt 3386796.731 19.000 178252.460
Lower-bound 3386796.731 19.000 178252.460
TIME Sphericity Assumed 222740.590 2 111370.295 .879 .424
Greenhouse-Geisser 222740.590 1.727 128998.968 .879 .411
Huynh-Feldt 222740.590 1.883 118261.010 .879 .418
Lower-bound 222740.590 1.000 222740.590 .879 .360
Error(TIME) Sphericity Assumed 4815765.937 38 126730.683
Greenhouse-Geisser 4815765.937 32.807 146790.733
Huynh-Feldt 4815765.937 35.786 134571.777
Lower-bound 4815765.937 19.000 253461.365
TX TIME Sphericity Assumed 58558.288 2 29279.144 .211 .811
Greenhouse-Geisser 58558.288 1.700 34436.943 .211 .775
Huynh-Feldt 58558.288 1.850 31648.357 .211 .794
Lower-bound 58558.288 1.000 58558.288 .211 .651
Error(TX*TIME) Sphericity Assumed 5269998.290 38 138684.166
Greenhouse-Geisser 5269998.290 32.309 163114.698
Huynh-Feldt 5269998.290 35.155 149906.228
Lower-bound 5269998.290 19.000 277368.331


Tests of Within-Subjects Contrasts

Measure: MEASURE 1
Type III Sum
Source TX TIME of Squares df Mean Square F Sig.
TX Linear 576515.498 1 576515.498 3.234 .088
Error(TX) Linear 3386796.731 19 178252.460
TIME Linear 206354.014 1 206354.014 1.355 .259
Quadratic 16386.576 1 16386.576 .162 .692
Error(TIME) Linear 2892596.448 19 152241.918
Quadratic 1923169.488 19 101219.447
TX* TIME Linear Linear 482.866 1 482.866 .004 .952
Quadratic 58075.422 1 58075.422 .391 .539
Error(TX*TIME) Linear Linear 2446773.143 19 128777.534
Quadratic 2823225.148 19 148590.797











Tests of Between-Subjects Effects


Measure: MEASURE 1
Transformed Variable: Average
Type III Sum
Source of Squares df Mean Square F Sig.
Intercept 227460954 1 227460953.7 428.364 .000
Error 10088974.8 19 530998.672

Estimated Marginal Means

1. Grand Mean


Measure: MEASURE 1
95% Confidence Interval
Mean Std. Error Lower Bound Upper Bound
1376.774 66.521 1237.545 1516.004


2. TX


Measure: MEASURE 1
95% Confidence Interval
TX Mean Std. Error Lower Bound Upper Bound
1 1446.088 81.153 1276.232 1615.943
2 1307.461 72.353 1156.024 1458.899


3. TIME

Measure: MEASURE 1
95% Confidence Interval
TIME Mean Std. Error Lower Bound Upper Bound
1 1419.300 72.373 1267.822 1570.777
2 1393.301 85.087 1215.212 1571.389
3 1317.723 84.463 1140.941 1494.506


4. TX TIME


Measure: MEASURE 1
95% Confidence Interval
TX TIME Mean Std. Error Lower Bound Upper Bound
1 1 1470.600 101.126 1258.941 1682.259
2 1493.725 115.015 1252.996 1734.454
3 1373.938 113.736 1135.886 1611.989
2 1 1367.999 81.736 1196.924 1539.074
2 1292.876 108.589 1065.596 1520.156
3 1261.509 84.504 1084.641 1438.377















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BIOGRAPHICAL SKETCH

I, Susan Miniello, am originally from Strongsville, OH, a suburb of Cleveland. I

grew up there and graduated from Strongsville High School. I went on to attend Marietta

College in Marietta, OH, where I majored in sports medicine. I then decided to attend the

University of Florida to pursue a master's degree in athletic training/sports medicine.

After UF, I plan to work as an athletic trainer and instructor at a small college.