Characteristics in female recreational runners with running related musculoskeletal injuries

The University of Toledo The University of Toledo Digital Repository Theses and Dissertations 2015 Characteristics in female recreational runners with running related musculoskeletal injuries Danielle M. Torp University of Toledo Follow this and additional works at: http://utdr.utoledo.edu/theses-dissertations Recommended Citation Torp, Danielle M., "Characteristics in female recreational runners with running related musculoskeletal injuries" (2015). Theses and Dissertations. 1868. http://utdr.utoledo.edu/theses-dissertations/1868 This Thesis is brought to you for free and open access by The University of Toledo Digital Repository. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of The University of Toledo Digital Repository. For more information, please see the repository's About page.

A Thesis entitled Characteristics in Female Recreational Runners with Running Related Musculoskeletal InJuries by Danielle M. Torp, ATC Submitted to the Graduate Faculty as partial fulfillment of the requirements for the Master of Science Degree In Exercise Science ATC, Committee Chÿ" Member ATC, FNATA, Committee jj f J ATC, Committee Member Patricia R. Komuniecki, PhD, Dean College of Graduate Studies The University of Toledo May 2015

Copyright 2015, Danielle M Torp This document is copyrighted material. Under copyright law, no parts of this document may be reproduced without the expressed permission of the author.

An Abstract of Characteristics in Female Recreational Runners with Running Related Musculoskeletal Injuries by Danielle M. Torp, ATC Submitted to the Graduate Faculty as partial fulfillment of the requirements for the Master of Science Degree in Exercise Science The University of Toledo May 2015 Context: Nearly 51 million Americans chose running as their primary form of exercise in 2012. However, with participation in running comes an increase in risk for sustaining a running related musculoskeletal injury (RRMI), with prevalence as high as 79%. It is estimated females sustain approximately 54% of all RRMI. Runners with a RRMI often exhibit with altered running kinematics, an imbalance in hip flexibility, and decreased hip strength. Tests such as the Star Excursion Balance Test (SEBT) and Single Leg Hop for Distance (SLHD) have been used within athletic populations to identify individuals at an increased risk of injury; however these tests have not been applied to the recreational running population. Objective: To determine baseline differences in running kinematics, hip strength and range of motion, and clinical screening tests between female runners who do or do not sustain a RRMI during a 16-week formalized training program. Design: Prospective cohort study. Setting: Research Laboratory. Patients or Other Participants: Fifty-four healthy female participants (38.75+9.6yrs, 1.66+0.07m, 66.29+13.2kg) enrolled in a 16-week formalized marathon running program volunteered. Interventions: All participants performed all assessment tests at one baseline testing iii

session. The testing order was randomized and performed bilaterally. Running kinematics was collected using a 3D motion capture system; value of interest was hip flexion angle at initial contact of stance phase. The SEBT in the anterior reach (SEBT-A), was normalized by true leg length and reported as a percentage. The SLHD was normalized by height and expressed as a percentage. Hip flexion and extension active range of motion (AROM) were measured using a standard goniometer and reported in degrees. Hip flexion and extension strength were measured using a hand held dynamometer, and were normalized and reported as torque per kilogram of body mass (Nm/kg). At the conclusion of the program, all participants were designated into either the RRMI (RRMI) or injury-free (INJF) group. A RRMI was a musculoskeletal injury of the lower extremity that occurred as a result of running, and resulted in the modification or removal of running for at least one training day. Main Outcome Measures: The independent variable was group (RRMI, Injury-free), and the dependent variables were hip flexion angle at initial contact, SEBT-A, SLHD, hip flexion and extension AROM, and hip flexion and extension torque. Scores of the injured limb was compared to the mean of the scores of injury free group. Independent t-tests with a Bonferroni Correction were used for each dependent variable; alpha was set a-priori at (p<0.05). Results: There were no significant differences between RRMI and INJF in hip flexion angles (RRMI: 25.27 + 4.79 o ; INJF: 27.80 + 4.79 o ; p=0.14), SEBT-A (RRMI: 63.56 + 4.73%; INJF: 63.98 + 5.39%; p=0.78), SLHD (RRMI: 37.50 + 11.31%; INJF: 34.37% + 9.31%; p=0.29), hip flexion (RRMI: 73.33 + 12.16 o ; INJF: 75.07 + 12.37 o ; p=0.63)or extension (RRMI: 15.09 + 5.40 o ; INJF: 15.86 + 4.88 o ; t(52)= -0.51, p=0.61) AROM, hip flexion (RRMI: 0.78 + 0.13nm/kg; INJF: 0.74 + 0.17nm/kg; p=0.38)or extension (RRMI: 0.71 + 0.14nm/kg; iv

INJF: 0.68 + 0.19nm/kg; p=0.55). Conclusions: Baseline sagittal plane hip angles at initial contact, AROM, and strength measurements are not different between runners sustaining a RRMI and those injury-free during training. Future research should focus on what batteries of clinical functional screening tools are most appropriate for running populations. v

I dedicate this thesis to my mother, Teri Lynn, for always believing in and encouraging me throughout my life. I always know you are my biggest fan and I couldn t have done this without your support. To my father, Kevin James, I strive to make you proud in everything I do; all my hard work is for you. I know you are always protecting and looking over me from above. Keep shining, Daddy-O. Lastly to my brothers and sisters- Kara, Michael, Tiana, and Kevin; you will never understand my thanks and appreciation for all your love and care throughout my life. I hope one day I can repay you all for the time, money, and effort you put into me.

Acknowledgements First and foremost, this would not have been a success without the help of my advisors and committee members; Phillip Gribble, Luke Donovan, and Michele Pye. I cannot thank you enough for investing your time in my growth and education. Most of all, I could have not done this without the guidance and support from Megan Quinlevan Beard. Thank you for allowing me to work with you, being patient with me, trusting me, and for your countless hours dedicated to reading my terrible drafts. A big thank you to my colleagues: Larry Cattell, Steve Berning, and Josh Tasma for the effort put forth during our endless collection sessions and making this thesis possible. Lastly, to the man who was by my side through the frustrations, the disappointments, the long hours, and the complaints. Thank you, Kyle Kosik, for keeping me focused and being my encourager, supporter, and best friend. v

Table of Contents Abstract... iii Acknowledgements...v Table of Contents... vi List of Tables... vii List of Figures... ix List of Abbreviations...x 1 Introduction.....1 1.1 Running Background...1 1.2 Statement of Problem...4 1.3 Statement of Purpose...4 1.4 Research Hypothesis...5 1.5 Significance of Study...6 2 Literature Review...7 2.1 Running Participation...7 2.2 Prevalence and Incident Rate of Injury...8 2.3 Biomechanics of Running...11 2.3.1 Running Gait Cycle...11 2.3.2 Running Kinematics...12 2.3.3 Neuromuscular Activity during Running...14 vi

2.4 Epidemiology of Running Injuries...15 2.4.1 Patellofemoral Pain Syndrome...15 2.4.2 Iliotibial Band Syndrome...17 2.4.3 Medial Tibial Stress Syndrome...18 2.4.4 Tibial Stress Fractures...20 2.5 Risk Factors of Running Injuries...21 2.5.1 Non-Modifiable Variables...22 2.5.2 Modifiable Variables...24 2.6 Functional Tests...25 2.7 Clinical Tests...26 2.7.1 Star Excursion Balance Test...27 2.7.2 Single Leg Hop for Distance...28 2.8 Summary...29 3 Methods...31 3.1 Study Design...31 3.2 Subjects...31 3.3 Instrumentation...32 3.4 Independent Variables...32 3.5 Dependent Variables...33 3.6 Procedure....33 3.7 Injury Tracking and Analysis...37 3.8 Data Processing...38 3.9 Statistical Analysis...39 vii

4 Results......40 4.1 Results......40 4.1.1 Kinematics......41 4.1.2 Active Range of Motion......41 4.1.3 Strength......42 4.1.4 Clinical Tests......43 5 Discussion....44 5.1 Discussion...44 5.2 Limitations...48 5.3 Conclusion...49 References...51 A Consent Form...60 B Block Randomization...71 C Kinematic Collection Set-up...72 D Data Collection...74 E RRMI Tracking...78 viii

List of Tables 3.1 Participant Demographics...32 4.1 Group Demographics...40 ix

List of Figures 4-1 Kinematic Data Graph...41 4-2 Active Range of Motion...42 4-3 Strength...42 4-3 Clinical Tests...43 A-1 Consent Form...60 B-1 Block Randomization...71 C-1 Runway Set-up...72 C-2 Market Set...73 D-1 Single Leg Hop for Distance...74 D-2 Star Excursion Balance Test...75 D-3 Flexion Range of Motion...75 D-4 Extension Range of Motion...76 D-5 Flexion Strength...76 D-6 Extension Strength...77 E-1 Injury Tracking...78 x

List of Abbreviations AROM...Active Range of Motion DM...Dynamic Malalignment EMG...Electromyography HEXT...Hip Extension HFLEX...Hip Flexion HHD...Hand Held Dynamometer INJF...Injury Free Group ITBS...Iliotibial Band Syndrome MTSS...Medial Tibial Stress Syndrome PFPS...Patellofemoral Pain Syndrome RRMI...Running Related Musculoskeletal Injury SEBT-A...Star Excursion Balance Test- Anterior Reach SKB...Small Knee Bend SLHD...Single Leg Hop for Distance TSFX...Tibial Stress Fracture xi

Chapter 1 Introduction 1.1 Running Background Approximately 54 million Americans, age range 7 to 75+ years, chose running as their primary form of exercise in 2013, which includes novice to core participants. 1 Since the early 1980 s, marathon running in particular has steadily increased to a total of 518,000 marathon finishers in 2011, a 73% increase over the last several years. 2 Americans choose to run, as it is an inexpensive, time efficient, and versatile form of exercise, which leads to substantial health benefits and well-being. Running as a form of fitness has been shown to counter act and reduce diet induced weight gain which is further associated with obesity and several other co-morbidities. 3 However, with participation in running comes an increase in risk for sustaining a running related musculoskeletal injury (RRMI). The incidence of RRMIs ranges from 19.4% to 79.3%. 4 This wide range of rates varies mainly due to modifications of definitions used by authors. The variance in time removed from running is the most altered within the definitions, ranging from one day to 1

one week. 5,6 RRMIs are the most common reason for race drop out among marathon runners. 7 Likewise, runners with one or more injuries are up to two times more likely to sustain a secondary injury. 8 Additionally, when runners sustain multiple RRMI, prolonged removal from running can occur resulting in increased psychological distress including depression, mood changes, low self-esteem, and anxiety. 9 Researchers have investigated a wide range of risk factors for runners to determine who will sustain a RRMI and who will remain injury free. Demographics, such as age, gender, weight, and height, and training variables, such as years of running experience, training techniques 10, and training errors, 11 are risk factors for a RRMI. However, most of these, including demographics and the training factors such as training errors, are not modifiable by health care professionals. Thus, there is a need to identify clinical and functional assessment tools in which clinicians can evaluate and then identify runners at risk for a RRMI. Several researchers have identified possible modifiable factors in the high school and collegiate athlete population such as running biomechanics 12, muscle weakness 13, and most commonly, history of previous injury. 4,14 Once clinicians can assess and screen runners using clinical and functional tests for possible risk factors, clinicians can then implement a prevention strategy. Ultimately, these clinical and functional assessment tools could be useful in decreasing the prevalence of runners sustaining a RRMI. Researchers 15 have recognized a variety of hip and core deficiencies across a variety of RRMIs. Patellofemoral pain syndrome (PFPS) iliotibial band syndrome (ITBS), medial tibial stress syndrome (MTSS), and tibial stress fractures (TSFX) account for approximately 30% to 61% of all RRMI and have all been linked to insufficiencies in 2

hip muscular strength and biomechanics during running. Runners who develop PFPS, ITBS, MTSS or TSFX are likely to present with hip weakness and delayed activation onset of the hip abductors, flexors, and external rotators on their injured side compared to their uninjured side. 13,16 Females with PFPS present with hip adductor and internal rotator weakness compared to healthy females. 17-19 In long distance runners with ITBS, the ipsilateral hip abductor muscles have significantly decreased strength compared to their healthy limb. 20 These specific injuries have similar etiology and show trends of having the same characteristics among runners, indicating the common factors should be addressed and studied prospectively to determine if they are in fact risk factors for development or they are resulting features from sustaining the injury. Several clinical and functional movement assessment tools have been used within the literature, to determine differences between injured and healthy participants. However, most of these studies have utilized high school and collegiate athletes, not the recreational physically active population who uses running as their primary means of fitness. 21-23 Additionally, if these tests can determine if a recovering injured athlete has the functional qualities to return to activity, then it should be established as to whether or not decreased performance on these tests can identify athletes at risk of sustaining an injury. The single leg hop for distance test (SLHD) has been used to assess athlete s movement performance which is comparable to the high functional demands of sport. 24 Collegiate female athletes with a side-to-side difference of 10% or greater were at a four times higher risk of an ankle or foot injury compared to female athletes that had less than a 10% difference. 21 3

The star excursion balance test (SEBT) is another functional test which has been shown to show significant differences in dynamic postural control in high school and collegiate athletes. 22 This test has been revised to be more clinically relevant by reducing the test time and using minimal equipment. It has also been shown to be a reliable and valid method between examiners (ICC=0.84-0.96) 25,26 allowing for accurate results. However, this test has not been extensively applied in the running population but shows potential for predicting injury in other athletic populations. If this test can show a trend for identifying those runners more at risk for developing a RRMI then it could become a standard clinical evaluation tool. 1.2 Statement of Problem To date, there are no clinical tests, functional movement assessment tools, or biomechanical analyses that have been used to detect recreational runners at risk for a RRMI. Because hip muscle weakness and biomechanical dysfunction have been identified in participants with a variety of RRMIs, there is a need to identify if these tests can be used prospectively as a screening tool for at risk runners. 1.3 Statement of Purpose The overall purpose of this study was to determine biomechanical, functional, and clinical test performance differences between full and half marathon runners who did or did not sustain a RRMI during the course of a 16 week formalized training program. The specific aims of this study were: 4

1. Determine if peak hip flexion at initial contact of running was different between runners who did or did not sustain a RRMI while enrolled in a 16 week formalized running program. 2. Determine if there was a difference in functional test performance on the single leg hop for distance (SLHD) and anterior reach of the star excursion balance test (SEBT-A) between runners who did or did not sustain a RRMI while enrolled in a 16 week formalized running program. 3. Determine if there was a difference in hip flexion and extension strength and active range of motion (AROM) between runners who did or did not sustain a RRMI while enrolled in a 16 week formalized running program. 1.4 Research Hypothesis 1. Runners who sustain a RRMI while enrolled in a 16 week formalized running program will have decreased peak hip flexion at initial contact of running, compared to runners who remain injury free. 2. Runners who sustain a RRMI while enrolled in a 16 week formalized running program will have a decreased SLHD score and a lower SEBT-A score compared to runners who remain injury free. 3. Runners who sustain a RRMI while enrolled in a 16 week formalized running program will have decreased hip flexion and extension strength, and hip flexion and extension AROM compared to runners who remain injury free 5

1.5 Significance of Study The significance of this study was to determine what adverse characteristics may present at the hip for habitual runners that would help explain development of RRMI. Once these factors can be identified, the next step would be to determine interventions that could be implemented to correct these faulty mechanics and reduce injury rate. 6

Chapter 2 Literature Review 2.1 Running Participation Running is one of the fastest growing physical activities in the United States as it is a relatively easy, convenient, and fairly inexpensive way to gain overall health benefits, challenge oneself, and on occasion support a note worthy cause. Participation in recreational races including the 5K, 10K, and half and full marathons have grown remarkably over the past decade. In 2012 these four road races had an estimated 15.5 million finishers, a 73% increase in finishers from 2000. 2 Entry rates for marathons have been steadily increasing since the 1980 s and spots in these races have been becoming more selective. Participant caps have been placed on some of the more popular races and runners will get denied entry due to fulfillment. Fletcher 27 describes a typical runner as training for enjoyment, relatively easy, and was determined and confident in their training and finishing the race. He also profiles a typical non-runner as entering a marathon to improve health and fitness but was unable to easily integrate training into daily life. Core runners are classified as active adult participants who tend to enter running events and 7

train year-round. A report by Running USA 2 surveyed core runners and their motivation to run being to stay in shape (77%), stay healthy (76%), relieve stress (61%), and have fun (61%). For many novice runners joining a running group gives them the motivation and guidance needed to safely begin distance running. 28 Chorley et al 10 describes the baseline characteristics of runners who start a running program to prepare for a marathon and concluded the typical participant in these programs are untrained and inexperienced with running, typically overweight females who have had little to no physical activity three months prior to starting the program. Since lack of running experience and training errors are among the top risk factors associated with sustaining a running related injury during training for a marathon, it is important for these training programs to tailor their protocols for those more at risk participants. 4,7,29 If training programs can properly progress novice runners then the incidence of running injuries could potentially be reduced. 10 2.2 Prevalence and Incidence Rates of Injury With a stark rise in the number of running participants comes an increased risk for a running-related musculoskeletal injury (RRMI). The prevalence of injuries in long distance recreational runners has been reported to be between 19.4% and 79.3%. 4 The large variation in RRMI rates is in part due to the multitude of definitions of a RRMI. The foundation of most definitions originates from Macera et al 30 which described a RRMI as an injury to muscle, joint, or bone of lower extremity that was attributed from running and affects training (distance, pace, speed), causes a visit to a health care professional, or the use of medications. Some researchers have taken this definition a 8

step further by placing a time frame on the number of days in which the injury affects their running or activity, while others state it has to remove them from activity completely for said number of days. A sold out race rarely has all the participants show up on race day. Along with this increasing entry rate there is an increase in the drop-out rate for these races. Runner s drop-out of a race for a variety of reasons, but the most concerning issue has been injuries. Excessive running is associated with the risk of sustaining a running related musculoskeletal injury. In the 1984 Aberdeen Marathon only 53% of the enrolled runners actually finished the race, Clough et al 7 collected questionnaires on 502 of the 1149 race drop-outs and reported that 42% of the runners didn t begin the race due to an injury. The large drop-out rates so close to race day have been causing issues among the race organizers who have to deny runners from entering the race and to those who were not able to run due to being injured. 27 There are various studies, both retrospective and prospective; examining the incidence and prevalence of runners sustaining injuries that cause these drop-out rates. However, in these studies the injuries are typically self-reported and in some cases the authors give no definition or criteria of what is considered an injury or the focus is only the injuries occurring at a specific joint and do not report the remaining injury sites. 6,31,32 The retrospective studies seen in the literature use surveys distributed to all participants, finishers and non-finishers, after the race. 7,10,33-35 Retrospective data on drop-out and injury rate is important in understanding the prevalence these injuries have on the running population; however it lacks the explanation as to why these injuries are so prevalent. These studies show trends of why runners will drop out and their rationale for doing so, 9

whereas the prospective studies track injuries along the training process to determine causes or factors associated with the development of running-related injuries. Prospective studies are needed in order to better explain and show trends among characteristics of runners who are developing injuries. Nonetheless, prospective surveys are reporting the same self-reported injuries and rely on recall similar to retrospective survey studies. The information collected from post-race questionnaires is received from the participants who either started the race and did not finish or did not start the race at all. Clough et al 7 reported that 23% of participants dropped out of because of a lack of training due to injury in the months leading up to the race, while Fletcher and Eadie 27 reported 48% of non-runners dropped out because of injury. Maughan and Miller 33 analyzed post-race questionnaire data which found 287 out of 497 (58%) of the respondents reported sustaining at least one running-related injury during preparation for the marathon. Of those 287, only 98 of them claimed that their performance in the race was adversely affected by an injury incurred during training. Van Middlekoop et al 36 collected pre- and post-race questionnaires on recreation runners and reported 65.2% of the runners did not start the 2005 Rotterdam Marathon because of an injury, and of those that did start but did not finish (5.4%) dropped-out due to an injury (51.4%). These authors also showed an injury incident rate of 18.2% occurring during the race itself. In a 12-month period preceding the Rotterdam Marathon, 54.8% of all study participants had sustained a lower extremity running related musculoskeletal injury. A study by Chorley 10 examined 1,548 runners enrolled in a 25-week training program, 52% of these runners were training for their first marathon and 12.5% of those who have trained for a marathon 10

have never completed one. Chorley also reported of the 31.7% of runners in this program who have completed a marathon, 35.8% of them had at least one failed attempt. 2.3 Biomechanics of Running 2.3.1 Running Gait Cycle The running gait cycle consists of two main phases, the stance phase and the swing phase, which is divided into 40% and 60%, respectively of one gait cycle. A gait cycle begins when one foot contacts the ground (initial contact) and ends when the same foot comes back into contact with the ground. At the beginning and end of each swing phase there is a moment where both feet are airborne, termed the double float, which comprises approximately 10% of the gait cycle. Schache et al 37 subdivides the stance phase into an initial contact, absorption, mid-stance, propulsion, and toe off periods. As the limb comes in contact with the ground it then absorbs the ground reaction forces. Midstance is marked when the center of mass horizontally decelerates and begins to move forward and vertical, thus beginning the propulsion phase. 38 The limb begins to propel the body forward until toe off, marking the start of the swing phase. The swing phase is made up of early, middle, and late swing, encompassing approximately 60% of the cycle. 39 The early swing occurs just after toe off until initial contact of the contralateral limb, midswing duration is from initial contact to toe off of the opposite limb, while the late swing occurs from toe-off of the opposite limb until the swing limb makes initial contact. 39 The periods of double float occur during early and late swing phases. 11

2.3.2 Running Kinematics In the sagittal plane, there are various findings concerning the motion of the lower extremity during each phase of the gait cycle. Many of these controversies are attributed to differences among research designs and variations in collection of gait speed, measurement methods, and running techniques. 37 As running velocities increase so does the step and stride lengths of the gait pattern, which in turn alters the running kinematics of the lower extremity. The range of motion at the hip, knee, and ankle joints vary depending on the variables previously mentioned as well as the onset of muscle fatigue. Another variable which alters kinematics is foot strike patterns which typically change as running speed increase as well; walking and slow jogging is more associated with heel striking while forefoot patterns are seen in running and sprinting. 40 Kasmer et al 41 examined foot strike patterns in 1991 runners at 8.1 km of a marathon and found 94% of runners were heel strikers while the remaining 6% made up of forefoot, midfoot, and split runners. Since the analysis occurred at 8.1 km the variable of fatigue was not accounted for. Typical distance running is performed at a medium running speed (actual speed not reported) and has been found to have an average of 46 degrees of hip and 63 degrees of knee range of motion during a heel strike gait cycle. 40 This is supported by Pink et al 42 who found the hip to go through 40 degrees of motion during a cycle at a self-selected running speed in recreational runners. During initial contact the hip is in roughly 20 degrees of flexion and the knee is in roughly 15 degrees of flexion. Maximal ankle dorsiflexion, hip flexion, and knee flexion were all observed at midstance. 42-44 At toe off 12

the hip is in roughly 11 degrees of extension and stays in the same position throughout the early swing phase. Franz et al 45 analyzed self-selected running speed gait of healthy runners and found maximal hip extension occurs at roughly 50% of the gait cycle which marked just before toe-off. During the propulsion phase, the knee moves into extension averaging 25 degrees of flexion. 38 During the early swing phase, the hip is already in maximal extension, the knee is fully extended and begins to flex in order for the foot to clear the ground. The hip begins moving into flexion at the beginning of the midswing reaching maximal flexion just at the end of the period. The transition between midswing and terminal swing is when the hip begins to extend to prepare for initial contact. Most authors are in agreement that maximal hip flexion occurs during late swing where it then begins to extend to prepare for initial contact. 37,38 Pink et al 42 reports maximal hip flexion to be 31 degrees, while Ounpuu 40 found hip flexion to reach as much as 45 degrees. At the end of late swing the hip stayed in a roughly fixed position of 16 degrees of flexion as it becomes in contact with the ground. As running velocity increases, hip flexion range of motion also increases, while the amount of hip extension and the overall time spent in stance decreases. 38,46 Chan- Roper et al 47 observed slow and fast runners during an actual marathon and found there to be significant changes in sagittal-plane peak knee and hip kinematics between 8 and 40 km (5 and 25 miles). These authors reported peak knee flexion during stance and peak hip extension during swing decreased while peak hip and knee flexion during swing increased at 40 km in both slow and fast running groups. They concluded the onset of muscle fatigue was responsible for changing these kinematic variables. 13

2.3.3 Neuromuscular Activity during Running Schache et a 48 l examine the kinematic changes in the hip, knee, and ankle at three increasing speeds. The authors reported finding a significant increase in the sagittal plane torques at all three joints. At initial contact electromyographic data shows that the rectus femoris of the quadriceps muscle group and the long head of biceps femoris of the hamstring group are most active. 39,44 Montgomery et al 39 found the lower portion of gluteus maximus to be active and functioning to stabilize the hip during the absorption period. These authors also observed the rectus femoris to be active from late swing until midstance as it prepares for shock absorption at initial contact during the absorption phase. Ounpuu 44 reported the rectus femoris to be concentrically contracting to produce an extension moment during initial contact, and at midstance the hip muscles switch from concentric to eccentric contractions. From midstance to toe-off the gluteus maximus is firing to produce an extension torque to assist in propelling the body forward. Then, as the body moves into propulsion, these authors also found the long head of the biceps femoris initiated hip extension. Gluteus medius and minimus remain active in terminal stance to help with lateral stabilization of the hip. 49 The hip extensors are most dominant immediately before and right after initial contact whereas the flexors are mainly dominate in the late stance and early swing phase. 38 Immediately after toe-off, rectus femoris and iliacus activate to initiate hip flexion and continue to concentrically work until middle swing where semimembranosus and biceps femoris eccentrically contract to control flexion. The rectus femoris is the only muscle still active during midswing in order to keep the tibia from translating posteriorly 14

as the knee begins to flex. 39 As the limb enters into late swing, in preparation for foot strike, the semimembranosus, biceps femoris, and lower gluteus maximus begin to activate and extend the hip. Thus, authors conclude that the hip flexors may be the most important for obtaining maximal forward momentum during running. 39,43 2.4 Epidemiology of Running Injuries Running long distances consistently is known to cause various overuse injuries of the lower extremity. 50 A review by Lopes et al 15 found medial tibial stress syndrome (MTSS), patellofemoral pain syndrome (PFPS), iliotibial stress syndrome (ITBS), and tibial stress fractures (TSFX) account for 30% to 61% of all RRMI s sustained during marathon training. 2.4.1 Patellofemoral Pain Syndrome Patellofemoral Pain Syndrome (PFPS) has been defined as an overuse injury characterized by chronic, aching pain around the patella that is exacerbated by climbing stairs, squatting, or sitting with the knees flexed for prolonged periods of time. 51 Several theories exist concerning the etiology of and predisposing factors for patellofemoral pain, with several stemming from complications at the patellofemoral joint itself. The development of PFP symptoms are considered to be multifactorial and occur when multiple dysfunctions and malalignments are happening simultaneously. 51 However, more recently researchers have moved proximally to the hip to determine if dysfunctions of the lumbo-pelvic-hip-complex could be a contributing factor in PFPS. 52 A review by Waryasz 53 reported on all the potential risk factors associated with PFPS, including 15

muscular tightness, muscular weakness, malalignment, and patellofemoral joint laxity. Earl et al 51 suggest three factors which lead to the development of PFPS which are dynamic malalignment (DM), abnormal muscle activation, and static alignments. Dynamic malalignment is defined by these authors as malalignment that occurs during movement as a result of poor neuromuscular control of the trunk and lower extremity. In a single leg step down task, DM is described as seeing contralateral pelvis drop, hip adduction and internal rotation, knee abduction, tibial rotation, and foot pronation. 51,52 Several case studies and retrospective studies have examined the various differences in subjects with and without PFPS, providing a clear understanding of how this injury alters variables such as muscle function and lower extremity kinematics. 18,51,52,54,55 It is important to understand what these changed factors are first before attempting to determine what makes an individual at risk for developing a running injury. A case report following two subjects with patellofemoral pain presented with excessive hip adduction and internal rotation with knee abduction during gait and a step down task while also presenting with weak hip extensors, abductors, and external rotators. 56 Two studies comparing eccentric hip strength between PFPS and healthy control groups found the injured group to have a significantly decreased eccentric hip abduction torque compared to the controls. 18,54 One of those studies found eccentric hip external rotation torque to be decreased 18, while the other found no differences between groups in either hip external or internal eccentric rotational torques. 54 Weakness in hip abduction will allow for excessive hip adduction during functional movements, which has been a variable of interest in predicting PFPS in individuals. Earl et al 51 were able to predict 92% of the patients with diagnosed PFPS when combining variables of iliotibial 16

band and hamstring flexibility, navicular drop and pronation of the foot, knee flexion, hip adduction, and gluteus medius and vastus medialis obliqus EMG onset. The prospective findings of risk factors for RRMI have been non-modifiable characteristics which lead researchers to aim at identifying which risk factors are modifiable in order to create better prevention and treatment protocols for PFPS. 57 Only one prospective study has been conducted examining the incidence and risk factors for PFPS; however it was within a military, rather than a running focused population. Boling et al 57 concluded that decreased quadriceps and hamstring strength, and increased hip external rotation strength were risk factors for the development of PFPS in naval academy cadets. Therefore, there is a need for more prospective studies to examine the risk factors associated with the development of patellofemoral pain syndrome in the running population. 2.4.2 Iliotibial Band Syndrome Iliotibial band syndrome is lateral knee pain caused by friction of the iliotibial band over the lateral femoral epicondyle during repetitive flexion and extension of the knee which causes inflammation and irritation. Lateral knee pain typically arises just after initial contact when the knee is in roughly 20 degrees of flexion in athletes with ITBS. 58 A theory that is not supported by published literature, but has been a variable of interest is excessive pronation that causes increased tibial internal rotation. 59 Some of the more studied factors potentially leading to the development of ITBS include tightness of the iliotibial band causing it to shorten, weak hip girdle musculature, high weekly running mileage, and tightness of the knee musculature complex. 20,59-62 A conclusion 17

made by Finoff et al 60 suggests the factors contributing to PFPS are similar to those in ITBS and runners who present with either injury have similar kinematic characteristics. A cross-sectional study by Ferber at al 61 found runners with history of ITBS had a greater peak hip adduction angle compared to matched healthy controls. Fredericson et al 20 found runners with ITBS had significantly decreased hip abductor strength in their affected limb compared to the uninjured limb and healthy controls. A prospective study of high school runners by Finoff et al 60 concluded that PFPS and ITBS have similar hip kinematic risk factors of weak hip external rotators and abductors. this is supported by a prospective biomechanical study performed by Noehren et al 62 which found factors such as increased peak hip adduction angle and greater frontal plane joint moments in runners with ITBS compared to healthy controls. 2.4.3 Medial Tibial Stress Syndrome Medial tibial stress syndrome (MTSS) is also among the top injuries developed by runners. 15 This condition has been better known as shin splints which in 1966 the American Medical Association 63 defined as pain or discomfort in the leg from repetitive running on hard surfaces or forcible excessive use of the foot flexors; diagnosis should be limited to musculotendinous inflammations, excluding fracture or ischaemic disorders. Updated definitions have been produced in the literature which varies from author to author making a combined review of the literature difficult. One controversy in defining MTSS is the inability to agree on a localization of pain, whether it is found in the proximal or distal tibia, or posterior, medial, anterior or lateral aspect of the lower leg. 64 The only common factors among shin splint diagnosis are being located in the lower 18

leg and exhibits in response to exertional stress. 64,65 However, the diagnosis of shin splints is unable to rule out or differ between diagnosis of other lower leg pathologies including deep vein thrombosis, periostitis, stress fractures, or tendinitis of the posterior or anterior tibialis, soleus, or flexor hallucis longus muscles. 64,65 To date, there is no universal resolution on the pathophysiology of MTSS, partly due to its broad general term and having no clear-cut diagnosis. Before an actual diagnosis of MTSS can be issued it is important to understand which muscles are involved with creating this pain and discomfort. Several muscles have been theorized to create MTSS: soleus, tibialis posterior, and flexor digitorum or hallucis longus. More specifically, periostitis or repeated traction on the periosteum of these muscles is the culprit of MTSS. 66 Another speculation is that the soleus undergoes strain as it is eccentrically working during running to resist excessive pronation. 67 There have been retrospective studies on athletic populations that identify non-modifiable characteristics such as excessive static foot pronation and increased navicular drop, varus rearfoot or forefoot, and increased knee varus tendencies. 65,68 Bennett et al 69 took measurements of calcaneal position, tibiofibular varum, and active dorsiflexion in cross country runners at three high schools at the beginning of a season. Cases of MTSS were reported and athletes who exhibited symptoms associated with MTSS and had pain during palpation along the medial tibial border were included in the injured group. A navicular drop test was then performed in these injured athletes at the time of injury onset and at the end of the season navicular drop tests were performed on matched healthy runners. The navicular drop test was the only significant finding among the four tests performed and indicated that the differences in the navicular drop 19

measurements were explained by 17-18% of the variability in development of MTSS. 69 However, since this measurement was taken after onset of injury it should be interpreted with caution. Another prospective study examining 230 high school runners found females who showed increased internal rotation range of motion at the hip had a significantly increased risk of developing MTSS (OR=0.91). 70 2.4.4 Tibial Stress Fractures Tibial stress fractures (TSFX) are considered one of the more severe conditions developed by runners and typically leads to a prolonged period of inactivity, and removal from practice and competition. Stress fractures are a result of excessive and repetitive loading, in conjunction with high impact forces during distance running. Authors believe these high impact peak values, vertical ground reaction forces, and high tibial shock are related to the development of stress fractures. 71 Other authors consider static anatomical alignment to be a risk factor of tibial stress fractures. 72 Kinematic factors such as greater rearfoot eversion and frontal plane alterations at the hip and knee during running could put runners at an increased risk of injury. 73 A survey by Laker et al 74 found factors such as training volume, intensity, shoe type, and surface did not significantly increase the risk of developing a stress fracture in elite cross country runners. A prospective study by Milner et al 73 found greater peak hip adduction and rearfoot eversion during the stance phase of running in runners who had a history of tibial stress fracture compared to healthy runners. The altered mechanics during running, especially at frequent and long distances, change the load distributions of the vertical ground reaction forces potentially causing TSFX. 71 One of the prospective studies in the 20

literature concerning TSFX collected anthropometric measurements in 230 high schools cross country and track athletes over 8 years. The only significant correlation found was a decreased straight leg raises score in males who sustained a TSFX. 70 2.5 Risk Factors of Running Injuries Anatomical, biomechanical, and training factors are the three main categories shown to have an association with running related injuries. 50 Within these categories are two different types of variables: modifiable and non-modifiable characteristics. The anatomical variables that have been found in the literature include characteristics which are considered alignment abnormalities genu varum or valgum, leg length discrepancies, anterior pelvic tilt, forefoot or rearfoot valgus or varus, pes cavus or planus. 75 The biomechanical factors, which have been attributed to injury susceptibility, have not been as intensively researched. Foot strikes patterns, rearfoot or forefoot striking, has been seen to either increase or decrease vertical ground reaction forces placed on the lower extremity. Alterations in running gait and striking patterns during distance running changes ground reaction forces, which is thought to be associated with RRMI. 76 The category of training variables includes a wide range of factors such as training frequency, duration, volume, experience, running surfaces, and recreational or competitive running. An epidemiological review by Van Mechelen et al 75 on running injuries established only four factors to be consistently associated with RRMI which are running experience, previous injury, competitive running, and excessive weekly distance. The majority of data on RRMIs comes from retrospective studies which tracked selfreported incidences and exposures during a period of training leading up to a marathon 21

and self-diagnosed injuries or pain before, during, or after a race. 8,34,50,77,78 These studies have made conclusions about associated factors for injury based upon questionnaires or retrospective measurements. Few studies have examined prospective characteristics that would predispose physically active populations to these overuse injuries. There is a need to prospectively identify the modifiable characteristics that are shared among runners in order to create more effective prevention and rehabilitation strategies. 2.5.1 Non-Modifiable Variables Non-modifiable variables are considered characteristics in which the runner has no control of changing or altering. Factors such as age, height, sex, and anatomical alignment such as: genu valgum/varum, pes cavus/planus, or leg length discrepancies, are all variables that cannot be changed in an individual. These factors are worth noting to make a person aware they may be more at risk for sustaining and injury if they possess these characteristics, however there will be little prevention strategies associated with these variables. Anthropometric variables such as pes cavus, ankle range of motion, leg length discrepancies, and lower extremity alignment have been considered variables associated with developing overuse injuries; however there is conflicting evidence regarding these factors. 79 A retrospective study by Wen et al 80 concluded no significant difference for arch index, knee varus, heel valgus, or leg length discrepancy, between injury groups. A prospective study investigating anatomical variables in distance runners such as knee and patellar alignment, pes cavus or planus, somatotype, and running shoe wear pattern found no significance associated with increased risk of injury. 8 A study by Lun et 22

al 81 concluded static lower extremity alignments of leg length, Q-angle, hip range of motion, or longitudinal arch length, shows no significant evidence of putting runners at risk for a RRMI during training. However, they did find a significant difference between anatomical characteristics such as ankle dorsiflexion, knee genu varum, and forefoot varus in runners developing PFPS compared to the development of other RRMIs. Age and sex have been two variables widely considered to be risk factors of developing an RRMI. Buist et al 29 suggests males and females simply have different risk profiles. A study by Claiborne et al 82 found no significant gender differences between men and women in frontal plane knee kinematics; however they did show a difference in raw and body-mass normalized hip strength measurements between the genders. Since there was no correlation between strength and movement patterns they were unable to conclude one gender as being significantly more at risk for injury than the other. 82 Another widely supported risk factor for sustaining a running injury is the history of a previous injury 4,8,20,30,36,75 Three conclusions have been made as to why previous injury would put runners at an increased risk for another injury: 1) the injury is not completely resolved, 2) damaged tissue is less protective or efficient than the original structures, or 3) the factors which caused the original injury might still be present. 83 A survey done by Macera et al 30 reported a new injury in the 12 months preceding a marathon was associated with the development of another injury in the 12 months after the marathon (OR =2.7 and 1.8, male and female runners, respectively). Walter et al 8 reported previous injuries to be a significant factor associated with developing an injury (RR= 1.69 and 2.35, male and female runners respectively). It is still important to identify 23

what caused the original injury in order to prevent a recurrent one and possibly lead to prevention of the first time injury altogether. 2.5.2 Modifiable Variables Characteristics and factors in which a runner has control of altering or avoiding are considered to be modifiable variables. Some of the most significant factors consistently reported within the RRMI literature include lack of running experience, training error, previous injury, excessive weekly distance, and competitive running. 4,34,50,65,75,84 A majority of studies examining training variables as risk factors have utilized questionnaires and self-reported data, possibly contributing to variability between studies due to the differences in interpretation, accuracy, and recall of information. Results from these studies should be considered cautiously and need to be examined prospectively before any of the variables can be exposed as putting a runner at an increased risk for injury. Certain modifiable training techniques include number of days, weekly mileage, months of preparation prior to race, stretching, various forms of cross-training (activities other than running), and variations of speed during workouts. Nonetheless, amongst a plethora of studies, weekly running distance has been the most agreed upon risk factor among authors. 4,65,75 Running a weekly average of 60-64 km or more per week places runners at an increased risk for a RRMI. 8,30,85 Specifically, runners who run more than 64 km per week have a 64% greater risk for an RRMI. 8 Some authors suggest the optimum mileage should be between 30 to 60 km per week in the 3 months prior to a race. 86 Several authors have discussed the appropriate range of weekly running mileage during the months leading up to a marathon. 8,30,36,80,85 24 Lysholm 11 reported a

trend in long distance and marathon runners having an increased injury rate in a month which followed a month with an increase in training distance and intensity. 11 In a prospective study by Macera et al 30, running more than 40 miles per week, having a lower extremity injury in the previous year, and running regularly for less than 3 years were significant predictors of risk for sustaining a RRMI. This is supported by Fields, 85 who reported that a history of previous injuries and total mileage are two factors that show a strong correlation to predict injuries. 2.6 Functional Tests Muscle flexibility can be categorized as either static, in which the range of motion is measured at a joint of an immobile subject, or dynamic, in which the resistance is measured in an active motion at a joint. 87 Some of the most common ways to assess hamstring muscle flexibility that can be used clinically are using a goniometer, inclinometer, or a sit and reach test. 50,88,89 In military populations, flexibility of the lower extremity is associated with an increased risk of injury. 90 A lack or imbalance in hip flexibility could also pre-dispose athletes for injuries. 91 Knapik et al 91 collected active range of motion and strength measurements during a pre-season screening of collegiate female athletes on 8 teams, they concluded athletes to be more at risk for injury if they had an imbalance of more than 15% of active hip extension range of motion. Witvrouw et al 88 collected standard goniometric measurements in professional male soccer players and reported a statistically significant correlation between decreased flexibility of the hamstrings and increased rates of a hamstring injury. They determined decreased hamstring flexibility to be an intrinsic risk 25

factor for the development of a hamstring injury. It is important to note this finding; however it can only be used in the male professional soccer population and used to predict hamstring muscle strains, not a lower extremity injury in general. The current way to clinically assess muscle strength is by using a 5-point scale, which has been noted as subjective and having poor validity and reliability. 92 Isokinetic machines are considered to be the standard in measuring muscle strength and have also been used in clinical settings but are extremely expensive therefore are not seen in many settings. Another tool that has been used by clinicians is the hand held dynamometers (HHD). These devices are much more practical to use in a clinical setting considering their simplicity, portability, and are rather inexpensive. Differences in reliability and validity stem from the various positions each muscle could potentially be measured in. 93 Thorborg et al 93 examined the reliability and validity using a HHD in assessing 6 different hip muscles each in two different testing positions and reported finding moderate to strong reliability in all 12 positions (ICC = 0.74-0.99). These strong findings suggest a HHD is a clinically relevant way of measuring muscle strength and gives the clinician an objective measurement, which can be used to see small differences in strength gains in athletes. 2.7 Clinical Tests Poor hip function and weak hip musculature is a known modifiable factor in runners with a RRMI compared to healthy runners, thus it is important to have a clinical assessment tool that can be used to identify these factors. There are several tests currently used by clinicians to screen athletes for these muscular imbalances and dynamic postural 26

control; however they have not been used in the running population as a pre-training assessment tool. 16,21,22 Such tests such as the single leg hop for distance (SLHD) and the star excursion balance test (SEBT) are among the functional assessment tests used in predicting imbalances and deficits among athletes. 16,21,22 In a review by Kivlan and Martin 23 the SEBT show evidence as valid in assessing gluteal function and tendinopathy. This shows clinicians are able to use these functional performance tests to identify hip dysfunction in athletic populations. The literature also shows the one-leg hop test to have strong test-retest reliability for three consecutive trials. 94,95 Due to the high validity of these tests in assessing dynamic control, the next step is to identify prospectively if they can be used as clinical prediction tests to screen athletes and recreational runners for injuries. 2.7.1 Star Excursion Balance Test The original task of the star excursion balance test (SEBT) consisted of 8 different reach directions, recently has been modified to only 3 reaching directions, anterior, posteromedial and posterolateral, and has moderate to strong associated reliability and validity in assessing dynamic postural control. 22 Robinson and Gribble 25 determined only 4 practice and 3 test trials were needed for accurate measurement of dynamic postural control, making the test more clinically relevant and efficient (ICC = 0.84-0.96). The anterior reach test is performed with the toes at the start of a tape measure secured to the ground with the objective to reach forward as far as possible, while maintaining the testing posture and balance, tap the toes on the tape measure and return to starting position. The subject is instructed to keep their hands on their hips and their heel in 27

contact with the ground during the duration of the test. The posteromedial and posterolateral reaching directions are similar to the anterior except the heel is placed on the start of the tape measure instead of the toes. The distance reached for each trial is recorded and the means are calculated. These means are normalized to the subjects leg length and presented as percentages. 96 The star excursion balance test has been shown to significantly identify dynamic postural control deficits in a wide population of athletes ranging from high school to collegiate in various sports such as basketball, soccer, and football. 22 According to a review by Gribble et al 22 the SEBT has potential to clinically predict athletes who are at risk for an injury. This test has yet to be studied extensively in the running population and there is a need to identify if the SEBT can be used to determine runners that are at risk for developing a RRMI. 2.7.2 Single Leg Hop for Distance There is a variety of methods in the literature regarding the performance of a single leg hop test. The protocol for a single leg hop measuring distance has many similarities among them with differences being location of measurement, heel-to-heel, heel-to-toe, or toe-to-toe, and the placement of the subject s hands during the test, behind the back, on the hips, or no restrictions. There is an agreement on the consideration of a successful trial, meaning balance was kept at landing and there was no shifting or moving of the foot after the jump was completed. 21,24,94,95,97 After practice trials, three test trials are recorded, means are calculated and normalized to leg length and presented as percentages. 28

The single leg hop for distance test has been useful as a preseason screening tool to predicting lower extremity injuries in collegiate athletes. 21 This test has also been used as a return to play assessment in athletes recovering from an anterior cruciate ligament (ACL) injury. 98 The SLHD has also been used to identity if patients with either ACL deficits or reconstructed ACL s had fully recovered from their injury and set out to determine if these patients had regained their landing strategies. 98 Van der Harst et al 97 examined the differences between leg dominance during the single leg hop test in healthy subjects. When comparing between legs for horizontal hop distance, they found a statistically significant difference between the dominant limb and the non-dominate limb within subjects. 2.8 Summary A concern with physical health has boomed in the past decade in America and people have begun to use running as their primary form of activity due to the diversity and ease of the activity. Popularity of recreational running has caused an increase in road racing participation causing people to run more mileage at faster speeds. As running continues to grow in popularity so does the increase in the rate of RRMIs among recreational runners. Many lower extremity running related musculoskeletal running injuries have the potential to cause runners to lower weekly mileage, drop out of a training program, drop out of a race, and potentially quit running altogether. A halt to regular exercise and prolonged periods of physical inactivity may lead to numerous detrimental health illnesses. 99 Therefore, there is a need to identify the causes of these running injuries, ways in which to screen runners for these risk factors, and eventually 29

determine ways to prevent injuries in hopes the popularity of running continues to steadily increase. Current research is needed to focus prospectively to determine the characteristics associated with the onset and development of these chronic issues. Once it is established as to why runners are sustaining these injuries during training then the focus needs to be on ways to screen these recreational runners before they begin their training programs in order to determine anyone at an increased risk for injury. Several tests have been assessed in hopes to predict those more at risk; however, a lack of evidence is seen for the recreational running population. This population has different loads placed on the body compared to high school or collegiate athletes in sports like football, soccer, and basketball. If there can be reliable and valid clinical assessment tools which clinicians can feasibly use to screen runners, then the next step should be to focus on the development of prevention strategies for these chronic running related injuries. Because the major risk factor associated with the development of these injuries is a history of a RRMI, the goal should be to prevent the first time injury in order to potentially reduce the recurrence rate among these runners. 30

Chapter 3 Methods 3.1 Study Design. Prospective cohort study. 3.2 Subjects All participants were females over the age of eighteen and enrolled in a 16 week formalized marathon and half marathon running program in the city of Toledo, Ohio (Table 3.1). All participants were cleared to participate by signing a waiver prior to enrolling in the program. Participants were excluded from the study if they had a neurological condition that affects muscle activity, were currently pregnant, or were currently injured. After being cleared for participation, participants signed an informed consent form approved by the University of Toledo s Institutional Review Board (#108498). 31

Table 3.1 Demographic mean and standard deviations for all participants Female Age Height Mass Participants 54 38.75+9.58 1.66+0.07 66.29+13.21 Age = Years; Height = Meters; Mass = Kilograms 3.3 Instrumentation 1. Motion Analysis 12-camera Eagle Digital motion capture system (Motion Analysis Corporation, Santa Rosa, CA) 2. Visual 3D Basics/RT software (C-Motion, Inc., Germantown, MD) for processing and analyzing all data 3. Hand-Held Dynamometer (microfet2, Hogan Health Industries, West Jordan, UT) 4. Standard tape measure 5. Standard goniometer 6. Standard inclinometer 7. Timing gaits 3.4 Independent Variables 1. Group a. RRMI group b. Injury free group 32

3.5 Dependent Variables 1. Joint Angles at Initial Contact of Stance Phase a. Peak hip flexion (HFXA) 2. Active Range of Motion a. Hip extension (HEXT AROM) b. Hip flexion (HFLX AROM) 3. Strength a. Hip extension (HEXT STRG) b. Hip flexion (HFLX STRG) 4. Single Leg Hop for Distance (SLHD) 5. Star Excursion Balance Test- Anterior Reach (SEBT-A) 3.6 Procedure All tests were performed at a one-time baseline testing session, prior to the start of the 16 week formalized running program. Each session lasted approximately two hours in length. Tests that would induce more fatigue were performed towards the end of the testing session in order to remove the effects of fatigue from the other tests and measurements. The order of the tests was block randomized (Figure B-1). Additionally, all tests were performed bilaterally and the starting limb was also randomized for each subject, and held consistent for all tests. 33

All participants filled out questionnaires that provided descriptive and demographic information that was extracted to define the two different cohorts (RRMI and injury free) as well as provided information of previous RRMI history. Running gait kinematics was recorded using a Motion Analysis 12-camera Eagle Digital motion capture system (Motion Analysis Corporation, Santa Rosa, CA) as the participants ran across the room and struck the force plate embedded in the floor (Figure C-1). To start, forty one reflective markers was placed on anatomical landmarks over the lower body and trunk using a modified version of a previously established marker set. 100 A static position image of the participant was taken to normalize the dynamic trials for each individual, allowing for comparison between individuals. Following the static trial, ten markers were removed leaving 31 tracking markers while the participants performed the dynamic tasks (Figure C-2). Participants were then instructed to run across the motion capture field at a selfselected pace. This pace was described as a normal running speed in which it is not slow enough for continuous conversation, yet not fast enough in which you are winded afterwards. The participants familiarized themselves with running across the force plate at this pace, while the researchers gave feedback on pace using timing gaits. Participants were instructed to look forward at an X on the wall instead of looking down at the force plate. Trials were afforded until the speed was on target; the running felt natural and resulted in a successful trial. A successful trial was denoted when the selected foot struck the force plate in entirety, and did not speed up or slow down while crossing the force plate, and did not take multiple shortened strides before striking the force plate. After the 34

practice trials, six successful collected trials were performed for that limb, followed by practice trials and six successful collected trials on the opposite limb. For the SLHD, the volunteers stood with their toe of the limb to be tested behind a designated line placed at the zero mark of a measuring tape. The participants were instructed to keep their hands on the hips as they hopped as far as possible on the single test limb. A successful trial was one in which the person kept the hands on the hips and maintained balance for at least three seconds (Figure D-1). An unsuccessful trial was when they lost balance, landed using assistance from the opposite leg, or took an extra step when landing. Unsuccessful trials were excluded from data collection and repeated until three successful trials were measured. The distance measured was from the starting line to where the heel of the test limb landed. 21 The distance was normalized using the subject s height and scores were reported as percentages. Participants also performed the anterior reach of the star excursion balance test (SEBT-A). The participants were barefoot during the test. The participant s toe was placed at the zero mark of a tape measure. While balancing on the test leg, the participants kept their hands on their hips and their heel flat on the ground while they reached forward as far as possible. At the maximum reach position the participants tapped their toe on the tape measure and returned to the starting position without losing balance (Figure D-2). Four practice trials were given followed by three test trials. The spot in which they touched the line with the toe was marked and measured. Trials were considered unsuccessful and repeated if hands were removed from the hips, stance leg heel lifted off from the ground, the participants lost balance, or their foot was moved from the starting position. The previously measured true leg length was used to normalize 35

reach distances and scores were reported as percentages. Hip flexion active range of motion (AROM) was performed with the participants placed in the supine position on a treatment table with arms at the side, and both lower limbs in hip and knee extension. The investigator placed the inclinometer at the distal end of the anterior tibia. Next, the participants actively flexed the test leg to maximum hip flexion and held it there while the investigator measured the angle in degrees on the inclinometer (Figure D-3). The investigator monitored for compensatory movements that would have distorted the measurement such as the opposite leg lifting off the ground or the knee flexing, the test leg flexing at the knee, or the pelvis rotating posteriorly. Additionally, if the participants produced a quick, uncontrolled hip flexion and could not hold the position for at least 3 seconds, the participant was asked to perform the movement again. Hip extension AROM was performed with the subject in the prone position on the treatment table with a stabilization strap placed over lower back. The investigator positioned the goniometer with the center point at the greater trochanter, stationary arm in line with the iliac crest and acromioclavicular joint of the shoulder and the moving arm was in line with the center of the lateral femoral condyle. Keeping both limbs in full extension, the investigator instructed the participant to lift the testing leg off the table into extension as far as possible. The investigator was watching for compensatory movements such as any pelvic rotation, knee flexion, or the hip rising off of the table (Figure D-4). Hip flexion strength was measured with the participants lying supine on the treatment table with a strap placed over the anterior superior iliac spine to stabilize the pelvis. The test limb was lifted into 90 degrees of hip and knee flexion (Figure D-5). The 36

tester placed the center of the hand-held dynamometer (HHD; microfet2, Hogan Health Industries, West Jordan, UT) 5.08 cm proximal to the lateral knee joint line on the anterior thigh. Participants were instructed to perform a 5 second contraction, with a ramp-up at seconds five and four, followed by three seconds of maximal contraction. Three trials on each limb were performed. There was a 30 second rest between trials while alternating limbs. Strength measurements were recorded in Newton s and averaged across all three trials. Additionally, moment arm measurements were taken. The moment arm was the distance from the greater trochanter of the femur to the lateral femoral condyle, minus the 5.08cm HHD placement. The moment arm measurement was then converted from centimeters to meters. Hip extension was performed with the participants positioned prone on the treatment table with a strap placed over the gluteus maximus to secure the pelvis to the treatment table (Figure D-6). The tester placed the center of the HHD 5.08cm proximal to the lateral femoral condyle on the posterior thigh. The knee of the limb being tested was flexed to 90 degrees while testing while lifting the thigh off the table, driving the heel upward towards the ceiling. The same instructions and procedures used to test hip flexion strength were utilized. 3.7 Injury Tracking and Analysis Once the 16 week formalized running program started the investigators attended the formalized group meetings twice a week, (Thursday nights and Saturday mornings) to track all RRMIs sustained by the participants. The definition used was a modified version of definitions previously used within the literature. 101 Injuries were defined as a 37

musculoskeletal injury of the lower extremity or low back that occurred as a result of running and met at least one of the three following criteria: 1) Assessed as an injury by same certified athletic trainer or licensed physical therapist attending bi-weekly meetings; or personal health care provider, 2) Required the athlete modify or be removed from running activity (time, distance, and/or speed) for at least one planned training day, or 3) Replaced running with a cross training activity (i.e., elliptical, swimming, cycling, etc.), for at least one training day. Participants were asked to report any pain or symptoms to the investigators, in which the investigators then performed an evaluation (Figure E-1). The investigators tracked the diagnoses and treatment for each RRMI, for each individual. Follow-up calls were made to track the amount of time participants were removed or modified physical activity due to an RRMI. Once diagnosed with a RRMI, participants would be placed in the RRMI group in which they would remain for analysis. (Figure F-1) 3.8 Data Processing Running kinematics was captured and processed using Cortex 3.6.1 software. Kinematics and kinetics were collected at a sampling rate of 200 Hz and 2000 Hz, respectively. A cut-off of 20N was used to identify initial contact and toe-off, which identified stance phase. Data was transferred to Visual 3D software and filtered using a 12 Hz low-pass, fourth order Butterworth filter. 55 Stance phases were normalized to 100% for each subject. The final measures of interest were peak hip flexion at initial contact during running. 38

Active range of motion of hip extension and flexion was recorded and analyzed in degrees. Strength measurements were extracted in forces (newtons, N), multiplied by the moment arm (m), and divided by body mass (kg). The final value was Nm/kg. The SLHD was measured as the average of the three jumps in centimeters, converted to meters, normalized to height, and expressed as a percentage. The SEBT-A was measured as the average of three trials in centimeters, normalized by leg length and expressed as a percentage. 3.9 Statistical Analysis Independent t-tests were used to analyze each dependent variable between the RRMI and injury free groups, for a total of seven independent t-tests. All data was processed using SPSS software (version 21.0). P values were set a priori at P < 0.05. Cohen s d effect sizes were calculated. 39

Chapter 4 Results 4.1 Results Fifty-four female runners were tested at the beginning of a 16 week formalized marathon training program to determine if differences exist on baseline strength, ROM, and clinical tests between runners who sustain a RRMI and those who remain injury free (INJF). Of these 54 females, 38 remained injury free (39.60 + 9.72yrs, 1.66 + 0.07m, 68.06 + 14.23kg) and 16 sustained a RRMI (36.75 + 9.22yrs, 1.64 + 0.07m, 62.00 + 9.47kg; p>0.05, and Table 4.1) Table 4.1 Group demographics mean and standard deviations Age Height Weight RRMI 36.75 + 9.22 1.64 + 0.07 62.00 + 9.47 Injury Free 39.60 + 9.72 1.66 + 0.07 68.09 + 14.23 40

4.1.1 Kinematics Peak hip flexion angles at initial contract during running showed no significant difference between RRMI (25.27 + 4.79 o ) and injury free groups (27.80 + 4.79 o ; t(52)= - 1.48, p=0.14; ES=0.38, and Figure 4-1). Figure 4-1. Hip sagittal plane angles during stance phase 4.1.2 Active Range of Motion There was no significant difference in hip extension (RRMI: 15.09 + 5.40 o ; INJF: 15.86 + 4.88 o ; t(52)= -0.51, p=0.61; ES=0.14) or flexion (RRMI: 73.33 + 12.16 o ; INJF: 75.07 + 12.37 o ; t(52)= -0.47, p=0.63; ES=0.14) range of motion between groups (Figure 4-2). 41

Degrees 100 90 80 70 60 50 40 30 20 10 0 HEXT HFLEX RRMI INJF Figure 4-2. Sagittal plane active range of motion 4.1.3 Strength Peak hip extension (RRMI: 0.71 + 0.14nm/kg; INJF: 0.68 + 0.19nm/kg; t(52)= 0.59, p=0.55; ES=0.15) and flexion (RRMI: 0.78 + 0.13nm/kg; INJF: 0.74 + 0.17nm/kg; t(52)=0.87, p=0.38; ES=0.23) strength between RRMI and INJF groups showed no significant difference (Figure 4-3). Nm/kg 1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 HEXT HFLEX RRMI INJF Figure 4-3. Sagittal plane hip strength 42

4.1.4 Clinical Tests There were no significant differences between groups on the SLHD (RRMI: 37.50 + 11.31%; INJF: 34.37 + 9.31%; t(52)= 1.05, p=0.29; ES=0.27) or the SEBT-A (RRMI: 63.56 + 4.73%; INJF: 63.98 + 5.39%; t(52)= -0.27, p=0.78; ES=0.07, and Figure 4-4). Percent 80 70 60 50 40 30 20 10 0 SEBT A SLHD RRMI INJF Figure 4-4. Star Excursion Balance Test and Single Leg Hop for Distance results 43

Chapter 5 Discussion 5.1 Discussion For 16 weeks a cohort of runners enrolled in a formalized marathon training program were followed prospectively to determine if their baseline performance on a variety of clinical tests would predispose them to a RRMI. This present study observed an injury rate of 29.6% which is lower than previously reported by Lun et al 81 with a 79% incident rate at a 6 month follow up tracking recreational runners not involved in a group training program. During a 13-week training program a 21% injury rate was observed among the runners; however, a RRMI was defined as a self-reported running injury that caused restriction for at least one week. 6 A 31% incident rate was detected during a 12- week follow up and had a similar RRMI definition as this present study: pain occurring during running preventing the participant from completing at least one training session. 5 A study observing injury rates among 17 different training programs reported a 29.5% incident rate while using a vague definition of pain after running. 14 These previous studies did not account for previous injury, even though history of injury is known as one 44

of the biggest risk factors for sustaining a RRMI. 4 Interestingly, results from this current study indicate that 75% of those in the injury free group actually reported having a previous running related injury, compared to just 56% of those in the RRMI group reporting a previous injury history. Though no correlation was made in this study, perhaps previous injury history may not be useful when identifying marathon training program participants who might be at risk of sustaining a RRMI. It has been suggested marathon training programs attract both novice and intermediate runners because of its interactive environment and progression plans. 14 Novice and intermediate runners have been thought to be at a higher risk for sustaining RRMI 12 ; leading to the speculation that novice runners would have a greater rate of injury. Group training program participants are usually females, over-weight, or were previously injured. 10 Improper running progression and BMI have been suggested as indicators of risk for RRMI. 14 Although this present study could not control for compliance to running progression, over half of the participants were considered as being overweight or obese. BMI may be an important factor to consider in the future, considering a large portion of marathon training programs consist of over-weight individuals. The injury free females displayed a mean hip flexion of 27.8 o and our RRMI group displayed 25.2 o at initial contact. Other 3-dimensional studies have reported higher averages of 35 o to 50 o of hip flexion at initial contact among healthy recreational runners. 38,44 Healthy participants running at a slow pace of 2.95 m/s had 20 o hip flexion at initial contact. 42 The average self-selected running speed of the present participants was 2.74 m/s, which was slower than most previous studies ranging between 3.17 to 4.19 m/s 45

analyzing marathon runners. 38,39 The smaller hip flexion angles seen in this study could be explained by the slower running speeds of the participants during testing. The rationale for self-selected pace was the wide range of training speeds the participants would be utilizing during the 16 week program, There is discrepancy in the literature between self-selected pace and a chosen speed for all participants. Future research should determine if a self-selected training speed or a faster designated pace would considerably alter running biomechanics in marathon runners. Additionally, sagittal plane kinematics has not been studied as extensively as frontal or transverse planes in marathon runners. This present study found sagittal plane kinematics did not show to be a characteristic related to sustaining a RRMI during training. This study did not find significant difference in sagittal plane active range of motion between injured and non-injured runners. Both groups presented with an average of 74 degrees active hip flexion ROM and 15 degrees active hip extension. Female collegiate athletes exhibited 92 degrees of hip flexion and 20 degrees extension. 91 Previous research has suggested a decrease in frontal plane hip ROM is a common characteristic in runners who have sustained PFPS, ITBS, or MTSS. 17,57,102 This study also did not find significant differences in hip flexion and extension strength between groups. Retrospective studies have identified that runners with a RRMI exhibit significantly weaker hip external rotators, 17,102 abductors, 17,19 and hip extensors 103 compared to healthy controls. Additionally, when comparing side-to-side differences in injured runners, the hip flexors of the injured limb was considerably weaker than the noninjured limb. 13 Collegiate runners with PFPS did not display a significant side-by-side difference in hip flexion or extension strength; however, they did exhibit weakness in 46

both hip flexion and extension strength when compared to healthy controls. 19 Compared with another prospective study, hip muscle weakness in all three planes was not seen as a predisposing factor for novice runners sustaining PFPS during a 10-week training program. 104 Therefore, it could be proposed strength deficits would occur as a consequence of injury instead of the influencing factor of RRMI. Secondly, it has been suggested isometric strength testing cannot effectively replicate how a muscle would contract during running. 105 Strength should be measured in an isokinetic manner to allow for the muscle to act in full range of motion, rather than a static contraction. Since isometric hip muscle strength has not been found prospectively to be a risk factor for overuse injury, perhaps the issue lies in a lack of neuromuscular control of the hip musculature to stabilize the pelvis during running. Both groups averaged normalized reach distances of 63% on the SEBT-A. The SEBT-A is a measurement of dynamic postural control involving movement around a base of support, 22 comparable to the stance of running. The Small Knee Bend (SKB) has similarities to running gait assessment, 106 whereas the SEBT-A does not directly mimic the running motion which could explain the non-significant findings in this study. Similar to the SEBT-A, the SKB also assess trunk and lower extremity dynamic alignment. Within the chronic ankle instability population, the SEBT-A can identify deficits in dynamic postural control, as well as detect ankle dorsiflexion insufficiencies. 100 Perhaps when using the SEBT in future research within the running population, examining the limb symmetry index in SEBT reach measurements would be more useful in identifying differences. Similar to the other variables assessed in this study, feasibly the degradation in movement patterns develops as a result of injury. 47

The SLHD is a functional test used to measure horizontal displacement of one limb and is a comparable measure of the functional demands required in sports. 24,97 The sagittal motion of the test is corresponding to that of the forward running motion. Primarily, this test has been used to determine when injured athletes are ready to return to full sports participation. Typically this test is used to determine if asymmetry exists between limbs within a subject, as is capable of measuring balance, strength, and motor control. 24 The SLHD has been tested prospectively as a screening tool for collegiate athletes in which females are at a greater risk of injury if they present with greater than 10% asymmetry between limbs. 21 Possibly, the inconclusive results from this study could be attributed to not examining symmetry index between limbs in the RRMI and INJF groups. Future research should consider analyzing the SLHD using the symmetry index. 5.2 Limitations Though we used a prospective study design, a limitation was not having a second testing session for those runners who sustained a RRMI during training. Secondly, it could also be beneficial to have repeated tests throughout a training program to determine when muscle strength begins to diminish in relation to onset of a RRMI. Perhaps this would explain if the characteristics seen retrospectively are directly caused from the injury or a predisposing factor. Furthermore, side-by-side comparisons should be analyzed prospectively to determine if an asymmetry exists in runners who sustain an injury. 72 In the present study we analyzed the RRMI limb to the average of limbs in the INJF group. Future research should determine if runners beginning a marathon training program present with asymmetrical characteristics in running kinematics, range of 48

motion, muscle strength, or clinical tests are at an increased risk of sustaining a RRMI during training. When observing running kinematics, there could be more of an explanation if analysis was made using multiple joints and their interactions instead of a single joint action. Presumably, there would be a more evident trend in hip flexion angles if considered with flexion angles at the knee during stance phase. Perhaps investigating hip excursion in the sagittal plane during swing phase would better express differences at baseline among runners who sustain an injury during training. Another suggestion for future research would be to collect kinematic data during a more fatigued state; this would show if any compensations are being made during longer runs and possibly be able to identify when the Another limitation of this study is the SEBT was only measured using the anterior direction. Since running is done in the sagittal plane, the anterior reach seemed the most likely to mimic running motions. The anterior reach has also been seen to be the most accurate when predicting injuries in high school and collegiate athletes. 22 Another reason only the SEBT-A was utilized was due to the time constraints of the testing sessions. Finally, this study was found to be significantly underpowered which could explain the lack of significance found. In order to determine if these factors have any clinically significant meaning, a larger population would be needed. 5.3 Conclusion The results of this study indicate sagittal plane isometric hip strength does not seem to be a baseline characteristic of running related musculoskeletal injuries in female 49

runners training for a marathon. While hip flexion angles at initial contact showed trends towards being significant, possibly examining total excursion would be able to better identify predisposing characteristics of injuries in females. Other variables should be analyzed using a symmetry index to determine if side-by-side differences are a better indicator of RRMI. 50

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99. Chakravarty EF, Hubert HB, Lingala VB, Fries JF. Reduced disability and mortality among aging runners: a 21 year longitudinal study. Archives of internal medicine. Aug 11 2008;168(15):1638 1646. 100. Basnett CR, Hanish MJ, Wheeler TJ, et al. Ankle dorsiflexion range of motion influences dynamic balance in individuals with chronic ankle instability. International journal of sports physical therapy. Apr 2013;8(2):121 128. 101. Macera CA, Pate RR, Powell KE, Jackson KL, Kendrick JS, Craven TE. Predicting lowerextremity injuries among habitual runners. Archives of internal medicine. Nov 1989;149(11):2565 2568. 102. Ireland ML, Willson JD, Ballantyne BT, Davis IM. Hip strength in females with and without patellofemoral pain. The Journal of orthopaedic and sports physical therapy. Nov 2003;33(11):671 676. 103. Robinson RL, Nee RJ. Analysis of hip strength in females seeking physical therapy treatment for unilateral patellofemoral pain syndrome. The Journal of orthopaedic and sports physical therapy. May 2007;37(5):232 238. 104. Thijs Y, Pattyn E, Van Tiggelen D, Rombaut L, Witvrouw E. Is hip muscle weakness a predisposing factor for patellofemoral pain in female novice runners? A prospective study. The American journal of sports medicine. Sep 2011;39(9):1877 1882. 105. Taylor Haas JA, Hugentobler JA, DiCesare CA, et al. Reduced hip strength is associated with increased hip motion during running in young adult and adolescent male longdistance runners. International journal of sports physical therapy. Aug 2014;9(4):456 467. 106. Whatman C, Hing W, Hume P. Kinematics during lower extremity functional screening tests are they reliable and related to jogging? Physical therapy in sport : official journal of the Association of Chartered Physiotherapists in Sports Medicine. Feb 2011;12(1):22 29. 59

Appendix A Consent Form 60

UT IRB # 108498 ICF Version Date: 12/1612013 TOLE Department of Kinesiology Mailstop #119 Toledo, Ohio 43606 Phone # (419) 530-2741 Fax # (419) 530-2744 ADULT RESEARCH SUBJECT INFORMATION AND CONSENT FORM BIOMECHANICAL, CLINICAL, AND FUNCTIONAL MOVEMENT RISK FACTORS FOR RUNNING-RELATED MUSCULOSKELETAL INJURIES Principal Investigator: Phillip A. Gribble, PhD, ATC, FNATA Other Staff (identified by role): Megan E. Quinlevan, MS, ATC (Sub-investigator) Abbey Thomas, PhD, ATC (Sub-investigator) Larry Cattell, ATC (Sub-investigator) Danielle Torp, ATC (Sub-investigator) Steven Berning (Sub-investigator) Contact Phone number(s): (419) 530-2691 (419) 530-2764 What you should know about this research study: We give you this consent form so that you may read about the purpose, risks, and benefits of this research study. All information in this form will be communicated to you verbally by the research staff as well. Routine clinical care is based upon the best-known treatment and is provided with the main goal of helping the individual patient. The main goal of research studies is to gain knowledge that may help future patients. We cannot promise that this research will benefit you. Just like routine care, this research can have side effects that can be serious or minor. You have the right to refuse to take part in this research, or agree to take part now and change your mind later. If you decide to take part in this research or not, or if you decide to take part now but change your mind later, your decision will not affect your routine care. Please review this form carefully. Ask any questions before you make a decision about whether or not you want to take part in this research. If you decide to take part in this research, you may ask any additional questions at any time. Your participation in this research is voluntary. IIIIIII IIII II II RR050 Page 1 of 10 UNIVERSITY OF TOLEDO I RB APPROVAL DATE: /ÿ'/ÿc/_3 / EXPIRATION D ATE: /.ÿ f'i.ÿ/-2 L7 ÿ" This space for IRB Approval Date Stamp

UT IRB # 108498 ICF Version Date: 12/16/2013 NO TEXT THIS PAGE IIII II I IIIII II IIIII II IJ IIIII RR050 Page 2 of 10 UNIVERSITY OF TOLEDO IRB APPROVAL DATE: 2ÿ -1ÿ -ÿ2ÿ/._ÿ EXPIRATION DATE:/2 -/,5"-ÿ-ÿ/'ÿ/- This space for IRB Approval Date Stamp/

UT IRB # 108498 ICF Version Date: 1211612013 PURPOSE (WHY THIS RESEARCH IS BEING DONE) You are being asked to take part in a research study that will examine your running mechanics, lower extremity flexibility and strength, core endurance, and functional movement performance. The purpose of the study is to determine if your running mechanics, clinical test outcomes, and functional movement test performance are related to the development of running-related musculoskeletal injuries. If we are able to confirm a relationship, clinicians will be able to screen runners and determine those at risk for an injury, as well as provide prevention programs targeting these variables. This will ultimately contribute to a decrease in overall running-related injury rates and more runners running injury free. You were selected as someone who may want to take part in this study because you are enrolled in a16 week formalized running program training for a half or full marathon. This research study will be conducted in the Musculoskeletal Healthy and Movement Science Laboratory in the Health Science and Human Services Building at the University of Toledo Main Campus. We will be enrolling 200 subjects over the age of 18 years. DESCRIPTION OF THE RESEARCH PROCEDURES AND DURATION OF YOUR INVOLVEMENT If you decide to take part in this study, you will be asked to fill out a medical history questionnaire to determine if you qualify to participate in the study. If you qualify your height, weight, and leg lengths will be measured, followed by a warm up on an exercise bike for five minutes. Once you have completed warming up you will perform a series of clinical tests including range of motion, strength, and endurance testing, as well as functional movement tests including the modified Functional Movement Screen (mfms), a single leg hop for distance, a single leg squat, and the star excursion balance test (SEBT). Lastly, we will also have you run across the lab, over a force plate that is flush with the ground, while wearing small, silver, retro-reflective markers so that we can analyze your running gait. All of these tests will be randomized between the two sessions; hence, the list below is not necessarily the order in which you will be performing the tasks. Each task that is performed on a limb will be performed on both limbs. Clinical Tests Active Range of Motion/Flexibility 1. The first ROM test will test the flexibility of the muscles on the front of your upper leg/thigh, by assessing your hip extension ROM. You will be positioned to lie on your stomach on a table. Then you will lift your leg up off of the table while keeping your knee as straight as possible. The tester will measure in degrees the angle at which your hip is extended. 2. The second ROM test will test the flexibility of the muscles on the back of your upper leg/thigh, by assessing your hip flexion ROM. You will be positioned on your back on a treatment table. You will then raise your leg as far as possible so that you are bending at the hip. The angle of your leg will be measured. 3. The last ROM test will test the flexibility of your posterior lower leg or calf muscles and your range of ankle dorsiflexion ROM. Dorsiflexion ROM will be assessed using the Weight Bearing Lunge Test (WBLT). You will positi.on..y.our..great.toe..two..centimeters... UNIVERSITY OF TOLEDO IRB EXPIRATION DATE: /,ÿ -/,j -ÿf/"ÿi Page 3 of l 0 This space for IRB Approval Date Stamp i RR050... i

UT IRB # 108498 ICF Version Date: 12/16/2013 from the wall and keep the heel firmly planted on the floor while flexing the knee to the wall. The purpose is to maintain knee contact with the wall while maintaining heel contact on the ground. Your foot will be moved back less than one centimeter at a time until you are unable to keep your heel on the ground while touching the knee to the wall. Muscle Strength During this study we will test the maximum strength of the muscles surrounding your ankles, knees and hips using a hand-held dynamometer (HHD). The HHD is a small device that you will press against when testing that will record your maximum force output, or how strong you are. In total you will perform 11 strength tests for each limb. For each test we will set you in the correct position, show you and tell you what the motion or test will be, and then have you perform one practice trial followed by three recorded trials. You will have 30 seconds of rest between each trial. For each trial we will count down from 5 to 0. At 5 and 4 we want you to ramp up, and for 3, 2, and 1 we want you to push with maximum strength. 1. Ankles: You will be seated on the edge of a treatment table with your knee and hips at.. IIIIIIIII IIIIIIIIlUlUl RR050 90 degrees, and back in an upright position. The tester will place the HHD on the bottom side of your foot around the ball of your foot or forefoot. The tester will ask you to push as hard as possible, and you will push down like you are pushing on a gas pedal in a car. Then the tester will place the HHD on the top side of your foot and you will be asked to pull your toes to your nose as hard as possible. Knees: To test your knee extension strength you will be seated on the edge of a treatment table with your knee and hips at 90 degrees, and back in an upright position. The tester will place the HHD on your lower leg or shin bone. You will be asked to kick your leg out as hard as possible. To test your knee flexion strength you will be in the same position, but this time the tester will place the HHD on the back of your lower leg over your calf muscles. You will be instructed to pull back, or flex your knee as hard as possible. Hips: To test your hip flexion strength you will be seated on the edge of a treatment table with your knee and hips at 90 degrees, and back in an upright position. The tester will slightly rotate your leg in. The HHD will be placed on the top of your thigh and you will be instructed to lift your leg off the table and drive it upwards as hard as possible. To test your hip extension strength you will be lying on your stomach on the treatment table with a strap over your buttock to stabilize your hips. You will then bend your knee to 90 degrees. The tester will place the HHD on the posterior part of your lower thigh. Then you will lift your leg off the table as hard as you can without lifting your pelvis off of the table. To test your hip abduction strength, or the muscles on the side of your hip we will have you lying on your opposite side of the limb to be tested. We will stabilize your hips by strapping you to the table with the strap placed around your waist. The goal of this test is to isolate two separate muscles, one by putting your leg into slight flexion, and one by putting you into slight extension, thus you will perform this test twice with slight differences in leg placement. For both tests the tester will place the HHD on the side of your distal thigh while you are instructed to lift your leg up to the ceiling. To test the strength of your hip adductors, or the muscles on the inside of your thigh you will lay on your back on the treatment table with a strap around your waist to control your hips. The tester will place the HHD on the inside of your lower leg, just above your ankle bone. You willthenpushagainstthehhdasif... UNIVERSITY OF TOLEDO IRB APPROVAL DATE: /ÿ -/ÿ -ÿ2ÿofff/.i Page 4 of 10 EXPIRATION DATE: / Y-- -/..ÿ<,-ÿ/ÿ)ÿ/-ÿ = This space for IRB Approval Date Stamp

UT IRB # 108498 ICF Version Date: 12/16/2013 trying to squeeze your legs together. For the last two strength tests of the muscles that rotate your leg out and in (your medial and lateral rotators) you will be positioned on your stomach, with a strap over your buttock to stabilize your hips, and your knee bent to 90 degrees. To test the muscles that rotate your leg in, the HHD will be placed just below your ankle bone on the inside of your leg, and to test the muscles that rotate your leg out the HHD will be placed just below your ankle bone on the outside of your leg. Core Endurance During this study you will perform endurance tests to test the endurance capabilities of the muscles of your abdomen, your back, and the sides of your core/trunk (trunk lateral flexors). You will perform a total of four tests. For each test time will be recorded and stopped when you fall out of the correct position for three consecutive seconds, or when you stop the test. You will receive a minimum of five minutes rest between tests to make sure your muscles do not become fatigued. 1. To test the muscles on the side or your core/trunk you will perform a lateral plank. You will support yourself on your forearm and feet. Time will be recorded and stopped when your hips drop, or you rotate frontwards or backwards. You will then perform the same test on your other limb. 2. To test your abdominal muscles you will sit against a wedge with feet flat on the table. The wedge will be pulled back a few centimeters and you will hold the position. Time will be recorded and stopped when you can no longer hold the position or your back makes contact with the wedge. 3. To test your back muscles you will lay on your stomach with only your legs and hips supported on the platform. You will cross your arms across your chest. You will hold a suspended position off of the platform, so that your upper trunk is horizontal or flat. Time will be recorded and stopped when you upper trunk falls below horizontal. Curl-up To test the strength of your abdominal muscles you will perform curl-ups or crunches to fatigue. You will lay flat on your back with knees bent and feet flat on the mat while a tester holds your feet. First we will set your curl-height be having you perform a crunch while reaching your arms out to the sides. We will have you curl-up enough that your fingers move 12 cm from start to the end of the curl. This position will be marked visually on a wall relative to your knees. For the test we will then have you fold your arms across the chest. You will then perform curl-ups to the previously set point at a rate of 25 per minute. A metronome will set the pace for you. A tester will count the number of curl-ups. If you become fatigued that you cannot continue, you lose pace with the metronome, or you fail to reach that maximum curl-up position the test will stop. Single Leg Heel Raise In addition to testing the strength of your calf muscles we are going to test their endurance. To do so you will perform single leg heel rises to fatigue. You will start standing with the non-testing knee bent to 90 degrees. A single finger from each hand can be placed on the tester for support. You will then lift up onto the ball of your foot and then lower back down to the starting position. This will be performed at a rate of 60 per minute. While you are performing the test another tester will be watching to see if you lean at the trunk, bend the knee of your testing limb, or leans too much on the other tester. If any of these movements occur you will be asked to correct them. If you are unable to do so for more than three seconds the test wil.l..stop... UNIVERSITY OF TOLEDO IRB RR050 Page 5 of lo 7ÿis space for IRB Approval Date Stamp "

UT IRB # 108498 ICF Version Date: 12/16/2013 Functional Movement Tests Single Leg Squat Then we will have you perform a single leg squat. A tester will demonstrate for you how to correctly perform a single leg squat, and then you will be asked to do it. Your may hold on to a tester using two fingers only. Your goal is to keep an upright posture and your knee over your foot when squatting. You will perform five consecutive single leg squats on both limbs. We will collect motion capture data of your performance just as we did the running trials. In addition, a tester will be standing to your side and grading your technique. This will allow us both a quantitative and qualitative assessment of your performance. Star Excursion Balance Test (SEBT) The SEBT is an assessment of your ability to balance while performing a small task, also known as dynamic balance. For this test the instructor will demonstrate what you will do as well as show you how to perform it. You will stand at the starting line or center of a "y" shaped grid. You will then balance on one leg. With your hands on your hips and your heel flat on the ground, your goal is to bend, twist, or do whatever possible to reach out as far as possible on the line tap down with your foot and come back to standing. You will do four practice trials on both limbs followed by three recorded trials on both limbs. If at any point during the recording sessions your hands come off your hip, your heel lifts up, or you lose balance that trial will be discarded and you will have to perform another. Single Leg hop for Distance To test the explosive strength of your leg muscles we are going to measure the distance in which you can perform a single leg hop. You will start standing with your toes on a line, on the limb to be tested with the non-testing knee bent to 90 degrees. You will then perform a single leg hop as far as possible. You then need to maintain your balance for five seconds. If you do not the hop distance will not be recorded. You will perform three successful trials for both limbs. The distance from the start line to the heel of your test limb will be recorded. Modified Functional Movement Screen (mfms) The mfms consists of four functional movements that are commonly performed in athletic settings. You will be graded on the quality of your movement from a 3 representing successful 'movement performance with no pain, to a 0 representing not able to perform movement due to pain. For all four tests you will be shown and told how to perform the movement, and then you will perform three trials each. For trials that are performed on a single limb, both limbs will be tested. 1. The deep squat is performed with you standing feet shoulder width apart and arms overhead while holding a wooden dowel. You will then be instructed to lower yourself as far as possible and then return to the starting position. 2. For the hurdle step you will start standing on both feet with a cord in front of you at the height of your shin bone. A wooden dowel will be held behind your head on your shoulders. Then with the limb to be tested, you will step over the cord, tap the ground with your heel, and then come back to the starting position. The goal is not to let your leg hit the cord while maintaining an upright posture. 3. The in-line lunge is performed in a fixed position on a board. The toes of the nontesting leg will be at the start line, while the heel of the limb to be tested is placed a distance away from the start line. The distance is equivalent to the height of the shin bone. Your hands will be holding a wooden dowel vertica[.behjnd.your..back...y..ou..wi]l... Ilil i Ill I iili Ill Illlil UNIVERSITY OF TOLEDO IRB ' APPROVAL DATE:/ ÿ -/ÿ* -ÿ, )ÿ./ EXPIRATION DATE: /,2 -/_3" :Jd/rÿ-ÿ Page 6 of 10 This space for IRB Approval Date Stamp RR050

UT IRB # 108498 ICF Version Date: 12/1612013 then perform a lunge such that the knee of the back leg touches the heel of the front leg, and then return to the starting position. Your goal is to remain balanced. 4. For the active straight leg raise you will be laying on your back with legs flat on the ground. A wooden dowel will be positioned next to the limb to be tested by your hip bone. You will then be asked to lift your leg to be tested straight up in the air while keeping your knee fully extended. Biomechanics Running 1. Reflective markers will be placed with double-sided tape on your foot, inner and outer ankle, outer lower leg (shank), inner and outer knee, outer thigh, hip (pelvis), and lower back using double-sided tape. When participating in the study, twelve cameras mounted near the ceiling will track your motions by recording the movements of the reflective marker. The computer will then be able to draw a stick-figure of your movements. One additional camera will be positioned on a tripod on the floor at your side to visually record your running trials across the force plate. 2. Next you will run along a run way and across a force plate so we can collect your ground reaction forces and biomechanics while running. The goal is to have you land with your right foot 5 times on the force plate and with your left foot five times. An unsuccessful trial is one in which you slow down, speed up, take irregular strides, or miss the force plate. The researchers encourage you to ask any questions you have prior to or during the study. any time you feel unable to participate in the study, for whatever reasons, please tell the researcher and you will be kindly dismissed from the study. If at RISKS AND DISCOMFORTS YOU MAY EXPERIENCE IF YOU TAKE PART IN THIS RESEARCH When participating in any research study, you may encounter some risks. Although the risks for taking part in this study are very low, you may experience one or more of the following: 1. Because you are participating in a functional activity, there is a chance that you could fall while running or performing any of the functional movement tests. However, since you are being asked to perform small movement tasks, this risk is minimal. 2. You may experience minor muscle soreness for two or three days following the study as you would after exercising. If you are pregnant, it is advised that you remove yourself from the study during your pregnancy. You may be able to participate following your pregnancy if volunteers are still needed. Due to balance changes during pregnancy you may have an increased risk of falling. There are no known additional risks for pregnant women taking part in this study. POSSIBLE BENEFIT TO YOU IF YOU DECIDE TO TAKE PART IN THIS RESEARCH We cannot and do not guarantee or promise that you will receive any benefits from this research. The benefit of participating in this study is to help further research regarding running related musculoskeletal injuries. COST TO YOU FOR TAKING PART IN THIS STUDY You are not directly responsible for making any type of payment to take part in this study. However, you are responsible for providing your own means of..transpo.rtation.to..and.from..the... UNIVERSITY OF TOLEDO IRB i Page 7 of 10 This space for IRB Approval Date Stamp i RR050...

UT IRB # 108498 ICF Version Date: 12116/2013 Health Science and Human Services Building at The University of Toledo. You will not be compensated for gas for travel or any other expenses to participate in this study. PAYMENT OR OTHER COMPENSATION TO YOU FOR TAKING PART IN THIS RESEARCH If you decide to take part in this research you will NOT receive any compensation including money, free treatment, free medications, or free transportation. PAYMENT OR OTHER COMPENSATION TO THE RESEARCH SITE The University of Toledo is NOT receiving money or other benefits, as there is NO sponsor of this research. ALTERNATIVE(S) TO TAKING PART IN THIS RESEARCH There is no alternative to taking part in this research. Exclusion from the study, however, will not affect the quality of care you may receive at the sports medicine/physical therapy facility, doctor's office, or other medical facilities. CONFIDENTIALITY By agreeing to take part in this research study, you give to The University of Toledo (UT), the Principal Investigator and all personnel associated with this research study your permission to use or disclose information that can be identified with you that we obtain in connection with this study. We will use this information solely for the purpose of conducting the research study as described in the research consent form. The researchers will make every effort to prevent anyone who is not on the research team from knowing that you provided this information, or what that information is. The consent forms with signatures will be kept separate from responses, which will not include names and which will be presented to others only when combined with other responses. Although we will make every effort to protect your confidentiality, there is a low risk that this might be breached. IN THE EVENT OF A RESEARCH-RELATED INJURY In the event of injury resulting from your taking part in this study, treatment can be obtained at a health care facility of your choice. You should understand that the costs of such treatment will be your responsibility. Financial compensation is not available through The University of Toledo or The University of Toledo Medical Center. In the event of an injury, contact Megan Quinlevan, MS, ATC at (262) 573-2154, or Phillip Gribble, PhD, ATC at (419) 530-4271. VOLUNTARY PARTICIPATION Taking part in this study is voluntary. You may refuse to participate or discontinue participation at any time without penalty or a loss of benefits to which you are otherwise entitled. If you decide not to participate or to discontinue participation, your decision will not affect your future relations with the University of Toledo or The University of Toledo Medical Center. IIIIIII I I f III IIJI IIIIII RR050 Page 8 of 10 UNIVERSITY OF TOLEDO IRB APPROVAL DATE: / L-//4 -ÿl";ÿ /ÿ EXPIRATION DATE: /oÿ -/.ÿ S.ÿ(,!ÿ/--i This space for IRB Approval Date Stamp

UT IRB # 108498 ICF Version Date: 12116/2013 NEW FINDINGS You will be notified of new information that might change your decision to be in this study if any becomes available. OTHER IMPORTANT INFORMATION There is no additional information. ADDITIONAL ELEMENTS There are no additional elements. CONTINUED NEXT PAGE I IIM Ill I Ill IIII II III RR050 Page 9 of 10 UNIVERSITY OF TOLEDO Iÿ APPROVAL DATE: / ÿ//ÿ/:ÿ"iy /i EXPIRATION DATE: ///_ÿ///s/ÿ.ÿ4j/ÿ/ÿi This space for IRB Approvai Date Stÿmp

UT IRB # 108498 ICF Version Date: 12/16/2013 OFFER TO ANSWER QUESTIONS Before you sign this form, please ask any questions on any aspect of this study that is unclear to you. You may take as much time as necessary to think it over. If you have questions regarding the research at any time before, during or after the study, you may contact Megan Quinlevan, (262) 573-2154. If you have questions beyond those answered by the research team or your rights as a research subject or research-related injuries, please feel free to contact the Chairperson of the University of Toledo Biomedical Institutional Review Board at 419-383-6796. SIGNATURE SECTION (Please read carefully) YOU ARE MAKING A DECISION WHETHER OR NOT TO PARTICIPATE IN THIS RESEARCH STUDY. YOUR SIGNATURE INDICATES THAT YOU HAVE READ THE INFORMATION PROVIDED ABOVE, YOU HAVE HAD ALL YOUR QUESTIONS ANSWERED, AND YOU HAVE DECIDED TO TAKE PART IN THIS RESEARCH. The date you sign this document to enroll in this study, that is, today's date, MUST fall between the dates indicated on the approval stamp affixed to the bottom of each page. These dates indicate that this form is valid when you enroll in the study but do not reflect how long you may participate in the study. Each page of this Consent/Authorization Form is stamped to indicate the form's validity as approved by the UT Biomedical Institutional Review Board (IRB). Name of Subject (please print) Signature of Subject or Person Authorized to Consent Date Relationship to the Subject (Healthcare Power of Attorney authority or Legal Guardian) a,m. Time p.m. Name of Person Obtaining Consent (please print) Signature of Person Obtaining Consent Date Name of Witness to Consent Process (when required by ICH Guidelines) (please print) Signature of Witness to Consent Process (when required by ICH Guidelines) Date YOU WILL BE GIVEN A SIGNED COPY OF THIS FORM TO KEEP. I IIIIIIIIII LL IIIIIII IIII III RR050 Page lo of lo UNIVERSITY OF TOLEDO IRB,a/ i APPROVAL DATE:/,ÿ -/ÿ/" ÿ!'fÿ-,i EXPIRATION DATE: /ÿ -/5-.ffd/ÿ/-ÿI This space for IRB Approval Date Stamp

Appendix B Block Randomization Model Baseline Assessment (N=54) Running Kinematics Clinical Assessment Tasks (1) SEBT A (2) SLHD Active Range of Motion (1) Flexion (2) Extension (1) Flexion Strength (2) Extension 16 week Training Program RRMI (N=16) Injury Free (N=38) Figure B-1 Block randomization of tests. 1 and 2 represents the tests which were randomized in each block 71

Appendix C Kinematic Data Collection Set-up Figure C-1. Runway, force plate, and timing gaits 72

Figure C-2. Forty-one reflective market set for static trials. 73

Appendix D Data Collecti ion Tests Figure D-1. The Single Leg Hop for Distance 74

Figure D-2. The Star Excursion Balance Test in the anterior direction Figure D-3. Hip Flexion Range of Motion 75

Figure D-4. Hip Extension Range of Motion Figure D-5. Hip Flexion Strength 76

Figure D-6. Hip Extension Strength 77

Appendix E Running Related Musculoskeletal Injury Tracking 78

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