EFFECTS OF Q-ANGLE ON LOWER EXTREMITY BIOMECHANICS AND
INJURIES IN FEMALE COLLEGIATE TRACK AND FIELD ATHLETES
By
MYRANDA HOPE HAM
Candidate for Master of Science in Engineering, Biomedical Engineering,
Mercer University, May 2020
A Thesis Submitted to the Graduate Faculty
of Mercer University School of Engineering
in Partial Fulfillment of the Requirements for the Degree
MASTER OF SCIENCE IN ENGINEERING
MACON, GA
2020
EFFECTS OF Q-ANGLE ON LOWER EXTREMITY BIOMECHANICS AND
INJURIES IN FEMALE COLLEGIATE TRACK AND FIELD ATHLETES
By
MYRANDA HOPE HAM
Approved:
______Date ______Dr. Ha Vo, Advisor
______Date ______Dr. Edward O’Brien, Committee Member
______Date ______Dr. Richard Kunz, Committee Member
______Date ______Dr. Laura Lackey, Dean
ACKNOWLEDGEMENTS
I would like to first thank Dr. Vo for all his help throughout this project. I would not have been able to complete this study without his guidance. Thank you to Dr. Kunz and Dr. O’Brien for serving as member of my committee. Thank you to Amos Mansfield for approving this study to be conducted with Mercer University student-athletes. Thank you to all the Mercer Women’s Track and Field coaches, including Josh Hayman, Leesa
Morales, and Jerod Wims, for being flexible and allowing the athletes to participate in this study around their practice schedule. Thank you to every member of the Mercer
Women’s Track and Field team who devoted time to participating in this study.
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TABLE OF CONTENTS
ACKNOWLEDGEMENTS ...... iii
LIST OF FIGURES ...... vi
LIST OF TABLES ...... xi
ABSTRACT ...... xii
CHAPTERS 1 INTRODUCTION AND BACKGROUND ...... 1
Introduction ...... 1
Background ...... 1
Anatomy of the Lower Extremity ...... 1
Quadriceps Angle (Q-angle) ...... 15
The Gait Cycle ...... 18
Common Injuries in Running ...... 24
2 MATERIALS AND METHODS
IRB Requirements ...... 30
Q-Angle and Limb Length Measurements...... 30
Gait Analysis Equipment and Procedure ...... 33
EMG Equipment and Procedure ...... 36
Statistical Analysis ...... 40
iv
TABLE OF CONTENTS (Continued)
3 RESULTS AND DISCUSSION ...... 41
Subject Information and Reported Injuries ...... 41
Gait Analysis Results ...... 47
EMG Results and Discussion ...... 61
Statistical Analysis ...... 76
Discussion of Reported Injuries ...... 76
Interesting Cases ...... 78
4 CONCLUSION ...... 82
5 FUTURE STUDIES AND RECOMMENDATIONS ...... 83
REFERENCES ...... 85
APPENDICES A IRB APPROVAL ...... 89
B CITI PROGRAM CERTIFICATION ...... 90
C INFORMED CONSENT FORM ...... 91
D SUBJECT INFORMATION ...... 94
E REPORTED INJURIES ...... 96
F GAIT DATA ...... 98
G EMG DATA ...... 113
H ANDERSON-DARLING NORMALITY TESTS ...... 128
I STATISTICAL ANALYSIS ...... 139
v
LIST OF FIGURES
Figure 1.1. Bones of the pelvis ...... 2
Figure 1.2. The ilium and important landmarks ...... 2
Figure 1.3. The ischium and important landmarks ...... 3
Figure 1.4. The pubis and important landmarks ...... 3
Figure 1.5. Ligaments of the hip joint...... 4
Figure 1.6. The femur and important landmarks ...... 4
Figure 1.7. Tendons and ligaments of the knee joint ...... 5
Figure 1.8. Ligaments and menisci of the knee joint ...... 6
Figure 1.9. The tibia and fibula and important landmarks ...... 6
Figure 1.10. Ligaments of the ankle ...... 7
Figure 1.11. The tarsal bones ...... 8
Figure 1.12. Muscles of the gluteal region ...... 9
Figure 1.13. The muscles of the anterior, medial, and posterior compartments of the thigh
...... 11
Figure 1.14. Muscles of the anterior and lateral compartments of the leg...... 12
Figure 1.15. Muscles of the posterior compartment of the leg ...... 13
Figure 1.16. The muscles of the dorsal aspect of the foot ...... 14
Figure 1.17. Muscles of the plantar aspect of the foot ...... 15
Figure 1.18. Q-angle and the lines from which it is measured ...... 16
Figure 1.19. Transition between types of gait...... 18
vi
LIST OF FIGURES (Continued)
Figure 1.20. Walking gait cycle phases ...... 19
Figure 1.21. Running gait cycle phases ...... 19
Figure 1.22. Pronation and supination and the effects those motions have on tibial rotation ...... 21
Figure 1.23. Knee joint axes for different alignments ...... 21
Figure 1.24. Joint range of motion for hip, knee, and ankle during the walking, running, and sprinting gait cycles...... 23
Figure 1.25. Muscle activation during the running gait cycle ...... 24
Figure 2.1. Investigator measuring limb length on a subject ...... 31
Figure 2.2. Steps of measuring Q-angle on a subject ...... 33
Figure 2.3. Marker setup for gait analysis on sagittal and frontal planes respectively ...... 36
Figure 2.4. AP and PA view of subject with EMG electrodes and sensors setup ...... 39
Figure 3.1. Average limb length measured to the medial malleolus and the floor for each group ...... 42
Figure 3.2. Average limb length discrepancy measured to the medial malleolus and the floor for each group ...... 43
Figure 3.3. Average Q-angle by group ...... 44
Figure 3.4. Type and quantity of injuries reported by group 1 ...... 45
Figure 3.5. Type and quantity of injuries reported by group 2 ...... 45
Figure 3.6. Type and quantity of injuries reported by group 3 ...... 46
Figure 3.7. Locations of injuries reported for each group ...... 47
Figure 3.8. Gait results for the left leg in the frontal plane at initial contact ...... 48
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LIST OF FIGURES (Continued)
Figure 3.9. Subject from groups 1, 2, and 3 respectively at initial contact in the frontal plane ...... 48
Figure 3.10. Gait results for the right leg in the frontal plane at initial contact ...... 49
Figure 3.11. Subject from group 1, 2, and 3 respectively at initial contact in the frontal plane ...... 50
Figure 3.12. Gait results for the left leg in the frontal plane at midstance ...... 51
Figure 3.13. Subject from group 1, 2, and 3 respectively at midstance in the frontal plane
...... 51
Figure 3.14. Gait results for the right leg in the frontal plane at midstance ...... 52
Figure 3.15. Subject from group 1, 2, and 3 respectively at midstance in the frontal plane
...... 53
Figure 3.16. Gait results for the right side in the sagittal plane at initial contact ...... 54
Figure 3.17. Subjects from groups 1, 2, and 3 respectively at initial contact in the sagittal plane ...... 54
Figure 3.18. Gait results for the right side in the sagittal plane at peak knee flexion ...... 55
Figure 3.19. Subjects from groups 1, 2, and 3 respectively at peak knee flexion in the sagittal plane ...... 56
Figure 3.20. Average gait results for the right side in the sagittal plane at push off ...... 57
Figure 3.21. Subjects from groups 1, 2, and 3 respectively at push off in the sagittal plane
...... 57
Figure 3.22. Average gait results from the right side in the sagittal plane during flight ...58
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LIST OF FIGURES (Continued)
Figure 3.23. Subjects from groups 1, 2, and 3 respectively during flight in the sagittal plane ...... 59
Figure 3.24. Average gait results from the right side in the sagittal plane during swing ..60
Figure 3.25. Subjects for groups 1, 2, and 3 respectively during swing in the sagittal plane
...... 60
Figure 3.26. Peak EMG values as a percentage of MVC for the vastus lateralis muscle in both right and left legs ...... 61
Figure 3.27. Mean EMG values as a percentage of MVC for the vastus lateralis muscle in both right and left legs ...... 62
Figure 3.28. AP view of free body diagram of the vastus lateralis muscle with low, average, and high (A, B, and C respectively) Q-angle ...... 63
Figure 3.29. Peak EMG values as a percentage of MVC for the rectus femoris muscle in both right and left legs ...... 64
Figure 3.30. Mean EMG values as a percentage of MVC for the rectus femoris muscle in both right and left legs ...... 65
Figure 3.31. AP view of free body diagram of the rectus femoris muscle with low, average, and high Q-angle (A, B, and C respectively) ...... 66
Figure 3.32. Peak EMG values as a percentage of MVC for the semitendinosus muscle in both right and left legs ...... 67
Figure 3.33. Mean EMG values as a percentage of MVC for the semitendinosus muscle in both right and left legs ...... 68
ix
LIST OF FIGURES (Continued)
Figure 3.34. PA view of free body diagram of the semitendinosus muscle with low, average, and high Q-angle (A, B, and C respectively) ...... 69
Figure 3.35. Peak EMG values as a percentage of MVC for the biceps femoris muscle in both right and left legs ...... 70
Figure 3.36. Mean EMG values as a percentage of MVC for the biceps femoris muscle in both right and left legs ...... 71
Figure 3.37. PA view of free body diagram of the biceps femoris muscle with low, average, and high Q-angle (A, B, and C respectively) ...... 72
Figure 3.38. Peak EMG values as a percentage of MVC for the lateral head of the gastrocnemius muscle in both right and left legs ...... 73
Figure 3.39. Mean EMG values as a percentage of MVC for the lateral head of the gastrocnemius muscle in both right and left legs ...... 74
Figure 3.40. PA view of free body diagram of the lateral head of the gastrocnemius muscle with low, average, and high Q-angle (A, B, and C respectively) ...... 75
Figure 3.41. AP view of free body diagrams showing the forces acting on the knee and ankle joint in valgus and varus alignment...... 81
x
LIST OF TABLES
Table 1.1. Effects of pronation and supination up the kinetic chain ...... 20
Table 3.1. Average limb length of each group...... 41
Table 3.2. Average limb length discrepancies for each group ...... 42
Table 3.3. Average Q-angle for each group ...... 43
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ABSTRACT
The purpose of this study is to investigate the effect that quadriceps angle, or Q- angle, has on lower extremity biomechanics in female collegiate track and field athletes, and in turn, investigate the effect that Q-angle has on the incidence of sports-related injury. Twenty members of the Mercer University Women’s Track and Field team were asked to participate in this study. Each subject’s limb length and Q-angle were measured and 2D gait analysis was performed in the Mercer Biomechanics and Gait Lab. Then, electromyographic (EMG) analysis was performed on eleven of the subjects on one of the university’s intramural fields. Each subject was also asked to provide a full history of sports injuries they had previously sustained. For data analysis, the subjects were divided into three groups based on Q-angle (group 1: 10⁰-14⁰, group 2: 15⁰-17⁰, and group 3:
18⁰+). Statistical analysis was performed using t-tests and Mood’s median tests to compare the three groups.
Subjects from group 1 were found to have a lower angle of hip adduction (p=0.002 compared to group 2 and p=0.05 compared to group 3) in the left frontal plane at initial contact and high incidence of shin splints (66.67%) and ankle sprains (33.33%). Subjects from group 2 were found to have larger range of motion of the knee in the sagittal plane on the right side (p=0.021 compared to group 1) and higher incidence of hamstring strains (50%) than the other groups. Subjects from group 3 were found to have high incidence of shin splints (50%) and injuries to the knee (26.67%). Although no statistical
xii
significance was found in the EMG data, meaningful trends were observed. Muscle activity in the vastus lateralis, rectus femoris, and lateral gastrocnemius was found to increase as Q-angle decreased (from group 3 to group 1). In the future, this study could be done with a higher sample size so more firm conclusions could be drawn.
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CHAPTER 1
INTRODUCTION AND BACKGROUND
This section introduces the study and provides background information that is pertinent to understand the results of the study.
Introduction
One of the most pertinent issues among collegiate athletes is sports-related injuries. Particularly among track and field athletes, muscles strains and overuse injuries, such as stress fractures, are very common. It has been speculated that female athletes have a higher risk of suffering from certain injuries than their male counterparts due to their larger quadriceps angle, commonly known as Q-angle. The purpose of this study is to examine how Q-angle correlates to biomechanics while running and, in turn, investigate how it could be related to different injuries suffered by female collegiate track and field athletes.
Background
Anatomy of the Lower Extremity
The pelvis is made up of three bones: the ilium, ischium, and pubis. Figure 1.1 shows the pelvis and the bones that make it up.
1
2
Figure 1.1. Bones of the pelvis[1]
Figure 1.2 shows the ilium bone in red. The iliac crest, greater sciatic notch, and the anterior superior, anterior inferior, posterior superior, and posterior inferior iliac spines are important landmarks.
Figure 1.2. The ilium and important landmarks[1]
Figure 1.3 shows the ischium bone in green. The ischial spine, ischial tuberosity, body of ischium, and superior and inferior ischial rami are important landmarks.
3
Figure 1.3. The ischium and important landmarks[1]
Figure 1.4 shows the pubis bone in yellow. Important landmarks include the pubic body and the superior and inferior pubic rami.
Figure 1.4. The pubis and important landmarks[1]
The bone that makes up the thigh is the femur. It is the longest bone of the body and provides point of attachment for many different muscles. The head of the femur articulates with the acetabulum of the pelvis to form the hip joint. Important ligaments in the hip joint include the ligament of the head of the femur, the iliofemoral ligament, pubofemoral ligament, and ischiofemoral ligament[1]. Figure 1.5 shows the hip joint and its ligaments.
4
Figure 1.5. Ligaments of the hip joint[1]
The hip joint is a ball-and-socket joint that allows for flexion and extension, abduction and adduction, and internal and external rotation[1]. Figure 1.6 shows the femur and all its important landmarks.
Figure 1.6. The femur and important landmarks[2]
5
The bones that make up the lower leg are the tibia and the fibula. The superior portion of the tibia articulates with the inferior portion of the femur to form the knee joint. The knee joint is a hinge-type joint that allows for flexion and extension and minimal internal and external rotation[1]. The patella is also an important part of the knee joint. The quadriceps femoris tendon and the patellar ligament stabilize the patella and provide leverage for the quadriceps muscles to extend the knee. Figure 1.7 shows the quadriceps femoris tendon and patellar ligament as well as all the bursae in the knee.
Figure 1.7. Tendons and ligaments of the knee joint[1]
The important ligaments that help maintain stability in the knee are the anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), lateral collateral ligament
(LCL), and medial collateral ligament (MCL). The ACL and PCL provide stability in the sagittal plane and the MCL and LCL provide stability in the frontal plane. On the superior end of the tibia, the medial and lateral menisci provide a smooth articulating surface that reduces friction in the knee joint[1]. Figure 1.8 shows the ligaments and menisci of the knee.
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Figure 1.8. Ligaments and menisci of the knee joint[1]
The inferior portions of the tibia and fibula articulate with the talus to form the ankle joint, which is part of the ankle complex. The ankle joint is a hinge-type joint that allows for dorsiflexion and plantarflexion of the ankle[1]. Figure 1.9 shows the tibia and fibula and their important landmarks.
Figure 1.9. The tibia and fibula and important landmarks[3]
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The important ligaments that provide stability for the ankle include the deltoid ligament on the medial side and the anterior talofibular ligament, calcaneofibular ligament, and the anterior and posterior inferior tibiofibular ligaments on the lateral side[1]. Figure 1.10 shows the ligaments of the ankle.
Figure 1.10. Ligaments of the ankle[1]
Figure 1.11 shows all the bones of the foot. The tarsal bones include the calcaneus, talus, navicular, cuboid, and medial, intermediate, and lateral cuneiform bones. The articulation between the calcaneus and the talus makes up the subtalar joint, which is part of the ankle complex. The subtalar joint is gliding-type joint that allows for eversion and inversion of the foot. The other bones of the foot include the metatarsals (I-
V) and the phalanges[1].
8
Figure 1.11. The tarsal bones[1]
The muscles of the gluteal region are separated into two categories: superficial and deep. The superficial muscles of the gluteal region include the gluteus maximus, medius, an minimus. The gluteus maximus is responsible for extending and externally rotating the thigh. The gluteus medius and the gluteus minimus are responsible for abducting and internally rotating the thigh. The deep muscles of the gluteal region include the piriformis, superior and inferior gemelli, obturator internus, and quadratus femoris. These muscles are primarily responsible for external rotation and abduction of the hip[1]. Figure 1.12 shows all the muscles of the gluteal region, both superficial and deep.
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Figure 1.12. Muscles of the gluteal region[1]
The muscles of the anterior portion of the thigh include the psoas major, iliacus, rectus femoris, vastus medialis, vastus intermedius, vastus lateralis, and sartorius. The psoas major and the iliacus converge to form the iliopsoas, which is responsible for flexing the thigh. The rectus femoris originates from the anterior inferior iliac spine and inserts into the patella via the quadriceps tendon. It is responsible for extending the knee and flexing the hip. The vastus medialis originates from the intertrochanteric line and medial lip of the linea aspera and is responsible for extending the knee and stabilizing the patella. The vastus intermedius originates from the anterior and lateral surfaces of the femoral shaft and is responsible for extending the knee and stabilizing the patella. The vastus lateralis originates from the greater trochanter and lateral lip of the linea aspera
10 and is responsible for extending the knee and stabilizing the patella. All three vasti insert into the patella via the quadriceps tendon. The sartorius is responsible for flexing, abducting, and externally rotating the hip and helping to flex the knee[1].
The muscles of the medial compartment of the thigh include the obturator externus, adductor brevis, longus, and magnus, and gracilis. The obturator externus is responsible for adducting an externally rotating the thigh. The adductor brevis and adductor longus are responsible for adducting the thigh. The adductor magnus has two parts. The adductor portion is responsible for adducting the thigh and the hamstring portion is responsible for extending the thigh. The gracilis is responsible for adducting the thigh and flexing the knee[1].
The muscles of the posterior compartment of the thigh include the biceps femoris, semitendinosus, and semimembranosus. This is commonly known as the hamstring group. The biceps femoris has both a long and short head. The long head is responsible for extending the hip and flexing the knee and the short head aids in externally rotating the lower leg at the knee. The semitendinosus and semimembranosus are responsible for extending the hip and flexing the knee[1]. Figure 1.13 shows all the muscles in the thigh in the anterior, medial, and posterior compartments.
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Figure 1.13. The muscles of the anterior, medial, and posterior compartments of the
thigh[1]
The muscles of the anterior compartment of the leg include the tibialis anterior, extensor digitorum longus, and extensor hallucis longus. The tibialis anterior is responsible for dorsiflexion of the ankle and inversion of the foot. The extensor digitorum longus is responsible for extending the lateral four toes and dorsiflexing the ankle. The extensor hallucis longus is responsible for extending the great toe and dorsiflexing the ankle[1].
The muscles of the lateral compartment of the leg include the peroneus (fibularis) longus and brevis. The peroneus longus is responsible for plantarflexing the ankle and everting the foot. It also supports the transverse arch of the foot. The peroneus brevis is responsible for eversion of the foot[1]. Figure 1.14 shows all the muscles of the anterior and lateral compartments of the leg.
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Figure 1.14. Muscles of the anterior and lateral compartments of the leg[1]
The muscles of the posterior compartment of the leg are divided into two classifications, superficial and deep. The superficial muscles include the gastrocnemius, soleus, and plantaris. The gastrocnemius has a lateral head and a medial head. The lateral head originates from the lateral femoral condyle and the medial head originates from the medial femoral condyle. The two heads converge and insert into the calcaneus via the calcaneal (Achilles) tendon. The gastrocnemius is responsible for plantarflexion of the ankle and aids in flexion of the knee. The soleus is responsible for plantarflexion of the ankle. The plantaris aids in plantar flexion of the ankle and flexion of the knee[1].
The deep muscles of the posterior compartment of the leg include the popliteus, tibialis posterior, flexor digitorum longus, and flexor hallucis longus. The popliteus is responsible for laterally rotating the femur on the tibia. The tibialis posterior originates from the interosseous membrane and the posterior surface of the tibia and fibula and inserts at the plantar surface of the medial tarsal bones. It is responsible for plantarflexion
13 of the ankle, inversion of the foot, and supporting the medial arch of the foot. The flexor digitorum longus is responsible for flexing the lateral four toes. The flexor hallucis longus is responsible for flexion of the great toe[1]. Figure 1.15 shows all the muscles of the posterior compartment of the leg, both superficial and deep.
Figure 1.15. Muscles of the posterior compartment of the leg[1]
The muscles of the plantar aspect of the foot can be divided into three layers. The first layer includes the abductor hallucis, flexor digitorum brevis, and abductor digiti minimi. The abductor hallucis is responsible for abducting and flexing the great toe. The flexor digitorum brevis is responsible for flexing the lateral four toes at the interphalangeal joints. The abductor digiti minimi abducts and flexes the fifth toe[1].
The second layer of muscles of the plantar aspect of the foot includes the quadratus plantae and lumbricals. The quadratus plantae helps flex the lateral four toes.
The lumbricals flexes the metatarsophalangeal joints and extends the interphalangeal joints[1].
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The third layer of muscles of the plantar aspect of the foot include the flexor hallucis brevis, adductor hallucis, and flexor digiti minimi brevis. The flexor hallucis brevis flexes the proximal phalanx of the great toe at the metatarsophalangeal joint. The adductor hallucis adducts the great toe and helps form the transvers arch of the foot. The flexor digiti minimi brevis flexes the proximal phalanx of the fifth toe[1]. Figure 1.16 shows all the muscles of the dorsal aspect of the foot.
Figure 1.16. The muscles of the dorsal aspect of the foot[1]
The muscles of the plantar aspect of the foot include the extensor digitorum brevis and extensor hallucis brevis. The extensor digitorum helps to extend the lateral four toes at the metatarsophalangeal and interphalangeal joints. The extensor hallucis brevis helps to extend the great toe at the metatarsophalangeal joint[1]. Figure 1.17 shows the muscles of the plantar aspect of the foot.
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Figure 1.17. Muscles of the plantar aspect of the foot[1]
Quadriceps Angle (Q-angle)
The quadriceps angle, or Q-angle, is the angle that is measured between pull of the quadriceps muscles from the quadriceps tendon and the pull of the patellar ligament
[4]. It is found by measuring the angle between the imaginary line formed between the anterior superior iliac spine and the center of the patella and the imaginary line formed between the center of the patella and the tibial tuberosity [5]. Figure 1.18 shows Q-angle and the lines from which it is measured.
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Figure 1.18. Q-angle and the lines from which it is measured [6]
For a long time, Q-angle has been speculated to play a role in injuries.
Specifically, a Q-angle of more than 15-20⁰ is considered to be a risk factor for overuse injuries to the knee [7]. Studies have shown that women have a larger Q-angle than men
(mean 3⁰ difference) and that Q-angles of the left and right leg are not always bilaterally symmetric (mean 3⁰ difference) [8]. Larger Q-angles in women are thought to be caused by either their wider pelvis [9] or higher degrees of femoral internal rotation [10]. Q- angle is also thought to be influenced by flexion and strength of the quadriceps femoris muscles. Isometric contraction has been found to decrease Q-angle when compared to measurements taken during relaxion [11]. This could explain the bilateral difference in
Q-angle, particularly in athletes participating in sports like soccer where the dominant leg
17 is stronger [8]. Additionally, females have been found to have higher angles of hip adduction and knee abduction during the running gait cycle [12], which contributes to a higher functional Q-angle.
In males, the average Q-angle has been found to be between 11.2⁰ and 12.7⁰
[13,14]. In females, the average Q-angle has been found to be 15.8⁰ when measured while subjects are in the supine position [13] and 17⁰ while measured in standing position
[14]. Additionally, females have been found to have a Q-angle that is, on average, 11⁰ greater than that of males during athletic tasks such as running and lateral direction change. Females have also been found to have higher quadriceps muscle activity and lower hamstring muscle activity when compared to males[15].
In one study that followed 393 male and female high school cross country athletes throughout their competition season, a statistically significant increased risk of knee injury was found in athletes with a Q-angle higher than 20⁰. Additionally, a significantly higher risk of injury in the lower leg and foot was found in athletes with a bilateral difference in Q-angle greater than 4⁰. The same study found that a bilateral limb length discrepancy greater than 2 cm was also related to a higher overall risk of injury [16].
Although many studies have been conducted to investigate the correlation between Q-angle and lower extremity injuries, studies that investigate the biomechanics related to differing Q-angle are lacking. This study aims to investigate the correlation between Q-angle and injuries, but also relate those injuries to biomechanical trends found through gait and EMG analysis.
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The Gait Cycle
The gait cycle can be examined in three different states: walking, running, and sprinting. The primary difference between walking and running is that walking has a phase of double limb support and running has a phase of double float, meaning that neither foot is touching the ground. The primary difference between running and sprinting is which part of the foot strikes the ground at initial contact. In running, 80% of people strike with the hindfoot at initial contact and the other 20% strike with the midfoot. In sprinting, initial contact is made with the forefoot, and the hindfoot often will not touch the ground at all[17]. In Figure 1.19 below, A marks the transition between walking running (double limb support to double float) and B marks the transition between running and sprinting (hindfoot strike to forefoot strike).
Figure 1.19. Transition between types of gait[17].
The walking gait cycle consists of two primary phases. The stance phase makes up 60% of the cycle. Stance phase if composed of initial contact, midstance, and terminal stance. The swing phase makes up 40% of the cycle. Swing phase consists of initial swing, midswing, and terminal swing[17]. Figure 1.20 shows the phases of the walking gait cycle.
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Figure 1.20. Walking gait cycle phases[18]
The running gait cycle also consists of stance phase and swing phase. During running, stance phase makes up 40% of the gait cycle. It consists of initial contact, midstance, and toe off. The swing phase makes up 60% of the gait cycle. It consists of initial swing and terminal swing. The different phases of the gait cycle are the same in running and sprinting, but in elite sprinters, the stance phase can make up as little as 22% of the gait cycle [17].
Figure 1.21. Running gait cycle phases[18]
The joint motions in the lower extremity that make up the gait cycle can be very complicated and are influenced by the joint motions that occur in the ankle and foot.
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Table 1.1 shows the joint motions that are affected by pronation and supination of the ankle up the kinetic chain.
Table 1.1. Effects of pronation and supination up the kinetic chain[18]
Pronation is the combination dorsiflexion, abduction, and eversion of the foot.
Supination is the combination of plantar flexion, adduction, and inversion of the foot[19].
Pronation occurs during initial contact and midstance of the stance phase and supination occurs as the heel begins to lift off the ground during stance phase and at push off[20].
Pronation is generally coupled with internal rotation of the tibia and supination is occurs in conjunction with external rotation of the tibia[21]. Figure 1.22 shows images of pronation and supination at the ankle joint. The left image shows these motions and the right image shows how these motions affects tibial rotation.
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Figure 1.22. Pronation and supination and the effects those motions have on tibial
rotation[21,22]
At initial contact, the knee joint flexes and continues to flex during loading response for shock absorption. As stance phase continues, the knee begins to extend to prepare for push off. In early swing, the knee is most extended, and then flexes to allow for clearance of the foot and to prepare for initial contact again[18]. Figure 1.23 shows the knee joint and its potential axes.
Figure 1.23. Knee joint axes for different alignments[23]
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At initial contact, the hip joint begins to flex as a shock absorption measure, as well as adduct and internally rotate. This continues through midstance, and then supination up the kinetic chain takes place to prepare for push off. At this point, the hip begins to extend, abduct, and externally rotate. During swing phase, the hip flexes to allow for clearance of the lower leg and to prepare for the next initial contact[18].
As the gait cycle progresses from walking to running to sprinting, the range of motion of the involved joints changes. For the hip, range of motion increases as speed increases at all stages of the gait cycle. For the knee, the range of motion during the stance phase increases from walking to running (~35⁰ and up to 45⁰), but then decreases in sprinting (~20⁰). While sprinting, the ankle plays a larger role in shock absorption than the knee. During the swing phase, knee flexion increases in running when compared to walking (140⁰ compared to 65⁰), but the range of motion is similar in running and sprinting. For the ankle, dorsiflexion increases during the stance phase when transitioning from walking to running and sprinting. Plantar flexion also increases during the late part of stance phase transitioning to into swing phase[24]. Figure 1.24 shows the range of motion for each joint.
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Figure 1.24. Joint range of motion for hip, knee, and ankle during the walking, running,
and sprinting gait cycles[24]
Figure 1.25 shows the muscles that are active at different points during the running gait cycle. The quadriceps group is active during early stance and functions to slow forward momentum and stabalize the thigh and knee[25]. The quadriceps are also active during the last 20% of the swing phase for running and the last 50 to 60% of the swing phase in sprinting, as they help extend the knee in preparation for contact[24]. The hamstring group, along with hip extensors like the gluteus maximus, are active in the second half of swing and the first half of stance phase to extend the hip. The hamstrings also help to decelerate the tibia prior to initial contact. The plantar flexors, including the gastrocnemius and the soleus, are most active during push off, where there is the most plantar flexion of the ankle. The tibialis anterior muscle is active concentrically throughout the swing phase to allow for clearance of the foot. It is also active eccentrically during initial contact to slowly lower the forefoot to the ground[17].
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Figure 1.25. Muscle activation during the running gait cycle[17]
Common Injuries in Running
Just as in other sports, injuries are common in running sports like track and field and cross country. The vast majority of injuries caused by running occur in the lower extremity[26]. Injuries can range in severity and can require no stoppage of training or as much as a year away from sport. This section describes the most common injuries caused by running as classified by anatomic areas.
Back Injuries
Muscle ruptures are relatively uncommon in runners but are common in weightlifting (which is commonly practiced by collegiate level track and field athletes), javelin and discus throwers, and pole-vaulters[26] .
Sciatica is a condition in which the sciatic nerve is compressed, causing pain, tingling, and numbness on the posterior portion of the leg. It is often caused by a slipped
25 disc. Although this injury is not commonly caused by running, it can be caused by supplementary fitness activity such as weightlifting[26].
Spondylolysis is a condition where a stress fracture occurs in the vertebral arch on one of the lumbar vertebrae of the spine. If the stress fracture worsens into a complete fracture, the vertebrae are prone to slip, which is a condition known as spondylolisthesis.
Like the other back injuries discussed, spondylolysis and spondylolisthesis are rarely caused by running. They are caused by excessive posterior bending in the lumbar portion of the spine, especially when weight is added[27]. Activities such as weightlifting, javelin throwing, and high jumping can make track and field athletes susceptible to this injury[26].
Groin Injuries
There are several injuries of the groin to which runners are susceptible. Overuse injury or rupture of the adductor muscle-tendon unit is caused by repetitive abduction and adduction of the hip. It is common in track and field athletes that participate in the hurdles. Overuse injury or rupture of the iliopsoas muscle is caused by repetitive flexion of the torso with respect to the hip. It can be caused by running, but is more common in events that require a larger range of motion of the hip, such as hurdles. Sports hernia is thought to be caused by a congenital weakness of the posterior wall of the inguinal channel that puts more strain on surrounding ligaments and tendons[26]. It most frequently occurs in athletes that participate in sprinting events and hurdles[28].
Thigh Injuries
There are also several injuries in the thigh that are common in runners. Rupture of quadriceps muscles are most commonly caused by a fast start or sprint. Hamstring
26 ruptures, which are very common among sprinters, commonly occur as a result of a forceful contraction of the muscle while the knee is in flexion or the hip is in extension[26]. In a study conducted on elite track and field athletes at the 2011 IAAF world championships, 67% of the injuries reported throughout the competition were hamstring strains, accounting for the most of any type of injury[29].
Knee Injuries
Knee injuries are common in runners. One of the most common injuries is patellofemoral pain syndrome. This is a syndrome in which, often, no direct cause can be found. Potential causes are thought to be malalignment and muscle imbalances in the quadriceps group. Conditions such as chondromalacia patellae and patellar tendinitis can be classified under the umbrella of patellofemoral pain syndrome[30].
Meniscus injuries are more common in contact sports than in running. They are usually caused by a twisting motion of the knee[26]. However, they do occur in runners and become more common in runners that are of an older age[31].
Jumper’s knee is an overuse injury of the patellar ligament. It is caused by repetitive explosive contraction of the knee extensor muscles that is common in jumping and sprinting. Runner’s knee is also known as iliotibial band friction syndrome. It is an overuse injury that can be caused by repetitive downhill running, and is therefore more common in cross country athletes. Pain begins when the iliotibial band repetitively passes over the lateral epicondyle of the femur as the knee is flexed and extended during running. Osgood-Schlatter disease is common among adolescent athletes. It occurs when the attachment of the patellar ligament to the tibial tuberosity becomes inflamed[26].
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Lower Leg Injuries
The lower leg is another common site of injury in runners. Medial tibial stress syndrome, also known as shin splints, is a common overuse injury in athletes. It can be exacerbated by running on hard surfaces, changing training shoes, and sudden increase in training intensity[26]. Medial tibial stress syndrome has been found to be caused by
“vasculitis, increased medial periosteal formation, and cortical hypertrophy evident radiographically, and a mildly positive bone scan along the distal one-third of the posterior medial border of the tibia[32].” It has also been speculated to have a higher prevalence in athletes with pes planus, or overpronation of the foot[33].
Another common lower leg injury in runners is tibial stress fractures. The most common type of tibial stress fractures in runners are central and anterior tibial stress fractures. These are caused by overuse and are difficult to treat because they are on the
“tension side” of the tibia, meaning that the tension applied by the plantar flexors makes union of the fracture more difficult to achieve[26]. In females, a number of other factors can increase susceptibility to this injury. In one study, 40% of women who reported stress fractures also had menstrual irregularities[34]. The “female athlete triad” is the combination of menstrual disfunction, disordered eating, and decreased bone density.
This is a dangerous condition that can drastically increase risk for stress fractures[35].
The calcaneal, or Achilles, tendon is another common site for injuries in runners.
Extrinsic factors for Achilles injuries include sudden change in training intensity, training surface, or training footwear. Intrinsic factors include pes planus (overpronation), muscle imbalances, plantar flexor stiffness, and malalignment. Achilles tendinosis, peritenonitis
(inflammation of the tendon sheath), and partial or complete ruptures can occur[26].
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Ankle Injuries
There are several injuries to the ankle that are common in track and field athletes.
Ligament injuries of the ankle, or ankle sprains, are a common injury for all types of athletes. In approximately 65-70% of ankle sprains, the anterior talofibular ligament is injured. The mechanism of this injury is over-supination of the foot[26]. Ankle sprains are classified a grade I, II, and III. Grade I is a partial tear of the ligament, grade II is a incomplete tear with moderate functional impairment, and grade III is a complete tear with loss of integrity of the ligament[36].
Tendon injury is also common in the ankle, as several tendons cross over or insert near the ankle joint. Two major tendons that are commonly injured in runners are the tibialis posterior tendon and the peroneal tendons (longus and brevis). Dysfunction of the tibialis posterior tendon can occur when the foot is in valgus, or over-pronated alignment[37]. Likewise, a risk factor for peroneal tendon dysfunction is varus, or over- supinated, alignment of the foot[38].
Foot Injuries
Fractures and stress fractures of the metatarsals are one of the most common injuries of the foot in runners. Stress fractures of the metatarsals make up about 20% of all stress fractures in the lower extremity. They are caused by the repetitive pounding that comes with running[26]. Insufficiency of the arch is another common issue that plagues runners. The foot is made up of the longitudinal and anterior transverse arches. Due to anatomical differences, some athletes are more prone to having a flat foot. Although this is not an injury in itself, it can lead to malalignment, which can cause a host of potential injuries[26].
CHAPTER 2
MATERIALS AND METHODS
IRB Requirements
Prior to beginning data collection, an application was submitted to the Mercer
Institutional Review Board (IRB). All procedures were approved by the IRB under project code H1904101_01 on 4 April 2019 until 3 April 2020. A copy of the approval letter can be found in Appendix A. The principle investigator had to complete the Basic
Course for Biomedical Research Investigations by the Collaborative Institutional
Training Initiative (CITI) prior to approval by the IRB. This certificate can be found in
Appendix B.
Prior to data collection with human subject, the principle investigator explained the testing procedures and goals of the study with each subject. The subject was asked to sign and date a consent form, which was also approved by the IRB. A copy of this consent form can be found in Appendix C.
Q-Angle and Limb Length Measurements
For this study, subjects were selected based on specific criteria. All subjects had to be current members of Mercer University’s women’s track and field team. 20 subjects
30
31 were selected to participate in the study. Of the 20 who participated, 8 were members of
Mercer’s cross country team in addition to track and field.
The first part of data collection occurred in Mercer University’s Biomechanics and Gait Lab in the Engineering Building. After subjects agreed to participate in the study and signed the informed consent form, they were asked to remove their shoes so that limb length should be measured. Limb length was measured to account for previous studies that found limb length discrepancy to be a factor for injury. Figure 2.1 shows this process. The principle investigator palpated to find each subject’s anterior superior iliac spine (ASIS) (A). A measuring tape was placed at the ASIS and the investigator measured from that landmark to the medial malleolus on the medial side of the ankle (B) and to the floor on the lateral side of the foot (C). This process was repeated for both legs.
A B C
Figure 2.1. Investigator measuring limb length on a subject
Next, the subjects were asked to lay in the supine position on the exam table. The investigator palpated the subjects’ legs to find the ASIS, the center of the patella, and the tibial tuberosity. Small marks were made with a marker on the center of the patella and tibial tuberosity of each leg. Then, a yardstick was used to draw a straight line with a
32 marker from the ASIS to the center of the patella and from the center of the patella to the tibial tuberosity. A goniometer was used to measure the angle between the two lines. This angle is the Q-angle. The values for limb length and Q-angle were recorded on a sheet of paper and later transferred into an Excel document. Figure 2.2 shows how the Q-angle was measured. Image A shows the investigator marking the center of the patella. Image B shows the investigator marking the tibial tuberosity. Image C shows the investigator using a yard stick to create a line from the ASIS to the center of the patella. Images D and
E show the investigator drawing the lines from the ASIS to the center of the patella and from the center of the patella. Image F shows the investigator using a goniometer to measure Q-angle.
33
A B C
D E F
Figure 2.2. Steps of measuring Q-angle on a subject
After Q-angle was measured, subjects were divided into three groups base on their Q-angle measurements (10⁰-14⁰, 15⁰-17⁰, and 18⁰+).
Gait Analysis Equipment and Procedure
After limb length and Q-angle were measured and recorded, all 20 the subjects participated in gait analysis (twelve subjects from group 1, four subjects from group 2, and four subjects from group 3. The gait research was conducted using Streifeneder’s
PRO.Vision 2D system. The components used included the PRO.Vision software, LED
34 markers, a high-speed camera, and a treadmill. The following procedure was used to collect experimental gait data:
1. Connect the PRO.Vision system and camera to the computer.
2. Open PRO.Vision 2D.
3. Place the LED markers on the subject, assigning them colors based upon their
location as described below and in Figure x.x:
Sagittal Plane
1. Shoulder, deltoid muscle → red marker
2. Hip, greater trochanter → blue marker
3. Knee, below the lateral femoral condyle → red marker
4. Ankle, beneath lateral malleolus (~2 inches from the ground) →
blue marker
5. Forefoot, head of the fifth metatarsal → green marker
Frontal Plane
1. Upper edge of sternum → green marker
2. Right ASIS → red marker
3. Left ASIS → blue marker
4. Knee, in the middle of patella→ red marker
5. Ankle, middle, end of the tibia and fibula → blue marker
4. Open the Running Analysis → Sagittal/Frontal Right/Left predefined report on
PRO.Vision.
5. Setup the camera in the sagittal or frontal view, depending of which predefined report was selected.
35
6. Complete 2D calibration by drawing horizontal and vertical lines in the view of the camera and assigning them accurate distance measurements. This will allow the system to interpret information from the camera as accurately as possible.
7. Define the space the subject should be viewed in.
8. Assure all angle measurements can be detected by the camera.
9. Set the treadmill to 7.4 mph (11.909 km/h) and allow the subject to get acclimated to the speed.
10. Record the run until at least 5 good running cycles have been captured.
11. Save the video.
12. Configure the video by determining the five major points in the subject’s running cycle: initial contact, peak knee flex, push off, flight phase, and swing for the sagittal plane; initial contact, midstance, and midstance of the opposite leg for the frontal plane.
13. Create a report: enter the patient’s information and treadmill speed, choose x- direction for calibration, and save the file.
14. Repeat the entire procedure for the remaining subjects.
Data was collected in the right sagittal, right frontal, left frontal, and left sagittal planes.
LED markers on a subject are shown in figure 2.3 for each orientation (A=right sagittal plane and B=left frontal plane).
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A B
Figure 2.3. Marker setup for gait analysis on sagittal and frontal planes respectively
EMG Equipment and Procedure
After the completion of gait analysis, all subjects were asked to come to Black
Field, an intramural field on Mercer’s campus. Eleven subjects were asked to participate in this portion of the study (seven from group 1, three from group 2, and one from group
3). A 20-meter section was marked off with cones. Subjects were asked to warm up prior to this portion of the study. Then, the following protocol was followed:
The EMG research was conducted on the Noraxon Desktop DTS system. The components used included the Noraxon receiver, USB cable connection, the Noraxon
MR3 software, 10 EMG sensors, 10 surface electrodes (2 cm dual AgCl electrodes), and the computer webcam. The following procedure was used to collect experimental EMG data:
37
1. Connect the receiver to the laptop via usb and turn on the receiver.
2. Open the Noraxon MR3 program.
3. Prepare the skin for electrode placement by cleaning the areas with alcohol wipes.
4. Place the EMG electrodes at each of the following landmarks on each leg[39]:
a. Biceps Femoris- Located halfway between the ischial tuberosity and
lateral epicondyle of the tibia.
b. Semitendinosus- Located halfway between the ischial tuberosity and
medial epicondyle of the tibia.
c. Rectus Femoris- Located halfway between the ASIS and superior aspect
of the patella.
d. Vastus Lateralis- Located at the distal ⅓ distance between the ASIS and
lateral aspect of the patella. Make sure to place the electrode at a 45°
angle, facing outward.
e. Lateral Head of the Gastrocnemius- At 1/3 of line head of fibula – heel
5. Place the surface EMG sensors (Note: 10 sensors are used):
EMG 1 – Rectus femoris (R)
EMG 2 – Vastus lateralis (R)
EMG 3 – Rectus femoris (L)
EMG 4 – Vastus lateralis (L)
EMG 5 – Semitendinosus (R)
EMG 6 – Biceps femoris (R)
EMG 7 – Lateral gastrocnemius (R)
EMG 8 – Semitendinosus (L)
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EMG 9 – Biceps femoris (L)
EMG 10 – Lateral gastrocnemius (L)
6. Tape around the sensors to prevent movement while running. Assure all wires are secure.
7. Create a new project in the Noraxon system and set up the noraxon devices: the web camera and noraxon receiver.
8. Set up a new configuration by assigning EMG sensors 1-10 to the corresponding muscles as described in step 6.
9. Click measure and watch the muscle activity. Assure that all muscle activity can be seen and no interference has occurred. If there is interference, check that the electrodes are properly attached to the skin, no wires are loose, no sensors are touching, and no garments are in the way of the sensor.
10. Record maximum contractions of the subject: knee flexion and extension and plantar flexion, three times on either side.
11. Record the subject sprinting for 20 m for two trials.
12. Assure the data is free of interference and save the measured data. Make sure to input the correct patient information (Name, Birthdate, Weight, and Height).
13. Perform signal processing on the obtained data by filtering the data with a bandpass filter from 50 to 500 Hz and smooth out the signal using RMS at 100 ms. Save the new data.
14. Generate a symmetry report for analysis.
15. Repeat the entire procedure for the next subject.
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Figure 2.4 shows a subject with the sensors and electrodes on her leg. Image A shows an AP view of the electrodes without the bandage, image B shows a PA view of the electrodes without the bandage, and images C and D show the same view of the subject with the bandage on the legs securing the sensors and electrodes.
A B
C D
Figure 2.4. AP and PA view of subject with EMG electrodes and sensors setup
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Statistical Analysis
Statistical analysis was performed on the EMG and gait data collected for this project. Data, which was generated in PDF reports by both gait and EMG software, was transferred into Microsoft Excel. Means and standard deviations for the data collected for each of the three groups were calculated in Excel. The next step was determining whether or not the data was normally distributed. For this, data was moved from Excel into
Minitab. In Minitab, an Anderson-Darling test was performed on each set of data. If the data was found to be normally distributed, a 2-sample t-test was performed in Minitab to asses statistically significant differences between the three groups. A t-test was chosen over an ANOVA test because of the small sample size and the small number of subjects in each of the groups. If the data was not normally distributed, the investigator intended to perform a Mood’s median test to asses statistically significant difference. This was successful with the gait data, however, because the there was only one subject was in group 3 during EMG analysis, this test was unsuccessful for this data. Therefore, for the
EMG data, a on1-sample t-test was used to asses statistically significant differences
CHAPTER 3
RESULTS AND DISCUSSION
Subject Information and Reported Injuries
All subject information including height, weight, age, dominant leg, and events within track and field is shown in Appendix D. All injuries reported by each of the 20 subjects are shown in a table in Appendix E. Table 3.1 shows the average limb length measured for each of the three groups.
Table 3.1. Average limb length of each group
Limb Length ASIS-MM (in) Limb Length ASIS-Floor (in)
R L R L
Group 1 34.9583 34.8125 37.25 37.2083
Group 2 34.3125 34.4375 36.625 36.75
Group 3 33.5625 33.8125 36.1875 36.375
Figure 3.1 shows the average limb length that was recorded for each group, measured from the ASIS to the medial malleolus and from the ASIS to the floor. The graph shows the trend of limb length decreasing by group. Group 1 had the longest limb length, followed by group 2 then group 3.
41
42
Average Limb Length 38
37
36
35
Inches 34
33
32
31 ASIS-MM R ASIS-MM L ASIS-Floor R ASIS-Floor L Axis Title
Group 1 Group 2 Group 3
Figure 3.1. Average limb length measured to the medial malleolus and the floor for each
group
Table 3.2 shows the average limb length discrepancy values for each group, measured for the ASIS to the medial malleolus and from the ASIS to the floor.
Table 3.2. Average limb length discrepancies for each group
Limb Length Discrepancy (in)
ASIS-MM ASIS-Floor
Group 1 0.1875 0.208
Group 2 0.125 0.25
Group 3 0.25 0.1875
Figure 3.2 shows the average limb length discrepancy recorded for each group, as measure from the ASIS to the medial malleolus and from the ASIS to the floor. The
43 graph shows that group 2 had the highest limb length discrepancy when measured to the floor and group 3 had the highest limb length discrepancy when measured to the medial malleolus. No group had limb length discrepancies large enough to be a factor for injury.
Average Limb Length Discrepency 0.3
0.25
0.2
0.15 Inches
0.1
0.05
0 Group 1 Group 2 Group 3
ASIS-MM ASIS-Floor
Figure 3.2. Average limb length discrepancy measured to the medial malleolus and the
floor for each group
Table 3.3 shows the average Q-angle values for each group and the average difference between Q-angle between the right and left legs.
Table 3.3. Average Q-angle for each group
Q-Angle (⁰)
R L Difference
Group 1 12.833 11.417 1.417
Group 2 16.25 16.25 0
Group 3 21.125 20.25 0.875
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Figure 3.3 shows the average Q-angle measured for each group on both the right and left legs. The groupings that were used for this study can be clearly seen on the graph. Group 3 has the highest Q-angle, followed by group 2, then group 1. Group 2 has the average Q-angle closest to average for females, which is 15.8⁰. Group 1 is below average and group 3 is above average.
Q-Angle 25
20
15
Degrees 10
5
0 Group 1 Group 2 Group 3
R L
Figure 3.3. Average Q-angle by group
Figure 3.4 shows all the injuries reported by group 1. These injuries were reported by the subjects, not by medical professionals. The most common injuries reported by group 1 were shin splints and sprained ankles, followed by patellar tendinitis, fractures in the metatarsals, hamstring strains, and tendinitis in the foot or ankle.
45
Group 1 Injuries
5th metatarsal stress fracture 2nd metatarsal stress fracture Tibia stress fracture Pubic ramus and iliac crest fracture Lisfranc sprain Hip avulsion fracture Osgood-Schlatter's Sports hernia Sciatica Herniated disc Lower back strain Achilles tendinitis Abductor hallucis strain Fractured metatarsal Strained quad Tendinitis in foot/ankle Strained achilles Type of Injury of Type Strained hamstring Strained hip flexor Shin splints Patellar tendinitis Torn MPFL Patellar dislocation Pain in arch of foot Sprained ankle Peroneus brevis tendinitis 0123456789 Number of Athletes with Injury
Figure 3.4. Type and quantity of injuries reported by group 1
Figure 3.5 shows all the injuries reported by group 2. The most common injuries reported are shin splints, patellar tendinitis, sprained ankles, and strained hamstring muscles.
Group 2 Injuries
Patella tracking problem Achilles tendinitis Strained hip flexor IT band strain 2nd metatarsal stress fracture Shin splints Strained groin Strain in arch of foot
Type of Injury of Type Lower back strain Patellar tendinitis Sprained ankle Strained hamstring Hip flexor strain 0 0.5 1 1.5 2 2.5 Number of Athletes with Injury
Figure 3.5. Type and quantity of injuries reported by group 2
46
Figure 3.6 shows all the injuries reported by group 3. The most common injury reported for this group was shin splints.
Group 3 Injuries
Torn medial meniscus Torn transverse ligament Osteochondral defect Patellar tendinitis Labrum tear Stress fracture in tibia Stress fracture in femur Sprained ankle Tibialis posterior tendinitis Type of Injury of Type Spondylolysis Shin splints Strained hamstring Achilles tendinitis Stress reaction in tibia 0 0.5 1 1.5 2 2.5 Number of Athletes with Injury
Figure 3.6. Type and quantity of injuries reported by group 3
Figure 3.7 shows the locations of the injuries that were reported by each group.
The values are reported as percentages of the total number of injuries reported in each group. Group 1 has the highest incidence of injury in the ankle and foot and the lowest incidence of injury in the knee. Group 2 had the highest incidence of injury in the thigh.
Group 3 had the highest incidence of injury in the lower leg and knee. This is concurrent with many studies that have suggested higher Q-angle is related to higher incidence of knee injuries. The most common injuries for each group, as well as the location of those injuries, will be discussed further in the context of the gait analysis and EMG results in later sections of this chapter.
47
Locations of Injuries 45 40 35 30 25 20 15 10 5 Percentage of Injuries Reported Injuries of Percentage 0 Back Hip Thigh Knee Lower Leg Ankle/Foot Injury Location
Group 1 Group 2 Group 3
Figure 3.7. Locations of injuries reported for each group
Gait Analysis Results
This section contains the results from gait analysis in both the frontal and sagittal planes. In the frontal plane, analysis was performed for both the right and left sides. In the sagittal plane, analysis was only performed on the right side due to errors with the software when attempting to collect data on the left side. All these results are reported as angles of the joints of interest in degrees. In the frontal plane, negative values indicate more valgus alignment and adduction of the leg, while positive values indicate varus alignment and abduction. The raw data collected for this study is shown in Appendix F.
Figure 3.8 is a bar graph showing the results for the frontal plane on the left side at initial contact. This graph shows the trend of all angles being larger for group 2, followed by group 3, and then group 1. This can be explained by the fact that group 2 has the average Q-angle that is closest to normal. A more normal Q-angle leads to more
48 normal biomechanics, and therefore a larger range of motion in the joints. Figure 3.9 shows pictures of subject from each of the three groups (1, 2, and 3 from left to right).
Frontal Left Initial Contact 0 Trunk Angle Pelvis Angle Valgus/varus Hip add/abd -2
-4
-6
-8
-10 Degrees
-12
-14
-16
-18
Group 1 Group 2 Group 3
Figure 3.8. Gait results for the left leg in the frontal plane at initial contact
1 2 3
Figure 3.9. Subject from groups 1, 2, and 3 respectively at initial contact in the frontal
plane
49
Figure 3.10 is a bar graph showing the gait analysis results from the right leg in the frontal plane at initial contact. Group 2 has the largest trunk angle during this phase.
Group 2 also has the highest average limb length discrepancy when measured from the
ASIS to the floor, which helps to explain the larger trunk angle. If one leg is longer than the other, at the point of initial contact, the pelvis will not be perfectly in line. For both the valgus/varus angle of the knee and hip adduction/abduction angle, the data shows a trend of increasing angle with increasing Q-angle. Group 3 has the most valgus knee angle and the most adducted hip angle, followed by group 2, then group 1. This is because a higher Q-angle leads to more valgus alignment of the knee and also more adduction at the hip joint. Figure 3.11 shows pictures of subjects from each of the three groups (1, 2, and 3 from left to right).
Frontal Right Initial Contact 15
10
5
0 Trunk Angle Pelvis Angle Valgus/varus Hip add/abd
Degrees -5
-10
-15
-20
Group 1 Group 2 Group 3
Figure 3.10. Gait results for the right leg in the frontal plane at initial contact
50
1 2 3
Figure 3.11. Subject from group 1, 2, and 3 respectively at initial contact in the frontal
plane
Figure 3.12 is a bar graph showing the gait results from the left leg in the frontal plane at midstance. At this phase, group 1 has the lowest trunk and pelvis angles. Group 1 also has the lowest hip adduction angle. Group 1 has the lowest Q-angle, so the hip is less adducted than the other two groups with higher Q-angles. Group 2 has the highest valgus angle of the three groups. This is contrary to what would be expected, as group 3 has a higher average Q-angle and should theoretically have a higher valgus alignment of the knee. This could be caused by misplacement of the markers or other human error. Figure
3.13 shows pictures of subjects from each of the three groups (1, 2, and 3 from right to left).
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Frontal Left Midstance 5
0 Trunk Angle Pelvis Angle Valgus/varus Hip add/abd
-5 Degrees -10
-15
-20
Group 1 Group 2 Group 3
Figure 3.12. Gait results for the left leg in the frontal plane at midstance
3 1 2
Figure 3.13. Subject from group 1, 2, and 3 respectively at midstance in the frontal plane
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Figure 3.14 is a bar graph showing the gait results from the right leg in the frontal plane at midstance. At this phase, group 2 has the highest trunk angle. Group 3 has the highest valgus knee angle and the highest hip adduction angle. This aligns with what is expected because group 3 has the highest average Q-angle. Figure 3.15 shows pictures of subjects from each of the three groups (1, 2, and 3 from right to left).
Frontal Right Midstance 15
10
5
0 Trunk Angle Pelvis Angle Valgus/varus Hip add/abd -5 Degrees -10
-15
-20
-25
Group 1 Group 2 Group 3
Figure 3.14. Gait results for the right leg in the frontal plane at midstance
53
1 2 3
Figure 3.15. Subject from group 1, 2, and 3 respectively at midstance in the frontal plane
Figure 3.16 is a bar graph showing the gait data from the right side in the sagittal plane at initial contact. In the sagittal plane gait analysis, positive values correspond to anterior trunk lean, hip flexion, knee flexion, and ankle dorsiflexion. Negative values correspond to posterior trunk lean, hip extension, knee extension, and ankle plantar flexion. At initial contact, group 3 has the highest angle of posterior trunk lean. Group 2 has the highest angle of hip flexion, the lowest angle of knee flexion, and the highest angle of plantar flexion. Figure 3.17 shows subjects from all three groups (1, 2, and 3 from left to right).
54
Sagittal Right Initial Contact 30
25
20
15
10
5
0 Degrees Trunk lean Hip flex/ext Knee flex/ext Ankle -5
-10
-15
-20
-25
Group 1 Group 2 Group 3
Figure 3.16. Gait results for the right side in the sagittal plane at initial contact
1 2 3
Figure 3.17. Subjects from groups 1, 2, and 3 respectively at initial contact in the sagittal
plane
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Figure 3.18 is a bar graph showing the average angle values recorded for the three groups on the right side in the sagittal plane at peak knee flexion during the stance phase.
Group 2 has the highest angle of hip flexion, knee flexion, and ankle dorsiflexion. A likely cause of this is the group’s more average Q-angle. With a Q-angle closer to normal, subjects in this group likely have smoother joint articulation, particularly at the knee, which allows for a larger range of motion. Group 1, which has a more varus alignment of the knee, will experience more pressure on the medial side of the knee joint that leads to fiction in the area of the medial meniscus. Group 3, which has a more valgus knee alignment, will experience more pressure on the lateral side of the knee joint. These both lead to less smooth joint articulation during movement Figure 3.19 shows subjects from all three groups (1, 2, and 3 from left to right) during peak knee flexion.
Sagittal Right Peak Knee Flex 50 45 40 35 30 25
Degrees 20 15 10 5 0 Trunk lean Hip flex/ext Knee flex/ext Ankle
Group 1 Group 2 Group 3
Figure 3.18. Gait results for the right side in the sagittal plane at peak knee flexion
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1 2 3
Figure 3.19. Subjects from groups 1, 2, and 3 respectively at peak knee flexion in the
sagittal plane
Figure 3.20 shows the average angle values for each group on the right side in the sagittal plane at push off. Group 2 has the largest angle of anterior trunk lean and the largest angle of knee flexion. Group 2 also has the smallest angle of hip extension and angle plantar flexion. Figure 3.21 shows subjects from all three groups (1, 2, and 3 from left to right) at push off.
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Sagittal Right Push Off 30
20
10
0
Degrees Trunk lean Hip flex/ext Knee flex/ext Ankle
-10
-20
-30
Group 1 Group 2 Group 3
Figure 3.20. Average gait results for the right side in the sagittal plane at push off
1 2 3
Figure 3.21. Subjects from groups 1, 2, and 3 respectively at push off in the sagittal plane
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Figure 3.22 is a bar graph showing the average angle values collected from the right side in the sagittal plane during flight, when neither foot is touching the ground. The figure shows that there is very little variance between the groups at this stage. Figure 3.23 shows subjects from all three groups (1, 2, and 3 from left to right) during the flight stage.
Sagittal Right Flight 30
20
10
0 Trunk lean Hip flex/ext Knee flex/ext Ankle
Degrees -10
-20
-30
-40
Group 1 Group 2 Group 3
Figure 3.22. Average gait results from the right side in the sagittal plane during flight
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1 2 3
Figure 3.23. Subjects from groups 1, 2, and 3 respectively during flight in the sagittal
plane
Figure 3.24 shows the average angles collected for each group on the right side in the sagittal plane during swing. This figure shows that group 2 has the largest angle of anterior trunk lean and the smallest angle of ankle plantar flexion. Figure 3.25 shows subjects from each of the three groups (1, 2, and 3 from left to right) at the swing phase.
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Sagittal Right Swing 60
50
40
30
20
10 Degrees
0 Trunk lean Hip flex/ext Knee flex/ext Ankle -10
-20
-30
Group 1 Group 2 Group 3
Figure 3.24. Average gait results from the right side in the sagittal plane during swing
1 2 3
Figure 3.25. Subjects for groups 1, 2, and 3 respectively during swing in the
sagittal plane
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EMG Results and Discussion
All the raw EMG data collected for this study is shown in Appendix G. Figure
3.26 shows the peak EMG data for the vastus lateralis. The graph shows a trend, particularly on the left leg, of decreasing muscle activity with increasing Q-angle.
Peak Values: Vastus Lateralis 1400
1200
1000
800
600
% of MVC %of 400
200
0 R Vastus Lateralis L Vastus Lateralis -200
Group 1 Group 2 Group 3
Figure 3.26. Peak EMG values as a percentage of MVC for the vastus lateralis muscle in
both right and left legs
Figure 3.27 shows the mean EMG data for the vastus lateralis. In both the right and left legs, the graph shows a trend of decreasing muscle activity with increasing Q- angle.
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Mean Values: Vastus Lateralis 160
140
120
100
80
% of MVC %of 60
40
20
0 R Vastus Lateralis L Vastus Lateralis
Group 1 Group 2 Group 3
Figure 3.27. Mean EMG values as a percentage of MVC for the vastus lateralis muscle in
both right and left legs
Figure 3.28 shows three free body diagrams of the vastus lateralis. A shows a low
Q-angle leg with a varus knee alignment. In this case, more tension is put on the lateral side of the knee, including the vastus lateralis muscle. Both mean and peak EMG values on the right and left legs support this theoretical drawing. The middle image shows an average Q-angle leg and the far-right image shows a high Q-angle leg. These FBDs show that compression force, rather than tension force, is exerted on the vastus lateralis decreases as Q-angle increases. This would result in less muscle activity, which is supported by both the mean and peak EMG values.
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A B C
Figure 3.28. AP view of free body diagram of the vastus lateralis muscle with low,
average, and high (A, B, and C respectively) Q-angle[40]
Figure 3.29 shows the peak EMG values for the rectus femoris. For both the right and left legs, the graph shows a trend of decreasing muscle activity with increasing Q- angle.
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Peak Values: Rectus Femoris 500 450 400 350 300 250
% of MVC %of 200 150 100 50 0 R Rectus Femoris L Rectus Femoris
Group 1 Group 2 Group 3
Figure 3.29. Peak EMG values as a percentage of MVC for the rectus femoris muscle in
both right and left legs
Figure 3.30 shows the mean EMG values of the rectus femoris muscle for each group. The graphs show a trend of decreasing muscle activity with increasing Q-angle for both the right and left legs.
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Mean Values: Rectus Femoris 50
45
40
35
30
25
% of MVC %of 20
15
10
5
0 R Rectus Femoris L Rectus Femoris
Group 1 Group 2 Group 3
Figure 3.30. Mean EMG values as a percentage of MVC for the rectus femoris muscle in
both right and left legs
Figure 31 shows three free body diagrams of the rectus femoris muscle. The rectus femoris originates at the AIIS and inserts into the patella via the quadriceps tendon and into the tibial tuberosity via the patellar ligament, which means that it acts on both the hip and knee joints. Therefore, it is affected by Q-angle. The FBD illustrates that, as
Q-angle decreases and the knee has a more varus alignment, tension forces on the muscle increase. This prediction is supported by the EMG data, which shows that muscle activity increases as Q-angle decreases.
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A B C
Figure 3.31. AP view of free body diagram of the rectus femoris muscle with low,
average, and high Q-angle (A, B, and C respectively)[40]
Figure 3.32 shows the peak EMG values for the semitendinosus. The graph shows, in both right and left legs, that muscle activity is highest in group 2, followed by group 1, then group 3.
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Peak Values: Semitendinosus 600
500
400
300 % of MVC %of 200
100
0 R Semitendinosus L Semitendinosus
Group 1 Group 2 Group 3
Figure 3.32. Peak EMG values as a percentage of MVC for the semitendinosus muscle in
both right and left legs
Figure 3.33 shows the mean EMG values for the semitendinosus. The graph shows, in both right and left legs, that muscle activity is highest in group 2, followed by group 1, then group 1.
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Mean Values: Semitendinosus 80
70
60
50
40
% of MVC %of 30
20
10
0 R Semitendinosus L Semitendinosus
Group 1 Group 2 Group 3
Figure 3.33. Mean EMG values as a percentage of MVC for the semitendinosus muscle
in both right and left legs
Figure 3.34 shows three theoretical free body diagrams showing the forces acting on the semitendinosus muscle. They show low Q-angle, average Q-angle, and high Q- angle. Theoretically, because the semitendinosus passes over the medial side of the knee joint, the tension forces and, subsequently, the muscle activity would increase with increasing Q-angle. However, the data recorded does not support his assumption. Group
3, which has the highest Q-angle, has the lowest level of muscle activity in the semitendinosus. This is likely explained by the fact that only one subject from group 3 was able to participate with EMG analysis. This subject may have been an exception to the rule. Further EMG analysis with a larger sample size would help to see if this subject fits with the trend or is an exception to the rule.
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Fitting with the predicted trend, group 2 has more muscle activity that group 1.
Additionally, group 2 reported the highest percentage of hamstring strains when compared to the other groups. 50% of the subjects in group 2 have experienced a hamstring strain at some point in their athletic career.
A B C
Figure 3.34. PA view of free body diagram of the semitendinosus muscle with low,
average, and high Q-angle (A, B, and C respectively)[40]
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Figure 3.35 shows the peak EMG values for the biceps femoris. For the left leg, the graph shows that the muscle activity is highest for group 2. For the right leg, the graph shows a trend decreasing muscle activity as Q-angle increases.
Peak Values: Biceps Femoris 500 450 400 350 300 250
% of MVC %of 200 150 100 50 0 R Biceps Femoris L Biceps Femoris
Group 1 Group 2 Group 3
Figure 3.35. Peak EMG values as a percentage of MVC for the biceps femoris muscle in
both right and left legs
Figure 3.36 shows the mean EMG values for the biceps femoris. For the left leg, the graph shows that the muscle activity is highest for group 2, followed by group 1, then group 3. For the right leg, the graph shows that muscle activity is highest for group 1, followed by group 3, then group 2.
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Mean Values: Biceps Femoris 60
50
40
30 % of MVC %of 20
10
0 R Biceps Femoris L Biceps Femoris
Group 1 Group 2 Group 3
Figure 3.36. Mean EMG values as a percentage of MVC for the biceps femoris muscle in
both right and left legs
Figure 3.37 shows three theoretical free body diagrams for the forces acting on the biceps femoris. The far left is and FBD for low Q-angle, the middle for average Q- angle, and the far right for high Q-angle. The images show that, since the biceps femoris passes over the knee joint on the lateral side, tension forces on the muscle increase as Q- angle increases. Theoretically, increased tension forces correlate to higher muscle activity. However, the EMG data does not support this predicted trend. For the left leg, group 2 shows the highest muscle activity in both peak and mean values. As previously mentioned, group 2 had the highest incidence of reported hamstring strains, which could explain the actual results. Further study with a larger sample size must be done to fully conclude whether the predicted trend is correct or incorrect.
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A B C
Figure 3.37. PA view of free body diagram of the biceps femoris muscle with low,
average, and high Q-angle (A, B, and C respectively)[40]
Figure 3.38 shows the peak EMG values for the lateral head of the gastrocnemius.
The graph shows a trend of decreasing muscle activity with increasing Q-angle for both the right and left legs.
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Peak Values: Lateral Gastrocnemius 1800
1600
1400
1200
1000
800 % of MVC %of 600
400
200
0 R Lateral Gastrocnemius L Lateral Gastrocnemius
Group 1 Group 2 Group 3
Figure 3.38. Peak EMG values as a percentage of MVC for the lateral head of the
gastrocnemius muscle in both right and left legs
Figure 3.39 shows the mean EMG values for the lateral head of the gastrocnemius. The graph shows a trend of decreasing muscle activity with increasing Q- angle for both the right and left legs.
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Mean Values: Lateral Gastrocnemius 250
200
150
% of MVC %of 100
50
0 R Lateral Gastrocnemius L Lateral Gastrocnemius
Group 1 Group 2 Group 3
Figure 3.39. Mean EMG values as a percentage of MVC for the lateral head of the
gastrocnemius muscle in both right and left legs
Figure 3.40 shows three theoretical free body diagrams for the lateral head of the gastrocnemius muscle. Image A is low Q-angle, image B is average Q-angle, and image
C is high Q-angle. They represent the forces that are acting on the muscle for groups 1, 2, and 3 respectively. Theoretically, the tension forces on the lateral head of the gastrocnemius should increase as Q-angle decreases and the knee has a more varus alignment. If the tension forces are increased, this should lead to more muscle activity recorded by EMG analysis, which could lead to more injuries in this area. The EMG data recorded supports this hypothesis, however, group 1 did not report more injuries in the gastrocneius or the Achilles tendon than the othet two groups. Group 1 did, however, report more ankle sprains and metatarsal injuries than the other group. This could be the
75 result of biomechanical changes a varus knee alignment has on the rest of the lower leg.
Varus knee alignment leads to supination of the ankle, which changes the way that ground reaction forces interact with the foot while running. This is discussed further in later sections of this chapter. Both peak and mean values show increased muscle activity for group 1, which has the lowest Q-angle.
A B C
Figure 3.40. PA view of free body diagram of the lateral head of the
gastrocnemius muscle with low, average, and high Q-angle (A, B, and C
respectively)[40]
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Statistical Analysis
Of all the data collected for this study, only a few pieces of data were found to be statistically significant. Many meaningful trends were observed, but due to the small sample size in each group for most collection methods, minimal statistical significance was found. For gait analysis in the frontal plane, statistically significant differences were found on the left side for the trunk angle between groups 1 and 2 (p=0.065), pelvis angle between groups 1 and 2 and groups 2 and 3 (p=0.002 and p=0.021), and the hip abduction/adduction angle between groups 1 and 2 and groups 1 and 3 (p=0.002 and p=0.05) at initial contact. Additionally, a significant difference was found on the left frontal plane at the pelvis angle between groups 1 and 2 (p=0.009). In the right side on the frontal plane, statistically significant difference was only found for the pelvis angle between groups 1 and 3 at midstance (p=0.008). In the right side of the sagittal plane, statistically significant differences were found at the pelvis angle between groups 1 and 2 and groups 1 and 3 (p=0 and p=0.045), and the at the knee angle between groups 1 and 2
(p=0.021) at peak knee flexion.
For EMG analysis, statistically significant difference was not found in any case.
All Anderson-Darling normality are shown in Appendix H. All p-values that were found through 1-sample and 2-sample t-test and Mood’s median test are shown in Appendix I.
Discussion of Reported Injuries
The most common injuries reported in group 1 include shin splints (66.67% of subjects reported), sprained ankles (33.33%), tendinitis in the foot or ankle (25%), and metatarsal fractures or stress fractures (25% and 16.67% respectively). The most common injuries reported in group 2 include strained hamstring muscles, sprained ankles,
77 patellar tendinitis, and shin splints (all reported by 50% of subjects in group 2). The most common injury reported in group 3 is shin splints (50%). All other injuries reported were only present in one subject from the group. Injuries of note include tibialis posterior tendinitis and stress reactions or stress fractures in the tibia and femur.
As mentioned in the background section, the most commonly effected ligament in sprained ankles in the anterior talofibular (ATF) ligament. This ligament connects the talus and the fibula on the lateral side of the ankle joint. The higher incidence of ankle sprains in group 1 can be explained by the biomechanics that are a result of a lower Q- angle. A lower Q-angle and more varus alignment of the knee commonly leads to more supination of the ankle. Supination causes increased tension on the lateral side of the ankle joint, which leads to increased tension on the ATF and a higher risk of injury in that location.
This biomechanical explanation can also explain the high incidence of shin splints in group 1. Although shin splints were reported in each group and are a common injury for all runners that is caused by overuse, group 1 had a higher incidence than the other two groups (66.67% vs. 50%). When the ankle is more supinated throughout the running gait cycle as a result of lower Q-angle, the tibialis anterior is more concentrically contracted. One action of the tibialis anterior is inversion of the foot, which occurs during supination. The tibialis anterior originates from the interosseous membrane between the tibia and fibula and runs vertically along the tibia. Therefore, increased muscle activity in the tibialis anterior can lead to microtears that cause the pain in the anterior portion of the lower leg that is known as shin splints.
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For group 2, one of the most reported injuries was hamstring strains. This high incidence of hamstring injuries aligns with the EMG data from both the semitendinosus and the biceps femoris muscles. Group 2 had the highest muscle activity in the semitendinosus in both legs and the highest muscle activity in the left biceps femoris.
This was contrary to what was predicted (that group 3 would have the highest semitendinosus activity and group 1 would have the highest biceps femoris activity), but the EMG data and reported injuries support one another.
For group 3, it was difficult to make any conclusions regarding injuries because the injuries reported were very diverse. Because of this, discussion will focus on the location of injuries rather than the exact injuries reported. Group 3 had the highest percentage of injuries reported in the knee and the lower leg compared to the other two groups. This supports the common theory that athletes with higher Q-angles are more prone to injuries in the knee. The high presence of injuries in the lower leg, particularly tibia stress fracture and shin splints, is also interesting. With lower Q-angles, the reaction forces from the ground that act on the tibia are closer to exactly vertical. With higher Q- angles, like in group 3, the forces on the tibia occur at an angle, which could explain the higher incidence of injuries in this location.
Interesting Cases
There are two particular cases that stand out when looking at the injuries reported by each of the subjects. The first is subject 12 and the other are subjects 1 and 18. Subject
12 is in group 1. She has a Q-angle in the right leg of 14⁰ and in the left leg of 10⁰. As mentioned in the background section, one study reported that a bilateral difference in Q- angle greater than 4⁰ results in a higher incidence of athletics related injuries[16]. Subject
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12 has a bilateral Q-angle difference of exactly 4⁰ and, by far, reported the highest number of injuries when compared to other subjects. She reported twelve different injuries that occurred over the course of her running career.
She reported fractures of the second and third metatarsals in the left foot and stress fractures in the second and fifth metatarsals of the left foot. Subject 12’s left leg has the smaller Q-angle. This can be explained by similar biomechanical mechanisms that explain why group 1 has higher incidence of ankle sprains and shin splints. In this case, subject 12 has a bilateral difference in Q-angle but has no limb length discrepancy when measured from the ASIS to the floor. This indicates that the subject has compensated for an existing limb length discrepancy, meaning that the subject’s alignment has adjusted to make the leg have the same functional length. The right leg was the longer leg before compensation and is now functionally shorter due to the more valgus knee alignment. The left leg was shorter before compensation and is now functionally longer due to a more varus alignment and functional supination of the ankle.
Due to the functional supination of the ankle, the metatarsal bones in the foot are subjected to forces that act in a different direction than with normal alignment. The forces act at an angle rather than purely normal to the metatarsals. This explains the higher incidence of injury in this area. Additionally, subject 12 reported a stress fracture in the right tibia. The right leg has a higher Q-angle and a more valgus knee alignment. This means that the reaction force from the ground does not act on the tibia in an exactly normal direction, but rather at an angle which makes it more prone to injury.
The second interesting case to note is subject 1 and subject 18. Subject 1 is a part of group 1 and subject 18 is a part of group 3. Among other injuries, subject 1 reported
80 peroneus brevis tendinitis and subject 18 reported tibialis posterior tendinitis. Subject 1 has a lower Q-angle and, therefore, a more varus alignment of the knee and functional supination of the ankle. This means that more tension force acts on the lateral side of the ankle joint, where the peroneus brevis muscle is located. Subject 18 has a higher Q-angle and, therefore, a more valgus alignment of the knee and functional pronation of the ankle.
This means that greater tension force acts on the medial side of the ankle, where the tibialis posterior muscle is located. These two subjects are a perfect example of the effects that differing biomechanics caused by differing Q-angle can cause different injuries. Figure 3.41 shows free body diagrams that illustrate this concept. Arrow in the picture depict the forces acting around specific joints. The force of body weight and ground reaction forces are shown. For image A, depicting valgus alignment, arrows indicate compression forces on the lateral side of the knee and ankle and tension forces on the medial side of the knee and ankle. For image B, depicting varus alignment, arrows indicate tension forces on the lateral side of the knee and ankle and compression forces on the medial side of the knee and ankle.
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A B
Figure 3.41. AP view of free body diagrams showing the forces acting on the knee and
ankle joint in valgus and varus alignment[41]
CHAPTER 4
CONCLUSION
In conclusion, this study was very successful. Although a larger sample size is needed to make any firm conclusions, the data collected shows many trends that support initial hypotheses. Gait data shows that the hip is more adducted and the knee is more valgus in groups with above average Q-angles. EMG data shows that the quadriceps muscles and the lateral gastrocnemius have higher muscle activity in groups with below average Q-angles. Additionally, the injury history data collected by interviewing subjects was promising. The group with below average Q-angle was found to have higher incidence of shin splints and ankle sprains, the group with average Q-angle was found to have the highest incidence of hamstring strains, and the group with above average Q- angle was found to have a high incidence of shin splints.
This study could prove to be a step forward for the scientific community in understanding all the biomechanical effects of Q-angle. Although Q-angle has previously been linked to certain injuries, a study such as this that investigates the biomechanics related to Q-angle that could contribute to injury has been lacking. Results from this study, and future studies that improve upon this study, could be very helpful in understanding injury mechanics in sport and identifying athletes at risk for injuries so that they can take preventative steps.
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CHAPTER 5
FUTURE STUDIES AND RECOMMENDATIONS
There are several recommendations that could be made to improve upon this study in the future. The largest impediment in this study was sample size. The small sample size made statistical analysis difficult. The sample used for this study also had a large number of subjects with below average Q-angles, which made grouping uneven. A larger sample size would more accurately represent the distribution of Q-angle present in the population.
Another issue with this study was the scheduling restraints of the subjects. All participating subjects were student-athletes at the Division I level, meaning that their daily schedules were very busy, and they were not able to devote much time to participation in this study. This limited the number of trials each subject could do for both
EMG and gait analysis. Results may be better in the future if this study is conducted while school in not in session or with professional athletes who do not have the same demanding school schedule.
Additionally, the investigator recommends that in the future, data on previous injuries suffered by the subjects be collected directly from a medical professional. In this study, injury data was collected through verbal and electronic interview with the subjects.
The subjects described their injuries to the best of their ability, but someone with medical training would be able to provide more accurate information. For example, a common
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injury reported in this study was hamstring strains, but the subjects were unable to specify which of the hamstring muscles were injured—information that would have been helpful in data analysis.
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[36] Wolfe, M. W., Uhl, T. L., Mattacola, C. G., & Mccluskey, L. C. (2001). Management of Ankle Sprains. American Family Physician, 63(1), 93–105.
[37] Braly, W. G. (2008). Posterior Tibialis Tendon Dysfunction. Baxters the Foot and Ankle in Sport, 183–203. doi: 10.1016/b978-032302358-0.10008-9
[38] Tong, F., & Myers, T. (2010, January 11). Peroneal Tendonitis. Retrieved from https://mospace.umsystem.edu/xmlui/bitstream/handle/10355/13895/PeronealTen donitis.pdf?sequence=1
[39] EMG Practicum 1: Electrode Location and Placement. (n.d.). Retrieved from http://www.dnbm.univr.it/documenti/OccorrenzaIns/matdid/matdid174356.pd
[40] Complete Anatomy 2020. (n.d.). Retrieved from https://3d4medical.com/
[41] Biondo, S. (2019, December 19). Knock Knees? - Can they be straightened without surgery? Retrieved from http://boroondaraosteopathy.com.au/knockknees/
APPENDIX A
IRB APPROVAL
89
APPENDIX B
CITI PROGRAM CERTIFICATION
90
APPENDIX C
INFORMED CONSENT FORM
91
92
93
APPENDIX D
SUBJECT INFORMATION
Event Dominant Leg
Subject 1 Sprints R
Subject 2 Distance/steeplechase R
Subject 3 Distance R
Subject 4 Distance R
Subject 5 Sprints L
Subject 6 Sprints R
Subject 7 Sprints/jumps R
Subject 8 Sprints R
Subject 9 Sprints L
Subject 10 Distance L
Subject 11 Sprints/hurdles L
Subject 12 Distance R
Subject 13 Sprints R
94
95
Subject 14 Sprints L
Subject 15 Sprints L
Subject 16 Distance R
Subject 17 Distance R
Subject 18 Sprints/hurdles/jumps R
Subject 19 Distance R
Subject 20 Distance/steeplechase R
APPENDIX E
REPORTED INJURIES
Reported Injuries
Subject 1 Peroneus brevis tendinitis, sprained ankles
Subject 2 Pain in arch of right foot, no diagnosed injuries
Subject 3 Frequent patellar dislocation that led to torn MPFL in left knee,
patellar tendinitis in left knee, shin splints in both legs
Subject 4 No injuries
Subject 5 Shin splints, L strained hip flexor, strained hamstrings, tendinitis in L
foot/ankle, sprained ankles, strained achilles
Subject 6 Sprained ankle, strained hamstrings, strained achilles
Subject 7 Sprained ankle, pulled quad, shin splints
Subject 8 Shin splints, tendinitis in the knee, fractured metatarsal in left foot x2
Subject 9 Abductor hallucis strain, hamstring tendinitis, achilles tendinitis, shin
splits, lower back pain/strain, hip flexor strain
Subject 10 Shin splints, calf tightness, tendinitis in the ankle
Subject 11 Tendinitis in both ankles, herniated disc, strained R quad, L sciatica, R
sports hernia, shin splints
96
97
Subject 12 Osgood-schlatters, patellar tendinitis, right hip avulsion fracture, left
2nd and 3rd metatarsal fracture, lisfranc sprain, left hip pubic ramus
and iliac crest fracture, right shin stress fracture, shin splints both legs,
left 2nd and 5th metatarsal stress fractures
Subject 13 Hip flexor strain, pulled hamstrings, sprained ankle, left knee
tendinitis
Subject 14 Left hamstring strain, hip misalignment, back strain, strain in right
foot, left groin strain
Subject 15 Tendinitis in both knees, sprained ankle, shin splints
Subject 16 Shin splints, stress fracture in metatarsal II, patella tracking problem,
IT band/hip flexor pain, right Achilles pain
Subject 17 Iron deficiency, stress reaction in right tibia
Subject 18 Achilles tendinitis, pulled hamstrings, shin splints, spondylosysis,
tibialis posterior tendinitis in right foot, sprained ankles
Subject 19 Stress fracture in right femur and right tibia, right labrum tear
Subject 20 Shins splints in right leg, tendinitis in both knees, osteochondral
defect and torn transverse ligament and medial meniscus in right knee
APPENDIX F
GAIT DATA Gr ou p 1 Fr Su Su Su Su Su Su Su Su Su Su Su Su Av ont bje bje bje bje bje bje bje bje bje bje bje bje era al ct ct ct ct ct ct ct ct ct ct ct ct ge Lef 1 2 3 4 5 6 7 8 9 10 11 12 t Init Trunk ------ial Angle 6.9 7.7 7.6 2.4 2.8 12. 5.1 5.4 7.8 4.6 4.7 8.2 6.3 Co 6 5 2 7 19 1 1 3 9 4 5 183 nta 3 ct Pelvis ------3.1 - - - - - Angle 5.6 6.1 5.6 1.5 0.7 6.6 1.8 4 2.6 0.0 1.2 2.4 2.6 7 3 2 4 6 1 9 5 7 6 8 283 3 Valgu - 2.0 - 4.3 - 1.9 1.9 - - - - 2.3 - s/varu 2.4 7 5.0 2 5.7 8 1 9.5 3.3 13. 2.8 3 2.5 s 4 5 4 5 8 6 108 3 Hip ------add/a 14. 11. 11. 4.5 4.1 8.8 3.7 3.6 6.3 12. 5.9 9.0 8.0 bd 1 72 85 4 1 1 1 52 5 7 233 3 Mi Trunk - - - 1.9 0.5 - - - - 0.8 - - - d Angle 4.0 6.2 10. 6 9 7.3 3.0 9.0 6.6 9 2.7 6.2 4.3 Sta 5 03 8 7 3 6 1 241 nce 7 left
98
99
Pelvis - - - 0. - - - -2 - 2. - - - Angle 4.3 5.8 10. 71 2. 6.6 2. 2. 82 2. 4.6 3.351 8 6 25 66 6 47 26 58 3 67 Valgus/ 5.6 1.6 - - - 10. 9. - - - - 3.2 - varus 9 8 6.0 0. 6. 31 48 4.1 5. 9. 4. 3 0.358 3 14 22 2 08 03 07 33 Hip ------add/abd 12. 14. 20. 7. 9. 8.8 4. 9.1 8. 7. 9. 13. 10.43 44 31 04 12 91 7 31 1 53 61 34 64 58 Mi Trunk 6.4 9.7 2.0 6. 3. 0.2 10. 7. 8. 5. 0.2 5.601 d Angle 7 7 7 41 86 2 98 87 42 34 1 818 sta nce rig ht Pelvis 3.2 7.9 1 4. - - 4. 11. 4. 7. 4. 0.2 4.025 Angle 1 5 92 2. 0.0 2 46 96 91 72 19 4
Group 2
Frontal Subject Subject Subject Subject Average
Left 13 14 15 16
Initial Trunk Angle -10.47 -13.28 -9.41 -6.77 -9.9825
Contact
Pelvis Angle -7.93 -6.65 -8.16 -5.18 -6.98
Valgus/varus -0.21 -3.41 -8 -6.8 -4.605
Hip add/abd -13.07 -12.87 -17.21 -13.62 -14.1925
Mid Trunk Angle -10.26 -9.65 -4.88 -5.52 -7.5775
Stance left
Pelvis Angle -7.68 -5.67 -6.07 -7.77 -6.7975
100
Valgus/varus 2.18 6.42 -6.5 -7.12 -1.255
Hip add/abd -14.3 -10.57 -15.81 -17.18 -14.465
Mid Trunk Angle 7.87 7.96 12.78 9.536667 stance right
Pelvis Angle 2.58 5.88 2.57 9.05 5.02
Group 3
Frontal Subject Subject Subject Subject Average
Left 17 18 19 20
Initial Trunk Angle -5.49 -3.6 -12.24 -6.44 -6.9425
Contact
Pelvis Angle -5.16 -2.79 -4.76 -3.36 -4.0175
Valgus/varus 1.86 -3.83 -12.07 -3.41 -4.3625
Hip add/abd -13.07 -9.74 -15.33 -10.16 -12.075
Mid Trunk Angle -4.39 -8.82 -7.01 -9.41 -7.4075
Stance left
Pelvis Angle -4.63 -9.81 -2.32 -9.18 -6.485
Valgus/varus 6.43 0.67 -4.56 -1.77 0.1925
Hip add/abd -11.55 -18.58 -11.03 -16.68 -14.46
101
Mid Trunk Angle 7.81 6.34 2.52 7.69 6.09 stance right
Pelvis Angle 4.35 3.41 5.76 7.85 5.3425
Group 1 Front Su Su Su Su Su Su Su Su Su Su Su Subje Av al bje bje bje bje bje bje bje bje bje bje bje ct 12 era Right ct ct ct ct ct ct ct ct ct ct ct ge 1 2 3 4 5 6 7 8 9 10 11 Initial Trun 10 8. 8. 7. 4. 3. 1. 11 11 8. 0.88 7.0 Contac k .6 58 2 83 65 99 93 .3 .0 5 50 t Angl 6 3 1 90 e 9 Pelvi 5. 4. 0. 4. 0. - - 0. 5. 10 3. -2.43 2.4 s 06 45 55 61 04 1. 1. 07 39 .4 58 13 Angl 74 03 1 33 e 3 Valg - - - - - 1. 4. ------us/va 7. 2. 0. 1. 10 7 19 9. 10 14 4. 10.43 5.3 rus 1 24 35 48 .0 5 .2 .9 03 77 4 7 8 5 Hip ------7.26 - add/a 15 12 5. 10 7. 3. 2. 13 15 25 12 11. bd .9 .5 82 .9 17 45 93 .0 .3 .2 .9 04 2 8 5 5 6 92 Mid Trun 7. 7. 3. 5. - 3. 0. 6. 5. 4. 2.13 4.2 Stance k 76 89 24 87 0. 79 58 17 12 42 37 right Angl 36 27 e 3 Pelvi 4. 6. 4. 2. 0. - 1. 2. 4. 5. 3. 1.07 2.8 s 15 1 21 39 9 1. 45 86 17 17 31 76 Angl 26 66 e 7 Valg 2. - - - - 6. 4. - -8 - - -6.51 - us/va 63 7. 1. 3. 9. 08 33 8. 16 3. 4.3 rus 24 22 64 77 86 .8 4 73 8 33
102
Hip ------add/a 11 17 11 12 9. 3. 5. 15 12 18 12 14.19 12. bd .1 .5 .7 .8 65 61 83 .4 .9 .7 .7 20 2 2 2 9 3 8 8 1 25 Mid Trun - - 0. 0. - - - - - 0. -8.76 - Stance k 2. 9. 12 2 10 7. 11 2. 5. 79 5.1 left Angl 77 74 .3 05 .2 28 07 09 e 8 6 09 Pelvi ------4.74 - s 2. 9. 10 0. 2. 4. 3. 6. 0. 2. 1. 4.1 Angl 82 92 .1 79 72 72 79 08 23 63 58 81 e 6 67
Group 2
Frontal Subject Subject Subject Subject Average
Right 13 14 15 16
Initial Trunk Angle 8.39 7.14 10.87 8.8
Contact
Pelvis Angle 1.86 1.43 0.99 2.55 1.7075
Valgus/varus -3.39 -6.5 -11.3 -9.03 -7.555
Hip add/abd -9.53 -12.7 -13.7 -12.98 -12.2275
Mid Trunk Angle 8.18 4.16 11.44 11.14 8.73
Stance right
Pelvis Angle 1.88 1.11 6.74 8.5 4.5575
Valgus/varus -0.66 2.96 -2.25 -3.72 -0.9175
Hip add/abd -9.39 -8.07 -16.89 -19.01 -13.34
103
Mid Trunk Angle -7.1 -13.37 -2.54 -5.12 -7.0325
Stance left
Pelvis Angle -5.42 -8.75 -5.31 -7.75 -6.8075
Group 3
Frontal Subject Subject Subject Subject Average
Right 17 18 19 20
Initial Trunk Angle 8.09 6.79 6.76 9.07 7.6775
Contact
Pelvis Angle 2.77 1.68 4.73 5.79 3.7425
Valgus/varus -7.44 -5.53 -14.03 -7.11 -8.5275
Hip add/abd -15.02 -9.54 -17.14 -14.01 -13.9275
Mid Trunk Angle 8.22 8.01 2.45 8.78 6.865
Stance right
Pelvis Angle 6.16 6.08 5.88 9.28 6.85
Valgus/varus -5.49 -8.31 -9.66 -0.48 -5.985
Hip add/abd -17.94 -18.96 -17.27 -16.39 -17.64
Mid Trunk Angle 1.26 -5.96 -4.81 -6.46 -3.9925
Stance left
Pelvis Angle -1.01 -7.19 0.28 -6.13 -3.5125
104
Gr ou p 1 Sag Su Su Su Su Su Su Su Su Su Su Su Su Ave itta bje bje bje bje bje bje bje bje bje bje bje bje rage l ct ct ct ct ct ct ct ct ct ct ct ct Lef 1 2 3 4 5 6 7 8 9 10 11 12 t Init Tru 0.3 - 1.1 - - 1.1 ------ial nk 4 8.4 9 5.3 6.1 5 13. 8.7 1.0 9.7 0.2 4.63 Co lea 5 5 8 99 5 4 3 2 909 nta n ct Hi 17. 11. 14. 17. 17. 20. 26. 20. 26. 17. 14. 18.4 p 8 45 29 01 06 52 03 3 17 45 65 3 fle x/e xt Pea Tru 12. - 10. - 7.6 7.1 - 2.1 8.7 6.6 12. 5.83 k nk 58 2.4 97 1.2 1 2 0.9 1 7 2 95 090 kne lea 4 1 4 9 e n flex Hi 12. 9.0 6.9 15. 11. 12. 22. 22. 16. 16. 12. 14.5 p 8 5 71 95 9 62 7 41 87 16 518 fle 2 x/e xt Pus Tru 13. 4.7 12. 8.7 8.3 13. 3.2 7.7 12. 12. 12. 10.0 h nk 24 7 85 2 58 2 3 83 89 95 981 off lea 8 n Hi ------18 ------p 19. 18. 18. 15. 17. 22. 17. 15. 14. 20. 18.1 fle 51 83 34 94 64 93 52 91 86 54 836 x/e xt Fli Tru 12. 6.0 10. 7.7 7.8 12. 3.0 7.0 12. 13. 13. 9.68 ght nk 95 4 39 4 8 18 6 4 52 52 24 727 lea 3 n Hi ------30 - - - - - p 24. 17. 21. 18. 23. 22. 19. 23. 21. 23. 22.4 fle 49 51 33 83 27 9 58 95 7 21 336
105
x/e xt Swi Tru 12. 4.6 8.1 6.1 0.3 10. 3.9 5.7 12. 9.6 13. 7.98 ng nk 54 4 3 7 69 8 4 62 45 727 lea 3 n Hi ------p 22. 12. 16. 14. 10. 19. 25. 15. 14. 8.4 20. 16.4 fle 44 63 82 32 83 93 18 66 94 1 28 945 x/e xt
Group 2
Sagittal Subject Subject Subject Subject Average
Left 13 14 15 16
Initial Trunk 9.68 -1.92 -2.27 -10.38 -1.2225
Contact lean
Hip 18.32 21.27 23.98 19.87 20.86
flex/ext
Peak knee Trunk 17.46 12.65 3.32 3.26 9.1725 flex lean
Hip 17.02 23.18 21.53 13.98 18.9275
flex/ext
Push off Trunk 18.82 14.01 8.55 10.85 13.0575
lean
Hip -21.42 -15.48 -21.61 -26.4 -21.2275
flex/ext
106
Flight Trunk 17.85 12.76 10.03 10.55 12.7975
lean
Hip -25.28 -18.33 -24.44 -27.07 -23.78
flex/ext
Swing Trunk 15.85 12.57 11.34 9.77 12.3825
lean
Hip -23.76 -13.15 -19.25 -18.11 -18.5675
flex/ext
Group 3
Sagittal Subject Subject Subject Subject Average
Left 17 18 19 20
Initial Trunk -6.35 -10.94 -9.14 -8.2 -8.6575
Contact lean
Hip 23.35 9.27 21.52 26.3 20.11
flex/ext
Peak knee Trunk 1.98 12.36 -1.01 3.18 4.1275 flex lean
Hip 13.17 14.23 20.31 22.19 17.475
flex/ext
Push off Trunk 7.32 10.86 5.71 11.66 8.8875
lean
107
Hip -20.73 -23.82 -19.66 -10.73 -18.735
flex/ext
Flight Trunk 7.66 8.05 5.25 11.44 8.1
lean
Hip -24.88 -29.51 -23.47 -23.49 -25.3375
flex/ext
Swing Trunk 6.52 7.76 3.31 8.37 6.49
lean
Hip -17.62 -22.82 -19.71 -12.57 -18.18
flex/ext
Gr ou p 1 Sag Su Su Su Su Su Su Su Su Su Su Su Su Ave itta bje bje bje bje bje bje bje bje bje bje bje bje rage l ct ct ct ct ct ct ct ct ct ct ct ct Rig 1 2 3 4 5 6 7 8 9 10 11 12 ht Init Tru ------ial nk 4.9 6.9 3.7 0.8 6.0 4.6 4.1 15. 6.4 3.1 5.4 2.8 5.35 Co lea 6 3 6 1 9 4 4 14 7 1 4 75 nta n ct Hi 14. 8.9 12. 19. 15. 18. 16. 23. 17. 21. 17. 14. 16.7 p 2 3 1 72 56 87 23 53 31 35 75 87 016 fle 7 x/e xt Kn 9.4 12. 3.3 21. 16. 20. 6.5 11. 3.0 12. 11. 15. 12.0 ee 47 3 1 75 45 5 46 1 45 66 42 041 fle 7 x/e xt
108
An - - 1.1 - - - - 5.8 3.4 4.1 3.8 - - kle 1.6 1.9 3 13. 5.1 5.9 10. 2 4 9 2.5 1.89 2 18 8 79 1 167 Pea Tru 4.8 - 6.3 13. 1.9 8.2 1.9 - 0.5 10. 11. 8.1 4.98 k nk 7 0.4 53 9 4 6.8 3 06 56 4 916 kne lea 4 1 7 e n flex Hi 11. 8.8 15. 12. 12. 16. 13. 25. 17. 16. 17. 17. 15.3 p 57 7 39 49 44 59 12 43 11 46 86 08 675 fle x/e xt Kn 37. 33. 42. 44. 33. 39. 33. 48. 36. 37. 36. 40. 38.7 ee 8 55 92 79 05 93 18 65 2 44 53 65 241 fle 7 x/e xt An 18. 18. 12. 21. 17. 16. 15. 18. 10. 12. 14. 14. 15.9 kle 54 88 04 25 89 44 53 1 72 39 84 28 083 3 Pus Tru 10. 6.8 17. 13. 10. 15. 8.0 0.8 8.6 14. 14. 12. 11.1 h nk 11 2 55 93 17 08 5 5 9 22 89 98 116 off lea 7 n Hi ------p 19. 19. 18. 15. 16. 14. 18. 22. 19. 16. 20. 25. 18.8 fle 12 36 92 37 18 67 43 19 11 85 87 29 633 x/e xt Kn 15. 10. 14. 25. 12. 17. 16. 18. 12. 18. 5.5 10. 14.6 ee 02 12 41 37 03 2 56 42 6 6 2 51 966 fle 7 x/e xt An - 0.5 ------kle 7.7 5 14. 16. 9.2 3.3 4.5 5.9 13. 4.1 16. 13. 8.99 1 45 17 6 8 7 5 51 7 25 1 75 Fli Tru 9.5 6.7 18. 12. 10. 14. 6.6 1.2 7.7 14. 13. 12. 10.7 ght nk 4 8 08 86 5 88 7 6 5 34 69 36 258 lea 3 n Hi ------p 25. 21. 24. 18. 20. 23. 24. 28. 24. 25. 23. 28. 24.0 fle 51 44 04 73 8 61 32 6 01 06 75 81 567
109
x/e xt Kn 13. 12. 12. 30. 17. 11. 16. 22. 14. 21. 8.6 14. 16.3 ee 85 16 9 21 11 66 3 39 29 41 2 88 15 fle x/e xt An ------kle 20. 9.9 28. 24. 28. 20. 20. 12. 24. 18. 25. 17. 20.9 34 8 34 76 53 59 85 26 65 44 6 12 55 Swi Tru 8.3 4.8 16. 11. 10. 11. 4.6 0.3 7.1 12. 8.4 11. 8.94 ng nk 8 9 85 33 41 39 8 1 7 37 6 04 lea n Hi ------p 22. 17. 18. 9.2 16. 17. 19. 22. 16. 16. 15. 27. 18.4 fle 46 88 99 3 7 04 45 83 38 59 88 4 025 x/e xt Kn 41. 34. 48. 75. 37. 54. 36. 45. 45. 60. 46. 47. 47.8 ee 6 61 71 06 23 94 91 3 65 11 12 95 491 fle 7 x/e xt An ------kle 14. 11. 21. 18. 28. 16. 17. 11. 24. 15. 17. 17. 17.9 45 87 22 68 54 28 84 09 21 96 55 35 2
Group 2
Sagittal Subject Subject Subject Subject Average
Right 13 14 15 16
Initial Trunk 0.96 -1.08 -10.9 -13.32 -6.085
Contact lean
Hip 11.54 21.8 22.2 23.23 19.6925
flex/ext
110
Knee -1.9 11.19 15.92 10.21 8.855
flex/ext
Ankle -3.61 -0.44 -53.54 6.13 -12.865
Peak knee Trunk 11.48 9.46 -1.24 -3.02 4.17 flex lean
Hip 22.4 23.91 21.41 26.01 23.4325
flex/ext
Knee 47.64 40.51 45.76 44.67 44.645
flex/ext
Ankle 11.56 14.05 26.33 16.34 17.07
Push off Trunk 17.21 18.39 8.85 7.57 13.005
lean
Hip -20.03 -8.66 -15.74 -15.08 -14.8775
flex/ext
Knee 15.64 27.7 25.67 17.99 21.75
flex/ext
Ankle -11.58 -3.79 7.42 -1.4 -2.3375
Flight Trunk 17.71 14.65 9.26 7.91 12.3825
lean
Hip -28.28 -21.64 -24.54 -24.69 -24.7875
flex/ext
Knee 12.6 25.45 22.15 12.07 18.0675
flex/ext
111
Ankle -22.58 -35.27 -7.91 -19.59 -21.3375
Swing Trunk 16.58 13.94 9.73 5.95 11.55
lean
Hip -27.23 -16.34 -25.17 -15.8 -21.135
flex/ext
Knee 37.81 49.36 37.3 50.7 43.7925
flex/ext
Ankle -16.91 -23.31 -4.65 -15.19 -15.015
Group 3
Sagittal Subject 17 Subject 18 Subject 19 Subject 20 Average
Right
Initial Trunk lean -3.42 -12.79 -7.19 -10.76 -8.54
Contact
Hip 16.48 16.23 20.29 20.91 18.4775
flex/ext
Knee 12.59 3.71 10.19 13.24 9.9325
flex/ext
Ankle -5.02 2.55 11.83 0.56 2.48
Peak knee Trunk lean 3.07 4.89 1.53 0.52 2.5025 flex
Hip 16.29 25.38 24.17 20.82 21.665
flex/ext
112
Knee 39.84 49.11 44.38 39.18 43.1275
flex/ext
Ankle 16.73 16.91 20.58 9.98 16.05
Push off Trunk lean 12.07 14.94 10.55 8.13 11.4225
Hip -21.49 -19.04 -17.51 -17.43 -18.8675
flex/ext
Knee 16.11 18.34 17.2 16.35 17
flex/ext
Ankle -3.64 -16.37 2.62 -8.39 -6.445
Flight Trunk lean 13.05 13.55 10.16 9.27 11.5075
Hip -29.14 -25.82 -26.52 -22.93 -26.1025
flex/ext
Knee 14.31 22.3 13.8 16.7 16.7775
flex/ext
Ankle -21.49 -30.23 -15.61 -23.42 -22.6875
Swing Trunk lean 11.2 11.71 7.24 10.03 10.045
Hip -25.93 -22.37 -23.99 -17.85 -22.535
flex/ext
Knee 40.77 57.35 36.36 37.07 42.8875
flex/ext
Ankle -17.01 -26.95 -12.22 -22.51 -19.6725
APPENDIX G
EMG DATA
Peak EMG Values
R Vastus Lateralis L Vastus Lateralis
Subject 15 Trial 1 339 177
Subject 15 Trial 2 318 245
Subject 11 Trial 1 400 187
Subject 7 Trial 1 317 1932
Subject 7 Trial 2 264 1668
Subject 6 Trial 1 759 699
Subject 6 Trial 2 727 843
Subject 5 Trial 1 725 636
Subject 5 Trial 2 640 597
Subject 13 Trial 1 330 328
Subject 13 Trial 2 256 424
Subject 18 Trial 1 503 605
113
114
Subject 18 Trial 2 415 655
Subject 14 Trial 1 670 1676
Subject 14 Trial 2 604 1978
Subject 8 Trial 1 419 110
Subject 8 Trial 2 514 130
Subject 9 Trial 1 2147 4560
Subject 9 Trial 2 1348 1225
Subject 10 Trial 1 2358 288
Subject 10 Trial 2 3069 481
Subject 15 Trial 1 R Rectus Femoris L Rectus Femoris
Subject 15 Trial 2 130 280
Subject 11 Trial 1 103 423
Subject 7 Trial 1 131 182
Subject 7 Trial 2 230 192
Subject 6 Trial 1 206 164
Subject 6 Trial 2 232 252
Subject 5 Trial 1 385 260
Subject 5 Trial 2 210 140
Subject 13 Trial 1 102 145
Subject 13 Trial 2 229 238
Subject 18 Trial 1 235 190
Subject 18 Trial 2 120 165
115
Subject 14 Trial 1 132
Subject 14 Trial 2 80.8 66.2
Subject 8 Trial 1 115 93.4
Subject 8 Trial 2 64.7 390
Subject 9 Trial 1 190 559
Subject 9 Trial 2 329 708
Subject 10 Trial 1 602 861
Subject 10 Trial 2 721 1041
R Semitendinosus L Semitendinosus
Subject 15 Trial 1 204 144
Subject 15 Trial 2 163 148
Subject 11 Trial 1 246 133
Subject 7 Trial 1 127 156
Subject 7 Trial 2 117 130
Subject 6 Trial 1 185 252
Subject 6 Trial 2 169 259
Subject 5 Trial 1 366 504
Subject 5 Trial 2 283 403
Subject 13 Trial 1 219 293
Subject 13 Trial 2 241 359
Subject 18 Trial 1 99.3 138
Subject 18 Trial 2 113 129
116
Subject 14 Trial 1 634 552
Subject 14 Trial 2 866 865
Subject 8 Trial 1 114 121
Subject 8 Trial 2 452 186
Subject 9 Trial 1 200 295
Subject 9 Trial 2 158 296
Subject 10 Trial 1 226 186
Subject 10 Trial 2 148 159
R Biceps Femoris L Biceps Femoris
Subject 15 Trial 1 214 251
Subject 15 Trial 2 185 264
Subject 11 Trial 1 235 330
Subject 7 Trial 1 294 103
Subject 7 Trial 2 217 92.8
Subject 6 Trial 1 290 221
Subject 6 Trial 2 204 241
Subject 5 Trial 1 289 255
Subject 5 Trial 2 259 186
Subject 13 Trial 1 133 142
Subject 13 Trial 2 143 148
Subject 18 Trial 1 140 204
Subject 18 Trial 2 165 162
117
Subject 14 Trial 1 142 713
Subject 14 Trial 2 128 709
Subject 8 Trial 1 109 101
Subject 8 Trial 2 148 183
Subject 9 Trial 1 283 296
Subject 9 Trial 2 328 178
Subject 10 Trial 1 295 141
Subject 10 Trial 2 367 241
Subject 15 Trial 1 R Lateral Gastrocnemius L Lateral Gastrocnemius
Subject 15 Trial 2 169 255
Subject 11 Trial 1 176 204
Subject 7 Trial 1 327 537
Subject 7 Trial 2 467 1512
Subject 6 Trial 1 238 210
Subject 6 Trial 2 598 231
Subject 5 Trial 1 281 217
Subject 5 Trial 2 239 318
Subject 13 Trial 1 193 211
Subject 13 Trial 2 209 178
Subject 18 Trial 1 228 258
Subject 18 Trial 2 193 224
118
Subject 14 Trial 1 278 189
Subject 14 Trial 2 2699 2322
Subject 8 Trial 1 1607 1018
Subject 8 Trial 2 1748 2046
Subject 9 Trial 1 1628 1810
Subject 9 Trial 2 1241 629
Subject 10 Trial 1 1018 2577
Subject 10 Trial 2 1862 2058
Mean EMG Values
R Vastus Lateralis L Vastus Lateralis
Subject 15 Trial 1 31.5 25.2
Subject 15 Trial 2 73.6 52.8
Subject 11 Trial 1 65.6 28.3
Subject 7 Trial 1 63.7 383
Subject 7 Trial 2 50.8 285
Subject 6 Trial 1 97.2 101
Subject 6 Trial 2 130 139
Subject 5 Trial 1 87.6 102
Subject 5 Trial 2 85.2 98.2
Subject 13 Trial 1 42.7 46.7
Subject 13 Trial 2 71.6 72.1
119
Subject 18 Trial 1 58.5 69.8
Subject 18 Trial 2 66.1 99
Subject 14 Trial 1 73 157
Subject 14 Trial 2 91.4 195
Subject 8 Trial 1 43.2 19.2
Subject 8 Trial 2 63.6 24.5
Subject 9 Trial 1 172 335
Subject 9 Trial 2 89.1 102
Subject 10 Trial 1 120 62.1
Subject 10 Trial 2 146 67.4
Subject 15 Trial 1 R Rectus Femoris L Rectus Femoris
Subject 15 Trial 2 12.9 23.5
Subject 11 Trial 1 25 52.1
Subject 7 Trial 1 9.41 24.6
Subject 7 Trial 2 49.7 31
Subject 6 Trial 1 35.8 24.3
Subject 6 Trial 2 35.8 35.5
Subject 5 Trial 1 57 52.1
Subject 5 Trial 2 27.7 21.6
Subject 13 Trial 1 19.7 21.5
Subject 13 Trial 2 31.5 36.7
Subject 18 Trial 1 45.9 42.9
120
Subject 18 Trial 2 17 26.5
Subject 14 Trial 1 26.2
Subject 14 Trial 2 11.4 9.86
Subject 8 Trial 1 14.7 14.3
Subject 8 Trial 2 9.4 23.6
Subject 9 Trial 1 17.1 41.7
Subject 9 Trial 2 56.6 38.5
Subject 10 Trial 1 36.3 26.9
Subject 10 Trial 2 50 74.3
R Semitendinosus L Semitendinosus
Subject 15 Trial 1 21.2 23.4
Subject 15 Trial 2 40.1 38.3
Subject 11 Trial 1 43.7 36.9
Subject 7 Trial 1 37.4 49.3
Subject 7 Trial 2 33.3 38.9
Subject 6 Trial 1 33.1 44.2
Subject 6 Trial 2 38.9 54.4
Subject 5 Trial 1 68.3 73.6
Subject 5 Trial 2 66 63.8
Subject 13 Trial 1 61.6 77
Subject 13 Trial 2 86.7 113
Subject 18 Trial 1 23.4 22.2
121
Subject 18 Trial 2 26.1 29.8
Subject 14 Trial 1 32.4 26.2
Subject 14 Trial 2 41.2 50.1
Subject 8 Trial 1 15.2 19.6
Subject 8 Trial 2 36.2 35.5
Subject 9 Trial 1 35.7 52.4
Subject 9 Trial 2 24.7 14.8
Subject 10 Trial 1 28.2 32.3
Subject 10 Trial 2 29.7 29.5
R Biceps Femoris L Biceps Femoris
Subject 15 Trial 1 23.9 38.5
Subject 15 Trial 2 41.5 69.9
Subject 11 Trial 1 48 66.2
Subject 7 Trial 1 57.9 25.6
Subject 7 Trial 2 51.5 23.6
Subject 6 Trial 1 35.9 37.8
Subject 6 Trial 2 45.1 48.7
Subject 5 Trial 1 50.9 48.1
Subject 5 Trial 2 50.2 40.8
Subject 13 Trial 1 23.2 34.3
Subject 13 Trial 2 35.7 47.5
Subject 18 Trial 1 26.8 31.5
122
Subject 18 Trial 2 41.8 35.4
Subject 14 Trial 1 26.5 32.4
Subject 14 Trial 2 33.5 40.2
Subject 8 Trial 1 20.8 17.2
Subject 8 Trial 2 29.3 28.2
Subject 9 Trial 1 54.1 47.3
Subject 9 Trial 2 38.9 26.2
Subject 10 Trial 1 54 32.7
Subject 10 Trial 2 64.5 41.1
R Lateral Gastrocnemius L Lateral Gastrocnemius
Subject 15 Trial 1 29.4 37.5
Subject 15 Trial 2 54.2 62
Subject 11 Trial 1 33.8 91.6
Subject 7 Trial 1 73.1 105
Subject 7 Trial 2 46.1 42.3
Subject 6 Trial 1 50.7 21.6
Subject 6 Trial 2 54.8 41.4
Subject 5 Trial 1 40.1 48.6
Subject 5 Trial 2 33.4 46.4
Subject 13 Trial 1 45.1 45.9
Subject 13 Trial 2 64.2 64
Subject 18 Trial 1 37.5 42.1
123
Subject 18 Trial 2 53.9 50.9
Subject 14 Trial 1 135 169
Subject 14 Trial 2 134 51.1
Subject 8 Trial 1 319 379
Subject 8 Trial 2 472 565
Subject 9 Trial 1 86.1 44
Subject 9 Trial 2 45.8 179
Subject 10 Trial 1 257 372
Subject 10 Trial 2 326 260
APPENDIX H
ANDERSON-DARLING NORMALITY TESTS
Frontal Left Initial Contact Normality Test
128
129
Frontal Left Midstance Normality Test
Frontal Left Midstance Right Leg Normality Test
130
Frontal Right Initial Contact Normality Tests
131
Frontal Right Midstance Normality Tests
Frontal Right Midstance Left Leg Normality Tests
132
Sagittal Right Initial Contact Normality Tests
133
Sagittal Right Peak Knee Flex Normality Tests
Sagittal Right Push Off Normality Tests
134
Sagittal Right Flight Normality Tests
135
Sagittal Right Swing Normality Tests
Peak Vastus Lateralis Normality Test
Mean Vastus Lateralis Normality Tests
136
Peak Rectus Femoris Normality Test
Mean Rectus Femoris Normality Test
Peak Semitendinosus Normality Tests
137
Mean Semitendinosus Normality Tests
Peak Biceps Femoris Normality Tests
Mean Biceps Femoris Normality Tests
138
Peak Lateral Gastrocnemius Normality Tests
Mean Lateral Gastrocnemius Normality Tests
APPENDIX I
STATISTICAL ANALYSIS p-values from Mood’s Median tests comparing normally distributed gait and EMG values
Groups p- Groups p- Groups p-
Frontal L IC Compared value Compared value Compared value
Trunk G1 v G2 0.065 G1 v G3 0.772 G2 v G3 0.243
Pelvis G1 v G2 0.002 G1 v G3 0.193 G2 v G3 0.021
ValVar G1 v G2 0.4 G1 v G3 0.602 G2 v G3 0.946
AbdAdd G1 v G2 0.002 G1 v G3 0.05 G2 v G3 0.259
Groups p- Groups p- Groups p-
Frontal L Mid Compared value Compared value Compared value
Trunk G1 v G2 0.112 G1 v G3 0.087 G2 v G3 0.982
Pelvis G1 v G2 0.009 G1 v G3 0.202 G2 v G3 0.879
ValVar G1 v G2 0.823 G1 v G3 0.859 G2 v G3 0.736
AbdAdd G1 v G2 0.067 G1 v G3 0.13 G2 v G3 0.998
139
140
Groups p- Groups p- Groups p-
Frontal L MidR Compared value Compared value Compared value
Trunk G1 v G2 0.115 G1 v G3 0.776 G2 v G3 0.166
Pelvis G1 v G2 0.623 G1 v G3 0.394 G2 v G3 0.867
Groups p- Groups p- Groups p-
Frontal R IC Compared value Compared value Compared value
Trunk G1 v G2 0.314 G1 v G3 0.663 G2 v G3 0.492
Pelvis G1 v G2 0.541 G1 v G3 0.34 G2 v G3 0.131
ValVar G1 v G2 0.387 G1 v G3 0.248 G2 v G3 0.717
AbdAdd G1 v G2 0.572 G1 v G3 0.261 G2 v G3 0.41
Groups p- Groups p- Groups p-
Frontal R Mid Compared value Compared value Compared value
Trunk G1 v G2 0.075 G1 v G3 0.195 G2 v G3 0.445
Pelvis G1 v G2 0.443 G1 v G3 0.008 G2 v G3 0.312
ValVar G1 v G2 0.173 G1 v G3 0.578 G2 v G3 0.097
AbdAdd G1 v G2 0.723 G1 v G3 0.002 G2 v G3 0.218
141
Groups p- Groups p- Groups p-
Frontal R Mid L Compared value Compared value Compared value
Trunk G1 v G2 0.506 G1 v G3 0.638 G2 v G3 0.345
Pelvis G1 v G2 0.064 G1 v G3 0.762 G2 v G3 0.181
Sag R Groups p- Groups p- Groups p-
IC Compared value Compared value Compared value
Trunk G1 v G2 0.865 G1 v G3 0.238 G2 v G3 0.581
Pelvis G1 v G2 0.371 G1 v G3 0.324 G2 v G3 0.706
Knee G1 v G2 0.491 G1 v G3 0.478 G2 v G3 0.818
Ankle G1 v G2 G1 v G3 G2 v G3
Sag R Groups p- Groups p- Groups p-
Peak Compared value Compared value Compared value
Trunk G1 v G2 0.849 G1 v G3 0.22 G2 v G3 0.69
Pelvis G1 v G2 0 G1 v G3 0.045 G2 v G3 0.479
Knee G1 v G2 0.021 G1 v G3 0.164 G2 v G3 0.605
Ankle G1 v G2 0.753 G1 v G3 0.956 G2 v G3 0.805
142
Sag R Groups p- Groups p- Groups p-
Push Compared value Compared value Compared value
Trunk G1 v G2 0.573 G1 v G3 0.877 G2 v G3 0.64
Pelvis G1 v G2 0.209 G1 v G3 0.997 G2 v G3 0.213
Knee G1 v G2 0.097 G1 v G3 0.163 G2 v G3 0.207
Ankle G1 v G2 0.191 G1 v G3 0.586 G2 v G3 0.496
Sag R Groups p- Groups p- Groups p-
Flight Compared value Compared value Compared value
Trunk G1 v G2 0.56 G1 v G3 0.654 G2 v G3 0.747
Pelvis G1 v G2 0.666 G1 v G3 0.238 G2 v G3 0.512
Knee G1 v G2 G1 v G3 G2 v G3
Ankle G1 v G2 0.952 G1 v G3 0.638 G2 v G3 0.843
Sag R Groups p- Groups p- Groups p-
Swing Compared value Compared value Compared value
Trunk G1 v G2 0.381 G1 v G3 0.504 G2 v G3 0.586
Pelvis G1 v G2 0.445 G1 v G3 0.104 G2 v G3 0.703
Knee G1 v G2 0.429 G1 v G3 0.439 G2 v G3 0.888
Ankle G1 v G2 0.532 G1 v G3 0.644 G2 v G3 0.397
143
p-value
Ankle at Initial Contact in Right Sagittal 0.513
Plane
Knee at Flight in Right Sagittal Plane 1.0
p-values from 2-sample and 1-sample t-test comparing peak EMG values
Groups p- Groups p- Groups p-
Muscle Compared value Compared value Compared value
R Vastus Lateralis G1 v G2 0.143 G1 v G3 0.157 G2 v G3 0.752
L Vastus Lateralis G1 v G2 0.812 G1 v G3 0.415 G2 v G3 0.766
R Rectus Femoris G1 v G2 0.132 G1 v G3 0.054 G2 v G3 0.641
L Rectus Femoris G1 v G2 0.206 G1 v G3 0.071 G2 v G3 0.588
R Semitendinosus G1 v G2 0.45 G1 v G3 0.006 G2 v G3 0.261
L Semitendinosus G1 v G2 0.44 G1 v G3 0.072 G2 v G3 0.257
R Biceps Femoris G1 v G2 0.024 G1 v G3 0.006 G2 v G3 0.834
L Biceps Femoris G1 v G2 0.448 G1 v G3 0.425 G2 v G3 0.39
R Lateral
Gastrocnemius G1 v G2 0.934 G1 v G3 0.051 G2 v G3 0.415
L Lateral
Gastrocnemius G1 v G2 0.563 G1 v G3 0.028 G2 v G3 0.409
144
p-values from 2-sample and 1-sample t-test comparing mean EMG values
Groups p- Groups p- Groups p-
Muscle Compared value Compared value Compared value
R Vastus Lateralis G1 v G2 0.128 G1 v G3 0.066 G2 v G3 0.873
L Vastus Lateralis G1 v G2 0.58 G1 v G3 0.359 G2 v G3 0.884
R Rectus Femoris G1 v G2 0.406 G1 v G3 0.128 G2 v G3 0.824
L Rectus Femoris G1 v G2 0.6 G1 v G3 0.174 G2 v G3 0.74
R Semitendinosus G1 v G2 0.598 G1 v G3 0.045 G2 v G3 0.24
L Semitendinosus G1 v G2 0.596 G1 v G3 0.027 G2 v G3 0.293
R Biceps Femoris G1 v G2 0.011 G1 v G3 0.029 G2 v G3 0.07
L Biceps Femoris G1 v G2 0.577 G1 v G3 0.331 G2 v G3 0.194
R Lateral
Gastrocnemius G1 v G2 0.395 G1 v G3 0.164 G2 v G3 0.393
L Lateral
Gastrocnemius G1 v G2 0.205 G1 v G3 0.112 G2 v G3 0.323