GLUTEAL AND HIP MUSCLE STRENGTH OF PHYSICALLY
ACTIVE COLLEGIATE STUDENTS FOLLOWING
A SIX WEEK EXERCISE PROGRAM

By
Kathleen Marie Scott

A THESIS
Submitted to
Michigan State University
in partial fulfillment of the requirements
for the degree of
Kinesiology – Master of Science
2013

ABSTRACT
GLUTEAL AND HIP MUSCLE STRENGTH OF PHYSICALLY ACTIVE COLLEGIATE
STUDENTS FOLLOWING A SIX WEEK EXERCISE PROGRAM
By
Kathleen Marie Scott
Background: Research has linked weakness in the hip abduction muscles with emphasis on the
gluteus medius muscle to injuries in the lower extremities. Studies completed have shown
performing strengthening exercise programs with hip abduction exercises helped with increasing
hip abduction strength. However, few studies have been performed that have actually measured
the amount of strength gain after performing a program.
Purpose: The purpose of this study was to determine if a 6 week exercise program (clam shells,
side lying hip abduction, side lying hip abduction with external rotation) created strength gains in
torque values of side lying hip abduction and side lying hip abduction measured with external
rotation with a BioDex System 3.
Methods: Three side lying exercises were performed over a 6 week period by 60 physically
active subjects between the ages of 18-35. Pre and post program peak torque was measured using
a Biodex dynamometer.
Results: The findings from the current study revealed that even with a significant statistical value
(p = .000) for all hypotheses tested, no clinically significant strength gains were noted following
the six week program.
Conclusion: There were no significant findings to suggest that performing a 6 week program of
side lying hip abduction, side lying hip abduction with external rotation, and clam shell exercises
would lead to strength gains for the gluteus medius muscle.

ACKNOWLEDGEMENTS

I would like to acknowledge the efforts of my thesis committee Dr. Tracey Covassin, Dr.
Sally Nogle and Dr. Thomas Mackowiak for their help and guidance throughout the process of
this thesis.
To Dr. Tracey Covassin, thank you for all of your positive encouragement and guidance
throughout this entire process. Without you, there is no possibility this would have been
accomplished. You helped me keep my head on my shoulders during this whole process. Thank
you for all of the long hours and all of your hard work. The memories made during this time will
be remembered forever.
To Dr. Sally Nogle, there are not enough words (or allowed space) to express the
gratitude I have for everything you have done for me the past two years. Thank you for being on
my committee. Thank you for being my guidance in the athletic training room. The amount of
growth I have gained this year is of credit to you. I am so grateful to have had the opportunity to
work under your supervision and wish we had more time together. Because of you, I have
become a more confident and knowledgeable athletic trainer. Even more so, you have deepened
my passion and love for this profession.
To Dr. Thomas “T-mack” Mackowiak, you are the reason I decided to write this thesis in
the first place. Thank you for always challenging me to achieve to be greater than average.
Thank you for all the time you have given me mentoring me to grow both as a professional and
as a person. The opportunities that I have achieved under your guidance are some that I will
never forget. The lessons and “tools” I have learned from you are some I will use forever.
To Mom and Dad, you are my rock. Thank you for always believing in me. Even when I
had my doubts of brighter times, you always believed I was meant for greater things. Thank you
iii

for never giving up on me. I hope this thesis can be an example to everyone that there can be
light that comes out of darkness. I love you both so much.
To my sister Chrissy; thank you for always having positive things completely unrelated
to school, thesis or work when I needed it the most. You are far beyond your years and I cannot
wait to see what the future has in store for you. Wherever you end up, I promise you success will
find its way to you. I hope Chicago is ready for us.
To Jeff Monroe, Brian Bratta, Lianna Hadden, Destiny Teachnor-Hauk, LouAnne
Jefferson, Dave Carrier, Quinton Sawyer, Dr. John Powell, Mike Straus, Katie Kelly, Rick
Atkinson, Seth Kesler, Mike Vorkapich, Sue Halsey, Darlene Howe, Carol Smith, and Salina
Halliday; whether it was your words of encouragement, motivation to stay positive, advice on
fixing my computer, gifts of caffeine, borrowing of equipment, or simply lending your ear, you
all have had an integral part of me completing this thesis. Thank you so much for your support; I
am forever grateful to have met and worked with all of you.
To Helen Knull, Molly Maloney, Shawn Hindy and the entire Field Hockey team; thank
you for your support, encouragement and understanding throughout this process. It was am
honor to work with you all this year. You have made me a better athletic trainer, and for that, I
am grateful.
Finally, to all of my participants, thank you for your great efforts and for volunteering for
this study. Without you, this would not have been possible.

iv

TABLE OF CONTENTS

LIST OF TABLES……………………………………………………………………………….vii
LIST OF FIGURES...…………………………………………………………………………...viii
CHAPTER 1
INTRODUCTION..……………………………………………………………………………….1
1.1 OVERVIEW OF PROBLEM.………………………………………………………...1
1.2 SIGNIFICANCE OF PROBLEM...…………………………………………………...3
1.3 PURPOSE OF THE STUDY...………………………………………………………..5
1.4 HYPOTHESES………………………………………………………………………..5
1.5 OPERATIONAL DEFINITION OF TERMS...………………………………………5
CHAPTER 2
REVIEW OF LITERATURE..……………………………………………………………………8
2.1 INTRODUCTION.……………………………………………………………………8
2.2 HIP ANATOMY…..………………………………………………………………….8
2.2.1 Bony Anatomy………………………………………………………………8
2.2.2 Hip Abduction Muscles/Attachments/Function……………………………..8
2.3 HIP ABDUCTION WEAKNESS……………………………………………………10
2.4 HIP ABDUCTION STRENGTH AND EXERCISE………………………………...13
2.5 REHABILITATION TECHNIQUES TO CORRECT WEAKNESS……………….17
2.6 RELIABILITY AND VALIDITY OF THE BIODEX ISOKINETIC
DYNAMOMETER………………………………………………………………………19
2.7 CONCLUSION……………………………………………………………………...21
CHAPTER 3
METHODS..……………………………………………………………………………………..22
3.1 RESEARCH DESIGN..……………………………………………………………...22
3.2 SAMPLE POPULATION AND PARTICIPANT SELECTION…..………………..22
3.3 INSTRUMENTATION...……………………………………………………………22
3.3.1 BioDex System 3 Dynamometer…………………………………………..22
3.4 STRENGTHENING INTERVENTION...…………………………………………...23
3.5 PROCEDURES...……………………………………………………………………26
3.5.1 Session 1…………………………………………………………………...26
3.5.2 Home Program Check-Ins………………………………………………….28
3.5.3 Session 2…………………………………………………………………...28
3.6 STATISTICAL ANALYSIS/DATA MANAGEMENT.……………………………28
CHAPTER 4
RESULTS..………………………………………………………………………………………30
4.1 OVERVIEW..………………………………………………………………………..30
4.2 SUBJECT DEMOGRAPHICS...…………………………………………………….30
4.3 RESULTS FOR SIDE LYING HIP ABDUCTION PEAK TORQUE…..………….31
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4.3.1 Side Lying Hip Abduction Peak Torque for the Dominant Leg…………...31
4.3.2 Side Lying Hip Abduction Peak Torque for the Non Dominant Leg……...32
4.4 RESULTS FOR SIDE LYING HIP ABDUCTION WITH EXTERNAL ROTATION
PEAK TORQUE…………………………………………………………………………33
4.4.1 Side Lying Hip Abduction with External Rotation Peak Torque for the
Dominant Leg…………………………………………………………………....33
4.4.2 Side Lying Hip Abduction with External Rotation Peak Torque for the Non
Dominant Leg...………………………………………………………………….34
4.5 RESULTS FOR MEASUREMENTS OF PAIN PRE AND POST EXERCISE
PROGRAM………………………………………………………………...…………….35
CHAPTER 5
DISCUSSION..…………………………………………………………………………………..36
5.1 OVERVIEW..………………………………………………………………………..36
5.2 ASSESSMENT OF HYPOTHESES………………………………………………...36
5.3 PEAK TORQUE OF HIP ABDUCTION AND HIP ABDUCTION WITH
EXTERNAL ROTATION FOR THE DOMINANT AND NON DOMINANT LEG
FOLLOWING A SIX WEEK EXERCISE PROGRAM……………………….………..37
5.4 UTILIZATION AND CLINICAL IMPLICATIONS FOR AN EXERCISE
PROGRAM TO CREATE STRENGTH GAINS IN HIP ABDUCTION AND HIP
ABDUCTION WITH EXTERNAL ROTATION…………………………….…………40
5.5 LIMITATIONS OF STUDY………………………………………………………...40
5.6 FUTURE RESEARCH.……………………………………………………………...41
5.7 CONCLUSION..……………………………………………………………………..42
APPENDICIES…………………………………………………………………………………..43
APPENDIX A. Health History Questionnaire…………………………………………..44
APPENDIX B. Informed Consent Form………………………………………………...47
APPENDIX C. Take Home Program……………………………………………………49
REFERENCES…………………………………………………………………………………..51

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LIST OF TABLES
Table 4-1 Descriptive Statistics for Subject Demographics……………………………..32
Table 4-2 Descriptive Statistics for Side Lying Hip Abduction for the Dominant Leg…33
Table 4-3 Paired Sample Statistics for Side Lying Hip Abduction for the Dominant
Leg……………………………………………………………………………33
Table 4-4 Descriptive Statistics for Side Lying Hip Abduction for the Non-Dominant
Leg……………………………………………………………………………34
Table 4-5 Paired Sample Statistics for Side Lying Hip Abduction for the Non-Dominant
Leg…………………………………………………………………………....34
Table 4-6 Descriptive Statistics for Side Lying Hip Abduction with External Rotation for
the Dominant Leg…………………………………………………………….35
Table 4-7 Paired Sample Statistics for Side Lying Hip Abduction with External Rotation
of the Dominant Leg….………………………………………………………36
Table 4-8 Descriptive Statistics for Side Lying Hip Abduction with External Rotation of
the Non-Dominant Leg.………………………………………………………37
Table 4-9 Paired Sample Statistics for Side Lying Hip Abduction with External Rotation
of the Non-Dominant Leg….…………………………………………………37
Table 4-10 Paired Sample Statistics for Likert Scale Rating Pain……..………………...38

vii

LIST OF FIGURES

Figure 3.1 The Clamshell Exercise……….……………………………………………...24
Figure 3.2 Side Lying Hip Abduction Exercise……….…………………………………25
Figure 3.3 Side Lying Hip Abduction with External Rotation Exercise………………...26

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CHAPTER 1
INTRODUCTION
1.1 OVERVIEW OF THE PROBLEM
Sport participation can often result in injury. The majority of injuries should entail some
type of rehabilitation to help the injured athlete heal. However, with athletic injuries, there is
usually no black and white rehabilitation protocol outline as to how to best rehabilitate the injury.
Certified athletic trainers best design their practices based upon their clinical experience and
published research. This challenge is even greater when the injury has no known mechanism.
Some injuries, specifically overuse, can be caused by previous or existing conditions that create
tightness or weakness within the musculoskeletal system. Gluteus medius weakness is one type
of condition that has been identified as a predisposing factor for lower extremity injuries
(Cichanowski, Schmitt, Johnson & Niemuth, 2007; Earl, Hertel & Denegar, 2005; Fredericson et
al., 2000; Niemuth, Johnson, Myers & Thieman, 2005). Gluteus medius weakness has been
targeted in the rehabilitation process to help with injuries related to the low back, hip, knee, and
ankle. Numerous researchers have examined exercises used to target the gluteus medius to
determine if an increase of activation occurs during the various exercises (Earl et al., 2005; Earl,
2004; Distefano, Blackburn, Marshall & Padua, 2009; Schmitz, Riemann & Thompson, 2002).
However, few studies have investigated the actual strength gains in torque after a six week
exercise program targeted at strengthening the gluteus medius.
The gluteus medius’ primary function is hip abduction, although it’s anterior fibers also has
secondary function in flexion and internal rotation and it’s posterior fibers in external rotation
and extension. Gluteus maximus and tensor fascia latae (TFL) are also contributors to hip
abduction. Recent studies have shown that there have been links to gluteus medius weakness
1

and other lower extremity injuries such as patellofemoral pain (Cichanowski et al., 2007;
Earl et al., 2005; Ferber, Kendall & Farr, 2011; Ireland, Willson, Ballantyne & Davis, 2003).
While these studies have stated gluteus medius weakness could be the main cause, the question
remains if this is the sole muscle contributing to the cause of injury or if the entire muscular
structure for hip abduction is responsible.
Prior research has linked a variety of therapeutic exercises for the hip abductors to an
increase in gluteus medius firing (Distefano et al., 2009; Earl, 2004) Distefano and associates
investigated quantifying and comparing gluteal muscle activation via EMG surface electrodes
over 12 strengthening exercises. The study concluded that while there was an ability to show the
differences in muscle activation among the different exercises, further research needs to be
performed to determine if the high levels of activity actually resulted in muscle strength gains
over time (Distefano et al., 2009). A previous graduate student from Michigan State University
examined an increase in EMG activation measures of the gluteus and other hip muscles during
non weight bearing exercises. Results revealed that using side-lying abduction, side-lying
abduction with external rotation, and clamshell exercises would create an increase in muscle
activation for the gluteus medius and TFL muscles. Furthermore, the study concluded that of the
three exercises tested, the side-lying abduction produced the greatest amount of activation for the
gluteus medius muscle (Sieve, 2007). However, this study did not include any strength training
program to be completed over a set period of time.
As previously stated, there have been several studies examining the activation measures
of the gluteus medius muscle as well as the other hip muscles; however, very little research has
been performed on the measurement of the strength value in torque after a hip strengthening
program. Fredericson and colleagues (2000) investigated the correlation between strength

2

deficits in hip abduction through a rehabilitation program aimed to successful return the
participants back to running. Following the 6 week protocol, females exhibited an increase in hip
abduction torque values by 34.9% in the injured limb, while males increased hip abduction
torque values by 51.4% (Fredericson et al., 2000). Another study by Mascal, Landel and Powers
(2003) discussed two case reports on females with patellofemoral pain. Following the
rehabilitative protocol, both subjects reported a significantly reduced pain level, improved
function, and gluteus medius torque values were increased by 50% in subject A and 90% in
subject B (Mascal, Landel, & Powers, 2003). While these studies have been able to show a
positive effect of strength gains and improvement of injury by returning to activity, further
research is needed to examine the strength torque gains to further support these results.
1.2 SIGNIFICANCE OF THE PROBLEM
When gluteus medius weakness has reached a significant point, it will create what is known
as a Trendelenburg’s gait (Presswood, 2008; Starkey & Ryan, 2002). This gait may already be
structurally present within a person’s body. Due to an increase in weakness of the hip abductors,
this gait may be exacerbated. A Trendelenburg’s gait is noted when there is a drop in the
opposite hip of the affected side during a single leg stance (Presswood, 2008). This drop creates
a different angle of force throughout the entire lower extremity chain, thus changing one’s gait
(Cichanowski et al., 2007; Fredericson et al., 2000). This is easily seen in severe cases, although
changes and injury can still occur in less noticeable cases. Many studies have linked weakness in
gluteus medius to injuries in the lower extremity such as patellofemoral pain, IT Band
Syndrome, anterior shin pain, ankle instability, ankle sprains, stress fractures, and even an
increase in risk of ACL injury. (Cichanowski et al., 2007; Ferber et al., 2011; Fredericson et al.,
2000). While there have been different treatment options tried to all of these injuries, one
3

consistent rehabilitation exercise has been to strength the gluteus medius/hip abduction muscle
group. Multiple research studies have noted that exercises such as the clamshell, side lying hip
abduction, and side lying hip abduction with external rotation have been the best at strengthening
the gluteus medius (Distefano et al., 2009; Earl, 2004). Most of these previous research methods
have investigated EMG activity that the muscles produce during a particular exercise. Few
articles have examined the actual gain in strength following a strengthening program.
By combining the results from previous research and measurements in torque of the strength
gains in the gluteus medius, it will be possible to determine if performing side lying exercises
will produce strength gains in the gluteus medius. Working in athletics, it is important that not
only the athlete receives the highest degree of care, but also that the care is provided in an
efficient manner. By providing the athlete with an exercise program that is efficient in creating
strength gains, it may also increase the potential the athlete will return from injury quicker and
maintain the athlete’s health throughout the season with little risk of secondary injury due to the
weakness presented.
There is significant amount of knowledge within the field linking an increase of hip
abduction activation to strengthening exercises through measurements with EMG (Distefano et
al., 2009; Earl, 2004; Sieve, 2007). However, little research has been performed on the
measurement of strength in torque values by testing the strength gains through a Biodex
(Fredericson et al., 2000). Studies have even mentioned the need for future research to collect
strength gain values (Distefano et al., 2009). By examining increases in muscle strength, it can
help determine rehabilitation protocols to promote hip abduction strengthening.

4

1.3 PURPOSE OF THE STUDY
The purpose of this study is to determine if an exercise program (clam shells, side lying
hip abduction, side lying hip abduction with external rotation) will create strength gains in torque
values (during measurement) of side lying hip abduction and side lying hip abduction with
external rotation with a BioDex System 3 over a period of six weeks.
1.4 HYPOTHESES
1. There will be increases in hip abduction strength in torque values of the dominant leg
following the 6 week exercise program.
2. There will be increases in hip abduction strength in torque values of the non dominant leg
following the 6 week exercise program.
3. There will be an increase in hip abduction with external rotation strength in torque values of
the dominant leg following the 6 week exercise program.
4. There will be an increase in hip abduction with external rotation strength in torque values of
the non dominant leg following the 6 week exercise program.
5. There will be greater increases in strength gain in the non dominant leg verses the dominant
leg following the 6 week exercise program.
1.5 OPERATIONAL DEFIINTIONS OF TERMS
Ball and Socket Joint: The name of the type of joint given to the hip joint. The ball and
socket joint of the hip is made up of the femoral head and acetabular fossa. The acetabular fossa
is bordered by the glenoid labrum. (Starkey & Ryan, 2002)
BioDex System 3: The isokinetic dynamometer that measures net muscle torque for the
ankle, knee, hip, wrist, elbow and shoulder. The modes of operation for exercise and testing
include isokinetic, passive, isometric, isotonic and reactive eccentric (Drouin, Valovich-mcLeod,

5

Shultz, Gansneder & Perrin, 2004; Feiring, Ellenbecker, & Derscheid, 1990; Zawadzki, Bober &
Siemienski, 2010).
Clam Shell Exercise: A side-lying hip strengthening exercise in which the patient will start
and end with 60 degrees of hip flexion and 90 degrees of knee flexion. Patient will then abduct
their hip (at the knee) while keeping their heels together, and return to starting position in a slow
and controlled manner (Distefano et al., 2009)
Electromyography (EMG): Measurement device used to record the amount of electrical
impulses of a muscle to determine contraction (Distefano et al., 2009; Earl, 2004).
Physically Active: Someone who accumulates at least 150 minutes of moderate-intensity
exercise per week. Exercise recommendations can be met through 30-60 minutes of moderateintensity exercise (five days per week) or 20-60 minutes of vigorous-intensity exercise (three
days per week). (Garber et al., 2011)
Q Angle: The relationship between the line of pull of the quadriceps and the patellar tendon.
With extended knee, normal Q Angle for men is 13 degrees and 18 degrees for women. With
flexed knee to 90 degrees, Q Angle is normal at 9 degrees for both genders (Starkey & Ryan,
2002).
Side Lying Hip Abduction Exercise: A hip strengthening exercise that has the patient sidelying on the floor with a starting position of full knee extension and neutral hip position. The
patient will abduct the hip of the top limb while keeping the knee locked out in extension. The
patient will stop at 30 degrees of hip abduction and then return to the starting position in a slow,
controlled manner (Distefano et al., 2009; Earl, 2004).
Side Lying Hip Abduction with External Rotation Exercise: A hip strengthening exercise that
has the patient side-lying on the floor with a starting position of full knee extension and neutral

6

hip position. The patient will abduct and externally rotation the hip of the top limb while keeping
the knee locked out in extension. The patient will stop at 30 degrees of hip abduction with about
10-15 degrees of external rotation and then return to the starting position in a slow, controlled
manner (Distefano et al., 2009; Earl, 2004).
Trendelenburg’s Gait: Occurs when one leg swings forward during gait and the gluteus
medius cannot stabilize the pelvis, resulting in a downward tilt when the swing leg is in the air.
(Presswood, 2008)

7

CHAPTER 2
REVIEW OF LITERATURE
2.1 INTRODUCTION
The review of literature is divided into five sections. First, an overview of hip and pelvis
anatomy including bony anatomy, bony and hip abduction muscular articulations, and function
of the hip abduction muscles are discussed. Second, there is a discussion of hip abduction
weakness and its relationship to injury. Third, there is a discussion on research of the correlation
between gluteus medius strength and exercise. Fourth, an overview is provided on rehabilitation
techniques used to prevent and/or correct gluteus medius weakness. Finally, this review of
literature discusses research that has utilized the Biodex system on hip abduction testing.
2.2 HIP ANATOMY
2.2.1 Bony Anatomy
The anterior and lateral portion of the pelvis consists of two innominate bones. Each
innominate is made up by the ilium, ischium, and pubis. The lateral portion of the pelvis also
articulates with the femoral head via the acetabulum. On the proximal portion of the femoral
shaft, the greater trochanter and lesser trochanter are two attachment sites for many pelvic and
hip muscles. The posterior portion of the pelvis is formed by an articulation with the sacrum
(Starkey & Ryan, 2002). The hip is a ball and socket joint. The musculature of the hip can be
placed into the six directional categories (DeStefano, 2011) including flexion-extension,
abduction-adduction, and internal-external rotation. This next section examines the abductor
musculature and its function.
2,2,2 Hip Abduction Muscles/Attachments/Function
The four hip muscles that contribute to hip abduction are gluteus medius, tensor fasciae
latae, gluteus minimus and sartorius. The gluteus medius originates on the outer surface of the
8

iliac crest and inserts on the greater trochanter of the femur (Earl, 2004; Starkey & Ryan, 2002).
There are 3 different areas of the gluteus medius that are distinct through their function.
Although the primary function in the medial fibers of the gluteus medius is abduction, the
anterior fibers contribute to hip flexion and hip internal rotation, and the posterior fibers assist in
hip extension, hip external rotation and contribute to the stabilization of the hip joint (Earl et al.,
2005; Presswood, Cronin, Keogh, Whatman, 2008; Starkey & Ryan, 2002). According to Earl et
al. (2005) and Presswood et al. (2008), the gluteus medius has dual purposes; a pelvic stabilizer
during stationary activities and a pelvic rotator during movement activities. Therefore, it is
important to note that the gluteus medius is important for both stabilization and movement.
The tensor fasciae latae (TFL) originates on the anterior superior iliac spine (ASIS) and
external lip of the iliac crest and inserts on the iliotibial tract in the middle third of the thigh (IT
band) (Starkey & Ryan, 2002). Similar to the gluteus medius, the TFL’s primary action is hip
abduction, however the TFL also assists in hip flexion and internal rotation (Starkey & Ryan,
2002). It is important to note that when one favors the TFL in hip abduction over the gluteus
medius, weakness and atrophy occurs in the gluteus medius (Bewyer & Bewyer, 2003).
Gluteus minimus originates off the lower portion of the ilium and greater sciatic notch
and inserts on the greater trochanter of the femur (Starkey & Ryan, 2002). The gluteus minimus’
primary action is hip abduction, but also contributes to hip internal rotation and hip flexion
(Starkey & Ryan, 2002). The sartorius originates on the ASIS and inserts on the proximal portion
of the anterior medial tibia (Starkey & Ryan, 2002). The sartorius contributes to abduction,
flexion, and internal rotation of the hip (Starkey & Ryan, 2002).

9

2.3 HIP ABDUCTION WEAKNESS
Since one of the gluteus medius’ functions is to act as a pelvic stabilizer, when it is weak, it
creates what is known as a Trendelenburg’s gait pattern (Presswood et al., 2008; Starkey &
Ryan, 2002). When one leg swings forward during gait, the opposite gluteus medius (non
swinging leg) contracts to prevent the pelvis from laterally tilting. During a Trendelenburg gait,
the gluteus medius cannot stabilize the pelvis, resulting in a downward tilt when the swing leg is
in the air (Presswood et al., 2008). In other words, when there is insufficient hip abduction
strength, it is believed there is excessive femoral internal rotation and hip adduction. Looking
further down the kinetic chain, this increase in hip movement affects the valgus motion of the
knee, resulting in an increase in the Q-angle (Cichanowski et al., 2007; Fredericson et al., 2000).
It is believed that this increase in Q-angle creates repetitive abnormal forces to the various areas
of the lower extremity, ultimately resulting in injury (Cichanowski et al., 2007; Ferber et al.,
2011; Fredericson et al., 2000).
Willson and Davis (2008) conducted a study that looked into the kinematic changes of the
lower extremities when comparing females with and without patellofemoral pain syndrome. In
this study, 20 females with patellofemoral pain and 20 female controls performed single leg
squats, running, and repeat sets of single leg jumps. As these exercises were performed, three
dimensional biomechanics were recorded. Transverse and frontal hip plane measurements were
compared between the two groups. Results showed that subjects who experienced patellofemoral
pain syndrome (PFPS) had greater hip adduction which was attributed to abnormal frontal plane
mechanics due to weak hip abductors when compared to a control group. The authors also
reported that the biomechanical changes in the various hip planes were consistently different
throughout the three exercises (Willson & Davis, 2008). Although this specific study didn’t

10

actually measure hip abductor strength, other studies have included hip abductor strength
measures.
In a study by Ireland, Willson, Ballantyne, and Davis (2003), the purpose of the study was to
examine hip strength in women diagnosed with patellofemoral joint pain (PFP). The authors
hypothesized that the women diagnosed with PFP would demonstrate lower strength values in
hip abduction and external rotation compared to the control group. Using side-lying hip
abduction isometric strength testing, 15 female subjects with PFP and 15 control group subjects
were tested. Results indicated that subjects with PFP demonstrated a 26% decrease in hip
abduction strength and 36% weaker hip external rotation strength then their control group
counterparts (Ireland et al., 2003).
Another study conducted by Niemuth, Johnson, Myers and Thieman (2005) tested the
strength of the six muscle groups (hip flexors/extensors, hip abductors/adductors,
internal/external rotators) in the involved leg of injured versus non injured recreational runners to
see if a difference in strength was prevalent. Of the 30 injured runners tested, 10 were diagnosed
with Achilles tendonitis, 9 with iliotibial band friction syndrome, 6 had anterior knee pain, 2 had
tibial or fibula stress fractures, 2 were diagnosed with medial tibial stress syndrome, and 1
experienced plantar fasciitis. Using a hand held dynamometer to measure maximal isometric
contraction strength; the study suggested that there was a relationship between hip muscle
imbalances and injury patterns in runners suffering from overuse injuries that didn’t exist in
healthy runners. The study went further to discuss the biomechanics of the running gate,
emphasizing the stabilizing factor of the gluteus medius (Niemuth et al., 2005).
Another study performed by Boling, Padua and Creighton, (2009) used a Biodex isokinetic
dynamometer system to measure strength differences in subjects with and without patellofemoral

11

pain. Forty volunteers between the ages of 18 and 40 years old were included in the study.
Twenty of those subjects were diagnosed with patellofemoral pain. Concentric and eccentric
torque of the hip extensors, external rotators, and abductors were assessed. All strength testing
was performed at 60 degrees range of motion. This degree was chosen because as stated in the
article, a muscle produces greatest concentric force at a slower isokinetic testing velocity.
Furthermore, there is a positive correlation between eccentric contraction velocity and force
production. Each participant was given two minutes of rest between strength test trials. Results
showed that the subjects with patellofemoral pain had weaker peak eccentric hip abduction
torque as well as average concentric and eccentric hip external rotation torque (Boling, Padua, &
Creighton, 2009).
Researchers have also examined the relationship of gender and hip biomechanical
differences. Ferber, Davis and Williams III (2003) conducted a study comparing the hip and
knee three dimensional joint angles and negative work during the stance phases of the running
gate. In his study, the gait of 20 men and 20 women were analyzed using retro-reflective
markers. The study found that female recreational runners demonstrated greater hip adduction,
hip internal rotation, and knee abduction. Females also demonstrated greater hip front and
transverse plane negative work when compared to males (Ferber, Davis & Williams, 2003).
Cichanowski, Schmitt, Johnson and Niemuth (2007) examined potential reasons behind
collegiate female athletes with PFPS. Once again in this study, the six aforementioned muscle
groups were tested using maximal isometric strength testing with a handheld dynamometer. They
hypothesized that women with PFPS would have weaker hip strength, specifically in the hip
abductor and external rotators versus their uninjured leg and the leg of the uninjured control
group. Twenty-six athletes were subjects for the study; 13 athletes diagnosed with patellofemoral

12

pain and 13 controls. Results found that the force produced by the injured leg’s hip abductors
and external rotators were significantly weaker than the uninjured leg. Furthermore, the study
also showed that there were no significant differences in strength of the hip flexors, extensors,
adductors or internal rotators. When compared to the uninjured control group, the injured
athletes legs had overall weaker hip strength values. The only muscle group that wasn’t unequal
was the hip adductors. The authors determined that future research was needed to determine if
adding exercises to address these weaknesses would promote recovery and allow for faster return
to full activity (Cichanowski et al., 2007).
2.4 HIP ABDUCTION STRENGTH AND EXERCISE
Some researchers have shown a positive correlation between hip abduction strength and
exercise programs. One of these studies by Fredericson and colleagues (2000) investigated the
correlation between corrections of strength deficits in hip abduction through a rehabilitation
program to successful return to running. In this study, 24 runners with diagnosed iliotibial band
syndrome (ITBS) were measured for hip abduction torque using the Nicholas Manual Muscle
Tester for both pre and post testing. During pre testing, it was found that hip abduction torque
values were decreased for the injured limb of both genders [7.82% body weight times height
(BWh) for females, 6.86% BWh for males] when compared to the uninjured limb [9.82% BWh
for females, 8.62% BWh for males] and the control group [10.19% BWh for females, 9.73%
BWh for males]. These runners were then administered a 6 week standardized rehabilitation
protocol that focused on the strengthening of the gluteus medius. During the 6 weeks, the
subjects were treated by the same physical therapist once a week. Exercises chosen for this
protocol included side-lying hip abduction and pelvic drops performed at 1 set of 15 repetitions
and increased over the next several weeks with a goal of 3 sets of 30 repetitions. The subjects

13

were instructed that as long as there was no significant post workout soreness the following day,
repetitions could be increased by 5 per day. Besides the physical rehabilitation protocol, subjects
were also administered non-steroidal anti-inflammatory drugs, application of ultrasound with a
corticosteroid gel, stretching protocol, and were told to discontinued running or any other
activity that continued to cause pain. However, cross training was allowed as long as it didn’t
recreate any pain. Following the 6 week protocol, females exhibited an increase in hip abduction
torque values by 34.9% in the injured limb, while males increased hip abduction torque values
by 51.4%. Following 6 weeks of this protocol, 22 of the 24 runners returned to running pain free
with no recurrent complications following a 6 month follow up. The authors suggest that the
strength gains in hip abduction allowed greater control of hip adduction and internal rotation,
thus, creating less valgus force at the knee (Fredericson et al., 2000).
Another study by Mascal, Landel and Powers (2003) discussed two case reports on females
with patellofemoral pain. Both subjects experienced hip abductor, extensor, and external
rotational weakness and displayed excessive hip adduction, internal rotation and knee valgus
forces. Both subjects were then placed on rehabilitation protocols that occurred over a 14 week
period and focused in stages on the training of the hip, pelvis, and truck musculature. The
subjects were scheduled to attend physical therapy sessions once to twice a week over the 3
month period. During weeks 0-6, non weight bearing exercises were performed. Weeks 6-10
incorporated weight bearing exercises, and weeks 10-14 incorporated functional training.
Following the protocol, both subjects reported a significantly reduced pain level, improved
function, and gluteus medius torque values were increased by 50% in subject A and 90% in
subject B. It was suggested that the prescribed exercises in this study should be considered in the

14

treatment of patients with PFP and that further research needed to be conducted to define the
relationship between proximal hip weakness and PFP (Mascal et al., 2003).
Ferber, Kendall and Farr (2011) examined a 3-week protocol consisting of 2 exercises
targeting hip abductors to see if there would be changes in strength, pain, and biomechanics in 15
runners diagnosed with patellofemoral pain syndrome. The protocol consisted of 2 theraband
exercises, the first in hip abduction and the second in hip extension with 45 degrees of hip
abduction. The subjects were instructed to perform 3 sets of 10 repetitions for each exercise daily
over the course of the 3 weeks. All subjects returned after 7-10 days to follow up on logging
exercise protocol compliance and to have their technique evaluated. For this study, the subjects
continued to run on a regular basis. Pain was measured using a 0 to 10 scale with 0 indicating no
pain and 10 indicating the most pain imaginable. Results of the study showed that the subjects
were compliant with the protocol, completing the exercises on average 6.2 days per week over
the 3 week period. Furthermore, post test results demonstrated an increase in isometric strength
testing by 32.69% and a 43.10% decrease in the pain scale compared to baseline values. It was
concluded that the 3 week program was effective in increasing hip abduction strength and
decreasing pain (Ferber et al., 2011).
Snyder and colleagues (2009) performed a study on 15 healthy females that included
measuring hip abduction with a hand held dynamometer and administering a 6 week
strengthening program using closed chain hip rotation exercises. Inclusionary study criteria
included physical activity level that met the American College of Sports Medicine requirements
for moderately active people (30 minutes of moderately intense activity on most days of the
week). The authors hypothesized that after 6 weeks; there would be an increase in isometric hip
abduction and external rotation strength. The three closed chain hip rotation exercises that

15

provided resistance to hip abduction and rotation were chosen because of previous literature that
described this position to produce a high amount of gluteus medius activity via
electromyography testing. The exercises were also chosen because of the ability to perform the
exercises at home. These three exercises were named toward, away, and hip hike. Strength
testing was repeated at the midpoint (week 3) and end of the protocol. Following the 6 week
program, hip abduction and external rotation strength increased by 13% and 23% respectively.
The authors interpreted the results as positive and believed that with the alteration in joint
loading due to increased strength, injury risk could be reduced (Snyder, Earl, O'Connor &
Ebersole, 2009).
It is important to note that not all studies have supported the idea of targeting hip abductors.
Tyler, Nicholas, Mullaney and McHugh (2006) conducted a study using 35 subjects diagnosed
with patellofemoral pain syndrome and placed them on a 6 week rehabilitation program to see if
a positive outcome (pain decrease) could be achieved. Even though there were 35 subjects in the
study, some of the subjects had bilateral PFP diagnoses, which allowed for 43 knees to be
studied. Prior to the start of the protocol, the subjects were measured for hip flexion, abduction
and adduction strength via a hand held dynamometer. These measurements indicated weakness
on the involved limb in hip flexion by 14% and hip abduction by 14% when compared to the
uninjured side. The therapeutic intervention consisted of a multi phased guideline that
incorporated open and closed kinetic chain exercises. The exercises were performed initially in a
non weight bearing format and progressively moved to a weight bearing format. Home programs
were given to each subject and progression of the program was allowed when the subject could
successfully perform the exercises during the clinic evaluations without verbal corrections.
Following the 6 week protocol, the study found that although there were improvements in the

16

different areas of strength (flexion 35%, abduction 18-28%, adduction 24-40%) there was a
significant difference in the positive outcomes based upon which hip motion was strengthened.
When hip flexion was increased by more than 20%, 17 of 19 lower extremities had a positive
outcome. When hip abduction was improved by more than 20%, only 14 of 22 lower extremities
had a positive outcome. The authors suggest that hip abduction and adduction exercises were not
pertinent to the treatment of patellofemoral pain syndrome (Tyler, Nicholas, Mullaney &
McHugh, 2006). Ferber et al. (2011) addressed this finding, indicating that other muscles in
addition to the hip abductors could be important in the treatment of injury; however, further
studies involving comprehensive hip muscle strengthening protocols would be necessary to
support the results found (Ferber et al., 2011).
2.5 REHABILITATION TECHNIQUES TO CORRECT WEAKNESS
While the previous research was able to show a relationship between gluteus medius strength
and exercises, there were different protocols and exercises chosen. This review of literature
examined to see if there was a reason specific exercises were chosen and to see if there were
some exercises that were more beneficial than others.
Schmitz and colleagues (2002) examined isometric closed chain external hip rotation
exercises to see if there was an increase in gluteus medius (GM) activity via surface EMG
recordings. Twenty college age subjects that were free from lower extremity injury were
recruited. Once the EMG electrodes were placed, subjects performed a five second stance on the
dominant limb in three different positions. These positions were 0° knee flexion with 0° hip
flexion, 0° knee flexion with 20° hip flexion, and knee flexed 20° to 30° with 20° hip flexion.
While these positions were being held, a posterior force of 8.9 Newtons (N), 17.8 N, and 26.7 N,
respectively were placed using a pulley belt system. These forces were chosen from results
17

during a pilot study done. Results showed that GM activity increased in response to isometric,
closed-chain, external hip-rotation forces (Schmitz, Riemann & Thompson, 2002). While this
study did show inference for creating a rehabilitation program designed to stabilize the pelvis
and trunk, it did not look into the abduction action of the muscle.
Another study that took the groundwork of Schmitz et al.’s was conducted by Earl (2004). In
the article, she stated that while frontal plane exercises such as side-lying straight leg raises and
standing hip hikes were good for early stages of improvements of neuromuscular control, they
weren’t a good representation of functional action in the gluteus medius. She suggested that a
program aimed towards functional strengthening would be one that incorporates both abduction
and internal rotation. Her study investigated which combination of hip rotation and abduction
loads caused the greatest activity of the gluteus medius and to determine if the gluteus medius
responded to the increased loads in these exercises. In this study, 20 healthy subjects 23  5
years (10 men, 10 women) were recruited. EMG data was collected using surface electrodes on
the dominant leg. Three variations of single leg stance isometric exercises were performed with
the force coming from a pulley belt system. The exercises used were abduction only (ABD),
abduction-internal-rotation exercise (ABD-IR), and abduction-external-rotation (ABD-ER). The
subjects were asked to hold this position for five seconds while measurements were taken.
Results showed that the ABD-IR produced the most activity in the anterior and middle sections
of the gluteus medius muscle. It also showed that the 4.53 kg load produced greater activity than
the 2.26 kg load. Based on these results, it was concluded that the gluteus medius was more
active when performing abduction and internal rotation of the hip (Earl, 2004).
Another study by Distefano and colleagues (2009) looked into quantifying and comparing
gluteal muscle activation via EMG surface electrodes over 12 strengthening exercises. The

18

exercises were side lying hip abduction, clam shell with 30 degrees of hip flexion, clam shell
with 60 degrees of hip flexion, single limb squat, single limb deadlift, lateral band walk, forward
lunge, sideways lunge, transverse lunge, forward hop, sideways hop, and transverse hop. The
exercises were chosen based upon feedback given on which exercises would be used to
strengthen gluteal muscles. Twenty-one uninjured subjects (nine males, 12 females) who
participated in physical activity for at least 60 minutes, three days per week participated in the
study. The subjects completed eight repetitions of each of the exercises. EMG data was collected
and revealed that there was a significant difference among the exercises for muscle activity for
the gluteus medius. The side lying hip abduction exercise was found to produce the greatest
amount of activation. In fact, this exercise produced almost 16% more activation than the other 4
top tier measured exercises and 30% more activation then the lower tier exercises. The study
concluded that while there was an ability to show the differences in muscle activation among the
different exercises, further research needs to be performed to determine if the high levels of
activity actually result in muscle strength gains over time (Distefano et al., 2009).

2.6 RELIABILTY AND VALIDITY OF THE BIODEX ISOKINETIC DYNAMOMETER
Finally, this overview of literature investigated previous research done on the reliability and
validity of the Biodex Isokinetic Dynamometer. There have been several studies performed on
the test-retest reliability of the Biodex unit, however, this review focused solely on the lower
extremity measurements.
The first study performed by Feiring, Ellenbecker and Derscheid (1990) examined the testretest reliability for isokinetic concentric forces of healthy active populations measuring peak
torque of knee extension and flexion. Nineteen healthy active males and females between the

19

ages of 20-35 with no history of knee injury were pre and post tested concentrically bilaterally at
60, 180, 240, and 300 degrees of knee extension and flexion. There were seven days between pre
and post tests. Analysis of the data showed that the intra-class coefficients (ICC) for all
measurements taken were between r = 0.95-0.97. All ICCs were significant at the 0.05 level.
Therefore, it was concluded that the isokinetic concentric mode for the BioDex dynamometer
were reliable for the test-retest measures of peak torque, and single repetition work (Feiring et
al., 1990).
Another study in 2004 assessed the mechanical reliability and validity of angular position,
isometric torque and concentric velocity measures of the BioDex System 3 isokinetic
dynamometer (Drouin et al., 2004). Position was measured at five degree increments throughout
the entire ability of the machine’s range of motion. Torque measurements were assessed
isometrically using six different hanging calibrated weights that were placed off the lever arm of
the machine. Velocity was measured from a range of 30 degrees per second to 500 degrees per
second across a 70 degree arc of motion by the administrators manually accelerating the
weighted lever arm. All measurements were compared to a criterion of data. Within the
limitations of the study, it was found that the Biodex unit provided mechanically reliable
measures of torque, position and velocity on repeated trials performed both same day and
different days (Drouin et al., 2004).
Finally, a study in 2010 examined the analysis of static measurements of torque and angular
position of the lever arm of the dynamometer. Two separate dynamometers were used in this
study. To measure torque, weights were hung on the lever arm to produce a constant force during
measurement. The angular position of the lever arm was tested by measuring the torque
produced by the weight attached to the lever at the distance from the axis of rotation. The results

20

of the measurements were determined by comparing them to previous results reported by the
Biodex report and the raw data collected from the measuring computer of the second isokinetic
machine. The results showed that the Biodex System 3 dynamometer was within the error range
specified by the manufacturer, and therefore results could be considered valid (Zawadzki et al.,
2010).
2.7 CONCLUSION
Many researchers have studied the increases in muscle activation in the gluteus medius
after performing a rehabilitation program. This research has concluded that increases in
activation have occurred in the gluteus medius muscle (Distefano et al., 2009; Earl, 2004;
Schmitz et al., 2002). Other studies have also shown that after performing rehabilitation
exercises aimed at increasing strength at the gluteus medius, lower extremity injuries have
decreased or resolved (Bewyer & Bewyer, 2003; Cichanowski et al., 2007; Ferber et al., 2011;
Mascal et al., 2003). However, very few studies have actually measured the strength gains in
torque values (Boling et al., 2009). Therefore, the purpose of this study is to determine if
rehabilitation exercises (clam shells, side lying hip abduction, side lying hip abduction with
external rotation) will create strength gains in torque values for both the dominant and non
dominant leg in healthy individuals over a period of six weeks.

21

CHAPTER 3
METHODS
3.1 RESEARCH DESIGN

A randomized, counterbalanced, within-subject experimental design was used to
determine if the 6 week exercise program would produce strength gains. The independent
variable was time (strength prior to 6 week program, strength post 6 week program) and the
dependent variable was peak torque.
3.2 SAMPLE POPULATION AND PARTICIPANT SELECTION
Sixty subjects from a large mid-western university between the ages of 18-35 were asked
to volunteer for the study. All participants fell into the category of physically active; defined by
the ACSM as someone who accumulated at least 150 minutes of moderate-intensity exercise per
week. Exercise recommendations can be met through 30-60 minutes of moderate-intensity
exercise (five days per week) or 20-60 minutes of vigorous-intensity exercise (three days per
week) (Garber et al., 2011). Participants were excluded from the study if they had a lower
extremity injury within the past 6 months. Participants were excluded from the study if they had
surgery on their lower extremity within the last 6 months. Participants were excluded from the
study if they have ever had hip surgery.
3.3 INSTRUMENTATION
3.3.1 BioDex System 3 Dynamometer
The BioDex system 3 dynamometer was used to collect peak torque values for the hip
during this study. Hip abduction and hip abduction with external rotation was measured. This
system is reliable and valid, used specifically for isolated muscle testing and rehabilitation. A
study performed in 2004 measured the mechanical reliability and validity of angular position,
22

isometric torque and concentric velocity measures of the BioDex System 3 Isokinetic
dynamometer. Position was measured at five degree increments throughout the entire ability of
the machine’s range of motion. Torque measurements were assessed isometrically using six
different hanging calibrated weights that were placed off the lever arm of the machine. Velocity
was measured from a range of 30 degrees per second to 500 degrees per second across a 70
degree arc of motion by the administrators manually accelerating the weighted lever arm. All
measurements were compared to a criterion of data. Within the limitations of the study, it was
found that the BioDex unit provided mechanically reliable measures of torque, position and
velocity on repeated trials performed both same day and different days (Drouin et al., 2004).
3.4 STRENGTHENING INTERVENTION
There were three exercises that were demonstrated during the first session and used
throughout the six week program. The first exercise was the clamshell exercise. For this exercise,
the participant was side-lying with the knees flexed to 90 degrees, the hips flexed to 60 degrees.
The hips and shoulders were perpendicular to the table with their feet together. Participants
abducted the hip by moving the top knee off the bottom knee while keeping their heels together
and their spine remaining in a neutral position. They returned to the starting position in a slow
and controlled manner (Distefano et al., 2009; Earl, 2004). This exercise was performed in 3 sets
of 10 repetitions (Bewyer & Bewyer, 2003; Ferber et al., 2011; Mascal et al., 2003). The
therband was placed just above the knees. The arm and hand on the top side rested on the table in
front of the body while the arm of the bottom side was bent resting underneath the participants
head. (See Figure 3.1)

23

Figure 3.1: The Clamshell Exercise
The second exercise was the side-lying hip abduction exercise. This exercise was
performed with the participant in a side-lying position with full knee extension and a neutral hip
position. The arm and hand on the top side rested on the table in front of the body while the arm
of the bottom side was bent resting underneath the participants head. The participant slowly
abducted the top leg while keeping the knee in extension, making sure the tibia and femur
remained in a neutral position. The bottom legremained stationary. The participant stopped at 30
degrees of hip abduction, and slowly returned to the starting position (Distefano et al., 2009;
Earl, 2004). This exercise was performed in 3 sets of 10 repetitions (Bewyer & Bewyer, 2003;
Ferber et al., 2011; Mascal et al., 2003). The therband was placed around the ankles. (See Figure
3.2)

24

Figure 3.2: Side Lying Hip Abduction Exercise
The third and final exercise was the side-lying hip abduction with external rotation. This
exercise was very similar to the side-lying hip abduction exercise in terms of patient positioning
with the exception that during this technique, the top leg had about 10-15 degrees of external
rotation added to it. Once the participant reached 30 degrees of hip abduction, they slowly
returned to the starting position in a slow, controlled manner (Earl, 2004; Distefano et al., 2009).
This exercise was performed in 3 sets of 10 repetitions (Bewyer & Bewyer, 2003; Ferber et al.,
2011; Mascal et al., 2003). The therband was placed around the ankles. (See Figure 3.3)
All three exercises included a therband for overload. There were three different
resistances that were used; yellow, red, and green. Therband resistance was determined during
the exercise educational component of Session 1 by completing 10 repetitions of the exercises
with the red therband. Participants self reported if the exercises were of moderate intensity. If
intensity was too easy, the higher therband color was chosen. If exercise intensity was
determined too high, or if exercise technique was compromised, the lower therband color was
chosen. During each check in session, research assistants asked if the resistance changed, and
made modifications using the same protocol if needed.

25

Figure 3.3: Side Lying Hip Abduction with External Rotation Exercise
3.5 PROCEDURES
Prior to data collection, this study was approved by the Institutional Review Board (IRB)
at Michigan State University. Each participant completed an informed consent (see Appendix A)
and healthy history questionnaire prior to participating in this study (see Appendix B).
Participants wore comfortable athletic clothing that allowed the participant to perform the
necessary exercises and the investigator to access the testing area. Only the participant,
investigator, and research assistants were present in the testing area. Data collection took place in
the Exercise Physiology Lab of IM Circle at Michigan State University. Participants were
required to attend two testing sessions (60 minutes, 30 minutes) with the investigator and
attended a check in meeting during week 2, 3, and 5 (15 minutes) with the research assistant who
reviewed the exercise program and exercise technique.
3.5.1 Session 1
The participants’ name, age, and side of their dominant leg were recorded. The dominant
leg was determined by asking the participants what leg they would kick a ball with. Session 1
26

was set for baseline testing. Baseline testing was done for hip abduction and hip abduction with
external rotation peak torques using the BioDex, respectively. Both the dominant and non
dominant leg was tested.
To test hip abduction, participants were side-lying facing away from the dynamometer
force sensor with the tested leg superior to the non tested leg. The knee of the tested leg was in
extension and the opposite knee was bent at 90 degrees. The axis of the dynamometer was
aligned perpendicular to the hip frontal plane of motion at the level of the greater trochanter. The
tested hip was positioned at 30 degrees of hip abduction in a neutral rotated position. The pad of
the dynamometer was placed just above the lateral knee joint line proximal to the lateral
epicondyle. The participants’ torso was stabilized with securing straps.
To test hip abduction with external rotation, participants were side-lying facing away
from the dynamometer force sensor with the tested leg superior to the non tested leg. The knee of
the tested leg was in extension and the opposite knee was bent at 90 degrees. The axis of the
dynamometer was aligned perpendicular to the hip frontal plane of motion at the level of the
greater trochanter. The tested hip was positioned at 30 degrees of hip abduction and 10-15
degrees externally rotated position. The pad of the dynamometer was placed just above the
lateral knee joint line proximal to the lateral epicondyle. The participants’ torso was stabilized
with securing straps.
All muscular testing was done isometrically. Participants performed three warm up
contractions with the muscular group being tested at 50%, 75%, and 100% of their maximum
perceived effort. After a ten second rest period, the participants were asked to produce maximal
voluntary isometric contraction. There were three trials performed for each motion tested, with a
ten second rest period between each trial. (Piva et al., 2011) (See Figures 3.5 and 3.6).

27

Following the peak torque measurements, participants in the exercise program group
were instructed and evaluated on the home program with the investigator. This included the
exercise protocols as well as the home management and contact procedures between the
participant and research assistants. An initial pain reading off a Likert scale with 0 representing
no pain and 10 representing excruciating pain was taken.
3.5.2 Home Program Check-Ins
The home program was kept on a exercise program card that allowed the participants to
keep track of the exercises performed and number of times per week they were performed (See
Appendix C). During week 2, 3, and 4, as scheduled by the investigator, the research assistants
checked in with the participants. The research assistants asked how many times per week the
participants were able to perform the exercises, and also asked for the pain rating on the Likert
scale with 0 being no pain and 10 being excruciating pain. They also had the participant perform
5 reps of each exercise to evaluate for proper technique.
3.5.3 Session 2
Baseline testing was performed for peak torque of hip abduction and hip abduction with
external rotation in Session 1. Following the 6 week rehabilitation program, post-testing
measurements were acquired using the same techniques for peak torque of hip abduction and hip
abduction with external rotation. At this time, the final pain measurement on the Likert scale was
taken.
3.6 STATISTICAL ANALYSIS/DATA MANAGEMENT
Means and standard deviations were calculated for descriptive statistics. Each dependent
variable (i.e., peak torque hip abduction, peak torque hip external rotation) in this study was
analyzed separately. Data was analyzed using paired sample t-tests. The level of significance was

28

set at p ≤ .05 and all analyses will be conducted using SPSS version 19.1 for Windows (SPSS
Inc., Chicago, IL). In order to correct for multiple t tests, a Bonferroni comparison was
performed to set the new p value at p=.0125.
H1. There would be increases in hip abduction strength in torque values for the dominant leg
after a six week exercise program. A paired sample t-test was performed on peak torque of hip
abduction.
H2. There would be increases in hip abduction strength in torque values for the nondominant leg after a six week exercise program. A paired sample t-test was performed on peak
torque of hip abduction.
H3. There would be increases in hip abduction with external rotation strength in torque
values for the dominant leg after a six week exercise program. A paired sample t-test was
performed on peak torque of hip abduction with external rotation.
H4. There would be increases in hip abduction with external rotation strength in torque
values for the non-dominant leg after a six week exercise program. A paired sample t-test was
performed on peak torque of hip abduction with external rotation.
H5. There would be a greater increase in hip abduction strength in torque values for the nondominant leg versus the dominant leg after a six week exercise program. The results from both
paired sample t-tests would be compared to determine.

29

CHAPTER 4

RESULTS
4.1 OVERVIEW
The purpose of this study was to determine if an exercise program (clam shells, side lying
hip abduction, side lying hip abduction with external rotation) would create strength gains in
torque values during measurement of side lying hip abduction and side lying hip abduction with
external rotation with a BioDex System 3 over a period of six weeks. For clarity, the results
section is separated into subject demographics, pre and post hip abduction strength of the non
dominant leg, pre and post hip abduction of the dominant leg, pre and post hip abduction with
external rotation strength of the non dominant leg, and pre and post hip abduction with external
rotation strength of the dominant leg.
4.2 SUBJECT DEMOGRAPHICS
A total of 60 physically active college students from a large mid-western university
between the ages of 18-35 volunteered to participate in the study (see Table 4.1). Thirteen
subjects were unable to complete the study (three due to injury, 10 due to incompletion of second
session); therefore, 47 subjects were used in the data set. There were 17 male subjects (36.2%)
and 30 female subjects (63.8%) (age = 19.87  1.87 years, 67.53  3.65 inches, 151.85  28.97
lbs). All were healthy individuals with no self-reported lower extremity injuries or surgery within
the last six months, or hip surgery. All participants met the ACSM category of physically active,
achieving at least 150 minutes of moderate intense activity per week. Of the subjects, none were
self reported as left leg dominant, thus 47 (100%) were self reported as right leg dominant. The
subjects completed the exercise program an average of 5.72  .949 days per week.

30

Table 4-1: Descriptive Statistics for Subject Demographics
N
Years
Pounds
Inches
Days

Minimum

Maximum

Mean

47
47
47
47

18
105
60
4

26
240
74
7

19.87
151.85
67.53
5.72

Std.
Deviation
 1.87
 28.97
 3.65
 .95

4.3 RESULTS FOR SIDE LYING HIP ABDUCTION PEAK TORQUE
Subjects participated in a pre and post testing session. During the pre testing session,
subjects were also educated on the exercise program that was to be performed for six weeks.
Baseline peak torque testing at 30 degrees abduction was performed using a Biodex System 3
Dynamometer which included measurements for both the dominant and non dominant leg. In the
case of this study, all subjects’ dominant leg was the right and the non dominant leg was the left.
4.3.1 Side Lying Hip Abduction Peak Torque for the Dominant Leg
Subjects performed a Biodex test to measure side lying hip abduction. Consistent with
other data analysis performed for hip strength, paired sample t-tests were conducted to determine
side lying hip abduction peak torque (average peak torque/body weight) and testing occasions
(pre vs post). In order to correct for multiple t tests, a bonferroni comparison was performed with
the new p value set at p=.0125. Significant differences were noted within the testing occasions
(mean RPreABD = 174.17 N/bW, mean RPostABD = 174.67 N/bW, t = -3.996, p= .000).
However, it is noted that these differences do not make clinically significant gains (see Tables 43, 4-4). It is also noted that when compared to the non dominant side, the dominant side recorded
a lower pre-test peak torque/body weight; however, made slightly larger gains when compared
pre vs. post testing to the non dominant side (RPreABD = 174.17 N/bW, LPreABD = 174.22
N/bW RPostABD = 174.67 N/bW, LPostABD = 174.63 N/bW) (See Figures 4-2, 4-3, 4-4, 4-5).
31

Table 4-2: Descriptive Statistics for Side Lying Hip Abduction for the Dominant Leg
N
Mean
Std. Deviation
RPreABD
47
174.17
 31.97
RPostABD
47
174.67
 32.03
*(measurements recorded as peak torque (N)/body weight (bW))

Table 4-3: Paired Sample Statistics for Side Lying Hip Abduction of the Dominant Leg
Paired Differences
95% Confidence Interval of
T
Sig. (2-tailed)
the Difference
Lower
Upper
RPreABDRPostABD

-.749

-.247

-3.996

.000

4.3.2 Side Lying Hip Abduction Peak Torque for the Non Dominant Leg
Subjects performed a Biodex test to measure side lying hip abduction for the nondominant leg. Paired sample t-tests with bonferroni correction (p=.0125) were conducted to
determine side lying hip abduction peak torque (average peak torque/body weight) and testing
occasions (pre vs post) for the non-dominant leg. Results revealed significant differences within
the testing occasions (mean LPreABD = 174.22 N/bW, mean LPostABD N/bW = 174.63, t = 3.952, p= .000). Again these differences do not represent clinically significant gains (see Tables
4-4, 4-5).
Table 4-4: Descriptive Statistics for Side Lying Hip Abduction for the Non-Dominant Leg
N
Mean
Std. Deviation
LPreABD
47
174.22
LPostABD
47
174.63
*(measurements recorded as peak torque (N)/body weight (bW))

32

 31.93
 32.20

Table 4-5: Paired Sample Statistics for Side Lying Hip Abduction of the Non-Dominant
Leg
Paired Differences
95% Confidence Interval of
T
Sig. (2-tailed)
the Difference
Lower
Upper
LPreABDLPostABD

-.610

-.198

-3.952

.000

4.4 RESULTS FOR SIDE LYING HIP ABDUCTION WITH EXTERNAL ROTATION
4.4.1 Side Lying Hip Abduction with External Rotation Peak Torque for the Dominant Leg
Subjects performed a Biodex test to measure side lying hip abduction with external
rotation. Paired sample t-tests (bonferroni corrected p=.0125) were conducted to determine side
lying hip abduction with external rotation peak torque and testing occasions. Results indicated
that there were significant differences within the testing occasions (mean RPreABDER = 174.23
N/bW, mean RPostABDER = 174.62 N/bW, t = -4.032, p= .000) although no clinically
significant gains (see Tables 4-6, 4-7). It is also noted that when compared to the non dominant
side, the dominant side recorded a higher pre-test peak torque/body weight; however, made
slightly smaller gains when compared pre vs. post testing to the non dominant side
(RPreABDER = 174.23 N/bW, LPreABDER = 174.06 N/bW, RPostABDER = 174.62 N/bW,
LPostABDER = 174.65 N/bW) (See Figures 4-6, 4-7, 4-8, 4-9).
Table 4-6: Descriptive Statistics for Side Lying Hip Abduction with External Rotation for
the Dominant Leg
N
Mean
Std. Deviation
RPreABDER
47
174.23
 31.97
RPostABDER
47
174.62
 32.09
*(measurements recorded as peak torque (N)/body weight (bW))

33

Table 4-7: Paired Sample Statistics for Side Lying Hip Abduction with External Rotation
of the Dominant Leg
Paired Differences
95% Confidence Interval of
the Difference
Lower
Upper

T

Sig. (2-tailed)

-4.032

.000

RPreABDERRPostABDER

-.590

-.197

4.4.2 Side Lying Hip Abduction with External Rotation Peak Torque for the Non Dominant
Leg
Similar analyses as mentioned above were performed on the non dominant leg for side
lying hip abduction with external rotation. Healthy participants exhibited significant differences
within the testing occasions (mean LPreABDER = 174.06 N/bW, mean LPostABDER = 174.65
N/bW, t = -5.100, p= .000) but did not demonstrate clinically significant gains (see Tables 4-8, 49).

Table 4-8: Descriptive Statistics for Side Lying Hip Abduction with External Rotation for
the Non-Dominant Leg
N

Mean

LPreABDER
47
174.06
LPostABDER
47
174.65
*(measurements recorded as peak torque (N)/body weight (bW))

34

Std. Deviation
 31.96
 32.16

Table 4-9: Paired Sample Statistics for Side Lying Hip Abduction with External Rotation
of the Non-Dominant Leg
Paired Differences
95% Confidence Interval of
T
Sig. (2-tailed)
the Difference
Lower
Upper
LPreABDERLPostABDER

-.834

-.362

-5.100

.000

4.5 RESULTS FOR MEASUREMENTS OF PAIN PRE AND POST EXERCISE
PROGRAM
For both sessions, subjects were asked to rate their current pain levels on a Likert scale (0
= no pain, 10 = extreme pain). A paired sample t-test was conducted to determine if there was a
significant difference in pain levels pre and post program. Results indicated there was not a
significant difference with pain levels pre and post program (t = -1.615, p = .113) (see figure 410).
Table 4-10: Paired Sample Statistics for Likert Scale Rating Pain

N

Pre Pain
Post Pain

Mean

Std. Deviation

47
47

.30
.57

 .78
 1.19

35

Paired Differences
95% Confidence
Interval of the
Difference
Lower
Upper
-.621

.068

t

Sig. (2tailed)

-1.62

.11

CHAPTER 5

DISCUSSION
5.1 OVERVIEW
The purpose for the study was to determine if an exercise program performed over a six
week period (clam shells, side lying hip abduction, side lying hip abduction with external
rotation) would create strength gains in torque values during measurement of side lying hip
abduction and side lying hip abduction with external rotation with a BioDex System 3. It was
hypothesized that there would be an increase in torque measurements for both the dominant and
non dominant legs. It was also hypothesized that after a period of six weeks, the non dominant
leg would have larger increases in torque measurements than the dominant leg. The discussion
section is organized into subsections. These include: a) hip abduction and hip abduction with
external rotation peak torque measurements of the dominant and non dominant legs, b)
utilization and clinical implications for an exercise program to create strength gains in hip
abduction and hip abduction with external rotation, c) limitations of current study, d) future
research implications, and e) conclusions.
5.2 ASSESSMENT OF HYPOTHESIS
There were five hypotheses for the current study. These were a) there would be increases
in hip abduction strength in torque values for the dominant leg after a six week exercise program,
b) there would be increases in hip abduction strength in torque values for the non-dominant leg
after a six week exercise program, c) there would be increases in hip abduction with external
rotation strength in torque values for the dominant leg after a six week exercise program, d) there
would be increases in hip abduction with external rotation strength in torque values for the nondominant leg after a six week exercise program, and e) there would be a greater increase in hip

36

abduction strength in torque values for the non-dominant leg versus the dominant leg after a six
week exercise program. Even though all p-values for the five hypotheses were p =.000, the
hypothesis were rejected due to the insignificant clinical gains in peak torque. Specifically,
college students only demonstrated a change of 1% increase in strength gains. Furthermore,
when comparing the dominant to the non dominant leg, even with the small gains noted, the
dominant leg measured with a greater increase than the non dominant leg.
5.3 PEAK TORQUE OF HIP ABDUCTION AND HIP ABDUCTION WITH EXTERNAL
ROTATION FOR THE DOMINANT AND NON DOMINANT LEG FOLLOWING A SIX
WEEK EXERCISE PROGRAM
While the current study’s findings revealed a statistical significant difference in peak
torque measurements of hip abduction for both the dominant and non dominant leg, clinically,
there was not a large enough increase in the measurements to suggest a significant difference. In
other words, there were minimal gains made in the strength of the hip abductors for both legs
following the six week exercise program. When the dominant and non dominant legs were
compared for differences in peak torque measurements for both pre and post program, it was
revealed that the non dominant side tested pre program had a higher peak torque measurement
than the dominant side. However, after the six week program was completed, the dominant side
had a higher peak torque measurement compared to the non dominant leg. Therefore, the
dominant leg had a larger increase in strength versus the non dominant leg.
Although the current study did not reveal clinically significant differences in strength
gains following the six week program, the findings are similar to a previous research. In 2000,
Fredericson and colleagues (2000) investigated strength gains produced after a rehabilitation
program. There were 24 subjects all diagnosed with iliotibial band syndrome (ITBS). They were

37

measured pre and post rehabilitation program by using the Nicholas Manual Muscle Tester. The
runners were taken through a 6 week rehabilitation program with the focus on the gluteus
medius. They were also administered NSAIDS, modalities, and discontinued all training.
Following the 6 week protocol, results revealed that females increased their hip abduction torque
values by 34.9% in the injured limb and males increased their hip abduction torque values by
51.4% in their injured limb. Furthermore, following the program, 22 out of the 24 runners
returned to their running programs pain free and remained that way after a six month follow-up
(Fredericson et al., 2000).
Similarly, Ferber, Kendall and Farr (2011) examined a three week protocol with two
therband exercises on 15 runners diagnosed with patellofemoral pain syndrome (PFPS). The
subjects were directed to perform 3 sets of 10 reps daily over a three week period. All subjects
returned in 7-10 days for follow up on exercise technique. The subjects were allowed to continue
to run on a regular basis. Results of the study revealed that there was a program completion rate
of 6.2 days per week. Furthermore, isometric strength testing revealed a 32.69% increase, and a
43.10% decrease in pain when compared to baseline values (Ferber et al., 2011). However, there
was not a significant difference in comparison to the control group which is more indicative of
our study participants. The greater significant gains in the aforementioned studies could be due
to their subjects being injured, therefore, one would assume that they would make considerable
gains following a rehabilitation program. Our study used healthy active college students which
possibly resulted in minor gains. Moreover, researchers have correlated gluteus medius weakness
to injury (Boling et al., 2009, Fredericson et al., 2000, Ireland et al., 2003, Niemuth et al., 2005).
Specifically, previous research has shown greater differences in baseline strength of the gluteus
medius when comparing the injured to non injured leg.

38

Another possible explanation between the current study and other studies could be due to
the type of overload/exercises selected. For the current study, rehabilitative therbands and side
lying exercises were used. Side lying exercises were chosen to stay consistent with the way the
subjects were being tested with the BioDex unit. In addition, these exercises were chosen based
upon results of Distefano and colleagues who reported that side lying hip abduction and clam
shells produced the most EMG feedback (Distefano et al., 2009). Previous researchers used
single leg stance exercise and exercises with abduction/internal rotation which may have
produced greater strength gains (Earl, 2004)
The current study also examined differences in strength gains between hip abduction and
hip abduction with external rotation. Based upon the results, (Difference RABD = + .50
Difference LABD = + .41 Difference RABDER = +.39 Difference LABDER = +.59) It was
found that during hip abduction, the dominant side made greater strength gains than the non
dominant side. However, during hip abduction with external rotation, the non dominant side
made greater strength gains than the dominant side. When comparing if hip abduction or hip
abduction with external rotation made more significant strength gains, no significance was
found. Furthermore, the three exercises selected for this study (clam shells, side lying hip
abduction, side lying hip abduction with external rotation) did not suggest that these exercises
resulted in more strength gains for either hip abduction or hip abduction with external rotation.
Therefore, the current study suggested that between the 3 exercises of clam shells, side lying hip
abduction, and side lying hip abduction with external rotation, none would make a significant
difference in strength gains between hip abduction or hip abduction with external rotation.

39

5.4 UTILIZATION AND CLINICAL IMPLICATIONS FOR AN EXERCISE PROGRAM
TO CREATE STRENGTH GAINS IN HIP ABDUCTION AND HIP ABDUCTION WITH
EXTERNAL ROTATION
Although the current study does not have clinically significant results for increases in hip
strength, it still provides athletic trainers, physical therapists, strength and conditioning
specialists and coaches important information regarding strengthening protocols for hip
abduction. The protocol of the current study could potentially help injured athletes through a
rehabilitative process as well as non injured athletes with sports performance.
In essence, the current study suggests that while the protocol did not produced clinical
strength gains in healthy collegiate individuals, one could imply that with the statistical gains and
previous research demonstrating more significant baseline strength deficits in injured athletes
that the protocol could be of value to them. Furthermore, a clinician could ideally use the current
study’s protocol as a starting point in their rehabilitative prescription as the loads are small, and
as the pain from injury decreases and minimal strength gains are noticed, the clinician could
increase the load and change the exercises to a more weight bearing method. However, further
research is warranted to determine if this protocol helps injured athletes gain hip strength.
5.5 LIMITATIONS OF STUDY

There are several limitations of the current study. First, the timing of the six week
program went into spring break for Michigan State. All subjects who participated were students
of MSU, therefore, program home check in sessions were unable to be completed this week. In
addition, the exercises were documented by writing down the date performed on a workout card.
While it is hoped that the subjects recorded and actually performed the exercises, it cannot be
guaranteed. Although there was a good number of subject participants (N=47) there was an
40

unequal number of males to females (36.2% to 63.8%, respectively). As a result, sex was not
equally represented and therefore, results may apply more to females than males. Another
limitation was peak torque was measured in a side lying position; however, this is not a
functional position to running or other sport specific activities. This is not a direct representation
of the sport specific skills used in activity, but rather a tool to represent the demands placed on
the body during these activities. Finally, only collegiate subjects at MSU were used for this
study. Thereby limiting the specificity of the current findings to other geographical locations.
5.6 FUTURE RESEARCH
As previously mentioned, the current study has led to the possibility of several future
studies. One potential future study could examine sex differences in hip strength gains. A study
by Ferber et al. (2003) examined sex differences in lower extremity and found that females
exhibit a greater peak hip adduction, internal rotation and knee abduction compared to men.
Other studies have also indicated that females exhibit a greater Q angle, which could lead to a
higher chance of injury (Cichanowski et al., 2007; Ferber et al., 2011; Fredericson et al., 2000).
This may determine if males or females require different protocols of various exercises to
achieve strength gains. Another study could potentially take the data presented in the current
study and compare it to a study examining strength gains over a six week period with a BioDex
only using single leg stance exercises with a pulley weight machine as overload. This would
allow one to compare different types of overload principals to levels of strength gain. Further
studies could investigate injured athletes compared to a control group using both side lying and
single leg stance protocols over a greater period of time (14 weeks). This study would allow
researchers to examine an entire progression of rehabilitation and potentially greater increases in
strength with the allowance for more muscular facilitation over time to occur.

41

5.7 CONCLUSIONS
Overall, this study illustrated there were no clinically significant differences in strength
gains of hip abduction and hip abduction with external rotation after a six week side lying
exercise program. Results of this study and other studies will allow clinicians to determine
different types of exercise protocols and overload to place on the client for the objective goal of
strength gain over time. It will also allow them to consider potentially trying other types of
gluteus medius exercises (single leg stance, abduction with internal rotation) for aims of
increasing strength in hip abduction and hip stabilization.

42

APPENDICES

43

APPENDIX A
Health History Questionnaire

44

GLUTEAL AND HIP MUSCLE STRENGTH OF PHYSICALLY ACTIVE
COLLEGIATE STUDENTS FOLLOWING A SIX WEEK EXERCISE PROGRAM
MICHGAN STATE UNIVERSITY
38 IM SPORTS CIRCLE
HEALTH HISTORY QUESTIONNAIRE
Every participant must fill out this questionnaire and sign a release before he/she will be allowed
to participate in an
exercise program or BioDex measures of muscular activity.
Name____________________________________ Phone_______________________
Date___________________
Address________________________________________________
Date of Birth_________________ Age_______
Email____________________________________ Ht_____________ Wt____________
1. Has your doctor ever said you have heart trouble?
Yes No
2. Have you ever had chest pain or heavy pressure in your chest as a result of exercise, walking,
or other physical activity, such as climbing a flight of stairs? (Note: This does not include the
normal out-of-breath feeling that results from vigorous exercise)
Yes No
3. Do you often feel faint or experience severe dizziness?
Yes No
4. Has a doctor ever told you that you have high blood pressure or diabetes?
Yes No
5. Have you ever had a real or suspected heart attack or stroke?
Yes No
6. Do you have any physical condition, impairment or disability, including any joint or muscle
problem that should
be considered before you undertake an exercise program?
Yes No
7. Have you ever taken medication to reduce your blood pressure or cholesterol levels?
Yes No
8. Are you excessively overweight?
Yes No
45

9. Is there any good physical reason not mentioned here why you should not follow an exercise
program even if you wanted to?
Yes No

If you answered YES to one or more questions, and if you have not recently done so, consult
with your physician BEFORE entering an exercise program or participating in an exercise test.
After medical evaluation or consultation, have your physician sign this form indicating your
suitability for the following activity:
______________________________________________________________________________
______________________________________________________________________________
___________________________
_____________________________________________________________________________
__________________________
________
_____________________
Signature of Physician
Date
Phone Number

Exclusion Criteria Questionnaire
Please answer the following questions regarding your health history.
Have you: (circle your response)
Had a lower extremity injury in the last six months? Y N
Had a lower extremity surgery in the last six months? Y N
Ever had a hip surgery? Y N
Do you obtain at least 150 minutes of moderately intense activity per week? Y N
Is there any reason that you can identify that you would not be able to complete the
exercises related to this study?
YN
Thank you for your participation. Answers to this questionnaire will remain confidential.
If you are not selected for this study, or choose not to participate, your questionnaire will
be shredded.

Signature: _________________________________________
Date:_________________________

46

APPENDIX B
Informed Consent Form

47

GLUTEAL AND HIP MUSCLE STRENGTH OF PHYSICALLY ACTIVE
COLLEGIATE STUDENTS FOLLOWING A SIX WEEK EXERCISE PROGRAM
Informed Consent
For questions regarding this study,
Please contact:
Tracey Covassin, Ph.D., ATC
Department of Kinesiology
Michigan State University
Phone: (527) 353-2010
E-mail: covassin@msu.edu

For questions regarding your rights as a
research participant, please contact:
Michigan State University’s Human
Research Protection Program
408 West Circle Drive #207
Michigan State University
East Lansing, MI 48824
E-mail: irb@msu.edu
Phone: (527) 355-2180
Fax: (517) 432-4503

OR
Kathleen Scott, ATC
Department of Kinesiology
Michigan State University
Phone: (847) 529-1633
E-mail: scottk19@msu.edu
Purpose:

The purpose of this study is to determine if an exercise program (clam shells, side lying hip
abduction, side lying hip abduction with external rotation) will create strength gains in torque
values during measurement with a BioDex System 3 over a period of six weeks. This study will
use the BioDex System 3 Dynamometer to determine hip strength.
Consent:
You have been selected to be a participant in this study because you are a physically active
individual who accumulates at least 150 minutes of moderate-intensity exercise per week. Your
participation in the research study is voluntary. You have the right to say no. You may
discontinue participation in the study at any time without penalty. You may change your mind at
any time and withdraw from the study. You may choose not to answer specific questions or to
stop participating at any time.

General Experimental Procedures:
Your participation in this research study will consist of one 60 minute session, one 30 minute
session and three 15 minute sessions. You will not be compensated for your participation in this
study. During the 60 minute session the therband exercises will be demonstrated for you and you
will have a chance to practice these exercises. You will also be measured for baseline strength
via the BioDex Dynamometer. An athletic trainer will then prepare you for measurement of
strength on the BioDex Dynamometer. You will be side-lying on the machine. You will do 3 sets
46

of 10 exercises for three different therband exercises (clam shells, side lying hip abduction, side
lying hip abduction with external rotation) for 6 weeks. During the three 15 minute sessions (2,
3, and 4 weeks into program) you will be evaluated on progress and verify your exercise form.
After six weeks, you will come back and do a 30 minute session where you will be re-evaluated
for strength gains via the BioDex Dynamometer.
Possible Risks:
It is impossible to completely eliminate the risk of injury during physical activity. However due
to the nature of the study the risks are minimal. There is potential for minimal muscular soreness
during or after the study as a result of completing the exercises and having strength tested. A
certified athletic trainer will be present during all sessions. There will be a phone easily
accessible during the study to contact emergency medical services if the need arises. Please be
assured that you may choose not to answer certain questions and still continue to participate in
this study. All answers are strictly confidential and will not be released to anyone.
Benefits:
You will directly benefit from participation in this study. You will learn and perform exercises to
increase gluteus and hip strength. This study will contribute to understanding the benefits of
various exercises for the gluteus and hip muscles.
Confidentiality/Anonymity:
Your participation in this study is completely voluntary. The only people who have access to
your answers are the researchers and Institutional Review Board. Your identity and information
recorded during the study will remain confidential. Confidentiality will be protected by; (a)
results of this study may be published or presented at professional meetings, but the identities of
all research participants will remain anonymous; and (b) all data will be stored in a computer that
is password protected, as well as all surveys will remain in the researchers office under double
lock and key for 3 years. Your privacy will be protected to the maximum extent allowable by
law. You may also discontinue participation at any time without penalty. Your participation in
this research project will not involve any additional costs to you or your health care insurer.
Disclaimer/Withdrawal:
If you are injured as a result of participation in this research project, Michigan State University
will assist you in obtaining emergency care, if necessary. If you have insurance for medical care,
your insurance carrier will be billed in the ordinary manner. As with any medical insurance,
costs that are not covered or in excess of what are paid by your insurance, including deductibles,
will be your responsibility. The University’s policy is not to provide financial compensation for
lost wages, disability, pain or discomfort, unless required by law to do so. This does not mean
that you are giving up any legal rights you may have. You may contact Dr. Tracey Covassin at
517-353-2010 with any questions or to report an injury.
Institutional Contacts:

47

If you have concerns or questions about this study, such as scientific issues, how to do any part
of it, or to report an injury, please contact the researcher Kathleen Scott at 847-529-1633 or email scottk19@msu.edu or regular mail at Department of Kinesiology, Michigan State
University, East Lansing, MI 48824.
If you have questions or concerns about your role and rights as a research participant, would like
to obtain information or offer input, or would like to register a complaint about this study, you
may contact, anonymously if you wish, the Michigan State University’s Human Research
Protection Program at 517-355-2180, Fax 517-432-4503, or e-mail irb@msu.edu or regular mail
at Olds Hall, 408 West Circle Drive #207, MSU, East Lansing, MI 48824.
Your signature below indicates your voluntary agreement to participate in this study.
I, ____________________, have read and agree to participate in this study as described above.
(Please Print Your Name)

___________________________________

________/_________/_________

48

APPENDIX C
Take Home Program

49

MICHIGAN STATE UNIVERSITY
6 WEEK EXERCISE PROGRAM CARD

EXERCISE: CLAM SHELL W/ THERBAND (3 SETS 10 REPS)
WEEK 1
WEEK 2
WEEK 3
WEEK 4
WEEK 5
WEEK 6
EXERCISE: SIDE LYING HIP ABDUCTION W/ THERBAND (3 SETS 10 REPS)
WEEK 1
WEEK 2
WEEK 3
WEEK 4
WEEK 5
WEEK 6
EXERCISE: SIDE LYING HIP ABDUCTION WITH EXTERNAL ROTATION W/ THERBAND
(3 SETS 10 REPS)
WEEK 1
WEEK 2
WEEK 3
WEEK 4
WEEK 5
WEEK 6

50

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51

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