CORRELATION BETWEEN PELVIC ROTATION AND GLUTEUS MAXIMUS
STRENGTH IN GOLFERS

A THESIS

Submitted to the Faculty of the School of Graduate Studies
and Research
of
California University of Pennsylvania
in partial fulfillment of the requirements for
the degree of Master of Science

by
Hyun Hong

Research Advisor, Dr. Thomas F. West
California, Pennsylvania
2012

ii

iii

ACKNOWLEDGEMENTS
It’s been a challenging year for me, but it has also
been an amazing experience. My experiences at CalU have
taught me the importance of research that will help me
apply to a PhD program later. I would like to take the time
to acknowledge some people whose support played a pivotal
role in my accomplishments with this thesis.
Thank you for the NExt generation Sport Talent (NEST)
for financially supporting and encouraging me to keep
focusing on my study.
I would like to thank some others who have helped me
to get where I am today. To everyone at University of
Nebraska at Omaha where my interest in athletic training
began, thank you. A special thanks to Dr. Melanie McGrath
and classmate Yongha Seo.
I would like to thank my committee members, Dr. Thomas
West, Dr. Shelly DiCesaro and professor Justin Barroner for
all their time, revisions, and guidance to make my thesis a
success.
I would like to thank all the people at CalU and
California High School. We made the best of this year and I
will always remember my time spent here. I would also like

iv
to say thanks to all the GA’s: Sean, Steve, Ted, Curt,
Preston, Joey, Joe, Mark, Paul, Sarah, Atsuko and all the
ladies.

Thanks to Sean’s family for the great times during

Christmas and Easter.
Lastly, I cannot thank my parents enough for what
they have done for me and graduation is only a tiny little
bit of my appreciation for what they have done, so
hopefully there’s bigger things for them in the future and
more things for us to share and celebrate. Your love and
support has helped me accomplish all that I have. I love
you mom and dad. I would also like to thank my brother and
sister-in-law. You all mean a lot to me and thank for
everything.

v
TABLE OF CONTENTS
Page
SIGNATURE PAGE

. . . . . . . . . . . . . . . ii

AKNOWLEDGEMENTS . . . . . . . . . . . . . . . iii
TABLE OF CONTENTS
LIST OF TABLES
INTRODUCTION
METHODS

. . . . . . . . . . . . . . v

. . . . . . . . . . . . . . . viii

. . . . . . . . . . . . . . . . 1

. . . . . . . . . . . . . . . . . . 5

Research Design
Subjects

. . . . . . . . . . . . . . 5

. . . . . . . . . . . . . . . . . 6

Preliminary Research. . . . . . . . . . . . . 7
Instruments . . . . . . . . . . . . . . . . 8
Procedures

. . . . . . . . . . . . . . . . 10

Hypotheses. . .
Data Analysis
RESULTS

. . . . . . . . . . . . . . 13

. . . . . . . . . . . . . . . 13

. . . . . . . . . . . . . . . . . . 14

Demographic Data . . . . . . . . . . . . . . 14
Hypothesis Testing

. . . . . . . . . . . . . 15

Additional Findings . . . . . . . . . . . . . 18
DISCUSSION . . . . . . . . . . . . . . . . . 20
Discussion of Results . . . . . . . . . . . . 20
Conclusions . . . . . . . . . . . . . . . . 24
Recommendations. . . . . . . . . . . . . . . 26

vi
REFERENCES . . . . . . . . . . . . . . . . . 28
APPENDICES . . . . . . . . . . . . . . . . . 30
APPENDIX A: Review of Literature

. . . . . . . . 31

Introduction . . . . . . . . . . . . . . . . 32
Biomechanics of the golf swing

. . . . . . . . 32

Anatomy of the golf swing

. . . . . . . 33

Modern and classic golf swing

. . . . . . . 36

Spine motion in golfers with and without low
Back pain . . . . . . . . . . . . . . . . 38
The function of gluteus maximus muscle in golf . 39
Golf Swing stresses on the low back . . . . . . .

40

Weakness of the gluteus maximus muscle and the
degree of pelvic rotation affect on low back
pain . . . . . . . . . . . . . . . . . . .

43

Summary . . . . . . . . . . . . . . . . . . 45
APPENDIX B: The Problem . . . . . . . . . . . . 47
Statement of the Problem . . . . . . . . . . . 48
Definition of Terms . . . . . . . . . . . . . 48
Basic Assumptions . . . . . . . . . . . . . . 49
Limitations of the Study . . . . . . . . . . . 49
Significance of the Study

. . . . . . . . . . 50

APPENDIX C: Additional Methods .

. . . . . . . . 51

Informed Consent Form (C1) . . . . . . . . . . 52
IRB: California University of Pennsylvania (C2) . . 56

vii
Data Collection Sheet

. . . . . . . . . . . 63

Subject Information Sheet

. . . . . . . . . . 65

Low Back Pain Questionnaire

. . . . . . . . . 67

REFERENCES . . . . . . . . . . . . . . . . . 71
ABSTRACT . . . . .

. .

. .

. .

. .

. .

. .

. . 74

viii
LIST OF TABLES

Table

Page

1

Intra-trial reliability of K-VEST at
Top of Backswing

16

2

Intra-trial reliability of K-VEST at Impact

16

3

Inter-session reliability of Test 1 and 2

17

4

Correlation between GM strength and position

17

5

GM strength intra test reliability

19

1

INTRODUCTION

Low back pain is the one of most common
musculoskeletal complaints experienced by both amateur and
professional golfers.1 According to the National Golf
Foundation’s annual participation study,2 the golfing
population in the USA reached 27.1 million participants in
2009 which ranked the sport 16th among 41 activities and
sports surveyed. The incidence of golf-related low back
injury ranges from 15-34% in the amateur golfer and 22-24%
in the professional ranks.3,4
There are many potential factors that can lead to low
back pain and muscle imbalance is one of these factors.
Almost every muscle in the body is used in some capacity
during the golf swing. A weakness or deficiency in one area
can alter biomechanics and impede the transfer of energy.
The body compensates for this weakness by overusing other
body parts in an attempt to make up for this lost energy.
As a result, the area of weakness is placed under great
stress and it leads to overuse injuries such as low back
pain. According to Evans,5 weakness of the abdominal muscles
and weakness of gluteus maximus, or imbalanced muscles are
commonly mentioned as major indicators of potential low

2
back pain.6 The gluteus maximus is the largest muscle in the
body and is important in many functional activities such as
walking, running and lifting, and plays a role in pelvic
stability.7 Its location, connecting the lower extremity to
the lumbar spine and pelvis, enables it to transfer forces
between these two areas. Weakness of gluteus maximus muscle
can lead to decreased transverse pelvic rotation and it may
require more upper torso torque to compensate for lack of
transverse motion during the golf swing.
Moreover, these days the majority of golfers tend to
use a more modern swing than the classic golf swing in
order to increase ball velocity and ball flight distance.
As a result, the differential amount of separation between
the shoulder and the pelvis tends to increase.8 The modern
golf swing emphasizes a large shoulder turn with a more
restricted hip turn. The reduced hip turn is accomplished
by keeping the front foot flat on the ground and maximizing
the hip-shoulder separation angle throughout the swing.8 On
the other hand, the classic golf swing emphasizes reducing
the hip-shoulder separation angle and this is accomplished
by raising the front heel during the backswing to increase
hip turn, shortening the back swing, or a combination of
the two.8 Hence, the increased separation of the modern
swing represents increased strain in the spine and it

3
creates mechanical load on the lower back that may result
in low back pain.1,8
While a number of classifications have been used to
describe the phases of the golf swing, this study will
divide the golf swing into five phases including backswing,
acceleration, impact, early following through and late
follow through. This study will primarily examine the
degree of the upper and lower body separation at impact but
will include the top of the golf backswing, and how this
separation degree might be related to the low back pain
scale.
It is further hypothesized that the degree of
separation may be related to gluteus maximus strength,
since the weakness of the gluteus maximus muscle may lead
to inappropriate or inadequate transverse pelvic rotation
during the golf swing, creating more upper torso torque. An
inappropriate golf swing may produce significant stress on
the body such as compression, anterior-posterior shearing,
torsion and lateral bending forces on the lumbar spine,
resulting in low back pain. Proper golf swing mechanics are
one of the keys to decrease the heavy load on the low back
area.
In order to accomplish this study, the separation
between lower and upper degree and gluteus maximus strength

4
will be measured and correlated utilizing 3D motion capture
and hand-held dynamometer. As a result, this study will
provide evidence as to gluteus maximus muscle strength and
its relationship to upper and lower body torsion degree
during the golf swing.

5

METHODS

The primary purpose of this study was to examine the
relationship between shoulder-pelvic separation and gluteus
maximus strength during the golf swing. This was done by
comparing the degree of pelvic rotation and degree of
shoulder rotation at the top of the golf backswing and at
the moment of impact. Additionally this project determined
the measures of pelvic and upper spine position utilizing a
K-VEST wireless motion analysis system. Moreover, to
measure gluteus maximus strength, a hand-held manual
dynamometer was used. This description of research methods
will include the following subsections:

research design,

subjects, instruments, procedures, hypotheses, and data
analysis.

Research Design

This research utilized a quasi-experimental design.
Correlations between the variables were drawn from the
data. Variables included degree of pelvic rotation and
degree of shoulder rotation as measured by K-VEST wireless

6
motion analysis system and gluteus maximus strength as
measured by a hand-held dynamometer. Reliability
coefficients for the K-VEST wireless motion analysis system
were also calculated.

Subjects

20 golfers, between 18 and 34 years old, were selected
randomly from volunteers. Following a brief introductory
meeting the subjects were collected from the Professional
Golf Management program, and athletes on California
University of Pennsylvania men’s and women’s golf teams.
Each subject was required to complete a low back pain
questionnaire (Appendix C5) and a demographic questionnaire
(Appendix C4) that provided information regarding age,
weight and height. The subject inclusion and exclusion
criteria were included: all subjects have consistently
played golf 2 to 4 years minimum, and have a 12 handicap or
lower. The subjects answered questions regarding how many 9
hole rounds of golf they play each month and how much time
the subject practices the game of golf both on and off the
golf course time increments include: 0-1, 2-4, 5-7, 8-10,
or more than 10 hours each month.

7
Subjects have not had any orthopedic problems
including lumbar degeneration, fracture or lumbar
herniation. Moreover, the subjects have not had any
previous history of orthopedic surgeries such as elbow,
shoulder, back, knee and ankle. Furthermore, the subjects
were free from neurological diseases and were not taking
any medications that could affect performance.
An informed consent form (Appendix C1) was obtained
from each subject that participated in the research study.
The subjects read and signed the informed consent form
before beginning any participation in the experiment. The
subjects were recruited during a program meeting, upon
approval from the Institutional Review Board (IRB)
(Appendix C2) at California University of Pennsylvania was
received.

Preliminary Research

A pilot study was conducted with this research
project.

Pilot study participants met all of the inclusion

criteria as met by other participants.
performed all of the testing procedures.

The subjects
The researcher

was looking for the subject’s ability to understand
directions, the amount of time used to complete the tasks

8
and if the warm-up protocol before testing is adequate.
Data was collected on the data collection sheet (Appendix
C3).

Instruments

The following instruments were used in this study: low
back pain questionnaire, golf club, golf ball, golf
simulator screen, Hand-held Dynamometer, and 3D motion
capture

Golf Equipment
In order to be consistent for each subject, all
subjects used a 5 iron golf club, a Callaway Hot® golf ball,
golf simulator screen and the golfers performed each stroke.

Hand-held Dynamometer
A hand-held dynamometer, Lafayette Instruments Model
01163, used to measure gluteus maximus strength during
manual muscle testing, and peak force was recorded for each
trial. Although the hand-held dynamometer is not the most
reliable device to measure muscle strength, the reliability
of the device has been high.9-12 The hand-held dynamometer
provided muscle peak force in kg and the following formula

9
was calculated by normative strength compared to subject’s
weight. The distance was measured as the distance from
Posterior Superior Iliac Spine (PSIS) to the center of
popliteal. Conversions of data was made using the following
formulas:
Newtons conversion: 1kg = 9.81N
Torque = (Force in Newtons) x (distance in meters)
Strength = Torque / Body weight in kilograms

3D Motion Capture
The K-VEST TPI 3D 4.1 technology is fully wireless,
with three inertial sensors located on subject’s hip,
shoulder and glove/hand. The shoulder sensor was attached
between T3 and T4 area, and hip sensor was attached to the
Posterior Superior Iliac Spine (PSIS) area to make accuracy.
The K-VEST works within the same software program that
displays live video and animation in the same screen. Once
a swing has been captured, the K-VEST analysis calculates
3D motion parameters including pelvis/thorax kinematic
sequence, rotations, forward bend, side bend, and spine
angle. Additionally, the collected data indicates as a red
and green color bar easily highlighting which swing
parameters are in or out of range at set-up, top of swing,
and impact.

10

Procedures

The study was approved by the California University of
Pennsylvania Institutional Review Board (IRB) (Appendix C2)
prior to any data collection. Professional golf management
students and athletes on California University of
Pennsylvania men’s and women’s golf teams were asked to
volunteer to participate in this study during a brief
meeting. The concept of the study was explained to the
participants and the informed consent form (Appendix C1)
was distributed for them to understand the need for and
risks of involvement in the study. All subjects completed
the informed consent forms before any testing or training
took place. Qualifications for the subjects were also
announced. The pre-screening tests were set up before the
testing date was scheduled for each subject.
After the subjects understood and signed the informed
consent form, the subjects completed the subject
information sheet (Appendix C4) and the Low Back Pain
Questionnaire form (Appendix C5). The researcher measured
the subject’s height and weight. The test procedure and
method were explained again prior to beginning of the test
session. All subjects did a warm up for approximately 5

11
minutes including 10 golf practice swings prior to
participating in the 3D K-VEST TPI analysis. This warmup
was the same as their standard pre-participation warmup.
While subjects warm up, the researcher set up
measurement equipment. The 3D analysis sensors were
attached via belts between the shoulder blades, on the
posterior pelvis and hand via a glove, and the subjects
were instructed to strike golf balls in the indoor golf
course simulator until they felt comfortable. These
practice swings allowed the subjects to become familiar
with the apparatus and permitted the researcher to check
the operation of the monitor. After the warm-up and check
of the operation of the monitor to calibrate subject’s
standard position, the subjects were asked to swing three
times into the golf simulator screen. In order to identify
the reliability of the 3D K-VEST analysis system, the
sensors were detached and reattached after first three golf
swings. The subject’s position was recalibrated and then
performed three more golf swings. Each stroke was recorded
using the K-VEST TPI 3D analysis system, and the average
degree of pelvic torsion and degree of upper torsion were
recorded for later use. After measuring the subject’s golf
swing, the subject had their gluteus maximus strength
tested.

12

Gluteus Maximus Strength Measurement
To measure gluteus maximus strength, subjects began by
having their leg length measured by tape measure (Posterior
Superior Iliac Spine to the center of popliteal space). The
subject was asked to lay prone and slowly extend their test
leg upward until contact was made with the hand-held manual
dynamometer (The Lafayette Manual Muscle Test System Model
01163). To better isolate the gluteus maximus strength, the
tested knee was maintained in a 90 degree flexed position
during testing to minimize hamstring activation. While the
subject performed the test, the researcher stabilized the
subject’s posterior pelvis and applied resistance to the
posterior aspect of the distal femur with the hand
dynamometer. The subject was instructed to push against the
manual dynamometer for four seconds as hard as possible.
This process was performed a total of three times, and
average peak force measures was recorded for later use.
Additionally, all subjects’ weight and power were converted
to Newtons. After gathering all the information about
gluteus maximus strength, and angle between pelvic and
shoulder position, the data was entered into a data
analysis program (SPSS 18.0).

13
Hypotheses

The following hypotheses were based on previous
research and the researcher’s intuition based on a review
of the literature:
1.

There will be a positive correlation between
pelvic position and shoulder position
measurements between individual trials and
between the testing sessions.

2.

There will be a positive correlation between
gluteus maximus strength and shoulder-pelvic
separation at the top of the golf backswing.

3.

There will be a positive correlation between
gluteus maximus strength and shoulder-pelvic
separation at impact.

Data Analysis

All data was analyzed by SPSS version 18.0 for windows
at an alpha level of 0.05.

The research hypotheses will be

analyzed using the Pearson Product-Moment Correlation
Coefficient analysis.

14

RESULTS

The purpose of this study is to examine the
relationship between shoulder-pelvic separation and gluteus
maximus strength during the golf swing. This was done by
comparing the degree of pelvic position and degree of
shoulder position. A Pearson Product-Moment Correlation
Coefficient analysis was applied to measure the correlation
between shoulder-pelvic separation and gluteus maximus
strength during the golf swing.

Demographic Data

The sample for this study included 20 professional
golf management students, 18 males and 2 females from
California University of Pennsylvania. Ages ranged from 19
to 34 years with a mean of 21y (+/- 3.25). All participants
were considered healthy by the low back pain questionnaire
and reported no injuries throughout the study.

15
Hypothesis Testing

The level of significance used for testing in this
study was set at an alpha level of .05.
Hypothesis 1: There will be a positive correlation
between pelvic position and shoulder position measurements
between individual trials and between the testing sessions.
The first goal of this study was to examine the
reliability of this equipment in measuring pelvic and
shoulder position. Intra-trial and intersession reliability
was examined.
In order to identify the intra-trial reliability of 3D
motion capture, The Pearson-Product Moment Correlation was
used to determine if there was a difference between the
measurement of shoulder and pelvic position during the
trials within each testing session. The Pearson correlation
was calculated comparing all the three trials on test 1 and
test 2 of the golf swing with 3D K-VEST TPI analysis system.
Table 1 shows that there was a strong, statistically
significant relationship between the trials of shoulder and
pelvic separation at the top of back swing (Table 1). This
indicates good intra-trial reliability of the K-Vest system.

16
Table 1. Intra-trial reliability of K-VEST at Top of
Backswing
Trial
1-2
2-3
1-3

Shoulder
Test 1
Test 2
.985**
.972**
.969**
.951**
.942**
.973**

Pelvic
Test 1
.978**
.957**
.953**

Test 2
.950**
.956**
.956**

** p<.001

Generally lower reliability was found when measuring
position of the pelvis and shoulders at impact.
Specifically, strong, significant correlation coefficients
were found for pelvic measures and a combination of strong
and moderate significant correlations were found at the
shoulders.

Findings can be found in Table 2.

Table 2. Intra-trial reliability of K-VEST at Impact
Trial
1-2
2-3
1-3

Shoulder
Test 1
Test 2
.708**
.550 *
.483 *
.717**
.732**
.600**

Pelvic
Test 1
.942**
.906**
.916**

Test 2
.928**
.938**
.952**

* p<.05, ** p<.001

Next the reliability of the 3D K-Vest TPI between test
sessions was examined.

Table 3 shows that the Inter-test

session reliability of the K-VEST ranged from .678 to .930
dependent upon the site measured (pelvis or shoulders) and
position (top of backswing or impact).

Pelvic measurements

at the top of the backswing demonstrated a strong
correlation coefficient (r = .913, p<.001) as did
measurements at impact (r = .930, p<.001).

Measurements of

the shoulders at impact also showed a strong correlation

17
(r = .748, p<.001) while a moderate correlation was found
at the top of the backswing (r = .678, p<.001).

Table 3. Inter-session reliability of Test 1 and 2
Top
Impact
Shoulder
.678**
.748**
Pelvic
.913**
.930**
** p<.001

Hypothesis 2: There will be a positive correlation
between gluteus maximus strength and shoulder-pelvic
separation at the top of the golf backswing.
Table 4 indicates that a weak, non-significant
correlation was found between the subject’s gluteus maximus
strength and pelvic torsion at the top of backswing (r=.
237, P > .05). There was also a weak correlation between
the subject’s gluteus maximus strength and shoulder torsion
at the top of backswing(r= -.222, P >. 05). However, there
was a moderate correlation between pelvic and shoulder
separation with gluteus maximus strength at the top of
backswing(r = .372, P > .05).

Table 4. Correlation between GM strength and position
TOP
Impact
Pelvic Torsion
.237
.360
Shoulder Torsion
-.222
.277
Pelvic & Shoulder Separation
.372
.316

18
Hypothesis 3: There will be a positive correlation
between gluteus maximus strength and shoulder-pelvic
separation at impact.
Table 4 shows that the Pearson-Product Moment
Correlation indicated a moderate correlation between
gluteus maximus strength and pelvic torsion at impact (r =
.360 P > .05) while there was a weak correlation between
gluteus maximus strength and shoulder torsion at impact (r
= .277, P > .05). However, a moderate correlation between
shoulder-pelvic separation and gluteus maximus strength
have been shown at impact(r = .316, P > .05).

Additional Findings

Several studies have examined the reliability of the
hand held dynamometer in testing strength. In order to
identify the reliability of hand-held dynamometer in this
study, the Pearson-Product Moment Correlation was
calculated comparing all the three trials on test 1, test 2
and test 3 of the gluteus maximus strength. The Pearson
Correlation demonstrated that there was a statistically
significant relationship between each test (see table 5).

19
Table 5. GM strength intra test reliability
Test 1
Test 2
Test 1
1
.867**
Test 2
.867**
1
Test 3
.804**
.938**
** p<.001

Test 3
.804**
.938**
1

20

DISCUSSION

Discussion of Results

This study examined the validity and reliability of
the K-VEST TPI 3D motion analysis software program. This
study considered the correlation between pelvic rotation
and gluteus maximus strength with low back pain in golfers.
However, all volunteer participants were in good health and
were not suffering from low back pain as measured by the
low back pain questionnaire.
Therefore, the hypotheses were focused more on
reliability of the K-VEST 3D motion analysis, and
correlation between gluteus maximus strength and the
shoulder-pelvic separation. In order words, the study
compared gluteus maximus strength with shoulder-pelvic
separation at the top of backswing and at impact.
Hypothesis 1 stated that the shoulder and pelvic
position measured with 3D motion capture would be reliable
on subsequent trials. The researcher proposed that the
results would not have significant variance between the

21
subsequent trials. This finding is important if the K-Vest
is to be used in research.
There was statistically significant Intra-trial
reliability of K-VEST 3D motion capture between at the top
of backswing in both shoulder and pelvic position. However,
the shoulder torsion measures had only moderate reliability
at impact and top of the backswing in Intra-trial measures.
Similar results were seen for the shoulder in inter-session
testing, with the shoulder reliability being moderate and
pelvic reliability as strong. It is considered that due to
the wider range of motion and higher velocity of the
shoulder when compared to the pelvis, the result of the
shoulder torsion reliability indicates less reliability
than pelvic torsion.
Even though a three-dimensional video motion analysis
system would be the most reliable method to obtain range of
motion measures, the K-VEST 3D motion capture also has been
found to be a reliable and valid measure of joint
separation. To improve the accuracy of data collection,
however, it is recommended to consider utilizing multiple
trials and averaging compensate for the moderate
reliability of the K-Vest 3D during high speed, dynamic
motions.

22
Hypothesis 2 stated that there is a positive
correlation between gluteus maximus strength and shoulderpelvic separation at the top of the golf backswing. The
researcher proposed that the results would have significant
correlation when comparing the gluteus maximus strength and
shoulder-pelvic separation at the top of the golf
backswing.
As discussed previously there was a weak correlation
between gluteus maximus strength and both shoulder and
pelvic torsion at the top of the golf backswing (r = .237,
r- -.222 respectively). However, there was a moderate
correlation between shoulder-pelvic separation and gluteus
maximus strength at the top of backswing(r = .372, P > .05).
This result may indicate a relationship between gluteus
maximus strength and shoulder-pelvic separation at the top
of the backswing but should be explored in future research.
According to McHardy and Pollard,14 electromyographic
studies on golf swing have demonstrated the most active
muscle in the upper body is the upper trapezius on the
right side while on the left side, subscapularis is the
most active muscle. In contrast, the most active muscle in
the lower body is the semimembranosus and the long head of
the biceps femoris on the right side. The present study
indicates that the gluteus maximus muscle seems to be

23
minimally activated during the backswing, which is the
opposite expectation from the second hypothesis.
Hypothesis 3 stated that there is a positive
correlation between gluteus maximus strength and shoulderpelvic separation at impact.
The researcher proposed that the results would have
correlation when comparing the gluteus maximus strength and
shoulder-pelvic separation at impact. The result shows that
there was a moderate correlation between shoulder-pelvic
separation and gluteus maximus strength at the impact (r =
.316). Moreover, gluteus maximus strength has a moderate
effect on pelvic torsion while there was a weak correlation
between shoulder torsion and gluteus maximus strength. The
result is almost similar to the top of the backswing. As a
result, gluteus maximus strength seems to have an effect on
the separation between pelvic and shoulder. In order words,
when gluteus maximus strength is stronger, the separation
between pelvic and shoulder seem to be wider than weak
gluteus maximus strength during the golf swing.
According to McHardy and Pollard electromyographic
studies on golf swing,14 the most active muscles are upper
and lower gluteus maximus on the right side during the
forward swing which stars at the top of swing and ends when
the club is horizontal to the ground. However, the left

24
biceps femoris, and the left upper and lower gluteus
maximus are the most active muscles during the acceleration
phase, which starts from the horizontal club to the impact
of the ball.11 Moreover, the abdominal oblique is the most
active muscle, followed by the gluteus medius on the right
side.11 As a result, even though gluteus medius is the most
active muscle during the acceleration phase, gluteus
maximus has some influence on pelvic rotation, which may
effect shoulder-pelvic separation.

Conclusions

All participants were healthy by the low back pain
questionnaire and reported no pain throughout the study.
Thus, this study could not reveal the relationship between
the degree of shoulder-pelvic separation and low back pain.
This is certainly something to be included in future
studies.
The results of the study revealed the following two
major conclusions. First, K-VEST TPI 3D motion analysis
software program and the hand-held manual dynamometer are
reliable tools to determine the degree of shoulder-pelvic
rotation, and gluteus maximus strength respectively.
Moreover, the K-VEST and hand-held manual dynamometer are

25
inexpensive tools when compared to other 3D motion capture
systems and strength evaluation tools like a Biodex.

These

two devices are easy to use, making them ideal for the
clinical setting and performance enhancement setting.
Second, there is a moderate correlation between
shoulder-pelvic separation and gluteus maximus strength at
the top of the backswing and at impact. These results
suggest that strong gluteus maximus strength contributes to
increase shoulder-pelvic separation (at the top the swing
and at impact).
From this study it can be concluded that K-VEST TPI 3D
motion analysis can be applied to study the quality and
quantity of golf swing motions in separation degree.
Moreover, this study shows a moderate relationship existed
between gluteus maximus strength and increased shoulderpelvic separation at the top of the swing and at impact.
This means that in order to create greater torque and
transferring a higher velocity to a club, shoulder-pelvic
separation seems to increase with strong gluteus maximus
group.

26
Recommendations

Based on the results of this study, the following
research recommendations were made. The K-VEST 3D motion
capture and hand-held manual dynamometer have been found to
produce reliable measurements. Despite the strong
reliability of the 3D motion capture, it is possible that
reliability could be further increased if the analysis
sensors were more firmly attached to the subject’s body
during the golf swing. Therefore, the pelvis and shoulder
sensors should be checked after every single trial of the
golf swing to increase the quality of measures. For
instance, the shoulder sensor should be repositioned
between T3 and T4 area and the hip sensor repositioned on
the PSIS area after each swing.
Moreover, although the hand-held manual dynamometer
was the reliable methods to measure gluteus maximus
strength, the researcher should maintain the subject’s knee
in a 90 degree flexed position and stabilize the subject’s
posterior pelvis to get better isolate the gluteus maximus
strength. Moreover, it would be better to have an assistant
to stabilize the subject’s pelvis, to allow for the
researcher to use both hands to hold the hand-held manual
dynamometer rather than one.

27
Lastly, the subjects who participate in this study
were in a good health so future research should further
test patients who have low back pain or a history of low
back pain. This would allow for an examination of the role
that separation angle may play in increasing low back
stress and pain in the golfing population.

28

REFERENCES
1.

McHardy A, Pollard H, Bayley G. A comparison of the
modern and classic golf swing: a clinician’s
perspective. SAJSM. 2006;18(3): 80-92.

2.

Beditz B, Kass AR. Golf participation America, 20102020. National Golf Foundation. 2009;1-8.

3.

Levine D, Walker JR, Tillman LJ. The effect of
abdominal muscle strengthening on pelvic tilt and
lumbar lordosis. Physiotherapy Throry and Practice.
1997;(12): 217-226.

4.

Mchardy A, Pollard H. Lower back pain in golfers.
Journal of Chiropractic Medicine. 2005;(4): 135-143.

5.

Horan SA, Evans K, Morris NR, Kavanagh JJ. Thorax and
pelvis kinematics during the downswing of male and
female skilled golfers. Journal of Biomechanics.
2010;(43): 1456-1462.

6.

Franke BA. Formative Dynamics: The Pelvic Girdle. The
Journal of Manual & Manipulative Therapy.
2003;11(1):12-40.

7.

Willson J, Ferris E, Heckler A, Maitland L, Taylor C.
A structured review of
the role of gluteus maximus
in rehabilitation. New Zealand Journal of
Physiotherapy . 2005;3(33): 95-100.

8.

Gluck GS, Bendo JA, Spivak JM. The lumbar spine and
low back pain in golf: a literature review of swing
biomechanics and injury prevention. The Spine Journal.
2008;(8): 778-788.

9.

Fenter PC, Bellew JW, Pitts TA, Kay RE. Reliability of
stabilized commercial dynamometers for measuring hip
abduction strength: a pilot study. British Journal of
Sports Medicine. 2003;37:331-334.

10.

Kolber MJ, Beekhuizen K, Cheng MSS, Fiebert IM. The
reliability of hand-held dynamometry in measuring
isometric strength of the shoulder internal and

29
external rotator musculature using a stabilization
devic. Physiotherapy Theory and Practice.
2007;23(2):119-124.
11.

Friel K, McLean N, Myers C, Caceres M. Ispsilalteral
Hip Abductor Weakness After Inversion Ankle Sprain.
Journal of Athletic Training. 2006;41(1):74-78.

12.

Hollman JH, Kolbeck KE, Hitchcock JL, Koverman JW,
Krause DA. Correlations Between Hip Strength and
Static Foot and Knee Posture. Journal of Sport
Rehabilitation. 2006;15:12-23.

13.

Burden AM, Grimshaw PN, Wallace ES. Hip and shoulder
rotations during the golf swing of sub-10 handicap
players. Journal of Sports Sciences. 1998;16:165-176.

14.

McHardy A, Pollard H, Bayley G. A comparison of the
modern and classic golf swing: a clinician’s
perspective. SAJSM. 2006;18(3): 80-92.

30

APPENDICES

31

APPENDIX A
Review of Literature

32

REVIEW OF LITERATURE

Several prevention and rehabilitation of low back pain
protocols have been developed for the non-operative
treatment of patients with low back pain. However, baseline
differences between treatment groups, such as different
types of sport may require different prevention strategies.
Additionally, the best treatment for low back pain is
prevention of the injury in the first place. Therefore, the
purpose of this literature review is to focus on 1)
biomechanics of the golf swings, 2) how the golf swing
stresses the low back, and 2) how weaknesses of gluteus
maximus muscle and the degree of pelvic rotation affect low
back pain.

Biomechanics of the Golf Swing

Low back pain is one of the most common golfing
injuries, representing in 26 % to 52% of all complaints.1
The repetition of a golf swing can create forces on the
spine, exposing it to hyperextension, anterior-posterior
shearing, torsion, and lateral bending.2 Therefore,
certified athletic trainers and other clinicians must have

33
an understanding of biomechanics of the golf swings in
order to prevent athletes from potential low back injuries.

Anatomy of the Golf Swing
While a number of classifications have been used to
describe the phases of the golf swing, in this thesis, the
golf swing is divided into five phases including backswing,
forward swing, acceleration, early follow through and late
follow through.
First, the back swing starts from when the club starts
movement to the top of the back swing with most backswing
motion results from shoulder and pelvic rotation. During
the backswing of a right-handed golfer, the upper trapezius
and the middle trapezius muscles are the most utilized
muscles on the right upper body causing scapular retraction,
while subscapularis and upper serratus muscles are the most
activated muscles on the left upper body, protracting the
scapula.3 In contrast, the semimembranosus and the long head
of the biceps femoris on the right lower body cause the
back swing motion, and erector spinae and abdominal oblique
on the left lower body are the most utilized muscles in the
lower body resulting in the back swing motion as well.
Second, the forward swing, which initiates the
downward motion of the club, starts at the top of the swing

34
and ends when the club is horizontal to the ground. Most
importantly during the forward swing phase, on the right
leg hip extensor and abductors, and the left leg adductor
magnus initiate left pelvic rotation during the golf swing.4
In other words, the left pelvic rotation starts before the
arms have completed the backswing.4 During the forward swing
phase, the most active muscles are rhomboid and middle
trapezius in the upper body on the left side while the most
active muscles are the pectoralis major and upper serratus
on the right side.11 In contrast, during the forward swing
phase the lower gluteus maximus and the biceps femoris are
most activated, 100% and 98% respectively measured by
manual muscle strength testing on the right side of the
lower body.3 On the left side, vastus lateralis and the
adductor magnus muscle are most activated during the
forward swing phase.3
Third, the acceleration phases starts from the club
reaching horizontal to the club head impact with the ball.
In this stage of the swing, the pectoralis major muscle
bilaterally being the most active muscle in the upper body.3
In the lower body, the left biceps femoris is the most
active muscle with the left upper and lower gluteus maximus,
along with the vastus lateralis being the second most

35
active muscles.3 On the right side, the abdominal oblique is
the most active muscle followed by the gluteus medius.3
Fourth, the early follow through phase starts at
impact to when the club is horizontal to the ground. During
this phase, pectoralis major bilaterally, subscapularis and
infraspinatus muscles are most active on the left upper
body.3 The most active muscle in the lower body is left long
head of biceps femoris, and left vastus lateralis.3 The
right gluteus medius and abdominal oblique muscles are the
most active on the right side.3
Last, the late follow through phase starts from at
impact to the ends of the completion of the swing. The
purpose of this phase is to decelerate the body by using
eccentric muscle actions.32 The infraspinatus and the
pectoralis major muscles in the left upper body are most
utilized during the late follow through while subscapularis
and serratus anterior muscles are most active on right
side.3 In the lower body, the right gluteus medius and the
vastus lateralis are the most active muscles on right side
while the semimembranosus and vastus lateralis are the most
active muscles on left side during the late follow through.3

36
Modern and Classic Golf Swing
Proper golf swing mechanics is one of the keys to
decrease the heavy load on the low back area. An
inappropriate golf swing seen in amateur golfers imparts
significant stress such as compression, anterior-posterior
shearing, torsion, and lateral bending forces on the lumbar
spine. Without knowledge of the proper swing mechanics,
golfers are exposed to the risk for the development of low
back pain.
There are many different types of the golf swing, and
the “modern” golf swing and the “classic” golf swing are
most common in these day. The “modern” golf swing
emphasizes a large shoulder turn with a restricted hip turn.
Reduced hip turn is accomplished by keeping the front foot
flat on the ground throughout the swing.6 This is thought to
“quiet” the lower body, and maximizing the hip-shoulder
separation angle in order to increase the viscoelastic
elements and increase rotational velocity.6 This separation
angle is known as the “X-factor” due to the “X” made by
lines drawn along the axial orientation of the shoulders
and hips at the transition between the end of the backswing
and start of the forward swing.6 Lindsay and Horton23
performed a swing analysis between 12 golfers with and
without low back pain to look for an association between

37
the “X-factor” and low back pain by focusing on trunk
rotation. They found that there was no significant
different in peak rotation between the groups during their
golf swing. However, “X-factor” produces the instantaneous
side bend angle and axial rotation velocity which
contributes to the degenerative changes in the lumbar
spines during the golf swing.7
Another high-risk motion causing the low back pain
during the modern swing is the “reverse C” position. During
the follow through phase, there is an increase in lateral
bending and exaggerated hyperextension on the spine known
as the “reverse C” position. A line drawn from the right
heel along the leg, up the pelvis and trunk to the left
shoulder and head resembles the line drawn by a backwards
‘C’.1 These relative “X-factor” and “reverse C” position may
represent excessive strain on viscoelastic structure in the
spine beyond their physiologic range of flexibility.6
On the other hand, the classic golf swing emphasizes
reducing the “X-factor” and this is accomplished by raising
the front heel during the backswing to increase hip turn,
shortening the back swing, or a combination of the two.6
This reduces the magnitude of the hip-shoulder separation
angle, and it decrease the torque on the lumbar spine.6
Despite the advantage of “classic swing” for decreasing the

38
risk of low back problems, most golfers tend to prefer the
“modern” swing due to power and greater potential for golf
ball distance.6,8,9
According to Myers9 and Fletcher10, “X-factor” could result
in eccentric loading of the torso musculature through
lengthening. This eccentric loading can play an important
role in increasing ball velocity through both increasing
uncoiling (torso-pelvic separation velocity) and upper
torso rotational velocity during the down swing.9

Spine Motion in Golfers With and Without Low Back Pain
Although there was no significant difference in
address position spinal posture between the golfers with
and without low back pain, the golfers with low back pain
tended to address the ball with considerably more spinal
flexion than the golfers without low back pain. Spinal
flexion for golfers with low back pain was 37.0 ± 11.4º and
25.3 ± 6.6º for participants without low back pain.11
Although there were no significant flexion angle difference,
increased lumbar disc pressure and risk of injury could
contribute to low back pain from golf. Interestingly, by
subtracting the start (address position) flexion from the
maximum (downswing) flexion, it would appear that spinal
flexion of the golfers without low back pain increased by

39
just over 25º on the downswing compared with just 7º for the
golfers with low back pain.11 However, both groups of
golfers showed that the trunk maintained a consistent angle
with the ground throughout the entire backswing and
downswing.11 Lindsay and Horton7 found that although the
golf swing maximum rotation angles did not vary between the
two groups, maximum rotation range of motion was more
restricted in the group with low back pain. The low back
pain group had less trunk rotation which resulted in a
relative ‘supramaximal’ rotation of their spines when
swinging and it could contribute to ongoing irritation of
the spinal structures.

The Function of Gluteus Maximus Muscle in Golf
Gluteus maximus is the largest muscle in the body and
is important in many functional activities such as walking,
running and lifting, and plays a role in pelvic stability.12
Wilson12 describes the insertion of gluteus maximus
proximally into the sacrum, the dorsal sacral ligaments,
the posterior portion of the crest of the ilium and the
sacrotuberous ligament. The muscle fibers run inferiorly
and laterally to the distal insertion, where it splits in
two components.12 The upper half of the muscle inserts into
the iliotibial tract of the fascia lata and the lower half

40
into the gluteal tuberosity of the femur.12 Due to its
attachments, gluteus maximus is primarily involved in
external rotation and extension of the hip joint.
Especially during the forward swing phase in the lower body,
upper and lower gluteus maximus muscles initiate left
pelvic rotation and create upper body torsion.
Moreover, the lower gluteus maximus is the most activated
muscles during the forward swing phase measured by manual
muscle strength testing on the right side of the lower body
with a right-handed player.13

Golf Swing Stresses on the Low Back

The current teaching philosophy of the golf swing
emphasizes an increase in torso coiling during the
backswing, which theoretically results in increased impulse
during the downswing, and subsequent increased ball
velocity and ball flight distance.9 These days, professional
golfers seem to maximize upper torso rotation during the
backswing while minimizing pelvic rotation to create torsopelvic separation (modern swing style). The separation
creates resistance between the upper torso and pelvis
during the backswing, and increases the viscoelastic
elements and increase rotational velocity during the down

41
swing. As a result of torso uncoiling power, potentially
increase club head speed, ball velocity, and therefore
increasing the ball fight distance.
According to Fletcher and Hartwell,10 the action of the
torso can be classified as a stretch-shortening movement
that utilize eccentric loading to load the muscle during
the back swing in order to increase power output and
explore concentric shortening during the forward swing. The
stretch-shortening results in increased force and power
production. According to Myers,9 maximum separation between
upper torso-pelvic tends to increase ball velocity. However,
the repetitive stretch-shortening produces the
instantaneous side bend angle and axial rotation velocity
which contributes to the degenerative changes in the lumbar
spines. The lumbar spines allow significant flexion and
extension with moderate lateral bending, but relatively
little axial rotation. Often many golf instructors put
emphasis on loading the lumbar spine and creating
tremendous amounts of torque to increase ball velocity.6
According to “Non-operative Treatment of LBI in athletes“,14
the most frequent cause of acute low back pain was the
limited range of axial rotation in the lumbar spine and the
emphasis on torsional loading during the golf swing. Those
poor golf mechanisms may potentially predispose a golfer to

42
muscle strains, herniated nucleus pulposus, stress
fractures of the vertebral body and pars interarticularis,
spndyloisthesis, and facet arthropahty.6,15
One side of repetitive play and practice may also
contribute asymmetric pattern of trunk rotation and may
cause side-to-side muscle imbalances in rotational strength.
These potential imbalances may create shear and compressive
loads on the lumbar spine and results in an increased
susceptibility of developing low back pain.16 According to
Lindsay16, elite player group and recreational player group
showed that a slight and consistent trend in muscle
asymmetry was noticed in both groups. Additionally, low
back pain group were observed to have greater gluteus
maximus strength differences in side-to-side strength than
without low back pain group.17,18 Moreover, the muscle
imbalance may contribute to limited hip-rotation range of
motion (ROM). For example, limited hip-rotation ROM
resulting from shortened muscles might contribute to
compensatory movement in the lumbopelvic region. This
limited ROM constantly contribute to low-magnitude loading
of the lumbopelvic region and accumulation of tissue stress
over time and cause tissue damage during the golf swing.19
Additionally, an asymmetry in hip-rotation ROM would result
in an asymmetry in the forces transmitted to the

43
lumbopelvic region.19 Study showed

19,20

that the low back

pain group demonstrated less total hip-rotation passive
range of motion than the group without low back pain. Also
the low back pain group indicated that the total rotation
between left and right lower extremities was less total
hip-rotation ROM than the group without a history of low
back pain group.19

Weakness of the Gluteus Maximus Muscle and the Degree of
Pelvic Rotation Affect on Low Back Pain

The movement of a golfer’s swing requires mostly
movement in the transverse plane. Many muscles help pelvic
rotation during a golf swing, and the gluteus maximus is
one of the strongest external rotators and extension of the
hip joint. It has been theorized that weakness of the
gluteus maximus may lead to increase tension in the low
back and may cause SI joint instability that can create low
back pain.2 Moreover, the weakness of the gluteus maximus
muscle may lead to inappropriate transverse pelvic rotation
during a golf swing and it may create more upper torso
torque which may cause stress on low back area.
According to the Willson12 gluteus maximus provides
sacroiliac joint (SIJ) stability, strength for lifting,

44
control of gait and transversal plane movement. There is
very little movement at the SIJ which is the primary
function of load transfer from the trunk to legs. If excess
and abnormal movement occur at the joint, a positional
change may occur between the ilia and sacrum thus
compromising the L5-S1 intervertebral joints and disc, SIJ,
pubic symphysis and could lead to SIJ dysfunction and low
back pain.12
Limited or excessive hip joint range of motion may be
one of the predisposing factors in musculoskeletal pain
syndromes of the trunk. These dysfunctional ROM patterns
may cause deleterious cumulative stress or strain on soft
tissue and bones of the spine. For example, limited hiprotation range of motion resulting from shortened muscles,
a stiff joint capsule, or a bony abnormality might
contribute to compensatory movement in the lumbopelvic
region.19 Such compensation could result in the lumbopelvic
region’s moving more often during activities that require
hip rotation, such as the golf swing.19 Thus, Harris-Hayes19
found that limited hip rotation ROM was significantly
correlated with low back pain. In theory, asymmetry of
pelvic rotation ROM and any loss of rotation at the hip may
place excessive mechanical stress on the lumbar spine, and
lead to low back dysfunction because of the anatomical

45
proximity of the hip and lumbopelvic region.20
Cole21 showed that golfers with low back pain tended to
demonstrate reduced lumbar erector spinae(ES) activity at
the top of the backswing and at the impact phase and
greater the external obliques(EO) activity throughout the
swing. The reduced ES and increased EO may be associated
with a reduced capacity to protect the spine and its
surrounding structures at the top of the backswing and at
impact, where the torsional loads are high.27 While, the
weakness of gluteus maximus strength and the increase in
upper body rotation may lead to increase spine angle during
the impact phase. Weakness of gluteus maximus which leads
to decrease hip ROM and the increase in upper body rotation
during at the impact phase may lead to increase spine angle,
and the increased spine angle will lead to the excessive
mechanical stress on the lumbar spine and cause low back
pain.

Summary

After studying the biomechanics of the golf swing in
relation to the lumbar spine, it is understandable how both
acute and chronic injuries can occur and how they can be
prevented. There is no one master key to reduce low back

46
pain but low back pain may be minimized with appropriate
management.
Proper strength training, increasing rotational
flexibility, knowledge of biomechanics, understanding the
anatomy of the golf swing and learning different types of
swing mechanics have all been shown to be beneficial in
decreasing potential low back pain in golfers.

47

APPENDIX B
The Problem

48

STATEMENT OF THE PROBLEM

The purpose of the study is to examine the effect of
gluteus maximus strength and degree of pelvic rotation on
chronic low back pain in golfers.

It is important to

examine this correlation because weakness of gluteus
maximus strength may reduce transverse pelvic rotation and
it may create stress on the low back area. If we know
gluteus maximus strength can interact with pelvic rotation
and it creates low back pain, we can enhance the gluteus
maximus strength in order to prevent chronic golfer’s low
back pain. Additionally it would be beneficial for athletes,
conditioning coaches and athletic trainers to know which
types of exercises are most effective in enhancing gluteus
maximus strength.

Definition of Terms
The following definitions of terms will be defined for
this study:
1)

Gluteus maximus – The gluteus maximus is the largest
and most superficial of the three gluteal muscles. It
makes up a large portion of the shape and appearance
of the buttocks. It has the power to maintain the

49
trunk in the erect posture and it also helps powerful
external rotation and extension of the hip joint.
2)

Transverse pelvic rotation – motion of the pelvic
girdle on right transverse (clockwise) and left
transverse (counterclockwise) rotation.

Basic Assumptions
The following are basic assumptions of this study:
1)

The subjects will be honest when they complete their
pain level questionnaire sheets.

2)

The subjects will perform to the best of their ability
during the testing sessions.

3)

Patients playing more than 5 years have not had any
orthopedic problems including lumber degeneration,
fracture and lumbar herniation.

4)

The subjects have not had any previous history of
surgery, and all are free from neurological diseases
and are not taking any pain medications.

Limitations of the Study
The following are possible limitations of the study:
1)

The validity of the pain level has not been
established.

2)

The subjects can use different types of golf swings.

50
3)

Motions of the knee can influence pelvic rotation
during the golf swing.

4)

Subjects may have different levels of flexibility
resulting in different separation measures.

5)

The cumulative load theory (the total number of hours
worked for more hours over their lifetimes, and high
force activity.22

6)

Warm-up: subjects were allowed to choose their own
warm-up.

Significance of the Study
If gluteus maximus strength has strong influence on
pelvic transverse plane during the golf swing and the
degree may be related to low back pain. Therefore,
clinician, educator and related population can add gluteus
maximus exercise on their conditioning training or
rehabilitation in order to prevent or decrease low back
pain.

51

APPENDIX C
Additional Methods

52

APPENDIX C1
Informed Consent Form

53
1.
Hyun Hong, a certified athletic trainer, who is a
Graduate Athletic Training Student at California University
of Pennsylvania, has requested my participation in a
research study at California University of Pennsylvania.
The title of the research is Correlation Between Pelvic
Rotation, Gluteus Maximus Strength and Low Back Pain in
Golfers.
2.
I have been informed that the purpose of this study is
to provide evidence as to correlation between rotation and
muscle strength during a golf swing. Specifically the
researcher will look at upper and lower body separation and
gluteus maximus strength, and its relationship to low back
pain. I understand that I must be 18 years of age or older
to participate. I understand that I have been asked to
participate because I do not have orthopedic problems that
affect my ability to participate in golf, including lumbar
degeneration, fracture and lumbar herniation, also I do not
have any general health problems that affect my golf
participation. Moreover, I have not had any previous
history of orthopedic surgeries such as surgery to the
elbow, shoulder, back, knee and/or ankle. Furthermore, I do
not have any neurological diseases or I am not taking any
medications that may affect my participation.
3.
I have been invited to participate in this research
project. Participation is voluntary and I can choose to
discontinue my participation at any time without penalty or
loss of benefits. Subjects in this study will perform a
golf swing and have their gluteus maximus strength
measured. My height, weight and leg length will be measured
and I will answer the Low Back Pain Questionnaire form. All
subjects will perform their typical warm up followed by 10
golf practice swings utilizing a 5 iron. The 3D analysis
system called K-VEST TPI 3D will be attached on subject’s
hip, shoulder and glove. After the warm-up, the subjects
will use a 5 iron to hit a golf ball (Callaway Hot) three
times into the simulator. Each stroke will be recorded
using the K-VEST TPI 3D analysis. After measuring subject's
golf wing, the subject will have their gluteus maximus
strength tested.
To measure gluteus maximus strength, subjects will
begin by having their leg length measured. A marker will be
placed halfway down the posterior aspect of hamstring. The
subjects will be asked to lay prone (face down) on a table
and slowly extend their test leg upward until contact will
be made with the hand-held dynamometer (a device to measure
strength). The subject will be instructed to push against
the manual dynamometer for four seconds as hard as

54
possible. This process will be performed a total of three
times, and average peak force measures will be recorded for
later use.
4.
I understand there are foreseeable risks or
discomforts to me if I agree to participate in the study.
With participation in a research program such as this there
is always the potential for unforeseeable risks as well.
There are minimal risks to the subjects in this study. The
warm-up I will perform is the same as my standard warm-up
prior to golfing. The golf swings are the same as I do
during normal participation in the sport. Still, as with
any physical activity, there is a risk of musculoskeletal
injury, including muscle strains and joint sprains. The
researcher will be present through the entire warm-up,
measurement and testing phases within the study. The
researcher is certified in first aid, CPR and as an
athletic trainer. Subjects will be instructed in proper
technique prior to all testing. Each test will be performed
under the close supervision of the researcher. Improper
technique or other potential injury-causing situations will
be identified and corrected by the researcher to ensure
that such injuries do not occur. In the case of injury the
investigator will care for and treat the injured subject
using the facilities available at the California University
of Pennsylvania. Any treatment beyond that rendered by the
investigator will be my financial responsibility.
5.
I understand that, in case of injury, I can expect to
receive treatment or care in Hamer Hall’s Athletic Training
Facility. This treatment will be provided by the
researcher, Hyun Hong, under the supervision of the Calu
athletic training faculty, all of which can administer
emergency care. Additional services needed for prolonged
care will be referred to the attending staff at the Downey
Garofola Health Services located on campus. Costs
associated with treatment will be my responsibility.
6.
There are no feasible alternative procedures available
for this study.
7.
I understand that the possible benefit of my
participation in the research is to understand the function
of gluteus maximus strength during the golf swing and how
the correlation between gluteus maximus strength and
separation between upper and lower body angle and its
effects on low back pain. This study can help golf coaches
and golfers decide whether to add gluteus maximus exercises
to a golf training program to reduce possible low back
pain.

55
8.
I understand that the results of the research study
may be published but my name or identity will not be
revealed. Only aggregate data will be reported. In order
to maintain confidentially of my records, Hyun Hong will
maintain all documents in a secure location on campus and
password protect all electronic files so that only the
student researcher and research advisor can access the
data. Each subject will be given a specific subject number
to represent his or her name so as to protect the anonymity
of each subject.
9.
I have been informed that I will not be compensated
for my participation.
10. I have been informed that any questions I have
concerning the research study or my participation in it,
before or after my consent, will be answered by Hyun Hong
MA, ATC hon0718@calu.edu 423 Wood St. California, PA 15419,
(540)686-6979 and Thomas F. West PhD, ATC, California
University of Penssylvania, west_t@calu.edu, 250 University
Ave California, PA 15419,(724) 938-5933
11. I understand that written responses may be used in
quotations for publication but my identity will remain
anonymous.
12.
I have read the above information and am electing to
participate in this study. The nature, demands, risks, and
benefits of the project have been explained to me. I
knowingly assume the risks involved, and understand that I
may withdraw my consent and discontinue participation at
any time without penalty or loss of benefit to myself. In
signing this consent form, I am not waiving any legal
claims, rights, or remedies. A copy of this consent form
will be given to me upon request.
13. This study has been approved by the California
University of Pennsylvania Institutional Review Board.
14. The IRB approval dates for this project are from:
01/01/2012 to 12/31/2012.
Subject's signature:___________________________________
Date:____________________
Witness signature:___________________________________
Date:____________________
Approved by the California University of Pennsylvania IRB

56

APPENDIX C2
Institutional Review Board –
California University of Pennsylvania

57

58

59

60

61

62

63

APPENDIX C3
Data Collection Sheet

64

65

APPENDIX C4
Subject Information Sheet

66

67

APPENDIX C5
Low Back Pain Questionnaire

68

69

70

71
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74

ABSTRACT
Title:

CORRELATION BETWEEN PELVIC ROTATION AND
GLUTEUS MAXIMUS STRENGTH IN GOLFERS

Researcher:

Hyun Hong

Advisor:

Dr. Thomas F. West

Data:

May 2012

Research Type: Master’s Thesis
Purpose:

The purpose of this study is to examine the
relationship between shoulder-pelvic
separation and gluteus maximus strength
during the golf swing.

Problem:

It is important to examine the correlation
between gluteus maximus strength and
transverse plane pelvic rotation as it may
create stress on the low back area during
the golf swing. If we know gluteus maximus
strength is related to pelvic rotation we
can enhance the gluteus maximus strength in
order to prevent or decrease a golfer’s low
back pain.

Method:

Twenty subjects from California University
of Pennsylvania participated in K-VEST 3D
motion analysis of a golf swing. A Pearson
Product-Moment Correlation Coefficient
analysis was applied to measure the
correlation between shoulder-pelvic
separation and gluteus maximus strength
during the golf swing. Moreover, a hand-held
manual dynamometer was used to measure
gluteus maximus strength.

Findings:

The K-VEST TPI motion analysis and hand-held
dynamometer were found to be both a reliable
and valid measure of shoulder-pelvic
separation and gluteus maximus strength
respectively.