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This is to certify that the
thesis entitled

RELATIONSHIPS BETWEEN HIP MUSCLE LENGTH, HIP
JOINT ANGLE, AND PELVIC TILT IN STATIC STANDING
POSTURE AMONG COLLEGE-AGED HEALTHY
CAUCASIAN AND EASTERN ASIAN MALES

presented by

Tom Tanaka

has been accepted towards fulfillment
of the requirements for the

MS. degree in Kinesiology

 

 

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-~—._ _ww

RELATIONSHIPS BETWEEN HIP MUSCLE LENGTH, HIP JOINT ANGLE, AND
PELVIC TILT IN STATIC STANDING POSTURE AMONG COLLEGE-AGED
HEALTHY CAUCASIAN AND EASTERN ASIAN MALES
By

Tom Tanaka

A THESIS
Submitted to
Michigan State University

in partial fulfillment of the requirements
for the degree of

MASTER OF SCIENCE
Department of Kinesiology

2005

ABSTRACT
RELATIONSHIPS BETWEEN HIP MUSCLE LENGTH, HIP JOINT ANGLE, AND
PELVIC TILT IN STATIC STANDING POSTURE AMONG COLLEGE-AGED
HEALTHY CAUCASIAN AND EASTERN ASIAN MALES

By

Toru Tanaka

Relationship between pelvic tilt in standing posture and hip muscle length has
been widely accepted, although it has not been sufficiently supported. First purpose of the
study was to examine relationships between pelvic tilt, hip joint angle, and center of
pressure in standing posture, and hip muscle length (one- and two-joint hip flexor and hip
extensor) among college-aged males. Second purpose was to analyze differences in
pelvic tilt and hip joint angle in standing posture and hip muscle length (one-joint hip
flexor and hip extensor) between Caucasian and Eastern Asian college-aged males.
Twenty one Caucasian (M = 28.78 years, SD=1.94) and 18 Eastern Asian (M = 25.36
years, SD=3.9S) male participants were recruited. No relationships were found between
variables except for relationship between pelvic tilt and hip joint angle (r = .896, P < .01).

There were no race differences in pelvic tilt, hip joint angle, and hip muscle length.

TABLE OF CONTENTS

LIST OF TABLES .................................................................................. v
LIST OF FIGURES ................................................................................. vi
CHAPTER 1
INTRODUCTION AND REVIEW OF LITERATURE ......................................... 1
Postural Imbalances and Low Back Pain in Western and Asian Populations .......... l
Postural Models by Kendall, KcCreary, and Provance for the Evaluation and
Rehabilitation of Postural Imbalances .................................................... 2
Review of Literatures that Examined the Postural Models Described by Kendall,
McCreary, and Provance .................................................................... 6
Significance of Problem ...................................................................... 9
Need for Study of Thigh Alignment and Hip Angle in Quiet Standing Posture. . . l 0
Need for Study of Change in Center of Pressure in Quiet Standing Posture ......... 13
Need for Study of Postural Differences between Races ................................. l4
Purposes of the Study ........................................................................ 15
Hypotheses .................................................................................... 16
Definitions of Terms ......................................................................... 16
CHAPTER 2
METHODS .......................................................................................... 20
Participants .................................................................................... 20
Instrumentation ................................................................................ 22
Research Design ............................................................................... 26
Procedures ..................................................................................... 29
Pelvic Tilt, Hip Angle, and Center of Pressure .................................... 31
One- and Two-Joint Hip F lexor Length Measurements ........................... 36
Hip Extensor (Hamstring) Length Measurement .................................. 42
Short Survey ............................................................................ 47
UCRIHS Approval ........................................................................... 47

iii

CHAPTER 3

RESULTS ............................................................................................. 48

CHAPTER 4

DISCUSSION AND IMPLICATIONS ........................................................... 52
Hypothesis 1 ................................................................................... 52
Hypothesis 2 ................................................................................... 55

CHAPTER 5

CONCLUSIONS .................................................................................... 59

APPENDICES ....................................................................................... 60
Appendix A: Flyer to Recruit Participants ................................................. 61
Appendix B: Informed Consent ............................................................ 63
Appendix C: Short Survey ................................................................... 66
Appendix D: Descriptive Statistics of Participants ....................................... 68
Appendix E: UCRIHS Approval Letter ................................................... 71
Appendix F: UCRIHS Approval Letter for Revision .................................... 73
Appendix G: Raw Data for Six Dependent Variables .................................... 75

REFERENCES ...................................................................................... 78

iv

LIST OF TABLES

Table 1 - Descriptive Statistics of Participants (Mean i Standard Deviation) .............. 21
Table 2 - Pilot Study for Measurements .......................................................... 28
Table 3 - Calculation of Two-joint Hip Flexor Length (96) .................................... 41
Table 4 - Descriptive Values and F-values of the Tested Variables ........................... 48

Table 5 - Correlation Coefficients and Coefficient of Determination between Variables.50

LIST OF FIGURES
Figure l - Standing postural patterns from Kendall, McCreary, and Provance (1993) as
modified by Norris (Norris, 1995) .................................................................. 4
Figure 2 - Hip joint ................................................................................. 12

Figure 3 - Subject wearing compressive shorts in a quiet standing posture, with colored
adhesive tapes and small dots identifying body landmarks .................................... 23

Figure 4 - Manual goniometer with a bubble balance and two 30 cm extension arms
added .................................................................................................. 24

Figure 5 - Orientation of the malleoli and force platform with respect to the Optic axis of
lens Of digital camera ............................................................................... 33

Figure 6 - Pelvic tilt, thigh alignment, and hip angle ........................................... 35

Figure 7 - Thomas test with the right lower extremity released and the one- and two- joint
hip flexors relaxed ................................................................................... 37

Figure 8 - Goniometer placement for one-joint hip flexor length ............................ 39
Figure 9 - Goniometer placement for two-joint hip flexor length...............................4l
Figure 10 - Three general conditions for two-joint hip flexor length (96). . . . . . . ....4........2
Figure 11 - 90/90 hamstring test .................................................................. 44

Figure 12 - Goniometer placement for hip extensor (hamstring) length ..................... 46

vi

CHAPTER 1

INTRODUCTION AND REVIEW OF LITERATURE

Postural Imbalances and Low Back Pain in Western and Asian Populations

Throughout a lifetime, 70-80% of the people in the western population have at
least one episode of low back pain (Nourbakhsh & Arab, 2002). There can be many
reasons for low back pain such as genetic, social, or biomechanical. From a
biomechanical point of view, many researchers have attempted to find relationships
between chronic low back pain and postural imbalances such as lumbar lordosis,
kyphosis, scoliosis, sway back, and flat back (Mulheam & George, 1999; Norris 1995;
Nourbakhsh & Arab, 2002; Watson, 1995). These studies used western populations, with
the exception of Nourbakhsh and Arab (2002) who used a population from Iran. Postural
imbalances may be the result of genetics, muscular imbalance, the assumption Of poor
posture of daily life, or all of them (Lee, Lee, Kim, Hong, & YOO, 2001; Mulheam &
George, 1999; Youdas, Garrett, Egan, & Themeau, 2000). In contrast, Asian people are
more prone to exhibit a flat back and sway back position than Americans and Europeans.
Since there may be differences in postural imbalances between different populations, it is

not clear whether or not these imbalances precipitate physical problems. According to

Kendall, McCreary, and Provance (1993), problems with flat back and sway back do not

Show health problems in Asian populations.

Postural Models by Kendall, KcCreary, and Provance for the Evaluation and

Rehabilitation of Postural Imbalances

There may be interrelationships between pelvic tilt, hip muscle tightness, and
low back pain. The orientation of the pelvis is directly related to postural imbalances and
may be associated with tightness of the hip musculature. Kendall, McCreary, and
Provance (1993) presented standing postural models that indicated imbalances such as
lordosis, kypholordosis, flat back, and sway back (Figure 1), caused by hip muscle
tightness. Approaches to the study of posture described by Kendall’s text took a broader
view relating whole body mechanics to interrelationships between joints, posture, and
muscles. Kendall, McCreary, and Provance (1993) stated;

Evaluation of faulty posture must include examination of the related parts and

not be limited to the areas where symptoms appear. A mechanical or functional

strain causing an imbalance in one part Of the body will soon result in
compensatory changes in other parts Of the body. The mechanics Of the low back

is inseparable from that of the overall posture but especially that of the pelvis

and the lower extremities. Pain manifested in the leg may be due to an
underlying problem in the back. Conversely, the symptoms appearing in the low
back may be due to underlying faulty mechanics of the feet, legs, or pelvis (pp.
349)
These models are widely accepted in clinical settings and are used extensively for
evaluation and rehabilitation of postural imbalance and accompanying low back pain

because they seem to explain mechanical reasons for the postural imbalances.

(a) Lordotlc

Body segment alignment
Pelvis is anterioriy tilted with Iordosle Increased.
Knees are hyperextended with angle Joints slightly
plantarilexed

Elongated and weak
Anterior abdominals.
Hamstrings may lengthen Inltlaliy or shorten to
compensate where posture has been present for
some time

Short and strong
Low back and hip flexors

(b) Kypholordotlc

Body segment alignment
Head held forwards with cervical spine
hyperextended. Scapulae may be abducted.
Increased lumbar lordosis, and increased thoracic
kyphosis. Pelvis anterioriy tilted.
i-llp flexed, knee hyperextended.
Head Ie usually most anterioriy placed body segment

Elongated and weak
Neck flexors, upper erector splnae. External oblique.
if scapulae are abducted, middle and lower trapezlus

Short and strong
Neck extensors and hip flexors.
If scapulae are abducted, serratus anterior, pectoralls
major andlor minor, upper trapezlus

 

Figure 1. Standing postural patterns from Kendall, McCreary, and Provance (1993) as
modified by Norris (Norris, 1995).

' ' j (c) Sway Back

Body segment alignment
Long kyphosls with pelvis the most anterior body segment,
hip joint moves forwards of posture line. Low lumbar area
flattens. Pelvis neutral or In posterior tilt.
Hip and knee joints hyperextended.
Where subject stands predominantly on one leg pelvis will
be tilted down to non-favoured side.
Favoured leg appears longer in standing only

+Elongated and weak
One joint hip flexors. External oblique. Upper back
extensors. Neck flexors. Where one leg is faboured, gluteus
medlus (especially posterior fibres) on favoured side

Short and strong
Hamstrings. Upper fibres and internal oblique.
Low back musculature short but not strong.
Where one leg ls favoured, tensor fascia Iata ls strong and
lliotlbial band ls tight on ravoured side.

 

(d) Flat Back

Body segment alignment
Loss of lordosls with pelvis In posterior tilt.
Hip and knee joints hyperextended.
Forward head posture with Increased fiexlon to upper
thoracic spine

Elongated and weak
One joint hlp flexors

Short and strong
Hamstrings

Abdominals may be strong, with back muscles slightly
elongated

 

Figure 1 (continued). Standing postural patterns from Kendall, McCreary, and Provance
(1993) as modified by Norris (Norris, 1995).

5

In the athletic training setting, hamstring stretching is frequently used as a
rehabilitation tool for chronic low back pain because it is believed that this technique
reduces pain producing postural imbalances. Although there are many scientific studies or
theories which Show relationships between chronic low back pain and postural
imbalances (e. g., lumbar lordosis, kyphosis, scoliosis, sway back, and flat back), these
relationships have not been sufficiently supported (Nourbakhsh & Arab, 2002). In fact,
Harreby et al. (1999) and Tafazzoli and Lamontagne (1996) concluded that there was no
relationship between low back pain and hamstring length. In addition, there is a paucity
of literature on the effectiveness of flexibility training, especially hamstring stretching, to
mitigate the mechanical causes of low back pain in spite of frequent clinical application

of hip joint muscle stretching.

Review of Literatures that Examined the Postural Models Described by Kendall,

McCreary, and Provance

Several studies have tried to explain the relationships of postural models
described by Kendall, McCreary, and Provance (1993). Gajdosik, Albert, and Mitman
(1994) studied relationships among hamstring tightness, pelvic tilt, and lumbar and

thoracic angles in standing posture. Thirty nondisabled and non-obese males participated

in this study. Pelvic tilt, lumber angle, and thoracic angle were measured in two different
positions (i.e., static standing and toe-touch position in standing) to study the effects of
hamstring length in the two positions. Pictures were taken by a still camera and these
angles were measured on the pictures with a protractor. There were no significant
differences in the two positions between pelvic tilt, lumbar angle, and thoracic angle with
respect to differences in hamstring muscle length. Gajdosik, Albert, and Mitman (1994)
concluded the length of the hamstrings had limited effect on these angles.

A research study conducted by Li, McClure, and Pratt (1996) evaluated the
relationships among hamstring stretch, lordosis, and pelvic tilt in a standing position and
during partial and full forward bending by using a three-dimensional digitizer. Thirty nine
volunteers without musculoskeletal impairment in the Spine and lower extremities and
with tight hamstring muscles participated in the study. Hamstring length had no
significant relationships with lumbar lordosis (r = -.11) and with pelvic tilt (r = .277).

Nourbakhsh and Arab (2002) studied the relationships between low back pain
and mechanical factors, including pelvic tilt and hip muscle flexibility. They recruited
600 participants 20 to 65 years of age. The participants were categorized into four groups,
150 asymptomatic men; 150 asymptomatic women; 150 men with low back pain; and

150 women with low back pain. The pelvic tilt of the subjects in a static standing posture

was measured with an inclinometer. Hip flexor muscle length was measured by the
Thomas test with a manual goniometer. Hamstrings muscle length was measured by the
active knee extension test (90/90 hamstrings test) with a manual goniometer. There were
no significant relationships between hamstring length and pelvic tilt (r = .08) and
between hamstring length and the size of lumbar lordosis (r = .11). NO relationships were
found between one-joint hip flexor length and the size of lumbar lordosis (r = -.05) and
between one-joint hip flexor length and pelvic tilt (r = .07).

Youdas, Garrett, Harmsen, Suman, and Carey (1996) studied the relationship
between pelvic tilt and lumbar lordosis in healthy adults. The participants were 90
asymptomatic volunteers (45 males and 45 females) between 40 and 69 years of age.
Pelvic tilt in a static standing posture was measured with an inclinometer. Lumbar
lordosis in a static standing posture was measured with a specific tool, called a flexible
curve. NO significant relationship between pelvic tilt and lumber lordosis (r = .06 for
males and r = -.08 for females) was found.

Youdas, Garrett, Egan, and Themeau (2000) studied relationships between
lumbar lordosis and pelvic tilt among people with or without low back pain. Sixty
volunteers (30 males and 30 females) between 40 and 69 years of age with chronic low

back pain participated in this study. These participants were compared with participants

without low back pain, who were taken from previously published data by Youdas,
Garrett, Harmsen, Suman, and Carey (1996). The same measurement protocols described
by Youdas, Garrett, Harmsen, Suman, and Carey (1996) were used for pelvic tilt and
lumbar lordosis measurements. Correlation coefficients between pelvic tilt and lumbar
lordosis among low back pain participants were r = .31 for males and r = .37 for females.
Neither the female nor male participants with chronic low back pain demonstrated an
increased lumbar lordosis and pelvic tilt compared with participants without low back

pain.

Significance of Problem

The results of all of these studies did not support the relationships between hip
muscle tightness and postural imbalances contended by Kendall, McCreary, and Provance
(1993). The use of hip muscle stretching as a rehabilitation tool for chronic low back pain
based on these postural models may be a questionable practice, since the results of these
studies did not support relationships between hip muscle length, postural imbalances, and
low back pain. Health care providers, who attempt to reduce and alleviate low back pain

in their patients, should be provided with the scientific understanding for the mechanisms

of low back pain as a basis for their treatment and not be encouraged to rely upon

unsubstantiated models.

Need for Study of Thigh Alignment and Hip Angle in Quiet Standing Posture

Research studies (Gajdosik, Albert, & Mitman, 1994; Li, McClure & Pratt, 1996;
Nourbakhsh & Arab, 2002; Youdas et al, 1996; Youdas et al, 2000) that have attempted to
find relationships between pelvic tilt and hip muscle length have not shown significant
relationships. However, these research studies, related to the postural model Of Kendall,
McCreary, and Provance (1993), are limited to the study of single relationships between
(a) hamstring tightness and pelvic tilt, (b) hamstring tightness and lordosis, and (c) pelvic
tilt and low back pain in attempting to explain whole body mechanics.

Pelvic tilt does not occur without accompanying movements of the sacrum and
femur. In the sagittal plane, the hip joint consists of the innominate and femur with the
greater trochanter as the axis of the movement (Figure 2). The hip joint angle is an angle
between the innominate and the femur. The innonminate does not move independently. It
moves relative to the sacrum and femur. Previously referenced researchers, who
challenged postural models described by Kendall, McCreary, and Provance (1993), only

focused on pelvic tilt without considering accompanying movements of the sacrum,

10

 

 

femur, or both. Additionally, these researchers considered the femur to be aligned
vertically in the sagittal plane without the possibility that it could be tilted. However, the
femur could also be tilted such that its head is either anterior or posterior to its condyles.
When the pelvis tilts, either forward (or anterior) or backward (or posterior), other parts
of the body must simultaneously move. Therefore, to more fully understand relationships
between hip muscle length and pelvic tilt, alignment of the femur must also be considered.
In addition, variation of position of the pelvis results in changes in the alignment of the
spine (Jackson, & McManus, 1994; Kendall, McCreary, & Provance, 1993; Levine &
Whittle, 1996; Nourbakhsh & Arab, 2002; Youdas et al., 2000). For example, excessive

pelvic tilt has an association with lumbar lordosis (Magee, 2002).

ll

ateral
, Epioondlye

 

Figure 2. Hip joint.

Need for Study of Change in Center of Pressure in Quiet Standing Posture

When changes occur in alignment and positioning of body parts, there are
accompanying changes in the mass distribution of the body and associated positioning of
the center of pressure. In a quiet standing posture, the body’s center of mass and center of
pressure move in phase with one another in the same direction (Winter, Patla, Prince,
Ishac, & Gielo-Perczak, 1998). Therefore, the position of the center of pressure in the
transverse plane provides an indirect measure of the position of the center of mass in this
same plane. Similarly, the center of pressure location, with respect to the lateral malleolus,
may be a tool to help in the understanding of postural relationships. In quiet standing, the
center of mass and center of pressure are afiected by alignments of lower extremity joints
including the hip, knee, and ankle. Changes in the angle of the hip joint can change the
curvature of the lumbar spine and simultaneously change the position of the body’s center
Of gravity and center of posture (Bot, Caspers, Van Royen, Toussaint, & Kingma, 1999).
Therefore, measuring the relative location of the center of pressure with respect to the
lateral malleolus may help to explain the position of the center of mass and indirectly

provide information about the position of the hip joint.

13

Need for Study of Postural Dtflerences between Races

Postural models described by Kendall, McCreary, and Provance (1993)
attempted to explain postural differences from a biomechanical point of view. Many
researchers (Lee, Lee, Kim, Hong, & YOO, 2001; Mulhearn & George, 1999; Youdas,
Garrett, Egan, & Themeau, 2000) stated that postural imbalances may be the result of
genetics, muscular imbalance, or the assumption of poor posture of daily life. In addition
to biomechanical relationships, other possible factors, such as racial or social differences,

should be studied well to understand the differences.

It is believed that there are race differences in standing posture. However,
research studies and books, stating these differences, are rare. Kendall, McCreary, and
Provance (1993) have stated that Asian people tend to have a specific type of postural
pattern that is similar to flat back without having a health problem. Although this
relationship in Asian people is a common belief, there is no research that has

scientifically demonstrated this.

14

Purposes of the Stuay

There were two purposes of this study. First purpose was to study biomechanical
relationships among hip muscle length, center of pressure, and pelvic tilt and hip angle
with respect to postural imbalance.

Second purpose of this study was to address the issue of differences in quiet
standing posture between Caucasian and Eastern Asian males. This study examined
another possible source to form postural imbalance, in addition to the biomechanical
relationships. Genetic and social variations may be possible sources of the variability for
racial differences in quiet standing posture examined by pelvic tilt and thigh alignment. A
single factor such as hip muscle length may not explain these differences.

Information gained from this study could potentially help athletic trainers and
other health care workers decide whether or not hip joint muscle stretching; especially the
hamstrings, one-joint hip flexor(i1iopsoas) and two-joint hip flexor (rectus femoris) is an
appropriate rehabilitation technique to treat low back pain. In addition, this study could
provide broader knowledge about posture by examining the race differences as well as

biomechanical differences.

15

 

Hypotheses

Based on the literature review, two hypotheses were determined for the current
study:

1. In quiet standing posture, hip angle and anterior-posterior position of the hip
(as determined by the relative position of the center of pressure) as well as pelvic tilt have
relationships with hip muscle length (one-joint hip flexor length, two-joint hip flexor
length, and hip extensor length) among college-aged males.

2. Pelvic tilt, hip angle, and hip muscle length (one-joint hip flexor length and
hip extensor length) have no differences between college-aged Caucasian and Eastern

Asian males.

Definitions of Terms

The following terms are defined as they apply in this study:

90/90 hamstring test - This is a broadly accepted test, in clinical settings, used to
measure hamstring (hip extensor) length (Figure 11). In this position, a participant
attempts to extend the knee joint as much as possible. An angle formed by a line
connecting the lateral malleolus and lateral epicondyle of the femur and a line connecting
the lateral epicondyle and the greater trochanter of the femur is measured by a manual

16

goniometer (Figure 12). The maximum knee angle is used to define relative hip extensor
muscle length.

Center of pressure — This is a displacement measure in the transverse plane at the
ground level that represents the location of the vertical ground reaction force vector
obtained from a force platform (Winter, 1990).

Flat back — This is type of postural malalignment in which the spine is straight
through the inferior thoracic to lumbar areas with accompanying posterior pelvic tilt
(Kendall, McCreary, & Provance, 1993) (Figure 1).

Forward and Backward Pelvic tilt — Forward (or anterior) pelvic tilt occurs when
the anterior superior iliac spine (ASIS) is displaced forward and inferior from a neutral
position of the pelvis and the pubic symphysis is displaced backward (posterior).
Backward (or posterior) pelvic tilt occurs when the ASIS is displaced backward and
superior from a neutral position of the pelvis and the pubic symphysis is displaced
forward (anterior) (Kendall, McCreary, & Provance, 1993).

Hip flexors — These are muscles, whose active shortening, result in flexion of the
hip joint. Examples include the iliopsoas (iliacs and psoas major), pectineus, adductor

brevis, and adductor longus defined as one-joint muscles, and the rectus femoris, tensor

l7

fascia latae, and sartorius defined as two-joint muscles (Kendall, McCreary, & Provance,

 

 

 

1993)

Hip pngle (03) — This is defined as the sum of pelvic tilt (01) and thigh alignment
(02) (Figure 6).

Hip position -— This is defined as the anterior-posterior displacement of the hip I
joint in the sagittal plane.

One-ioint hip flexor — The iliopsoas is designated as this type of muscle in the

Thomas test because the lumbar spine is stabilized on a hard and flat surface and the only
movement permitted at the hip joint is in the sagittal plane. Passive tension in the
iliopsoas muscle tends to cause hip flexion against the weight of the lower extremity.

Sway back - This is a malalignment associated with a posterior displacement of
the upper trunk and an anterior displacement of the pelvis. There is a backward curve of
the spine and a flattening of the lower lumbar region. The pelvis is in posterior tilt and the
hip joints are extended. The head and neck are in a forward head position (Kendall,
McCreary, & Provance, 1993) (Figure l).

Thigh augment (02) — This is the orientation of the thigh as determined by a
line connecting the greater trochanter and lateral epicondyle of the femur and a vertical

line passing through the greater trochanter (Figure 6).

18

 

Thomas test — This is a broadly accepted test, in clinical settings, used to
differentiate between tightness of the iliopsoas muscle group (one-joint hip flexor) and
tightness of the rectus femoris muscle (two-joint hip flexor ) (Starkey & Ryan, 1996)
(Figure 7). Angles of the hip and knee are measured by a manual goniometer. The
measured hip angle represents one-joint hip flexor length and the measured knee angle
represents two-joint hip flexor length (Kendall, McCreary, & Provance, 1993) (Figure 7).

Two-ioint hip flexor — The rectus femoris is designated as this type of muscle in
the Thomas test. It crosses both the hip and knee joints. Tension in this muscle resists hip

extension and knee flexion.

l9

CHAPTER 2

METHODS

Participants

Since sample size is important in MANOVA, it was explored using a method
proposed by D’amico, Neilands, and Zambarano (2001). By using SPSS and data values
from a similar research (N ourbakhsh & Arab, 2002), the sample size for the current study
was determined. The SPSS analyses indicated that more than 20 participants for each
independent variable (Caucasian and Eastern Asian groups) was a sufi'rcient sample size.
This sample size was approximated in the current study.

Participants were recruited by using flyers (Appendix A) and email lists. The
flyers were posted on campus sites at Michigan State University (MSU) frequented by
students. The email lists were used to recruit Eastern Asian participants and composed Of
the same information as the flyers. Emails were sent to lists of international students in
College of Education at MSU, Chinese Students and Scholars Association at MSU, and
Japanese Club at MSU. Each participant received 10 dollars for his involvement in the
study.

Thirty-nine college males, between the ages of 19 and 35 years (M= 25.36 yrs,

20

SD = 4.39), participated in this study. Participants included 21 Caucasians (M= 22.43 yrs,
SD = 1.94) and 18 Eastern Asians (M= 28.78 yrs, SD = 3.95) composed of Chinese,
Koreans, and Japanese. Each participant was informed of the experimental procedure and
signed an informed consent form (Appendix B) prior to the participation.

All participants answered a short survey (Appendix C) which asked if they had
ever been diagnosed by a physician with a severe injury related to the pelvis, spine, and
lower extremity. As a result of this survey, it was determined that all participants had no
diagnosed history of serious injuries related to the pelvis, spine, and lower extremity. In
addition, the Eastern Asian participants did not have ancestors from other ethnic origins.
The mean age, height, mass, and BMI of the participants in each group are shown in

Table 1 and the data set for all participants is included in Appendix D.

Table 1
Descriptive Statistics of Participants (Mean :t Standard Deviation)

 

Total (n = 39) Caucasian (n = 21) Eastern Asian (n = 18)

 

Age (year) 25.36 :1: 4.39 22.43 a: 1.94 28.78 :i: 3.95
Height (cm) 175.2 :1: 6.90 177.3 i 8.24 172.8 s 3.88
Weight (kg) 74.99 d: 11.99 79.51 a 12.86 69.71 a: 8.49

BMI 24.38 :i: 3.28 25.26 :I: 3.44 23.36 i 2.84

 

21

Instrumentation

Colored adhesive tape was attached to a point on the compressive shorts, worn

by the participants, directly over their palpated greater trochanter of the femur or on their

 

skin over other body landmarks, (i.e., anterior superior iliac spine (ASIS), posterior
superior iliac spine (PSIS), lateral epicondyle of the femur, and lateral malleolus of the

fibula) (Figure 3). A small dot was marked on each piece of tape to more precisely define

 

each bony landmark. These dots on the colored tapes were used for angle measurements
in all tests to identify specific locations of the landmarks. This author, with several years
of experience in the study and practice of athletic training, performed all palpations and

subsequent placement of tape markers and dots.

22

 

Greater
.Trochanter 1‘

Lateral l,
Epicondyle

 

Figure 3. Subject wearing compressive shorts in a quiet standing posture, with colored
adhesive tapes and small dots identifying body landmarks.

23

A manual goniometer with 12 inch arms (Figure 4) was used for angle
measurements in the Thomas test (Figure 7) and 90/90 hamstring test (Figure 11). Two 30
cm plastic rulers were aligned with and attached to the arms of the goniometer to extend
the arms so that they could cover the entire length of the lower extremity of the
participants. For the Thomas test, a bubble balance was aligned with and attached to one

of the arms of the goniometer to determine the horizontal line.

Bubble
Balance

4;

Extension
Arms

 

Figure 4. Manual goniometer with a bubble balance and two 30 cm extension arms
added.

24

A digital camera (DSC-P2, SONY Corporation, Tokyo, Japan), with 1600x1200
pixel density, was set on a tripod with the optic axis of its lens one meter above the
ground and six meters away from the force platform, where participants were to assume a
quiet standing position. The horizontal and vertical orientations of the camera relative to
the ground were carefully set using the bubble balances built into its tripod. The captured
digital images were transported to Microsoft Photo Editor software to identify Cartesian
coordinate locations of bony landmarks (i.e., ASIS, PSIS, greater trochanter and lateral
epicondyle of the femur, and lateral malleolus of the fibula) of the participants as pixels
on a computer screen. Cartesian coordinates from the digital images were subsequently
used to measure pelvic tilt and thigh alignment (Figures 3 and 6).

For each participant, the center of pressure in a quiet standing posture was
measured by an AMTI force platform (AMTI, Watertown, MA). APAS system (Ariel
Dynamics, Inc., San Diego, CA) software quantified the data obtained from the force
platform. Anterior-posterior displacement of center of pressure in the saggital plane was
measured in meters at the ground level relative to the horizontal coordinate of the right
lateral malleolus. Vertical ground reaction force (F2) and lateral moment (My) was
sampled at 50 Hz over a 7 second time period using the AMTI force platform and APAS

software. Five seconds of data (i.e., from 1 to 6 seconds) of the 7 second time period was

25

 

used for the calculation of the center of pressure. Anterior-posterior displacements of the
center of pressure were obtained by the following formula (Shimba, 1984):

Center of pressure = My/Fz
and the average value over the 5 second period (250 samples) was defined as the center

of pressure value.

Average Center of Pressure = Z 25 0

i=51

30° [Myi/ F 2i]

Research Design

Six dependent variables for hypothesis 1 included: (a) pelvic tilt in quiet
standing posture (in degrees); (b) hip angle in quiet standing posture (in degrees); (c)
horizontal displacement in the saggital plane of center of pressure (in meters) in quiet
standing posture relative to the lateral malleolus; (d) hip extensor (hamstring) length (in
degrees); (e) one-joint hip flexor length (in degrees); and (f) two-joint hip flexor length
(in degrees). All dependent variables were continuous scores and ratio scales. Twelve
pairs of selected Pearson product moment correlation coefficients were calculated for the
six dependent variables. In addition, for each of these selected pairs, coefficients of

determination were obtained to test the degree of these relationships.

26

For hypothesis 2, a multivariate analysis of variance (MAN OVA) was used to
examine the relationships of race (Caucasian and Eastern Asian males) to four dependent
variables: pelvic tilt, hip angle, hamstring length, and one-joint hip flexor length. All
dependent variables were continuous scores and ratio scales. The independent variable
was race, which was a nominal scale. ANOVA was calculated on two of the four

dependent variables (hip extensor length and one-j oint hip flexor length). The level of

 

significance was set at p<.05.

Validity of the testing was controlled by subject selection procedures and timing
of the administration of a questionnaire. Participants were asked to answer a short survey
about their ethnic origin and injury history related to the pelvis, spine, and lower
extremity. Participants answered the survey at the end of the experimental sessions so that
they did not focus on controlling their posture and testing performance because of related

a priori questions.

Pilot study was performed for all measurements (pelvic tilt, hip angle, center of
pressure, one-joint hip flexor length, two-joint hip flexor length, and hip extensor length)
by this author. Three participants were recruited for this pilot study. All of them had two

experimental sessions. The interval between each experimental session had at least two

27

days. Correlation coefficients between measures made at the first and second sessions

were r = .849 for pelvic tilt, r = .933 for hip angle, r = .963 for one-joint hip flexor length,

r = .699 for two-joint hip flexor length, and r = .738 for hip extensor length. Results of

the pilot study are shown on Table 2.

 

 

 

 

 

Table 2
Pilot Study for Measurements
. 90/90
Standrng Posture Thomas Test , ,-
Hamstrrng
Pl' O-"tT-"t H'
Participants Session evrc Hip Center of .ne jom wo jorn 1p
tilt hip flexor hrp flexor extensor
angle pressure
length length length
( deg ) (deg) (m)
(deg) (deg) (deg)
1 10 186 .064053 183 109 162
A
2 10 189 X 185 103 162
1 14 196 .052882 168 90 161
B
2 21 206 .093454 170 90 160
1 15 194 .04584 169 96 153
C
2 17 197 .060566 175 104 165
Correlation
coefficient - .849 .933 .963 .699 .738
r

 

28

Procedures

Each participant experienced one measurement session. Each session was
directed by this author. Each session was conducted in a locked setting Opened only to the
participant, an assistant experienced at collecting center of pressure data via force
platform, and this author to protect the participant’s privacy and to remove any effect
from extraneous individuals. The experienced assistant stayed in a separate room to
collect data for the center of pressure at the same times this author took pictures for
pelvic tilt and hip angle measurements.

The order of testing within each session was as follows:

1. informed consent (Appendix B);

2. height and weight measurements;

3. three to five minutes for wann-up on a stationary bike;

4. pelvic tilt, hip angle, and center of pressure digital picture in a static quiet

standing posture;

5. Thomas test;

6. 90/90 hamstring test; and

7. short survey about injury history and ethnic origin (Appendix C).

29

All angle measurements (i.e., pelvic tilt, hip angle, Thomas test, and 90/90 hamstring
test) were made on the right side of the participants’ body. For these measurements, the
participants only wore compressive type shorts (Figure 3).

The experimental session started with an informed consent. All participants read
and signed the informed consent form and were given time to ask questions about this
study.

Height was measured with a stadiometer. The stadiometer had two meters of
length and the increments of the measurement were one millimeter. A participant stood
barefoot on the floor facing away from the wall. The feet were together and parallel to
each other. The heels, buttocks, and upper back touched the wall, which was at a right
angle to the floor. The head was positioned in the Frankfort plane line connecting the eye
and car on the horizontal plane. The stadiometer was positioned parallel to the wall in the
mid-frontal plane and perpendicular to the floor. The sliding bar of the stadiometer was
brought down on the vertex of the head with sufficient pressure to depress the hair. After
this position was established, height was measured.

Weight was measured with a platform scale that had a balancing beam, with two
movable weights and one tare-screw weight. The increments of the measurements were

0.1 pound. The participant was only allowed to wear compressive shorts during the

30

measurement. The participant stood on and faced the scale. In this position, weight was
measured. The measured value was divided by 2.2046 to convert the English value
(pound) to metric value (kilogram).

Before starting the angle measurements, the participants warmed up by engaging
in light aerobics exercise, for 3 to 5 minutes, using a stationary bike so that all
participants would experience a similar pre-measurement preparation.

Adhesive tapes were directly placed on bony landmarks or on the cloth of the
compressive shorts directly above the greater trochanter. The landmarks included the
most anterior aspect of the ASIS, the most posterior aspect of the P818, the most lateral
aspect of the greater trochanter, the most lateral aspect of the lateral epicondyle of the
femur, and the most lateral aspect of the lateral malleolus. On the adhesive tapes, small
dots were marked by a permanent marker to identify the specific point locations of the

bony landmarks (Figure 3). The landmarks were determined by palpation by this author.

Pelvic Tilt, Hip Angle, and Center of Pressure. TO measure pelvic tilt, hip angle,
and center of pressure, each participant was asked to stand barefoot on a force platform
so that the right side of the body faced toward the digital camera. A line formed by the

alignment of the lateral malleolus of each lower extremity was parallel to the optic axis of

31

 

 

the lens of the digital camera and was at a right angle to the anterior-posterior axis of the
force platform (Figure 5). The digital camera was placed so that the optic axis of its lens
was one meter above and parallel to the ground and the perpendicular distance of the
center of its lens was six meters from a vertical plane passing through the right lateral
side of the force platform. This arrangement maximized the size of the subjects in the
field of view of the camera. The participants were assisted in setting the width of their
lateral malleoli the same as the width of their greater trochanters so that both the greater
trochanters and lateral malleoli were on the same vertical planes. After determining the
feet position, the participants were asked to stand as natural and comfortable as possible
(i.e., quiet standing posture) while maintaining the designated body orientation and
malleoli alignment with respect to the digital camera and force platform. The participants
were asked to maintain this position for approximately 10 seconds. During this time, the
force platform and the APAS software were used to record F2 and My for 7 seconds.
During the middle of the time interval, a picture was taken by the digital camera. In case
that the locations of the bony landmarks were blocked by the right hand, the hand was
placed on the stomach only to take a picture by the digital camera (Figure 3). The
participants were instructed so that they did not change alignment of quiet standing

posture. The right hand was not moved when recording the center of pressure.

32

 
   
 

Medial-lateral axis of

orce platform

. parallel to optic axis

.f lens of digital
amera)

  
 

     
 
 
 
 
 
 
  

"Line connect ng
lateral malleoli
”*of lower
extremities
(parallel to optic
axis of lens of

digital camera)

 
    
 
 

' 2‘ ntrlor—posterlor
A- is of force platform

I. .g» z. ;.
_,, .7 . .

 

Figure 5. Orientation of the malleoli and force platform with respect to the optic axis of
lens of digital camera.

Pelvic tilt (01) and hip angle (03) (Figure 6) were calculated by using Cartesian
coordinate values of selected pixels representing bony landmarks (i.e., ASIS, PSIS,
greater trochanter, lateral epicondyle of the femur) from a digital picture of the
participants displayed on a computer screen. Pelvic tilt was defined as the angle formed
by a line connecting the ASIS and P818 and a horizontal line passing through the ASIS. It

was calculated using the following trigonometric function.

33

 

Pelvic Tilt (01) = tan-1{(Ay-Py)/(Ax-Px)} (in degrees),

where the Cartesian coordinates for ASIS = Ax, Ay and PSlS = Px, Py.

Thigh Alignment (92) = 180 - tan'1{(GTx-LEx)/(GTy-LEy)} (in degrees),

where Cartesian coordinates for the greater trochanter = GTx, GTy, and lateral
epicondyle = LEx, LEy (See section on Definitions of Terms).

Hip angle (03) was defined as sum of pelvic tilt (01) and thigh alignment (02) (See

 

section on Definitions of Terms).

Hip Angle (03) = Pelvic Tilt + Thigh Alignment= 01 + 02 (in degrees).
Alviso, Dong, and Lentell (1988) investigated the intertester reliability of a method to
measure angle of pelvic tilt. Six physical therapists measured the angles of pelvic tilt of
twelve participants (six males and six females) in a relaxed position. The participants
actively tilted the pelvis anteriorly and posteriorly. Testers used depth calipers, modified
meter stick and adhesive markers and used a trigonometric equation to determine the
angle of pelvic tilt. The authors indicated that there were good intertester reliabilities (r
= .88 to .95 for six different measurements). Gajdosik, Simpson, Smith, and DonTigny
(1985) examined intratester reliability Of a test designed to measure the standing
pelvic-tilt angle, active posterior and anterior pelvic-tilt angles and ranges of motion, and

the total pelvic-tilt range of motion (ROM). The pelvic-tilt angles of the right side of 20

34

men were calculated using trigonometric functions. Intratester reliability coefficients
(Pearson r) for test and retest measurements were .88 for the standing pelvic-tilt

angle, .88 for the posterior pelvic-tilt angle, .92 for the anterior pelvic-tilt angle, .62 for
the posterior pelvic-tilt ROM, .92 for the anterior pelvic-tilt ROM, and .87 for the total

ROM.

PSIS (Px. Py)

.\
. ASIS (Ax, Av)
\

91

Greater Trochanter
0 2 ”(GI-X. GTy)

 

 

 

 

 

 

91=Pelvlc Tllt
9 2=Thigh Alignment
6 3: 6 1+ 9 2
=Hip An fl
Lateral
Eprcondyle Gravity Line
(LEx. LEy)

Figure 6. Pelvic tilt, thigh alignment, and hip angle.

35

One- and Two-Joint Hip F lexor Length Measurements. To measure length of
one- and two-joint hip flexors (See section on Definition of Terms), the Thomas test was
used (Kendall, McCreary & Provance, 1993) (Figure 7). Gabbe, Bennell, Waj swelner,
and Finch (2004) reported inter-rater reliability and test-retest reliability of the Thomas
test. Two raters (A and B) measured fifteen participants (six males and nine females) with
a manual goniometer. For one-joint hip flexor length measurement, an inter-rater
intraclass correlation coefficient (ICC) was .92. Test-retest ICCS were .63 for the rater A
and .75 for the rater B. For two-joint hip flexor length measurement, an inter-rater ICC
was .90. Test-retest ICCS were .69 for the rater A and .69 for the rater B. Harvey (1998)
used the modified Thomas test and Obtained measures of flexibility for the iliopsoas,
quadriceps and tensor fascia lata/iliotibial band on 117 elite athletes in tennis, basketball,
rowing, and running to determine hip muscle length. A manual goniometer was used for

measurements. The ICCS for two trials demonstrated high reliability (r = .91 to 94).

36

lmmovable
Object

Lateral

2 ’ Epicondyle
Greater l
Trochanter

Lateral
Malleolus

 

Figure 7. Thomas test with the right lower extremity released and the one- and two-
joint hip flexors relaxed.

To accomplish the Thomas test, the participant first lay in a supine position on a
table or other hard and flat surface. The participant then flexed both hips and knees to
make the lumbar spine and sacrum flat on the surface. Because the most common error of
the Thomas test was that the subject fails to maintain the lumbar back in a flat position
(Kendall, McCreary, & Provance, 1993), an immovable object was placed so one of its
flat surfaces forms a vertical plane in front of the soles of the feet to prevent subsequent
forward movement of the feet and tilt of the pelvis. Then, the foot on the side to be
measured (right side) was released from the immovable object permitting this lower

extremity to extend at the hip and flex at the knee. During this release, the participants

37

were instructed to maintain a relaxed state in the lower extremity muscles on the side to
be measured. Angles of the hip and knee were measured by a manual goniometer. The
measured hip angle represented one-joint hip flexor length and the measured knee angle
represented two-joint hip flexor length (Kendall, McCreary, & Provance, 1993). With the
participant in this relaxed position, one-joint (04) and two-joint (95) hip flexor length
were measured.

One-joint hip flexor length (04) was measured with a manual goniometer (See
section on Definitions of Terms and Figures 7 and 8). An angle formed by a line
connecting the greater trochanter and lateral epicondyle of the femur and a horizontal line

passing through the greater trochanter of the femur was designated as 04.

38

Bubble
Balance

 

Figure 8. Goniometer placement for one-joint hip flexor length.

The calculation of two-joint hip flexor length (06) was used as an indirect

representation of the two-joint muscle length. An angle formed by a line connecting the

greater trochanter and the lateral epicondyle of the femur and a line connecting the lateral

epicondyle of the femur and the lateral malleolus of the fibula was designated as 05.

39

Since 06 was dependent upon a combination of values from both 04 and 05 (See section
on Definitions Of Terms and Figures 7 to 9), there were many possible pairs of values Of
04 and 05 that could equal a single value of 06. In general, there were three possible
conditions of 04 for the calculation of 06 (Table 3 and Figure 10). Each of these
conditions depended on the size of 04 (condition 1: 04 < 180 degrees, condition 2: 04 =
180 degrees, and condition 3: 04 > 180 degrees). Considering only variations in 04, in the
first condition, the hip joint was in a relatively flexed position because of tightness in the
one-joint hip flexor. Therefore, 05, associated with the two-joint hip flexor, was likely to
be relatively small. In condition two (Figure 10), the hip joint was at 180 degrees. Since
04 has increased with respect to condition 1, 05 was likely to also increase. Finally, in
condition three (Figure 10), 04 was shown to be larger than 180 degrees. Therefore, 05
was likely to be larger than in conditions 1 or 2. For two-joint hip flexor length (06), the
smaller angle value was interpreted as better muscle extensibility. Note that the minimum
value possible for 06 in the Thomas test was 90 degrees because (a) it was a gravity
dependent test, (b) the participant was not suppose to apply knee flexor muscle

contraction, and (c) the table or flat surface was positioned horizontally.

40

‘ Lateral
Epicondyle .

G reater
Trochanter

Lateral
Malleolus

 

Figure 9. Goniometer placement for two-joint hip flexor length.

 

 

Table 3

Calculation of Two-joint Hip Flexor Length (06)

Conditions Of 04 Equations for determining 06 (in degree)*
04<180° 05 +(180°—04)
04 = 180° 05
04 > 180° 05 — (04 — 180°)

 

*Note that these equations are the same but are written here in a different format to Show
the influence of 04 on two-joint hip flexor length.

41

Condition 1: ““80; 06-06-9080“)
knee joint

95

 

9 4
hip joint
Condition 2: 04-180; 06-06

94 knee joint
4\

hip joint 05

Condition 3: “>180; OBIS-(04480)

     
  

 

kn Int
hip joint °° 1°

Figure 10. Three general conditions for two-joint hip flexor length (06).

Hip Extensor (Hamstring) Muscle Length Measurement. To test hip extensor

(hamstring) muscle length, the 90/90 hamstrings test (active knee extension test) (Figure

11) was used (Konin, Wilksten, & Isear, 1997) (See section on Definitions of Terms and

42

Figure 11). Gajdosik and Lusin (1983) showed high reliability of this method. The
hamstring (hip extensor) muscle length of both extremities of 15 men was measured
during test and retest sessions. The ICCS for test and retest measurements were .99 for
both the left and right extremities. Gabbe, Bennell, Waj swelner, and (2004) reported
inter-rater reliability and test-retest reliability of the active knee extension (90/90
hamstring) test. Two raters (A and B) measured fifteen participants (six males and nine
females) with a manual goniometer. An inter-rater intraclass correlation coefficient (ICC)

was .93. Test-retest ICCS were .96 for the rater A and .94 for the rater B.

43

Lateral
Malleolus

Lateral
Epicondyl -

L?
Greater
Trochanter

 

Figure 11. 90/90 hamstring test.

For the 90/90 test (Figure 11), the participant lay in a supine position on a table
or other hard and flat surface. The participant then flexed both hips and knees to 90
degrees to position the lumbar spine in a position flat on the table and the posterior
surfaces of the calves on a bench or other adjustable object that helped to maintain a right
angle at the knees and hips. Next, the knee on the side to be measured was actively

extended as much as possible by the participant via knee extensor muscle contraction

44

while maintaining the hips at 90 degrees and the knee on the Opposite side at 90 degrees.
An angle formed by a line connecting the lateral malleolus and lateral epicondyle of the
femur and a line connecting the lateral epicondyle and the greater trochanter of the femur
was measured by a manual goniometer (Figure 12). This angle (07) was used to define

hamstring length.

45

Lateral
Malleolus —

Lateral
Epicondyle

Greater
Trochanter

 

Figure 12. Goniometer placement for hip extensor (hamstring) length.

46

Short Survey. The participants were asked to answer a short survey (Appendix °
C). The survey asked questions about ethnic origin and injury history. Ethnic origin .was
asked because the current study was limited to participants who were Caucasians and
who were Eastern Asians. Participants who had ever been diagnosed by a physician with
a severe injury of the pelvis, spine, or lower extremity were also excluded from
participation in this study. This survey was administered after all physical measurements

and tests to remove its potential effect on how the participants performed.

UCRIHS Approval. The current study was approved by the University
Committee on Research Involving Human Subjects (U CRIHS) at Michigan State
University On June 2004. The revisions about the intensive and informed consent were

approved on July 2004. The approval letters are shown in Appendix E and F.

47

CHAPTER 3

RESULTS

Raw data for six dependent variables are Shown in Appendix G. The means and

standard deviations of the tested variables are shown in Table 4.

 

 

Table 4
Descriptive Values and F-values of the Tested Variables
Total Caucasian Eastern Asian F - p
Population (n = 21) (n = 18) value '
(n = 39)
Pelvic Tilt (01) 16.90 i 4.31 16.90 :1: 5.06 16.91 :l: 3.37 .000 .994
(deg)
Hip Angle (03) 196.46 i 5.18 196.35 i 6.51 196.58 :1: 3.18 .019 .891
(deg)
One-Joint Hip 183.64 at 7.26 185.10 :E 6.91 181.94 :1: 7.49 1.867 .180
Flexor Length (04)
(deg)
Two-Joint Hip 110.00 i 9.96 108.00 i 9.35 112.33 :t 10.40 - -
F lexor Length (06)
(deg)
Hip Extensor Length 153.21 i 9.08 153.62 i 9.64 152.72 i 8.63 .092 .763
(97) (deg)
Center of Pressure 0.062 i 0.020 0.056 :1: 0.015 0.068 i 0.024 - -
(m)

 

Table 5 presents selected correlation coefficients and coefficient of

determination between six variables. The results revealed that a relationship between

pelvic tilt (01) and hip angle (03) was significant (r = .896, p < .01) and a relationship

48

between pelvic tilt (01) and two-joint hip flexor length (06) was significant (r = .299, p

< .05). There were no other significant relationships at p < .05 or < .01 levels. Pelvic tilt
(01) had no significant relationships with other variables except for relationships with hip
angle (03) and two-joint hip flexor length (06). Hip angle (03) and Two-joint hip flexor
length (06) had no significant relationships with other variables except for relationships

with pelvic tilt (01). One-joint hip flexor length (04), hip extensor length (07), and center of

pressure had no significant relationships with other variables.

49

Table 5

Correlation Coefficients and Coefficient of Determination between Variables

 

 

Pelvic One-Joint Two-Joint Hip
_ . Hip Angle . . Center Of
Variables Tilt Hip Flexor Hip Flexor Extensor
(03) Pressure
(01) Length (04) Length (06) Length (07)
CC CD CC CD CC CD CC CD CC CD

 

Pelvic Tilt
(01) X 8961' .803

Hip Angle
(93) X

One-Joint
Hip F lexor
Length
(94)

Two-Joint
Hip Flexor
Length
(96)

Hip
Extensor

Length
(97)

Center of
Pressure
CC = Correlation coefficients.
CD = Coefficient of determination.
'I’p< .01.
El: p< .05.

-.l3l .0172 .2991: .0894 -.010.000100 -.018 .000324

-.057 .00325 .161 .0259 -.098 .00960 -.039 .00152

X -.l46 .0213
X .145 .0210
X .115 .0132

X

50

The MANOVA results (Table 4) indicated that there was no significant
difference between the Caucasian and Eastern Asian males relative to the four dependent
variables (i.e., pelvic tilt, p =.994; hip angle, p = .891; one-joint hip flexor length, p
= .180; and hip extensor length, p = .763). Subsequently, AN OVA was calculated on two
of the four dependent variables (hip extensor length and one-joint hip flexor length).
ANOVA was not calculated for pelvic tilt and hip angle, because values of hip angle were
included in values of pelvic tilt. This also resulted in no significant differences of hip
muscle length (one-joint hip flexor length and hip extensor length) between Caucasian
and Eastern Asian males.

51

CHAPTER 4

DISCUSSIONS AND IMPLICATIONS

Hypothesis 1

The following is a modified restatement of hypothesis 1. In quiet standing
posture, hip angle and anterior-posterior position of the hip (as determined by the
relative position of the center of pressure) as well as pelvic tilt have relationships with
one-joint hip flexor length and two-joint hip flexor length (as measured by the Thomas
test), and hip extensor length (as measured by the 90/90 hamstring test) among
college-aged males.

The relationships between pelvic tilt and hip angle and between pelvic tilt and
two-joint hip flexor length were the only significant correlations (i.e., there were no
significant relationships between pelvic tilt, hip angle, one-joint hip flexor length,
two-joint hip flexor length, hip extensor length, and center of pressure).

In comparison to previous studies (Gajdosik, Albert, & Mitman, 1994; Li,
McClure & Pratt, 1996; Nourbakhsh & Arab, 2002; Youdas et al, 1996; Youdas et al,
2000), the current study added hip angle as a variable because the one- and two-joint hip

flexors, and hamstrings have their insertions on the femur. However, the hip joint consists

52

of the innominate, femur, with the greater trochanter as the axis Of rotation. A significant
relationship (r = .896, p<.01) between pelvic tilt and hip angle was found. This result
indicates that larger pelvic tilt is associated with larger hip angle and smaller pelvic tilt is
associated with smaller hip angle. However, this high correlation might not have a
significant meaning because pelvic tilt (01) is imbedded in the value of for hip angle (i.e.,
hip angle = 03 = 01 + 02). Since the variability of 01 is relatively large (from 9.62 to
31.00 degrees, M = 16.90, SD = 4.31) and the variability of 02 is relatively small (from
175.86 to 185.86 degrees, M = 179.55, SD = 2.32) and the Pearson correlation coefficient
between pelvic tilt (01) and thigh alignment (02) was not significant (r = .145) the
preponderance of the relationship between pelvic tilt and hip angle was likely the result
of the correlation between 01 and itself embedded in 03.

Because a relationship between pelvic tilt and hip angle can be primarily
explained by imbedding Of pelvic tilt in the value of hip angle, even though there was a
high correlation between the two variables, its support for hypothesis 1 is very limited. In
addition, the low correlation (r = .299) between pelvic tilt and two-joint hip flexor length
does not provide strong support for hypothesis 1. In summary, two significant
correlations do not provide strong support for the postural models described by Kendall,

McCreary, and Provance (1993). These results supported previous findings of no

53

significant relationships between hamstring tightness and pelvic tilt (Gajdosik, Albert, &
Mitman, 1994; Li, McClure, & Pratt, 1996) and between pelvic tilt and hip muscle
flexibility (Hellsing, 1988; Nourbakhsh & Arab, 2002).

The current study also measured the location of the body’s center Of pressure
relative to the lateral malleolus and hip angle that were not selected as variables in similar
research studies. From center of pressure calculations a relationship between (a) center of
pressure distance from the lateral malleolus and pelvic tilt and (b) center of pressure
distance from the lateral malleolus and hip angle were expected to be found because
center of mass is affected by movements of lower extremity joints (Bot, Caspers, Van
Royen, Toussaint, & Kingrna, 1999). In addition, center of pressure distance from the
lateral malleolus was expected to help explain anterior-posterior positioning of the hip
joint. However, no relationships between center of pressure and other variables were
found.

Body Mass Index (BMI) was calculated and compared with pelvic tilt to explore
another possible source that might influence posture during quiet standing. There was no
significant correlation between BMI and pelvic tilt (r = -.0075). Youdas, Garrett, Egan,
and Themeau (2000) have also reported that there were no correlations between pelvic tilt

and BMI (r = .41 for females and r = .20 for males).

54

Hypothesis 2

The following is a restatement of hypothesis 2: Pelvic tilt, hip angle, and hip
muscle length (one-joint hip flexor length and hip extensor length) have no diflerences
between college-aged Caucasian and Eastern Asian males.

In the current study no significant differences in pelvic tilt and hip angle in quiet
standing posture; one-j oint hip flexor length, and hip extensor length were found between
Caucasian and Eastern Asian male participants. The results did not support belief that
there was a difference in standing posture between Caucasian and Eastern Asian races. In
Eastern Asian participants, their standing posture (pelvic tilt and thigh alignment) was not
significantly different from the Caucasian participants.

The current study only focused on anterior-posterior or single plane relationships
(i.e., sagittal plane relationships) in quiet standing posture. However, hip joint actions
occur in three dimensions (i.e., flexion—extension in the sagittal plane,
adduction-abduction in the frontal plane, and intemal-extemal rotation in the transverse
plane). In the current study the greater trochanter was simply dealt with as the axis of
rotation for sagittal plane movement of the femur. However, the hip joint is a

ball-and-socket joint in which the head of the femur articulates with the acetabulum of

55

 

the innominate. This means that the hip joint does not have an exact and immovable point
for joint actions as represented in this study by the greater trochanter. Because the pelvis,
spine, and femur engage in three dimensional movements, two dimensional analysis of
the movements of the body may not be enough to explain real life movement in this
region. Further study Should take these factors into consideration.

The current study recruited Caucasian and Eastern Asian male participants so
that in addition to hip muscle length race could be explored as a possible variable to
influence standing posture. No differences were found in standing posture between
Caucasians and EaStem Asians. One possible reason for this result was that the recruited
participants may not have been good representatives of their respective races. All
participants were recruited in the United States. Differences might have been found if
Eastern Asians were recruited in their country of origin because culture may precipitate
functional and structural differences in quiet standing posture. In addition to race, the
culture in which the participants live over an extended period of time should be
considered in future studies.

Kendall, McCreary, and Provance (1993) had stated that Asian people exhibit
flat-back posture, different from most American and Europeans, without indicating where

they made their observations. The current study did not find any supportable relationships

56

between variables measured and race of the participants associated with quiet standing
posture. The number of participants was minimally enough to study race differences. A
much larger population may have helped to elucidate differences.

Kendall, McCreary, and Provance (1993) presented the postural models in quiet
standing to show relationships between hip muscle length, standing posture, and low back
pain. Many researchers attempted to find the relationships. However, these relationships
have not been sufficiently supported. Gajdosik, Albert, and Mitman (1994) concluded
that hamstring length had limited effect on pelvic tilt, lumbar angle, and thoracic angle.
Li, McClure, and Pratt (1996) reported that hamstring length had no significant
relationships with lumbar lordosis (r = -.11) and with pelvic. tilt (r = .277). Nourbakhsh
and Arab (2002) studied the relationships between low back pain and mechanical factors,
including pelvic tilt and hip muscle flexibility. There were no significant relationships
between hamstring length and pelvic tilt (r = .08) and between hamstring length and the
size of lumbar lordosis (r = .11). NO relationships between one-joint hip flexor length and
the size of lumbar lordosis (r = -.05) and between one-joint hip flexor length and pelvic
tilt (r = .07) were found. Youdas, Garrett, Harmsen, Suman, and Carey (1996) studied the
relationship between pelvic tilt and lumbar lordosis in healthy adults. No relationship

between pelvic tilt and lumber lordosis (r = .06 for males and r = -.08 for females) was

57

found. Youdas, Garrett, Egan, and Themeau (2000) studied relationships between lumbar
lordosis and pelvic tilt among people with or without low back pain. Neither the female
nor male participants with chronic low back pain demonstrated an increased lumbar
lordosis and pelvic tilt compared with participants without low back pain. Harreby et a1.
(1999) and Tafazzoli and Lamontagne (1996) concluded that there was no relationship
between low back pain and hamstring length.

The current study supported the results of the previous researches in
relationships between quiet standing posture and hip muscle length. In addition, the
current study demonstrated that racial difference (Caucasian and Eastern Asian males) did
not have significant effect on quiet standing posture and hip muscle length. Since posture
is a complicated mechanism, differences in posture may not be explained by a single
factor. Other reasons such as genetic, social, or geographical differences as well as

physical reasons such as skeletal or muscle mass differences should be considered.

58

CHAPTER 5
CONCLUSIONS
There were no relationships between pelvic tilt, hip angle, one- and two-joint hip
flexor length, hip extensor length, and center of pressure location relative to the lateral
malleolus among Caucasian and Eastern Asian male participants, except for a relationship
between pelvic tilt and hip angle. However, this relationship was not clear due to the fact
that pelvic tilt was embedded in hip angle. These results were consistent with previous
researches that explored relationships between postural imbalances and hip muscle length.
NO race difference was found in standing posture (pelvic tilt and hip angle) and hip
muscle length (one-joint hip flexor length and hip extensor length) between Caucasian
and Eastern Asian males. Standing posture in Eastern Asian participants was not
significantly different from the Caucasian participants. The results did not support a
belief that there were differences in quiet standing posture between races. Posture is a
complicated mechanism and not determined by a single factor such as hip muscle length

or racial difference.

59

APPENDICES

60

APPENDIX A
Flyer to Recruit Participants

61

Research Participants Needed

Relationships between hip muscle extensibility, hip joint angle,
and pelvic tilt in static standing posture among college-aged
healthy Caucasian and Eastern Asian

Eligibility:
0 Healthy males (18-30 years of age)
0 Caucasian (White) or
0 Eastern Asian (Chinese, Korean, Taiwanese, or
Japanese)
0 No recent history of serious leg and low back injury

Measurements:
0 Standing posture analysis
Range of motion of lower extremity
Weight distribution under feet
Short survey about national origin and injury history
Need only one session
Will take about 20 minutes for each participant

You will receive: $10 for participation
Location: Biomechanics Research Station (107 IM Circle)
Date: 6I28l04 to BIS/04, 9am to 6pm

Contact:
Tom Tanaka, ATC, CSCS.
Graduate Student in Department of Kinesiology,

Email: tanakato@msu.edu

<> Email or visit Biomechanics Research Station (107 IM
Circle) for detail information and scheduling

62

APPENDIX B
Informed Consent

63

Consent Form — “Relationships between hip muscle length, hip joint angle, and
pelvic tilt in static standing posture among college-aged healthy Caucasian and

Eastern Asian males”

The purposes of this study are to understand the 1) relationship between hip
joint angle and effect of hip joint muscle flexibility and 2) race differences in standing
posture and the possible reasons. It is believed that hip joint muscle flexibility has
associations with standing postural patterns and there are differences in standing posture
between Caucasian and Asian people. This study will attempt to find their possible
explanations by assessing and comparing measurements of physical characteristics.

The data collection session will last approximately 30 minutes and participants
will be asked to participate in only one data collection session. Participants should not
have any lower extremity injury, low back pain, and extreme postural imbalance. Data
collection will have following stages:

1. General information: You will be given general information about this study and a
chance to ask questions.

2. Measurements: All measurements will be collected in private in the Department of
Kinesiology’s Biomechanics Research Station located in the IM Sports Circle
Building on the campus of Michigan State University.

0 Weight will be assessed on a standard weight balance while you are wearing only

shorts and t-shirt (tucked into shorts)

Height will be assessed with a standard stadiometer

You will be asked to warm up by using a stationary bike in 3 minutes

0 A picture in a static and comfortable standing posture will be taken from your right
side by using a digital camera. Five colored marks will be placed on your body to
identify bony landmarks. The picture will be used to measure angles of pelvic tilt and
hip joint.

0 Center of pressure will be measured at the same time when you will be taken a
picture in standing posture

0 Range of motion of your hip flexor and extensor muscles will be measured with a
mechanical goniometer. You will be asked to perform two different tasks while you
will lie down on your back on the table.

3. Survey: About your origin and injury history

4. Payment: You will receive $10 for your participation

You are asked to participate in this study because you are college-aged healthy

Caucasian or Eastern Asian. Your participation is totally voluntary. You may choose to

64

participate or not and discontinue your participation at any time without any explanation.
By participating in this study, you agree that the materials and data generated (picture
and measurements) may be used for research and academic purposes. You have also been
assured that your privacy will be protected to the maximum extent allowable by law.
When this research is completed, an abstract of the results will be emailed to you. You
may also seek personal data for comparison to your and other ability and race group.

If you are injured as a result of your participation in this research project,
Michigan State University will assist you in obtaining emergency care, if necessary, for
your research related injuries. If you have insurance for medical care, your insurance
carrier will be billed in the ordinary manner. As with any medical insurance, any costs
that are not covered or in excess of what are paid by your insurance, including
deductibles, will be your responsibility. Financial compensation for lost wages, disability,
pain or discomfort is not available. This does not mean that you are giving up any legal
rights you may have.

If you have any questions about this study, please contact Dr. Eugene Brown
(353-6491, ewbrown@mus.edu) or Tom Tanaka (355-5881, tanakato@msu.edu) at the
Kinesiology Department, Michigan State University. If you have questions or concerns
regarding your rights as a study participant, or are dissatisfied at any time with any
aspect of this study, you may contact — anonymously, if you wish- Peter Vasilenko, Ph.D.,
Chair of the University Committee on Research Involving Human Subject (UCRIHS) by
phone: (517)355-2180, fax: (517)432-4503, email: ucrihs@msu.edu, or regular mail: 202
Olds Hall, East Lansing, MI 48824.

Your signature below indicates your voluntary agreement to participate in this
study.

Name of Participant: Signature:
Date:

Mailing Address:

Phone: Email Address:

Date of Birth:

 

 

 

 

 

65

APPENDIX C
Short Survey

66

Survey Form - “Relationships between hip muscle length, hip joint angle,
and pelvic tilt in static standing posture among college-aged healthy
Caucasian and Eastern Asian males

 

 

 

 

 

 

 

1. Name:

2. Age:

3. Are you _Caucasian or _Eastern Asian (Chinese, Korean, Taiwanese, or
Japanese)?

4. Do you have an ancestor from other ethnic origin? _Yes _No
If yes, from where?

5. Have you ever been diagnosed with low back pain? _Yes _No
If yes, when?

6. Have you ever been diagnosed with lower extremity injury? _Yes _No
if yes, which body part?
If yes, when?

7. Have you ever been diagnosed with pubic symphysis, pelvic girdle, or sacrum
problems?
_Yes _No
If yes, when?

Signature: Date:

 

 

 

67

APPENDIX D
Descriptive Statistics of Participants

68

 

Participants Age (yrs) Height (cm) Weight (kg) BMI
Cl 26 183.6 100 29.67
C2 23 178.9 69.13 21.6
C3 22 167.5 73.39 26.16
C4 22 166.7 69.44 24.99
C5 21 177 94.59 30.19
C6 23 176.2 86.98 28.01
C7 21 179.3 70.12 21.81
C8 25 176.2 83.62 26.94
C9 19 171.8 59.34 20.11
C10 23 183.2 83.26 24.81
C11 21 178.8 98.66 30.86
C12 23 181.2 73.48 22.38
C13 23 183.3 97.85 29.12
C14 22 194.9 97.35 25.63
C15 25 175 72.84 23.79
C16 23 173.8 78.82 26.09
C17 21 159 61.34 24.26
C18 19 179.3 77.15 24
C19 22 193.4 73.84 19.74
C20 21 172.8 61.97 20.75
C21 26 171.2 86.61 29.55
A1 24 171 64.46 22.05
A2 22 182.1 76.56 23.09
A3 25 175.4 67.04 21.79
A4 28 172.9 66.82 22.35
A5 28 169.2 53.54 18.7
A6 24 171.2 56.63 19.32
A7 30 175 63.33 20.68
A8 29 175 64.78 21.15
A9 24 173.3 72.89 24.27

A10 35 174.3 89.38 29.42
A1 1 34 169.7 76.65 26.62
A12 26 173 63.96 21.37

69

 

 

 

 

Participants Age (yrs) Height (cm) Weight (kg) BMI
A13 32 167.3 77.83 27.81
A14 32 166.3 68.31 24.7
A15 29 171.4 71.48 24.33
A16 30 177.3 70.85 22.54
A17 34 176.5 78.82 25.3
A18 32 169.2 71.39 24.94

C — Mean 22.43 177.3 79.51 25.26
C — SD 1.938 8.242 12.86 3.439
A— Mean 28.78 172.8 69.71 23.36
A— SD 3.949 3.875 8.484 2.838
TP - Mean 25.36 175.2 74.99 24.38
TP - SD 4.386 6.903 11.99 3.279

 

C = Caucasian
A = Eastern Asian
TP = Total Population

SD = Standard Deviation

70

APPENDIX E
UCRIHS Approval Letter

71

MICHIGAN STATE

UNIVERSITY

 

June 22, 2004

TO: Eugene W. BROWN
204 lM Sports Circle Bldg

RE: IRB# 04-434 CATEGORY: EXPEDITED 2-4, 2-6

APPROVAL DATE: June 8, 2004
EXPIRATION DATEJune 8, 2005

TITLE: Relationships between hip muscle extensibility, hip joint angle, and pelvic tilt in
static standing posture among college-aged healthy Caucasian and Eastern
Asian

The University Committee on Research Involving Human Subjects' (UCRIHS) review of this
project is complete and i am pleased to advise that the rights and welfare of the human
subjects appear to be adequately protected and methods to obtain informed consent are
appropriate. Therefore, the UCRIHS approved this project.

RENEWALS: UCRIHS approval is valid until the expiration date listed above. Projects
continuing beyond this date must be renewed with the renewal form. A maximum of four such
expedited renewals are possible. Investigators wishing to continue a project beyond that time
need to submit a 5-year application for a complete review.

REVISIONS: UCRIHS must review any changes in procedures involving human subjects, prior
to initiation of the change. If this is done at the time of renewal, please include a revision form
with the renewal. To revise an approved protocol at any other time during the year, send your
written request with an attached revision cover sheet to the UCRIHS Chair, requesting revised
approval and referencing the project‘s IRB# and title. include in your request a description of
the change and any revised instruments, consent forms or advertisements that are applicable.
PROBLEMSICHANGES: Should either of the following arise during the course of the work,
notify UCRIHS promptly: 1) problems (unexpected side effects, complaints, etc.) involving
human subjects or 2) changes in the research environment or new information indicating
greater risk to the human subjects than existed when the protocol was previously reviewed and
approved.

If we can be of further assistance, please contact us at (517) 355-2180 or via email:
UCRIHS@msu.edu. Please note that all UCRIHS forms are located on the web:
http://www.humanresearchmsuedu

Sincerely,

Peter Vasilenko, PhD.
UCRIHS Chair

72

APPENDIX F
UCRIHS Approval Letter for Revision

73

MICHIGAN STATE
U N l V E R S I T Y
Ju|y15,2004

 

TO: Eugene W. BROWN
204 IM Sports Circle Bldg

RE: IRB# 04-434 CATEGORY: 2-4. 2-6 EXPEDITED

APPROVAL DATE: June 8, 2004
EXPIRATION DATE: June 8, 2005

TITLE: Relationships between hip muscle extensibility, hip joint angle, and pelvic tilt in static
standing posture among college-aged healthy Caucasian and Eastern Asian

The University Committee on Research Involving Human Subjects' (UCRIHS) review of this project is
complete and I am pleased to advise that the rights and welfare of the human subjects appear to be
adequately protected and methods to obtain informed consent are appropriate. Therefore, the
UCRIHS APPROVED THIS PROJECT'S REVISION.

REVISION REQUESTED: July 9, 2004
REVISION APPROVAL DATE: July 9. 2004

Revision to include a change In the subject incentive and consent. The new consent
is to replace the current one.

REVISIONS: UCRIHS must review any changes in procedures involving human subjects, prior to
initiation of the change. If this is done at the time of renewal, please use the green renewal form.
To revise an approved protocol at any other time during the year, send your written request to the
UCRIHS Chair, requesting revised approval and referencing the project's IRB# and title. Include in
your request a description of the change and any revised instruments, consent forms or
advertisements that are applicable.

PROBLEMS/CHANGES: Should either of the following arise during the course of the work, notify
UCRIHS promptly: 1) problems (unexpected side effects, complaints, etc.) involving human
subjects or 2) changes in the research environment or new information indicating greater risk to the
human subjects than existed when the protocol was previously reviewed and approved.

if we can be of further assistance, please contact us at (517) 355-2180 or via email:
UCRIHS@msu.edu.

Sincerely,

fled/'8’”?

Peter Vasilenko, Ph.D.
UCRIHS Chair

74

APPENDIX G
Raw Data for Six Dependent Variables

75

 

One-Joint Two-Joint Hip
Pelvic Thigh . Center of
Hip Flexor Hip Flexor Extensor
Participants Tilt 01 Alignment Length 04 Length 06 Length 07 Pressure
(deg) 03 (deg) (m)
(deg) (deg) (deg)

C1 10.06906 188.9501 186 105 162 0.064053
C2 30.963 76 216.8253 185 110 149 0.067455
C3 20.28256 200.2826 189 117 157 0.044188
C4 21.69511 201.1695 187 106 163 0.041665
C5 9.619728 187.1516 186 113 140 0.056049
C6 19.24188 195.6971 164 118 176 0.073745
C7 13.87753 198.3853 189 100 160 0.044628
C8 20.73871 204.5027 178 120 143 0.050545
C9 19.65382 198.9494 173 119 158 0.055487
C10 15.61939 194.1813 191 107 146 0.070029
C11 18.13019 198.5998 182 90 150 0.034513
C 12 13.59095 194.0664 190 90 154 0.075078
C13 10.26137 188.224 191 108 156 0.035761
C 14 18.43495 195.3646 187 95 145 0.069023
C15 17.60463 195.9409 192 98 138 0.034922
C16 17.22344 196.5132 192 112 164 0.058198

C17 15.76718 196.3373 183 113 141 0.03393
C18 18.04782 195.7294 181 122 162 0.073698
C19 11.66877 189.2646 192 104 157 0.054351
C20 11.17384 190.1508 186 108 147 0.084416
C21 21.27497 197.1341 183 113 158 0.064485
A1 10.12467 187.9636 169 101 155 0.098552
A2 17.42986 199.6707 187 104 152 0.127692
A3 12.77873 195.0899 196 100 144 0.047996
A4 14.97288 192.8903 191 104 151 0.055302
A5 22.19029 200.5918 174 118 148 0.055901
A6 16.69924 196.4523 178 103 143 0.051546
A7 16.03994 196.0399 173 116 143 0.063667
A8 17.70043 199.277 189 125 140 0.089334
A9 22.61986 199.5751 179 128 153 0.060019

 

76

 

 

 

 

One-Joint Two-Joint Hip
Pelvic Thigh Center of
. Hip Flexor Hip Flexor Extensor
Participants Tilt 01 Alignment Length 94 Length 06 Length 07 Pressure
(deg) 93 (deg) (m)
(deg) (deg) (deg)

A10 14.55357 194.5536 183 126 161 0.066012
A11 18.78862 198.5305 185 117 165 0.066757
A12 18.97041 197.9609 187 119 153 0.076195
A13 22.91283 199.0622 191 110 145 0.049176
A14 15.64225 194.2783 178 120 157 0.06786
A15 15.00492 199.6342 183 90 146 0.037617
A16 18.08345 197.5916 182 110 159 0.106886
A17 15.12401 195.4514 171 120 164 0.048918
A18 14.77455 193.9152 179 111 170 0.049752
C — Mean 16.90189 196.3533 185.0952 108 153.619 0.056487

C — SD 5.058925 6.507301 6.905829 9.348797 9.635747 0.015401
A — Mean 16.9117 196.5849 181.9444 112.3333 152.7222 0.067732
A - SD 3.367365 3.183399 7.487026 10.40362 8.628309 0.023727
TP — Mean 16.90641 196.4602 183.641 110 153.2051 0.061677
TP — SD 4.306118 5.180168 7.260155 9.960448 9.076225 0.020223

 

 

C = Caucasian

A = Eastern Asian

TP = Total Population
SD = Standard Deviation

77

REFERENCES

Alviso, D. J ., Dong, G T., & Lentell, G L. (1988). Intertester reliability for measuring
pelvic tilt in standing. Physical therapy, 68(9), 1347-1351.

Bot, S. D. M., Caspers, M., Van Royen, B. J ., Toussaint, H. M., & Kingma, I. (1999).
Biomechanical analysis of posture in patients with spinal kyphosis due to
ankylosing spondylitis: a pilot study. Rheumatology, 38, 441 -443.

D’amico, E. J ., Neilands, T. B., & Zambarano, R. (2001). Power analysis for multivariate
and repeated measures designs: A flexible approach using the SPSS MAN OVA
procedure. Behavior Research Methods, Instruments, & Computers, 33(4),
479-484.

Gabbe, B. J ., Bennell, K. L., Wajswelner, H., Finch, C. F. (2004). Reliability of common
lower extremity musculoskeletal screening tests. Physical Therapy in Sport, 5,
90-97.

Gajdosik, R. L., Albert, C. R., & Mitman, J. J. (1994). Influence of hamstring length on
the standing position and flexion range of motion of the pelvic angle, lumbar

angle, and thoracic angle. Journal of Orthopaedic and Sports Physical Therapy,
20(4), 213-219.

Gajdosik, R. L., & Lusin, G (1983). Hamstring muscle tightness. Reliability of an
active-knee-extension test. Physical Therapy, 63(7), 1085-1088.

Gajdosik, R., Simpson, R., Smith, R., & DonTigny, R. L. (1985). Pelvic tilt. Intratester
reliability of measuring the standing position and range of motion. Physical
Therapy, 65(2), 169-74.

Harreby, M., Nygaard, B., Jessen, T., Larsen, E., Storr-Paulsen, A., Lindahl, A., Fisker, 1.,
& Laegaard, E. (1999). Risk factors for low back pain in a cohort of 1389

Danish school children: An epidemiologic study. European Spine Journal, 8,
444-450.

78

Harvey, D. (1998). Assessment of the flexibility of elite athletes using the modified
Thomas test. British Journal of Sports Medicine, 32(1), 68-70

Hellsing, A. L. (1988). Tightness of hamstring- and psoas major muscles: A prospective
study of back pain in young men during their military service. Uppsala Journal
of Medicine and Science, 93, 267-276.

Jackson, R. P., & McManus, A. C. (1994). Radiographic analysis of sagittal plane
alignment and balance in standing volunteers and patients with low back pain

matched for age, sex, and size: A prospective controlled clinical study. Spine,
19(14), 1611-1618.

Kendall, F. P., McCreary, E. K., & Provance, P. G (1993). Muscles: Testing and function,
(pp. 20, 75, 354, & 419). Baltimore, ML: Williams & Wilkins.

Konin, J. F., Wiksten, D. L., & Isear, J. A. (1997). Special Tests for Orthopedic
Examination, (pp. 132). Thorofare, NJ: SLACK Incorporated.

Lee, C. S., Lee, C. K., Kim, Y. T., Hong, Y. M., & Yoo, J. H. (2001). Dynamic sagittal
imbalance of the spine in degenerative flat back: Significance of pelvic tilt in
surgical treatment. Spine, 26(18), 2029-2035.

Levine, D., & Whittle, M. W. (1996). The effects of pelvic movement of lumbar lordosis

in the standing position. Journal of orthopaedic and sports physical therapy,
24(3), 130-135.

Li, Y., McClure, P. W., & Pratt, N. (1996). The effect of hamstring muscle stretching on
standing posture and on lumbar and hip motions during forward bending.
Physical Therapy, 76(8), 836-845.

Magee, D. J. (2002). Orthopedic Physical Assessment, (pp.571, 634). Philadelphia, PA:
Saunders.

Mulhearn, S., & George, K. (1999). Abdominal muscle endurance and its association
with posture and low back pain: An initial investigation in male and female
elite gymnasts. Physiotherapy, 85(4), 210-216.

79

Norris, C. M. (1995). Spinal stabilization: 2. Limiting factors to end-range motion in the
lumbar spine. Physiotherapy, 81(2), 64-72

Nourbakhsh, M. R., & Arab, A. M. (2002). Relationship between mechanical factors and
incidence Of low back pain. Journal of Orthopaedic and Sports Physical
Therapy, 32(9), 447-460.

Shimba, T. (1984). An estimation of center of gravity from force platform data. Journal
of Biomechanics, 1 7(1), 53-60.

Starkey, C., & Ryan, J. L. (1996). Evaluation of Orthopedic and Athletic Injuries, (pp.
218). Philadelphia, PA: F. A. Davis Company.

Tafazzoli, F., & Lamontagne, M. (1996). Mechanical behavior of hamstring muscle in

low-back pain patients and control subjects. Clinical Biomechanics, 11(1),
16-24.

Watson, A. W. S. (1995). Sports injuries in footballers related to defects of posture and
body mechanics. Journal of Sports Medicine and Physical Fitness, 35,
289-294.

Winter, D. A. (1990). Biomechanics and Motor Control of Human Movement, (pp. 94).
New York, NY: John Wiley & Sons, Inc.

Winter, D. A., Patla, A. E., Prince, F., Ishac, M., & Gielo-Perczak, K. (1998). Stiffness

control of balance in quiet standing. Journal of Neurophysiology, 80,
1211-1221.

Youdas, J. W., Garrett, T. R., Egan, K. S., & Themeau, T. M. (2000). Lumbar lordosis and

pelvic inclination in adults with chronic low back pain. Physical Therapy, 80(3)
261-275.

9

Youdas, J. W., Garrett, T. R., Harmsen, S., Suman. V. J ., & Carey, J. R. (1996). Lumbar

lordosis and pelvic inclination of asymptomatic adults. Physical Therapy,
76(10), 1066-1081.

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