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Effects of Specific Movement Control Exercises on Lumbopelvic Motion and Trunk Muscle Activity During Walking

in Subjects With Lumbar Extension Rotation Pattern

The Graduate School

Yonsei University

Department of Physical Therapy

Sihyun Kim

Effects of Specific Movement Control Exercises on Lumbopelvic Motion and Trunk Muscle Activity During Walking

in Subjects With Lumbar Extension Rotation Pattern

Sihyun Kim

A Dissertation Submitted to the Department of Physical Therapy

and the Graduate School of Yonsei University in partial fulfillment of the

requirements for the degree ofDoctor of Philosophy

June 2014

This certifies that the doctoral dissertation ofSihyun Kim is approved.

The Graduate SchoolYonsei University

June 2014

Thesis Supervisor: Ohyun Kwon

Chunghwi Yi: Thesis Committee Member #1

Heonseock Cynn: Thesis Committee Member #2

Houngsik Choi: Thesis Committee Member #3

Jonghyuck Weon: Thesis Committee Member #4

Acknowledgements

In my life, the greatest opportunity was meeting my principal supervisor, Prof. Oh–

yun Kwon. In my early 20s, I was young and lacking in expertise in my area, but after

I met him, he provided a chance for me to grow. His creative thinking and

professional mind influenced me, so that I did not settle for the present and studied

and developed endlessly as a scholar. Without his help and guidance, it would have

been impossible for me to accomplish this research and develop my clinical skills. I

will not forget his assistance and affection. I take this chance to express my thanks to

him once again.

I also acknowledge Prof. Chung–hwi Yi for academic support and continued

attention. I thank Prof. Heon–seock Cynn for detailed comments and warm advice. I

learned so much from them and the quality of my dissertation was improved greatly

with their help. I want to express my deep appreciation to Prof. Jong–hyuck Weon

and Prof. Houng–sik Choi, who gave sincere advice and encouragement. I also

sincerely appreciate the help from Sang–hyun Cho, Joshua You, and Hye–seon Jeon

who gave continuous assistance and teaching during my doctoral courses.

I also thank my seniors, Jae–seop Oh, Mun–hwan Kim, Won–whee Lee, Sung–min

Ha, Su–jung Kim, Kyue–nam Park, and Sung–dae Choung, who spent a long time

with me during graduate school and were always willing to help. I am also grateful to

Young Kim, In–cheol Jeon, Ui–jae Hwang, Sun–hee Ahn, Sung–hoon Jung, and

Hyun–a Kim. I thoroughly enjoyed my doctoral student life with them. I am

immeasurably grateful for their support and help. I also thank all of my fellow

graduate students in the Department of Physical therapy and the subjects who

participated in my research.

Besides scholarly support, above all, I express deep appreciation to my family who

gave continuous affection and care. I could concentrate on my studies without any

difficulty with their support.

Although graduate school was difficult, it was also a challenge to constantly

develop more; I learned and gained many things. I sincerely express my deepest

gratitude once again to all the people who helped me to finish my dissertation.

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Table of Contents

List of Figures ···································································· ⅳ

List of Tables ····································································· ⅵ

Abstract ··········································································· ⅶ

Chapter

I. Introduction ····································································· 1

II. Comparison of Lumbopelvic Motion and Trunk Muscle Activity During

· Walking between Subjects With and Without Lumbar Extension Rotation

Pattern (Study 1)

Introduction ······································································· 3

Method ············································································· 7

1. Subjects ······································································ 7

2. Procedure ··································································· 10

3. Measurements ······························································ 11

3.1 Clinical Measures ····················································· 11

3.2 Surface Electromyography ··········································· 11

3.3 Kinematic Data ························································ 12

4. Data Analysis ······························································· 13

5. Statistical Analysis ························································ 15

Results ············································································ 16

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1. Spatio–temporal Parameters During Walking ·························· 16

2. Kinematics of Lumbopelvic Region ····································· 17

3. Electromyography Activities of Trunk Muscle ························ 20

Discussion ········································································ 25

III. Effects of a 6–week Program of Specific Movement Control Exercises

on Lumbopelvic Motion and Trunk Muscle Activity During Walking

in Subjects with Lumbar Extension Rotation Pattern (Study 2)

Introduction ······································································ 33

Method ············································································ 37

1. Design ······································································· 37

2. Subjects ····································································· 38

3. Measurements ······························································ 40

3.1 Clinical Measures ····················································· 40

3.2 Kinematics and Surface Electromyography ························ 40

4. Procedure ··································································· 42

5. Intervention ································································· 43

6. Data Analysis ······························································· 44

7. Statistical Analysis ························································ 46

Results ············································································ 47

1. Subject Characteristics ···················································· 47

2. Clinical Measures ·························································· 48

3. Spatio–temporal Parameters During Walking ·························· 50

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4. Kinematics of Lumbopelvic Region ····································· 51

5. Electromyography Activities of Trunk Muscle ························ 56

Discussion ········································································ 61

IV. Summary and Conclusion ·················································· 68

References ········································································ 70

Abstract in Korean ······························································· 79

Appendix 1. Protocol for the movement control exercise ···················· 83

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List of Figures

Figure 1. Comparison of the averaged pelvic and lumbar angles in the

sagittal and transverse planes between subjects with and without

the lumbar ExtRot pattern ··········································· 19

Figure 2. Comparison of the averaged ES and RA muscle activities

between subjects with and without the lumbar ExtRot pattern ·· 23

Figure 3. Comparison of the averaged EO and IO muscle activities

between subjects with and without the lumbar ExtRot pattern ·· 24

Figure 4. Flow chart for subject selection ····································· 39

Figure 5. Comparison of the averaged pelvic angle in the sagittal and

transverse planes during walking between pre– and post–

intervention ···························································· 54

Figure 6. Comparison of the averaged lumbar spine angle in the sagittal

and transverse planes during walking between pre– and post–

intervention ···························································· 55

Figure 7. Comparison of the averaged ES muscle activities during walking

between pre– and post–intervention ································ 57

Figure 8. Comparison of the averaged RA muscle activities during walking


Figure 9. Comparison of the averaged EO muscle activities during walking

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Figure 10. Comparison of the averaged IO muscle activities during walking


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List of Tables

Table 1. Subject’s characteristics ··············································· 9

Table 2. Stride characteristics ·················································· 16

Table 3. Pelvic and lumbar angles in sagittal and transverse planes in

subjects with and without the lumbar ExtRot pattern ············· 18

Table 4. Trunk muscle activities for subjects with and without the lumbar

ExtRot pattern ························································· 21

Table 5. Subject’s characteristics ·············································· 47

Table 6. Changes in pain intensity, disability, and fear avoidance beliefs

after 6–week intervention ··········································· 49

Table 7. Stride characteristics at pre–intervention ··························· 50

Table 8. Pelvic and lumbar angles in the sagittal and transverse planes ·· 52

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ABSTRACT

Effects of Specific Movement Control Exercises on

Lumbopelvic Motion and Trunk Muscle Activity

During Walking in Subjects With Lumbar

Extension Rotation Pattern

Sihyun Kim

Dept. of Physical Therapy

The Graduate School

Yonsei University

Walking is one of the most repetitive movements in daily activities and changes in

lumbopelvic motion and trunk muscle activities during walking are critical indicators

of spinal dysfunction. The purpose of Study 1 was to demonstrate the differences in

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lumbopelvic motion and trunk muscle activities during walking between subjects with

and without a lumbar extension rotation (ExtRot) pattern. In total, 26 subjects with a

lumbar ExtRot pattern and 18 subjects without lumbar ExtRot were recruited. Twenty

reflective markers were placed on the lower extremity and lumbar spine and a 3–D

motion analysis system was used to measure lumbopelvic kinematics. A surface

electromyography (EMG) system was used to measure the trunk muscle activities and

surface electrodes were attached on both rectus abdominis (RA), abdominal external

oblique (EO), abdominal internal oblique (IO), and erector spinae (ES) muscles. All

subjects walked 12 times at a self–selected (comfortable) walking speed on the

walkway. Kinematic data, at initial heel strike (HS), left toe–off (TO), left HS, and

right TO, and EMG data at first double support, left swing, second double support,

and right swing phase were used for the statistical analyses. To compare kinematic

and EMG data between subjects with and without the lumbar ExtRot pattern,

independent t–tests for parametric variables and Mann–Whitney U–tests for non–

parametric variables were used. Subjects with a lumbar ExtRot pattern showed

significantly increased pelvic and lumbar angles in the sagittal plane (p < 0.05);

however, there was no significant difference in the pelvic or lumbar angle in the

transverse plane between subjects with and without a lumbar ExtRot pattern (p >

0.05). In EMG activity, significantly increased activities in both ES muscles at all

events and decreased right IO muscle activity at the second double support phase

were seen in subjects with a lumbar ExtRot pattern versus subjects without (p < 0.05).

Both RA, EO, and IO muscle activities, except the right IO muscle activity at the

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second double support phase, were not significantly different between subjects with

and without the lumbar ExtRot pattern (p > 0.05).

The purpose of Study 2 was to demonstrate the effects of a 6–week specific

movement control exercise on pain behavior, lumbopelvic motion, and trunk muscle

activities during walking in subjects with a lumbar ExtRot pattern. In total, 39

subjects with lumbar a ExtRot pattern (experimental = 19; control = 20) participated

in this study. Subjects in the experimental group performed 6 weeks of movement

control exercises and the exercise level of difficulty was adjusted progressively.

Clinical outcome measures included pain intensity (visual analog scale), level of

disability (Oswestry disability index and Roland Morris disability questionnaire), and

fear and avoidance level (Fear–avoidance beliefs questionnaire) caused by low back

pain (LBP). To measure lumbopelvic kinematics and EMG activities in the trunk

muscles (RA, EO, IO, and ES) during walking, all subjects walked on an 8–m–long

straight walkway. Kinematic data at initial right HS, left TO, left HS, and right TO

and the EMG data at first double support, left swing, second double support and right

swing phase were used for the statistical analysis. The Wilcoxon signed–rank test for

non–parametric variables and the paired t–test for parametric variables were used to

compare baseline and follow–up treatment within a group. After the 6–week

intervention, pain intensity, level of disability, and fear and avoidance level caused by

LBP were decreased significantly in the experimental group. Additionally, there were

significantly decreased angles in the lumbar spine and pelvic region in the sagittal

plane at all events in the experimental group. However, there was no significant

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difference in the pelvic or lumbar angle in the transverse plane in either group. In the

EMG data, right ES muscle activity was decreased significantly during the first and

second double support phase and left ES muscle activity was also decreased

significantly during the second double support phase in the experimental group.

However, in the control group, there was no significant difference in lumbopelvic

motion or ES muscle activity. After the 6–week intervention, there was no significant

difference in abdominal muscle activity in either group.

Based on these two studies, it was demonstrated that subjects with a lumbar ExtRot

pattern had greater angle in the lumbar spine and pelvic region in the sagittal plane,

increased ES muscle activities at all events, and decreased right IO at the second

double support phase during walking, compared with subjects without a lumbar

ExtRot pattern. These changed patterns of lumbopelvic motion in the sagittal plane

and ES muscle activity and pain behavior in subjects with a lumbar ExtRot pattern

can be improved by specific movement control exercises over a 6–week course. Thus,

specific movement control exercises can be an effective treatment for subjects with a

lumbar ExtRot pattern to modify their excessive lumbopelvic motion in the sagittal

plane and excessive muscle activity of the ES in walking.

Key Words: Abdominal muscle, Electromyography, Erector spinae muscle, Low

back pain, Lumbar extension rotation pattern, Lumbopelvic motion,

Walking.

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Chapter Ⅰ

Introduction

Non–specific low back pain (LBP) is a common musculoskeletal problem (Crosbie

et al. 2013; Lamoth et al. 2006a; Seay, Van Emmerik, and Hamill 2011). Patients

with LBP have been reported to change their lumbopelvic kinematics and abdominal

muscle activities during walking (Arendt Nielsen et al. 1996; Crosbie et al. 2013;

Hanada, Johnson, and Hubley Kozey 2011; van der Hulst et al. 2010a, 2010b).

Altered lumbopelvic kinematics and abdominal muscle activities during walking are

important indicators for evaluation and treatment of LBP.

Recently, researchers and clinicians have suggested that sub–classification is

needed regarding treating patients with LBP, based on movement pattern–provoking

pain and/or symptoms in the lumbar spine during lumbar spine or lower extremity

movement (Hoffman et al. 2011; Hoffman et al. 2012; Kim et al. 2013; Sahrmann

2002; Scholtes, Gombatto, and Van Dillen 2009; Van Dillen et al. 2003). Non–

specific LBP is classified into extension, extension rotation (ExtRot), rotation, flexion

rotation, and flexion patterns. The lumbar ExtRot pattern is the most common form of

mechanical LBP (Sahrmann 2002). However, there is insufficient information related

to lumbopelvic motion and trunk muscle activity during walking in subjects with the

lumbar ExtRot pattern.

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For the management of patients with LBP, specific movement control exercises,

based on the sub–classification, have been emphasized by physical therapists (Kim et

al. 2013; Park et al. 2011; Sahrmann 2002; Scholtes, Gombatto, and Van Dillen 2009;

Van Dillen et al. 2003). Although several studies have reported the effects of specific

movement control exercises on LBP, there has been no report of the effects of

specific movement control exercises on lumbopelvic motion or trunk muscle

activities during walking in subjects with a lumbar ExtRot pattern (Hoffman et al.

2011; Maluf, Sahrmann, and Van Dillen 2000; Scholtes et al. 2010).

Thus, this study was designed to compare lumbopelvic motion and trunk muscle

activities during walking in subjects with and without the lumbar ExtRot pattern and

to examine the effects of a specific movement control exercise on lumbopelvic

motion, trunk muscle activity, and pain behavior during walking in subjects with the

lumbar ExtRot pattern.

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Chapter II

Comparison of Lumbopelvic Motion and Trunk Muscle

Activity During Walking between Subjects With and

Without Lumbar Extension Rotation Pattern

(Study 1)

Introduction

Low back pain (LBP) is a major musculoskeletal problem and the relationship

between LBP and motor performance has been studied under dynamic movement

(Crosbie et al. 2013; Lamoth et al. 2006a, 200b; Seay, Van Emmerik, and Hamill

2011). Some investigators have reported that impaired control of lumbopelvic motion

could cause excessive or early lumbopelvic motion during lower extremity movement

(Kim et al. 2013; Park et al. 2011; Scholtes, Gombatto, and Van Dillen 2009;

Scholtes et al. 2010). Specifically, in functional activities, continuous and repetitive

movement of the lumbar spine is one of the important factors in cumulative stress in

soft tissue, which may lead to macro–trauma and pain in the low back. According to

the movement impairment system model, mechanical LBP can be classified into

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lumbar extension, extension rotation (ExtRot), rotation, flexion rotation, and flexion

patterns, based on movement direction of the lumbar spine that induces pain and/or

symptoms (Maluf, Sahrmann, and Van Dillen 2000; Sahrmann 2002; Trudelle-

Jackson, Sarvaiya-Shah, and Wang 2008). These sub–classifications can be diagnosed

through trunk and lower extremity movement tests and patients with lumbar ExtRot

pattern represent the highest proportion of mechanical LBP cases (Hoffman et al.

2011, 2012; Kim et al. 2013; Sahrmann 2002; Scholtes, Gombatto, and Van Dillen

2009; Van Dillen et al. 2003).

Walking is one of most important tasks in daily activities and optimal

neuromuscular control of the lumbopelvic motion is required to maintain trunk

posture in walking (Saunders et al. 2005). Patients with LBP show slower gait

velocity than pain–free individuals (Hanada, Johnson, and Hubley Kozey 2011).

Additionally, a less variable and more tightly coordinated movement between the

pelvic and lumbar spine was demonstrated in individuals with LBP versus healthy

subjects. An abnormal coupling motion may be an indicator of spine dysfunction

(Crosbie et al. 2013; Lamoth et al. 2006a). Thus, it is believed that altered lumbar

motion may be closely related to LBP during walking.

The trunk muscles have been reported to play an important role in the control of

lumbopelvic motion during physical activities (Panjabi 1992; Saunders et al. 2005)

and differences in activation patterns of trunk muscles were demonstrated in patients

with LBP compared with asymptomatic controls (Saunders et al. 2005; van der Hulst

et al. 2010a, 2010b). Erector spinae (ES) muscle activity tends to decrease during the

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ipsilateral and contralateral swing phases of gait, and to increase during double stance

in healthy subjects (Lamoth 2006b; van der Hulst et al. 2010b). However, higher ES

activity was demonstrated in patients with LBP during all gait phases (van der Hulst

et al. 2010a, 2010b). During gait, the rectus abdominis (RA), abdominal external

oblique (EO), and abdominal internal oblique (IO) muscle were activated

continuously during all stride phases, and increased activity of the superficial

abdominal muscles was demonstrated in subjects with LBP compared with controls as

a guarding mechanism for pain (van der Hulst et al. 2010a, 2010b; White, and

McNair 2002). Hanada, Johnson, and Hubley Kozey (2011) reported both RA and

right IO muscle activity in the left loading response phase were activated significantly

more in the control group than in the LBP group. However, these studies were

conducted using different electromyography (EMG) normalization methods and

performed without sub–classification of the mechanical LBP.

Although changes in lumbopelvic kinematics and trunk muscle activities during

walking in the LBP have been reported, the reports have been inconsistent and it is

difficult to demonstrate altered movement and muscle activities during walking

according to the sub–type of LBP. In particular, subjects with the lumbar ExtRot

pattern showed excessive lumbar extension and rotation in standing alignment and

movement of the lumbar spine, towards extension and rotation, during knee flexion,

hip rotation in the prone position, and when returning from forward bending

(Hoffman et al. 2011; Park et al. 2011; Sahrmann 2002). Although these studies have

demonstrated movement characteristics in subjects with lumbar ExtRot pattern using

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lower limb or trunk movement tests (Hoffman et al. 2011; Kim et al. 2013; Park et al.

2011; Sahrmann 2002; Scholtes, Gombatto, and Van Dillen 2009), there has been no

reported study of the movement changes in the lumbopelvic region in the lumbar

ExtRot pattern during walking. Thus, in this study, it was expected that subjects with

a lumbar ExtRot pattern would show excessive lumbar extension and rotation

movement during walking, compared with healthy subjects. The purpose of this study was to compare the kinematics of the lumbar spine and

pelvic region in the sagittal and transverse planes and trunk muscle activities (RA, EO,

IO, and ES) during walking between subjects with and without a lumbar ExtRot

pattern. It was hypothesized that subjects with a lumbar ExtRot pattern would show

greater lumbopelvic motion in the sagittal and transverse planes, reflected by

decreased activities of the superficial abdominal muscles and increased activity of the

ES muscle.

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Method

1. Subjects

First, 63 subjects with LBP were screened by a physical therapist with 4 years

clinical experience in evaluating and managing LBP, based on a movement

impairment classification. In total, 26 subjects with a lumbar ExtRot pattern

participated (Table 1). In all subjects, the duration of LBP was over 7 weeks. An

examination based on the movement impairment classification by Sahrmann (2002)

was used to identify the sub–group with a lumbar ExtRot pattern among the

mechanical LBP cases. A two–step procedure consisted of primary and secondary

tests. The primary test was a symptom–provocation test designed to assess movement

of the lumbar spine associated with the symptoms and/or pain, while the secondary

test was a confirmatory test designed to decrease or inhibit the symptoms by

modifying the subject’s movement patterns in the lumbar spine. Test items consisted

of standing (alignment, return from forward bending, lumbar extension, and side

bending), sitting (alignment and lumbar extension), supine (active hip abduction and

external rotation), prone (alignment, active hip internal/external rotation, hip

extension, and knee flexion), and quadruped position (alignment, active arm lift,

rocking backward, and rocking forward). The test was positive, if 1) lumbar spine

alignment tended to be extended and rotated relative to neutral and 2) the lumbar

- 8 -

spine moved towards the direction of extension and rotation with movements in the

spine or extremities. If the subjects with LBP reported an increase in symptoms or

pain with lumbar extension and rotation during the primary test, the secondary test

was performed. All subjects with a lumbar ExtRot pattern had dominant symptoms on

the right side.

The 18 matched subjects with no lumbar ExtRot pattern had no history of LBP

during the last 6 months (Table 1). Subjects were excluded if they reported having a

1) neurological signs or a diagnosis by a physician, 2) fracture, injury, or surgery on

the lower back, hip, knee, and ankle, or 3) pain or symptoms that affected movement

of the hip, knee, or ankle joint. All participants signed an informed consent statement

and were supplied with information sheets prior to participation. The study was

approved by the Yonsei University Wonju institutional review board.

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Table 1. Subjects’ characteristics

Parameter With lumbar

ExtRot pattern

Without lumbar

ExtRot pattern Statistic p

Gender (male/female) M=11/F=15 M=10/F=8 N/A N/A

Age (years) 23.15 ± 1.97a 22.78 ± 1.96 0.624 0.536

Body mass (㎏) 62.31 ± 11.56 60.50 ± 7.66 0.624 0.536

Height (㎝) 164.28 ± 22.41 169.89 ± 7.32 -1.021 0.313

Pain duration (months) 21.69 ± 16.47 N/A N/A N/A

VASb (㎜) 31.76 ± 16.49 N/A N/A N/A

Modified ODIc (%) 11.96 ± 6.55 N/A N/A N/A aMeans ± standard deviation. bVAS: visual analog scale. cODI: Oswestry disability index. N/A = not applicable.

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2. Procedure

Subjects were allowed to walk on the walkway until they were accustomed to the

walking conditions in the experimental room. Subjects were asked to walk on an 8–

m–long straight walkway at their preferred speed using more than 12 time–strides for

data collection. A rest of 30 s was provided between trials.

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3. Measurements

3.1 Clinical Measures

To measure the severity and perception of LBP, a visual analog scale (VAS) was

used (Marshall, and Murphy 2010). Subjects were required to mark their subjective

pain level on a 100–㎜ horizontal line with 10–㎜ marks. VAS scores represented

pain values from “0” (no pain) to “100” (worst pain imaginable).

The modified Oswestry disability index (ODI) was used to measure disability

related to LBP (Kim et al. 2005). The modified ODI questionnaire was scored on a

scale of 0–5, and consisted of 10 items with six answers per item. The total score for

each subject was showed as a relative value (total possible score / total score × 100).

The index was scored from “0” (no disability) to “100” (total disability).

3.2 Surface Electromyography

EMG data were collected using a Noraxon system (Noraxon, Scottsdale, Arizona,

USA) with 1000 ㎐ sampling rate. For all EMG data, first–order high–pass filters

were set to 10 ㎐ and low–pass filters were set to 1500 ㎐. All channels had tenth–

order low–pass smoothing filters too. Surface EMG electrodes with a 2–㎝ inter–

electrode distance were attached at the muscle belly of both abdominal muscles (RA,

EO and IO) and the ES after the removal of hair and cleaning the patient’s skin with

alcohol.

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3.3 Kinematic Data

Lumbar and pelvic motion during gait were recorded using a motion–analysis

system with six cameras (Vicon MX system, Oxford Metrics, Oxford, UK) with 100

㎐ sampling rate. All marker coordinates were smoothed with a Woltring filter (Lee

et al. 2013). Twenty reflective markers (14–㎜ circles) were placed including lower

lumbar markers (on the spinous processes of T12 and L1, and 3 ㎝ on the left and

right sides of the spinous process of L1), and lower extremity markers (bilaterally on

the skin overlying the anterior superior iliac spine, posterior superior iliac spine,

lateral aspect of the thigh, lateral epicondyle of the femur, lateral surface of the shank,

lateral malleolus, second metatarsal head, and the posterior midpoint of the calcaneus).

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4. Data Analysis

EMG and kinematic data were collected using Nexus 1.4 software and imported

into the Polygon software for data analysis. Spatio–temporal parameters such as

walking speed, cadence, step length, and step time were computed from the 3D

kinematics. Events of the gait cycle (heel strike, HS, and toe–off, TO) were

determined by heel and second metatarsal head markers according to Pijnappels,

Bobbert, and van-DieÃn (2001). HS was defined by the minimum in the vertical

velocity of the second metatarsal head marker and TO was defined by the maximum

in the vertical velocity of the heel marker. A one–stride cycle was defined from the

initial HS to the next HS of the same leg and all data were analyzed based on the right

leg. For each kinematic and EMG recording, each of these time series were time–

normalized and resampled to 0–100 % of the stride cycle. Twelve time–normalized

kinematic and EMG data sets were used for data analysis of the within–participant

ensemble average.

The raw EMG data were processed using a root–mean–square algorithm. The

muscle activity recorded during the walk was then expressed as a percentage of the

sub–maximal voluntary isometric contraction (sub–MVIC). The sub–MVIC for the

abdominal muscle was performed to lift in hook–lying both legs 1 ㎝ from the table

(Dankaerts et al. 2004). For ES sub–MVIC, subjects raised both leg with knee flexion

at 90° from the table in a prone position (Dankaerts et al. 2004). Three repetitions of

- 14 -

5–s–long contractions for each task were conducted with a 30–s rest between them.

Each mean EMG activities of the RA, EO, IO, and ES were used for statistical

analysis at first double support, left swing, second double support, and right swing.

The first double support was defined from right HS to left TO, followed by left swing

until left HS. The second double support was defined from left HS to right TO,

followed by right swing until right HS.

The three–dimensional angle of the lumbar spine and the pelvic region were

analyzed using a global xyz–coordinate system, with the x–axis corresponding to the

line of progression, the y–axis pointing sideways, and the z–axis, vertically upwards.

The segment axes were aligned with the global system of reference. The pelvic angle

was obtained relative to the global coordinate system and the angle of the lumbar

spine was calculated using the relative orientation of the pelvic segment. Data were

collected in the sagittal and transverse plane. Each angle of the lumbar and pelvic

movements was used for statistical analysis at right HS, left TO, left HS, and right TO.

- 15 -

5. Statistical Analysis

SPSS 21.0 for Windows (SPSS, Inc., Chicago, IL, USA) was used for all statistical

analyses. The Shapiro–Wilk test was used to assess the normality of the distribution

of the variables (spatiotemoral parameters, kinematic data of the lumbar spine and

pelvis, and EMG data of the trunk muscles). If variables were confirmed to be

normally distributed, parametric statistics (independent t–test) were used while if not,

non–parametric statistics (Mann–Whitney U–test) were used to compare variables

between subjects with and without lumbar ExtRot pattern. The level of statistical

significance was set at p < 0.05.

- 16 -

Results

1. Spatio–temporal Parameters During Walking

There was no significant difference between the groups in walking speed, cadence,

stride time, or stride length (p > 0.05; Table 2)

Table 2. Stride characteristics

Stride characteristics With lumbar ExtRot

pattern (n = 26)

Without lumbar ExtRot

pattern (n = 18) p

Walking speed (㎧) 1.14 ± 0.13a 1.14 ± 0.18 0.926

Cadence (steps/min) 117.83 ± 14.68 112.79 ± 10.08 0.214

Stride time (s) 1.03 ± 0.09 1.07 ± 0.09 0.128

Stride length (m) 1.17 ± 0.20 1.21 ± 0.11 0.474 aMean ± standard deviation.

- 17 -

2. Kinematics of Lumbopelvic Region

There were significant differences in pelvic anterior tilting and the lumbar

extension angle at all events between subjects with and without lumbar ExtRot

pattern (p < 0.05; Table 3). Subjects with a lumbar ExtRot pattern showed greater

pelvic anterior tilting and lumbar extension angles at all events than subjects without

a lumbar ExtRot pattern (Figure 1). There was no significant difference in pelvic or

lumbar rotation angle in any event between subjects with and without the lumbar

ExtRot pattern (p > 0.05; Table 3).

- 18 -

Table 3. Pelvic and lumbar angles in the sagittal and transverse planes in subjects

with and without the lumbar ExtRot pattern

aHS: heel strike. bTO: Toe–off. cMean ± standard deviation (°). ‘+’ indicates counter–clockwise rotation and ‘−’ indicates clockwise rotation in transverse plane. *p < 0.05.

Motion Event With lumbar

ExtRot pattern

Without lumbar

ExtRot pattern p

Pelvic

anterior tilting

Right HSa 10.82 ± 3.53c 8.17 ± 3.97 0.025*

Left TOb 10.59 ± 3.59 7.76 ± 3.88 0.017*

Left HS 11.17 ± 3.68 8.64 ± 4.18 0.040*

Right TO 11.02 ± 3.75 8.38 ± 4.19 0.034*

Pelvic rotation Right HS 4.19 ± 2.83 3.08 ± 3.11 0.262

Left TO 4.10 ± 2.48 2.90 ± 2.93 0.149

Left HS -4.56 ± 3.53 -3.72 ± 3.39 0.435

Right TO -4.15 ± 3.49 -3.25 ± 3.41 0.364

Lumbar

extension

Right HS 11.46 ± 6.21 5.42 ± 5.78 0.002*

Left TO 12.40 ± 6.44 5.96 ± 6.04 0.002*

Left HS 11.14 ± 6.00 5.25 ± 5.90 0.002*

Right TO 11.42 ± 6.48 6.04 ± 5.90 0.008*

Lumbar rotation Right HS -0.18 ± 3.54 0.69 ± 3.36 0.417

Left TO -0.16 ± 3.56 0.87 ± 3.42 0.348

Left HS -4.03 ± 4.19 -3.59 ± 2.90 0.535

Right TO -4.54 ± 4.77 -3.92 ± 3.11 0.628

- 19 -

0

2

4

6

8

10

12 * * * *

Rt. HS Lt. TO Lt. HS Rt. TO

Pelv

ic a

nter

ior t

iltin

g (º

)

0

2

4

6

8

10

12

14

16

* ** *


Lum

bar e

xten

sion

(º)

Figure 1. Comparison of the averaged pelvic and lumbar angles in the sagittal and

transverse planes between subjects with and without the lumbar ExtRot

pattern. ‘+’ indicates counterclockwise rotation and ‘−’ indicates clockwise

rotation in the transverse plane (HS, heel strike; TO, toe–off). *p < 0.05

significantly different between the groups.

-8

-6

-4

-2

0

2

4With lumbar ExtRot patternWithout lumbar ExtRot pattern


Lum

bar r

otat

ion

(º)

-5

-4

-3

-2

-1

0

1

2

3

4


Pelv

ic ro

tatio

n (º

)

- 20 -

3. Electromyography Activities of Trunk Muscle

There were significant differences in both ES muscle activities in all events and in

right IO muscle activities at the second double support phase between subjects with

and without a lumbar ExtRot pattern (p < 0.05; Table 4). Both ES muscle activities

increased significantly in subjects with lumbar ExtRot pattern compared with subjects

without the lumbar ExtRot pattern in all events (Figure 2). Right IO muscle activity

decreased significantly in subjects with a lumbar ExtRot pattern than subjects without

the lumbar ExtRot pattern at the second double support phase (Figure 3). There was

no significant difference in either RA, EO, or IO muscle activities in any event except

for right IO muscle activities in the second double support phase between subjects

with and without a lumbar ExtRot pattern (p > 0.05).

- 21 -

Table 4. Trunk muscle activities for subjects with and without the lumbar ExtRot

pattern

Muscle Phase With lumbar

ExtRot pattern

Without lumbar

ExtRot pattern p

ESa

Rt First double support 26.26 ± 11.27e 17.91 ± 8.40 0.009*

Left swing 22.76 ± 8.96 16.25 ± 7.78 0.013*

Second double support 24.15 ± 9.22 17.15 ± 6.54 0.003*

Right swing 23.96 ± 8.15 18.54 ± 6.47 0.026*

Lt First double support 23.28 ± 9.55 16.65 ± 8.05 0.009*

Left swing 24.27 ± 14.70 18.13 ± 10.58 0.011*


Right swing 22.42 ± 14.53 14.30 ± 7.29 0.005*

RAb

Rt First double support 27.59 ± 16.79 26.70 ± 27.79 0.328

Left swing 38.04 ± 47. 65 29.01 ± 20.26 0.352

Second double support 29.01 ± 20.26 31.04 ± 37.07 0.390

Right swing 38.80 ± 45.12 33.96 ± 42.18 0.105

Lt First double support 29.52 ± 16.11 28.55 ± 24.92 0.352

Left swing 36.60 ± 24.93 36.15 ± 39.33 0.417


Right swing 38.62 ± 31.03 36.74 ± 49.54 0.252 aES: erector spine muscle. bRA: rectus abdominis muscle. cEO: abdominal external oblique muscle. dIO: abdominal internal oblique muscle. eMean ± standard deviation (% sub–MVIC). *p < 0.05.

- 22 -

Table 4. (Continued)

Muscle Phase With lumbar

ExtRot pattern

Without lumbar

ExtRot pattern p

EOc


Left swing 47.34 ± 39.93 37.84 ± 28.08 0.252


Right swing 52.24 ± 45.89 42.83 ± 32.41 0.283


Left swing 57.11 ± 50.32 54.73 ± 37.73 0.793


Right swing 52.25 ± 45.48 46.60 ± 32.34 0.504

IOd


Left swing 67.20 ± 40.80 75.66 ± 44.63 0.445


Right swing 68.64 ± 41.16 84.55 ± 53.49 0.262


Left swing 62.06 ± 33.20 71.77 ± 48.12 0.811


Right swing 57.02 ± 31.02 67.42 ± 5073 0.685 aES: erector spine muscle. bRA: rectus abdominis muscle. cEO: abdominal external oblique muscle. dIO: abdominal internal oblique muscle. eMean ± standard deviation (% sub–MVIC). *p < 0.05.

- 23 -

0

10

20

30

40

Rt ES

*** *

Firstdouble support

Lt. swing Rt. swingSeconddouble support

EM

G a

ctiv

ity (

% s

ub M

VIC

)

0

10

20

30

40

50

60

Rt RA

Firstdouble support


EM

G a

ctiv

ity

(%

su

b M

VIC

)

Figure 2. Comparison of the averaged ES and RA muscle activities between subjects

with and without the lumbar ExtRot pattern (MVIC: maximal voluntary

isometric contraction, ES: erector spine muscle, RA: rectus abdominis

muscle). *p < 0.05significantly different between the groups.

0

10

20

30

40

50

60With lumbar ExtRot pattern

Without lumbar ExtRot pattern

Lt RA

Firstdouble support


0

10

20

30

40

Lt ES

* * *

Firstdouble support


*

- 24 -

0

10

20

30

40

50

60

70

80

Rt EO

Firstdouble support


EM

G a

ctiv

ity (

% s

ub M

VIC

)

0

10

20

30

40

50

60

70

80

Lt EO

Firstdouble support


0

20

40

60

80

100

120

Rt IO

Firstdouble support


*

EM

G a

ctiv

ity

(%

su

b M

VIC

)

Figure 3. Comparison of the averaged EO and IO muscle activities between subjects

with and without the lumbar ExtRot pattern (MVIC: maximal voluntary

isometric contraction, EO: abdominal external oblique muscle, IO:

abdominal internal oblique muscle). *p < 0.05 significantly different

between the groups.

0

20

40

60

80

100

120 With lumbar ExtRot pattern

Without lumbar ExtRot pattern

Lt IO

Firstdouble support


- 25 -

Discussion

LBP is common musculoskeletal problem and has been investigated continuously

the diagnosis and management of LBP according to specific sub–groups. Although

many previous studies have examined the relationship between lumbopelvic motion

and trunk muscle activity between patients with LBP and a healthy control group in

walking (Arendt Nielsen et al. 1996; Crosbie et al. 2013; Hanada, Johnson, and

Hubley Kozey 2011; van der Hulst et al. 2010a, 2010b), this is the first reported study

to determine whether subjects with a lumbar ExtRot pattern demonstrated different

lumbopelvic motion and trunk muscle activities in walking. Novel findings from this

study include that the pelvic and lumbar angles in the sagittal plane were greater in

subjects with the ExtRot pattern than in subjects without a lumbar ExtRot pattern in

walking. Increased muscle activity was also observed in both ES at all events and

decreased right IO muscle activity was seen at the second double support phase in

subjects with the ExtRot pattern compared with subjects without a lumbar ExtRot

pattern. However, in contrast to the initial hypothesis, there was no difference

between the two groups in RA, EO, and IO muscle activities, with the exception of

right IO muscle activity at the second double support phase throughout walking.

Walking speed influences trunk muscle activities and movement amplitudes in the

lumbopelvic region (Crosbie et al. 2013; Lamoth et al. 2006a; Seay, Van Emmerik,

and Hamill 2011). Seay, Van Emmerik, and Hamill (2011) reported that pelvis and

- 26 -

trunk range of motion during walking increased as speed increased, in LBP and pain–

free subjects, and Lamoth et al. (2006a) demonstrated that subjects with LBP have a

decreased ability to adapt trunk–pelvis coordination and ES muscle activities in

response to gait velocity. Although previous researchers have found differences in

spatiotemporal parameters between patients with LBP and pain–free control subjects,

with LBP patients tending to have a slower speed of the walking and a shorter step

length (Crosbie et al. 2013; Lamoth et al. 2006b), this study showed no significant

difference in spatiotemporal parameters in walking between subjects with and without

a lumbar ExtRot pattern. Thus, the similarity in the spatiotemporal parameters

between subjects with and without a lumbar ExtRot pattern is not likely a major

contributor affecting lumbopelvic kinematics or muscle activities of the trunk muscles

in this study.

Lumbopelvic motion is important because a greater movement angle may

contribute to evoking pain in the lumbopelvic region (Scholtes, Gombatto, and Van

Dillen 2009). Repetitive and/or sustained movement of the lumbar spine towards a

specific direction contributes to increase stress in the lumbopelvic region and can

induces microtrauma, resulting in LBP (Sahrmann 2002). Individuals with a lumbar

ExtRot pattern are characterized by a tendency to move and align the lumbar region

in rotation and extension in movement tests and functional activities (Maluf,

Sahrmann, and Van Dillen 2000; Sahrmann 2002; Trudelle-Jackson, Sarvaiya-Shah,

and Wang 2008). Previous studies have demonstrated differences in lumbopelvic

- 27 -

motion between subjects with LBP and healthy controls during movement tests, such

as hip extension, hip lateral rotation, and knee flexion in a prone position (Park et al.

2011; Scholtes, Gombatto, and Van Dillen 2009). Researchers have suggested that

increased and greater movement amplitude of the lumbar spine during these

movement tests is one of the reasons for LBP, which influences daily activities such

as gait and running. The results of the present study are consistent with previous

studies on LBP: increased anterior pelvic tilting and lumbar extension angle in all

events in subjects with the lumbar ExtRot pattern compared with subjects without a

lumbar ExtRot pattern. Thus, the altered lumbopelvic kinematics in subjects with

lumbar ExtRot pattern may cause excessive stress with extension into the lumbar

spine, resulting in induction of LBP in walking.

In this study, there was no significant difference in pelvic or lumbar angle in the

transverse plane during walking (p > 0.05). A reason for this result may be that the

subjects participating in this study had relatively mild pain (VAS = 31.76 ± 16.49 ㎜)

and were university students in their early 20s. Although the subjects satisfied the

criteria for the lumbar ExtRot pattern, it is possible that pain severity was not

sufficient to change their movement patterns in the lumbopelvic region during

walking. Although there was no significant difference in the pelvic or lumbar angle in

the transverse plane between subjects with and without a lumbar ExtRot pattern, the

overall pelvic rotation angle was greater at all events in subjects with lumbar ExtRot

pattern compared to subjects without lumbar ExtRot pattern. Thus, further studies are

- 28 -

needed to confirm the changes in lumbopelvic motion in the transverse plane in

subjects with lumbar ExtRot pattern while having more severe LBP.

Several mechanisms could explain the greater lumbopelvic angle in sagittal plane

in subjects with a lumbar ExtRot pattern. First, biomechanical limitations may alter

the lumbopelvic motion. Previous studies explained that greater amplitude in the

lumbopelvic region with knee flexion in people with LBP is caused by a short or stiff

rectus femoris muscle and tensor fascia latae/iliotibial band because this muscle

passes across two joints (hip and knee joint) (Kim et al. 2013; Park et al. 2011;

Scholtes, Gombatto, and Van Dillen 2009). After initial HS, the ipsilateral leg goes

into a stance phase with ipsilateral knee flexion and hip extension initiation. Thus, the

greater pelvic motion in the sagittal plane at TO in this study may be attributable to a

lack of flexibility or the length of the rectus femoris and tensor fascial latae/iliotibial

band. Also, individuals with a lumbar ExtRot pattern have hyperlordosis

characteristics in standing, which can be caused by a short and stiff iliopsoas muscle

(Harris-Hayes, Van Dillen, and Sahrmann 2005; Sahrmann 2002). Thus, changes in

biomechanical aspects could influence lumbopelvic kinematics during walking. A

second reason may involve a learned movement strategy. People with a lumbar

ExtRot pattern present with easier movement into anterior pelvic tilting and rotation.

Relatively greater flexibility of the abdominal muscle, compared with the rectus

femoris, could induce greater pelvic anterior tiling. Kim et al. (2013) and Park et al.

(2011) examined that greater lumbopelvic motion during knee flexion in standing and

- 29 -

prone positions in subjects with a lumbar ExtRot pattern compared with subjects with

no lumbar ExtRot pattern. This result was consistent with previous findings of greater

lumbar extension and anterior tilting during walking in subjects with a lumbar ExtRot

pattern. Third, the altered EMG activity of the trunk muscle is a factor in the greater

lumbopelvic angle. The primary action of the ES is to control the lumbar spine

motion in the sagittal plane (Lamoth et al. 2006b). Figure 2 shows, in both ES

muscles, greater muscle activation in subjects with a lumbar ExtRot pattern in all

events. Excessive muscle activation of the ES could contribute to an excessive lumbar

lordotic curve in walking. Also, this study did not show significant differences in RA,

EO, and IO muscle activities, except in the right IO muscle at the second double

support phase during walking between the groups. However, right IO muscle activity

at the second double support phase was decreased significantly and both IO muscle

activities showed a decreasing tendency across all events in subjects with a lumbar

ExtRot pattern compared with subjects without a lumbar ExtRot pattern (Figure 3).

Abdominal muscles, especially the IO muscles, act as stabilizers of the lumbar spine

(O'Sullivan, Twomey, and Allison 1998; van Dieën, Cholewicki, and Radebold 2003).

Insufficient recruitment of the IO muscle may contribute to excessive lumbopelvic

motion in subjects with a lumbar ExtRot pattern. Thus, it is possible that decreased IO

muscle activity makes it difficult to maintain spinal stability.

The ES muscle showed peak activation in the double–leg stance, to control trunk

movement, in contrast to the lack of EMG activity in a single leg stance (van der Huls

- 30 -

et al. 2010a, 2010b). Increased muscle activity of the ES during a double–leg stance

could facilitate efficient control of anterior or lateral deviation of the trunk in the

sagittal plane. However, overall higher ES muscle EMG activities have been reported

during walking in people with LBP than in healthy controls (van der Huls et al. 2010a,

2010b). The previous results are consistent with this study in that both ES muscle

activity was greater at all phases in subjects with the lumbar ExtRot pattern (p < 0.05).

This result could be explained by the pain–spasm–pain model (van Dieën, Cholewicki,

and Radebold 2003; Vogt, Pfeifer, and Banzer 2003). Continuous activity of the ES to

maintain posture causes localized muscle fatigue, and this can exacerbate and

continue the LBP. In this study, subjects with a lumbar ExtRot pattern showed

increased muscle activities in the ES compared with those in subjects without a

lumbar ExtRot pattern; this change may be a factor in LBP.

Previous studies have reported the patterns of abdominal muscle activation during

gait; however, inconsistent results have been reported (Hanada, Johnson, and Hubley

Kozey 2011; van der Hulst et al. 2010a; White, and McNair 2002). Several studies

have reported that the RA, as an anterior global muscle, is activated constantly

without a connection to the dynamic movement of the gait cycle (Hanada, Johnson,

and Hubley Kozey 2011; Saunders et al. 2005; van der Hulst et al. 2010a), while

other studies have reported that RA contributes to lumbopelvic movement in the

sagittal plane in healthy subjects (White, and McNair 2002). Additionally, the EO

muscle, anatomically, would seem to be plausibly associated with lumbopelvic

- 31 -

motion in the transverse plane during stance, while White, and McNair (2002)

reported that most subjects used the EO muscle at a level of < 5% MVC throughout

the stride. A similar pattern is also seen in the IO muscle, with relatively constant

low–level activity during slow gait in most subjects (Anders et al. 2007; White, and

McNair 2002). Variability in the abdominal muscle activation patterns among

individuals may have led to inconsistent results during walking. Thus, this study

showed no significant differences of the RA, EO, or IO, except in the right IO muscle

at the second double support phase, during walking between subjects with and

without a lumbar ExtRot pattern.

Several previous studies compared abdominal muscle activities between LBP and

control groups and reported increased muscle activity of the RA, but not the OE, in

subjects with LBP compared with those without during walking (Hanada, Johnson,

and Hubley Kozey 2011; van der Hulst et al. 2010a). However, in the present study,

no significant difference in abdominal muscle activity was found between the two

groups during walking. The inconsistency between the results of prior studies and our

findings may be explained by methodology: specifically, the normalization of the

EMG data. Generally, although MVIC is often used to normalize EMG activity, this

method is unreliable for patients because patients with LBP are usually unwilling or

unable to perform maximum contractions of the abdominal muscle, not least because

of fear of pain. Thus, methodological differences in normalizing the EMG activities

of the abdominal muscle may be the reason for the differing results.

- 32 -

Although this study demonstrated differences in lumbopelvic motion and trunk

muscle activities between subjects with and without a lumbar ExtRot pattern, it had

several limitations. The first limitation was the difficulty in determining whether

these changes cause LBP or occur due to pain, because this was a cross–sectional

study. Repetitive and/or continuous movement of the lumbar spine may be a risk

factor for LBP; however, in this study, it is difficult to demonstrate a cause and effect

relationship between LBP and excessive pelvic anterior tilting and lumbar extension

angle and increased ES muscle activities. Further study is necessary to determine the

effects of the decreased pelvic and lumbar angle in the sagittal plane that could

influence changes in ES muscle activities during walking and pain intensity in

subjects with a lumbar ExtRot pattern. Second, these results may not be

generalizable; all subjects in this study were university students. Thus, further

research is required to examine lumbopelvic motion in walking in people with LBP

over a variety of ages. Third, because the subjects participating in this study had

symptoms and/or pain related to their lumbar ExtRot pattern, it is unknown whether

the movement patterns of the lumbopelvic region and EMG activity of the trunk

muscle would be generalizable to other sub–groups of LBP, such as subjects with

lumbar flexion, flexion and rotation, rotation, and extension patterns. Further studies

are necessary to confirm the differences in the lumbopelvic motion and trunk muscle

activities in diverse sub–groups of LBP.

- 33 -

Chapter III

Effects of a 6–week Program of Specific Movement

Control Exercises on Lumbopelvic Motion and Trunk

Muscle Activity During Walking in Subjects with

Lumbar Extension Rotation Pattern

(Study 2)

Introduction

LBP is one of the major musculoskeletal disorders, and its treatment and

management in modern society incur enormous costs (Magalhaes et al. 2013;

Maniadakis, and Gray 2000; O'Sullivan 2005; Rasmussen-Barr et al. 2009). One

reason for LBP is motor control impairment in the lumbar spine (Vogt et al. 2001).

Excessive and repetitive movement in the lumbar spine may cause stress and

microtrauma in facet joints, resulting in pain of the low back region (Sahrmann 2002;

Scholtes, Gombatto, and Van Dillen 2009). Thus, it is important to focus on

controlling lumbopelvic motion during rehabilitation from chronic LBP.

Spinal coordination during walking has been considered to be important in

- 34 -

preventing LBP (Crosbie et al. 2013). Patients with chronic and recurrent LBP have

shown altered movement patterns and poor adjustment abilities in the lumbar spine

(Lamoth et al. 2006a, 2006b; Seay, Van Emmerik, and Hamill 2011). Several studies

have assessed coordination of the lumbar spine and pelvis between subjects with and

without LBP during walking (Crosbie et al. 2013; Lamoth et al. 2006a; Seay, Van

Emmerik, and Hamill 2011). Lamoth et al. (2006a) showed decreased coordination

between the pelvic segment and the trunk in patients with LBP and tighter and less

variable coordinated motion between the spinal segments over the whole gait cycle.

Although many researchers have sought to demonstrate differences in spinal motion

between pain–free and LBP subjects (Crosbie et al. 2013; Lamoth et al. 2006a,

2006b; Seay, Van Emmerik, and Hamill 2011), they have not suggested means to

relieve the LBP, such as changes in lumbopelvic motion during walking. Most

research has simply demonstrated differences in the lumbopelvic kinematics between

subjects with and without LBP during walking (Crosbie et al. 2013; Lamoth et al.

2006b; Seay, Van Emmerik, and Hamill 2011). Some studies have suggested

interventions to control lumbopelvic motion in subjects with LBP (Hoffman et al.

2011; Van Dillen et al. 2003); however, the effects of these interventions to control

lumbopelvic motion were not assessed in functional activities, such as walking.

Trunk muscles contribute to controlling lumbopelvic motion during walking

(Hanada, Johnson, and Hubley Kozey 2011; van der Hulst et al. 2010a, 2010b).

Normally, the ES muscle is activated in double support and relaxes during the period

of swing; however, in LBP, higher ES activities were observed, as a guarding

- 35 -

mechanism, in the whole stride cycle (Arendt Nielsen et al. 1996; van der Hulst et al.

2010a, 2010b). Additionally, van der Hulst de al. (2010a) reported that subjects with

chronic LBP showed increased activity of the ES and RA muscles, but there was no

significant difference in EO activity during any period of the stride compared with

healthy subjects. Although changes in trunk muscle activity have been demonstrated

in subjects with LBP compared with healthy control subjects, during walking, there is

insufficient evidence regarding which intervention influences trunk muscle activity

during walking in LBP.

Recently, there has been a growing consensus among clinicians and researchers

that LBP should be managed by classification–specific interventions in homogeneous

groups (Hoffman et al. 2011; O'Sullivan 2005; Sahrmann 2002; Van Dillen et al.

2003). Patients with mechanical LBP should be divided into several homogenous

subgroups, determined by the direction of the lumbar spine movement that evokes

pain and/or symptoms (Maluf, Sahrmann, and Van Dillen 2000; Sahrmann 2002). It

has been considered that specific management according to LBP subgroup can

improve pain relief. Several studies have demonstrated that classification–specific

movement control exercises could improve early and excessive lumbopelvic motion

and relieve pain by modifying lumbopelvic motion (Park et al. 2011; Scholtes et al.

2010; Smith, O'Sullivan, and Straker 2008). Although training and education to

control specific movement of the lumbar spine has been demonstrated to help prevent

and manage pain and symptoms, there has been no report that specific movement

control exercises affect lumbopelvic motion and trunk muscle activities during

- 36 -

walking.

Patients with a lumbar ExtRot pattern have difficulty in controlling the

lumbopelvic region towards lumbar extension and rotation during lower extremity

movements (Hoffman et al. 2011; Park et al. 2011; Sahrmann 2002). To resolve this

difficulty in patients with a lumbar ExtRot pattern, several specific movement control

exercises have been suggested: abdominal control in hook–lying, hip abduction and

lateral rotation in a supine position, hip extension with the knee extended, knee

flexion, and hip internal and external rotation in a prone position (Hoffman et al.

2011; Sahrmann 2002, Van Dillen et al. 2003). To date, there has been no report of

the effect of specific movement control exercises on lumbopelvic kinematics in

subjects with a lumbar ExtRot pattern during walking.

Thus, the purpose of this study was to assess the effects of specific movement

control exercises in subjects with a lumbar ExtRot pattern on 1) pain intensity,

disability, and fear avoidance in daily activities, and 2) lumbopelvic motion and trunk

muscle activities during walking.

- 37 -

Method

1. Design

This randomized, controlled trial was conducted in the Physical Therapy

Department of Yonsei University, Korea. Subjects visited the laboratory twice for

pre– and post–treatment assessments at an interval of 6 weeks. Before the pre–

treatment laboratory visit, each subject with LBP was screened by a physical therapist

for classification into a LBP subgroup according to the movement impairment

classification system. Through this classification examination, only subjects with a

lumbar ExtRot pattern were enrolled. The subjects with a lumbar ExtRot pattern were

allocated randomly to the experimental or control group.

- 38 -

2. Subjects

In total, 39 subjects (experimental group = 19; control group = 20) with LBP

participated (Figure 4). The inclusion criteria for LBP subjects were 1) more than 7

weeks continuing or recurrent LBP, and 2) pain localized from the costal margin to

above the inferior gluteal folds. To assess whether subjects showed a lumbar ExtRot

pattern, a physical therapist examined their lumbar motions and alignments in

response to several different tests, based on Sahrmann (2002). If subject responses

increased symptoms and/or pain with lumbar extension and rotation during trunk or

lower extremity movement, they were classified as the lumbar ExtRot pattern.

Selection of the subjects was performed by a physical therapist with training and

experience in assessing and treating related movement impairment in rehabilitation

programs. Exclusion criteria were 1) pain radiating to the leg or both legs with

neurological signs, 2) diagnosis of lumbar disc herniation, spinal deformity, or

fracture 3) having a history of back surgery, and 4) limitations in walking because of

a lower extremity injury. All participants signed an informed consent statement and

were supplied with information sheets prior to participation. The study was approved

by the Yonsei University Wonju institutional review board.

- 39 -

Figure 4. Flow chart for subject selection.

Excluded (n=43) Not meeting inclusion criteria (n=39) Declined to participate (n=4)

Allocated to experimental group (n=19) : Specific movement control exercises

Randomization

Subjects with low back pain (n=82)

Assessed for eligibility

Pre–treatment assessment (n=39)

Allocated to control group (n=20) : not applied

Post–intervention assessment (n=19)

Post–intervention assessment (n=17)

- 40 -

3. Measurements

3.1 Clinical Measures

A VAS was used to assess the severity and perception of the LBP experience

(Marshall, and Murphy 2010). VAS values range from 0 to 100. To assess disability

related to LBP, the modified ODI and Roland Morris disability questionnaire

(RMDQ) were used (Kim et al. 2005; Lee et al. 2011). The modified ODI

questionnaire consists of 10 items with six answers per item, and items are scored

from 0 to 5. The total score for each subject is presented as a relative value (total

possible score / total score × 100). The RMDQ consists of 24 items related to

limitations in activities of daily living. RMDQ values range from 0 (no disability) to

24 (maximum disability). The “Fear–avoidance beliefs questionnaire” (FABQ) was

used to explain how much fear and avoidance affected the subjects with LBP (Joo et

al. 2009; Waddell, and Burton 2005). The FABQ consists 16 items with a score range

each of 0–6. Higher scores indicate increased levels of fear–avoidance beliefs.

3.2 Kinematics and Surface Electromyography

Kinematic and surface EMG data were collected simultaneously during walking. A

three–dimensional motion–analysis system with six cameras (Vicon MX system,

Oxford Metrics, Oxford, UK) was used to determine events of the gait cycle (HS and

TO) and to measure lumbopelvic motion during gait. Twenty reflective markers (14–

- 41 -

㎜ circles) were attached to specific anatomical landmarks: lumbar markers (on the

spinous processes of T12 and L1, and 3 ㎝ on the left and right sides of the spinous

process of L1) and lower–extremity markers (bilaterally on the skin overlying the

anterior superior iliac spine, posterior superior iliac spine, lateral aspect of the thigh,

lateral epicondyle of the femur, lateral surface of the shank, lateral malleolus, second

metatarsal head, and the posterior midpoint of the calcaneus). All marker coordinates

were smoothed with a Woltring filter. Sampling rate was set at 100 ㎐.

Muscle activities of the abdominal muscles (RA, EO and IO) and the ES were

measured using a Noraxon TeleMyo 2400T instrument (Noraxon, Scottsdale, AZ,

USA). The surface EMG electrodes were attached to the RA (2 ㎝ lateral and 1 ㎝

superior to the umbilicus), EO (midway between the anterior superior iliac spine and

the rib cage), IO (1 ㎝ medial part to the anterior superior iliac spine) and ES (2 ㎝

lateral to the spinous process of L3) muscles. Sampling rate was set at 1000 ㎐. All

EMG data have 1st order high–pass filters was set to 10 ㎐ and low pass filters set to

1500 ㎐. All channels have 10th order low pass smoothing filters.

- 42 -

4. Procedure

All subjects walked on an 8–m–long straight walkway at their preferred speed.

Before testing, subjects are required to walk on the walkway until they had

familiarized themselves with walking conditions at a comfortable walking speed. To

collect kinematic and EMG data, subjects were asked to walk at least 12 times with a

rest of 30 s between trials.

- 43 -

5. Intervention

The treatment period was 6 weeks in duration. Subjects in the experimental group

were supervised individually with progressively more difficult exercise by a physical

therapist bi–weekly for 30 min. The completion of home exercise five times per week

was recorded over the 6 weeks. Specific movement control exercises consisted of 1)

education regarding the specific directions of movement in the lumbopelvic region

and postures thought to be associated with their LBP symptoms and 2) specific

movement control exercises (Appendix 1). Subjects were required to perform two sets

of 10 repetitions per day. All subjects in the experimental group were encouraged to

perform exercise without any symptom or pain during exercise periods. Although

subjects in the control group were also provided with general education regarding

neutral spinal alignment, spinal anatomy, and the causes of LBP at the pre–treatment

session; follow–up instructions were not provided.

- 44 -

6. Data Analysis

EMG and kinematic data were collected using Nexus 1.4 software and imported

into the Polygon software for data analysis. All data were averaged over 12 gait

cycles and normalized to one full stride from initial HS to the next HS in the same leg

(0–100 %). Gait parameters for HS and TO were determined by heel and second

metatarsal head markers, according to Pijnappels, Bobbert, and van-DieÃn (2001).

Spatio–temporal parameters (walking speed, cadence, step length, and step time) were

computed from the 3D kinematics. Three–dimensional angle of the lumbar spine and

pelvic region were analyzed using a global xyz–coordinate system. The pelvic

segment angle was defined relative to the global coordinate system. The lumbar angle

was defined relative to the pelvic segment. For statistical analyses, the angles of the

lumbar and pelvic segment in sagittal and transverse plane were used at the right HS,

left TO, left HS, and right TO.

The raw EMG data were processed using a root–mean–square algorithm. To

normalize the EMG activities of each subject, sub–MVIC tests were performed and

the EMG activity of the each muscle during walking was expressed as a percentage of

the sub–MVIC. For abdominal muscles (RA, EO, and IO), subjects were positioned

in a hook–lying position on a table, and were then required to lift both feet 1 ㎝ from

the table (Dankaerts et al. 2004). For ES muscle, subjects lay on their abdomens with

both knees at 90° flexion and then lifted both legs 5 ㎝ from the table (Dankaerts et

- 45 -

al. 2004). Sub–MVIC tests were performed with three trials in each position and the

EMG activities in the middle 3 s of the 5–s contraction were averaged. Mean EMG

activities of the RA, EO, IO, and ES were used for statistical analyses at the first

double support (from initial HS to left TO), left swing (from left TO to left HS),

second double support (from left HS to right TO), and right swing (from right TO to

right HS).

- 46 -

7. Statistical Analysis

SPSS version 21.0 (SPSS, Inc., Chicago, IL, USA) was used for all statistical

analyses. The Shapiro–Wilk test was conducted to ensure normal distribution of the

variables (spatiotemoral parameters, kinematic data of the lumbar spine and pelvis,

and EMG data of the trunk muscles). For non–parametric variables, the Mann–

Whitney U–test was used to evaluate between–group differences and the Wilcoxon

signed–ranks test was used to compare within–group variables between pre– and

post–intervention. For parametric variables, independent t–tests were used to compare

between–group differences and the paired t–test was used to compare variables

within–groups between pre– and post–intervention. An intention–to–treat analysis

was used, in which all subjects were analyzed in the group to which they were

originally assigned. Significance was set at p < 0.05.

- 47 -

Results

1. Subject Characteristics

Subject characteristics are listed in Table 5.

Table 5. Subjects’ characteristics

Parameter Experimental

(n =19)

Control

(n = 20) Statistic p

Gender (male/female) M=11/F=8 M=10/F=10 N/A N/A

Age (years) 23.05 ± 2.09a 23.35 ± 1.73 -0.485 0.630

Body mass (㎏) 63.00 ± 14.67 62.20 ± 10.14 0.199 0.843

Height (㎝) 171.95 ± 7.32 168.20 ± 8.02 1.522 0.137

Pain duration (months) 26.316 ± 19.15 20.50 ± 18.19 0.973 0.337 aMean ± standard deviation.

- 48 -

2. Clinical Measures

Table 6 shows the average values of the scores at baseline and after the 6–week

intervention. After the 6–week intervention, VAS, ODI, RMDQ, and FABQ scores

were decreased significantly from baseline in the experimental group (p < 0.05).

However, there was no significant difference in the VAS, ODI, RMDQ, or FABQ at

the 6–week follow–up in the control group (p > 0.05).

- 49

-

Tabl

e 6.

Cha

nges

in p

ain

inte

nsity

, dis

abili

ty, a

nd fe

ar a

void

ance

belie

fs a

fter 6

–wee

k in

terv

entio

n

Gro

upPr

e–in

terv

entio

nPo

st–i

nter

vent

ion

p

VA

Sa(㎜

)Ex

perim

enta

l40

.00

±15

.63e

15.7

9±

8.38

<0.

001*

Con

trol

39.0

0±

15.4

433

.50

±15

.28

0.09

1

Mod

ified

OD

Ib(%

)Ex

perim

enta

l11

.26

±5.

425.

05±

4.08

0.00

4*

Con

trol

12.9

0 ±

6.66

10.5

2±

6.44

0.06

7

RM

DQ

c(s

core

)Ex

perim

enta

l2.

42±

2.97

0.84

±0.

690.

017*

Con

trol

2.10

±1.

971.

52±

1.09

0.05

0

FAB

Qd

(sco

re)

Expe

rimen

tal

32.0

5±

15.8

721

.21

±13

.29

0.01

2*

Con

trol

34.1

0 ±

16.7

030

.73

±18

.30

0.07

9a V

AS:

vis

ual a

nalo

g sc

ale,

scor

ed fr

om 0

(no

pain

) to

10 (w

orst

pai

n).

b OD

I:O

swes

try d

isab

ility

inde

x, sc

ored

from

0 (n

o di

sabi

lity)

to 1

00 (h

igh

disa

bilit

y).

c RM

DQ

: Rol

and–

Mor

ris d

isab

ility

que

stio

nnai

re, s

core

d fr

om 0

(no

disa

bilit

y) to

24

(hig

h di

sabi

lity)

.d FA

BQ

: Fea

r–av

oida

nce

belie

fs q

uest

ionn

aire

, sco

red

from

0 (n

o av

oida

nce)

to 9

6 (s

ever

e fe

ar–a

void

ance

).e M

ean

±st

anda

rd d

evia

tion.

*p<

0.05

.

- 49 -

Table 6. Changes in pain intensity, disability, and fear avoidance beliefs after 6–week intervention

Group Pre–intervention Post–intervention p

VASa (㎜)Experimental 40.00 ± 15.63e 15.79 ± 8.38 < 0.001*

Control 39.00 ± 15.44 33.50 ± 15.28 0.091

Modified ODIb (%)Experimental 11.26 ± 5.42 5.05 ± 4.08 0.004*

Control 12.90 ± 6.66 10.52 ± 6.44 0.067

RMDQc (score)Experimental 2.42 ± 2.97 0.84 ± 0.69 0.017*

Control 2.10 ± 1.97 1.52 ± 1.09 0.050

FABQd (score)Experimental 32.05 ± 15.87 21.21 ± 13.29 0.012*

Control 34.10 ± 16.70 30.73 ± 18.30 0.079aVAS: visual analog scale, scored from 0 (no pain) to 10 (worst pain).bODI: Oswestry disability index, scored from 0 (no disability) to 100 (high disability).cRMDQ: Roland–Morris disability questionnaire, scored from 0 (no disability) to 24 (high disability).dFABQ: Fear–avoidance beliefs questionnaire, scored from 0 (no avoidance) to 96 (severe fear–avoidance).eMean ± standard deviation.*p < 0.05.

- 50 -

3. Spatio–temporal Parameters During Walking

Table 7 shows the spatiotemporal parameters at pre–intervention. There was no

significant difference in walking speed, cadence, or stride length between two groups

(p > 0.05). A significant difference between the experimental and control group in

stride time was identified (p < 0.05).

Table 7. Stride characteristics at pre–intervention

Stride characteristics Experimental

(n =19)

Control

(n = 20) p

Walking speed (㎧) 1.21 ± 0.23a 1.15 ± 0.11 0.344

Cadence (steps/min) 121.14 ± 16.50 113.48 ± 5.06 0.055

Stride time (s) 1.00 ± 0.10 1.06 ± 0.05 0.033*

Stride length (m) 1.23 ± 0.24 1.18 ± 0.10 0.474 aMean ± standard deviation. *p < 0.05.

- 51 -

4. Kinematics of Lumbopelvic Region

Table 8 shows mean values and standard deviations of the pelvic and lumbar angles

in the sagittal and transverse plane pre– and post–intervention of the two groups.

After the 6–week intervention, there was a significant decrease in the pelvic and

lumbar angles in the sagittal plane in the experimental group for all events (p < 0.05;

Figure 5 and 6). However, there was no significant difference in the lumbar or pelvic

angle in the transverse plane in the experimental group after the 6–week intervention

(p > 0.05; Figure 5 and 6). After the 6–week intervention, there was no significant

difference in the pelvic or lumbar angle in the sagittal or transverse plane in the

control group in any event (p > 0.05).

- 52

-

Tabl

e 8.

Pelv

ic a

nd lu

mba

r ang

lesi

n th

e sa

gitta

l and

tran

sver

se p

lane

s

Rig

htH

SaLe

ftTO

b

Mot

ion

Gro

upPr

ePo

stPr

ePo

st

Pelv

ic a

nter

ior t

iltin

gEx

perim

enta

l10

.58

±4.

64c

7.49

±2.

7210

.31

±4.

577.

46±

2.72

Con

trol

11.2

8±

2.93

12.7

0±

2.79

11.1

4±

2.87

12.5

5±

2.91

Pelv

ic ro

tatio

nEx

perim

enta

l3.

59±

3.50

4.91

±3.

352.

50±

4.35

4.35

±3.

78

Con

trol

3.23

±3.

433.

19±

2.34

3.09

±3.

192.

46±

2.45

Lum

bar e

xten

sion

Expe

rimen

tal

10.0

1±

6.93

6.69

±5.

7410

.48

±7.

067.

33±

5.80

Con

trol

10.3

2±

6.37

10.6

7±

8.34

11.0

1±

7.20

11.6

6±

8.70

Lum

bar r

otat

ion

Expe

rimen

tal

-.50

±2.

681.

13±

3.28

-0.3

0±

2.81

1.14

±3.

38

Con

trol

-.048

±4.

350.

79±

3.07

-0.2

5±

4.13

0.89

±3.

07a H

S: h

eel s

trike

.b TO

: toe

–off

.c M

ean

±st

anda

rd d

evia

tion

(°).

‘+’i

ndic

ates

cou

nter

cloc

kwis

e ro

tatio

nan

d ‘−’i

ndic

ates

clo

ckw

ise

rota

tion

inth

e tra

nsve

rse

plan

e.

- 52 -

Table 8. Pelvic and lumbar angles in the sagittal and transverse planes

Right HSa Left TOb

Motion Group Pre Post Pre Post

Pelvic anterior tiltingExperimental 10.58 ± 4.64c 7.49 ± 2.72 10.31 ± 4.57 7.46 ± 2.72

Control 11.28 ± 2.93 12.70 ± 2.79 11.14 ± 2.87 12.55 ± 2.91

Pelvic rotationExperimental 3.59 ± 3.50 4.91 ± 3.35 2.50 ± 4.35 4.35 ± 3.78

Control 3.23 ± 3.43 3.19 ± 2.34 3.09 ± 3.19 2.46 ± 2.45

Lumbar extensionExperimental 10.01 ± 6.93 6.69 ± 5.74 10.48 ± 7.06 7.33 ± 5.80

Control 10.32 ± 6.37 10.67 ± 8.34 11.01 ± 7.20 11.66 ± 8.70

Lumbar rotationExperimental -.50 ± 2.68 1.13 ± 3.28 -0.30 ± 2.81 1.14 ± 3.38

Control -.048 ± 4.35 0.79 ± 3.07 -0.25 ± 4.13 0.89 ± 3.07aHS: heel strike.bTO: toe–off.cMean ± standard deviation (°).‘+’ indicates counterclockwise rotation and ‘−’ indicates clockwise rotation in the transverse plane.

- 53 -

Table 8. (Continued)

Left HSa Right TOb

Motion Group Pre Post Pre Post

Pelvic anterior tiltingExperimental 10.80 ± 4.91c 7.85 ± 2.83 10.38 ± 4.86 7.51 ± 2.88

Control 11.48 ± 2.96 12.69 ± 3.04 11.20 ± 3.12 12.45 ± 3.20

Pelvic rotationExperimental -3.35 ± 5.18 -3.53 ± 3.39 -4.03 ± 3.21 -3.68 ± 3.68

Control -3.01 ± 4.92 -4.88 ± 3.21 -3.95 ± 3.95 -4.40 ± 3.22

Lumbar extensionExperimental 9.83 ± 7.30 6.03 ± 5.57 10.58 ± 7.12 6.98 ± 5.77

Control 9.43 ± 6.75 10.21 ± 8.07 10.47 ± 6.84 11.17 ± 8.13

Lumbar rotationExperimental -4.07 ± 4.38 -4.26 ± 3.16 -4.27 ± 4.41 -4.56 ± 3.26

Control -4.78 ± 4.27 -3.77 ± 2.68 -4.79 ± 4.45 -3.82 ± 2.75aHS: heel strike.bTO: toe–off.cMean ± standard deviation (°). ‘+’ indicates counter–clockwise rotation and ‘−’ indicates clockwise rotation in transverse plane.

- 53

-

Tabl

e 8.

(Con

tinue

d)

Left

HSa

Rig

htTO

b

Mot

ion

Gro

upPr

ePo

stPr

ePo

st

Pelv

ic a

nter

ior t

iltin

gEx

perim

enta

l10

.80

±4.

91c

7.85

±2.

8310

.38

±4.

867.

51±

2.88

Con

trol

11.4

8±

2.96

12.6

9±

3.04

11.2

0±

3.12

12.4

5±

3.20

Pelv

ic ro

tatio

nEx

perim

enta

l-3

.35

±5.

18-3

.53

±3.

39-4

.03

±3.

21-3

.68

±3.

68

Con

trol

-3.0

1±

4.92

-4.8

8±

3.21

-3.9

5±

3.95

-4.4

0±

3.22

Lum

bar e

xten

sion

Expe

rimen

tal

9.83

±7.

306.

03±

5.57

10.5

8±

7.12

6.98

±5.

77

Con

trol

9.43

±6.

7510

.21

±8.

0710

.47

±6.

8411

.17

±8.

13

Lum

bar r

otat

ion

Expe

rimen

tal

-4.0

7±

4.38

-4.2

6±

3.16

-4.2

7±

4.41

-4.5

6±

3.26

Con

trol

-4.7

8±

4.27

-3.7

7±

2.68

-4.7

9±

4.45

-3.8

2±

2.75

a HS:

hee

l stri

ke.

b TO: t

oe–o

ff.

c Mea

n ±

stan

dard

dev

iatio

n (°

). ‘+

’ind

icat

es c

ount

er–c

lock

wis

e ro

tatio

nan

d ‘−’i

ndic

ates

clo

ckw

ise

rota

tion

in tr

ansv

erse

pla

ne.

- 54 -

0

2

4

6

8

10

12

14

Experimental

* * * *


Pelv

ic a

nter

ior t

iltin

g (d

eg)

0

2

4

6

8

10

12

14

ControlRt. HS Lt. TO Lt. HS Rt. TO

-8

-6

-4

-2

0

2

4

6

8

Experimental


Pelv

ic ro

tatio

n (d

eg)

-8

-6

-4

-2

0

2

4

6

8

Pre-interventionPost-intervention

Control


Figure 5. Comparison of the averaged pelvic angle in the sagittal and transverse

planes during walking between pre– and post–intervention. ‘+’ indicates

counter–clockwise rotation and ‘−‘ indicates clockwise rotation in

transverse plane (HS, heel strike; TO, toe–off). *p < 0.05 significantly

different between pre– and post– intervention within groups.

- 55 -

0

2

4

6

8

10

12

14

Experimental

* * * *


Lum

bar

exte

nsio

n (d

eg)

0

2

4

6

8

10

12

14

Control


-6

-5

-4

-3

-2

-1

0

1

2

3

Experimental


Lum

bar r

otat

ion

(deg

)

-6

-5

-4

-3

-2

-1

0

1

2

3


Control


Figure 6. Comparison of the averaged lumbar spine angle in the sagittal and

transverse planes during walking between pre– and post–intervention. ‘+’

indicates counter–clockwise rotation and ‘−‘ indicates clockwise rotation in

transverse plane (HS, heel strike; TO, toe–off). *p < 0.05 significantly

different between pre– and post– intervention within groups.

- 56 -

5. Electromyography Activities of Trunk Muscle

In the experimental group, right ES muscle activity decreased significantly during

first (p = 0.040) and second double support (p = 0.009) after the 6–week intervention

(Figure 7). The left ES also decreased significantly in the experimental group during

second double support (p = 0.014). There was no significant difference in either ES

muscle activity in the control group in any period (p > 0.05).

After the 6–week intervention, abdominal muscles (RA, EO, and IO) showed no

significant difference in any event in either group (p > 0.05; Figure 8, 9 and 10).

- 57 -

0

5

10

15

20

25

30

Experimental

**

Firstdouble support


Rt E

S m

uscl

e ac

tivity

(% s

ub M

VIC

)

0

5

10

15

20

25

30

Control

Firstdouble support


0

5

10

15

20

25

30

Experimental

*

Firstdouble support


Lt E

S mu

scle

activ

ity (%

sub M

VIC)

0

5

10

15

20

25

30


Control

Firstdouble support


Figure 7. Comparison of the averaged ES muscle activities during walking between

pre– and post–intervention (MVIC: maximal voluntary isometric

contraction, ES: erector spine muscle). *p < 0.05 significantly different

between pre– and post–intervention within groups.

- 58 -

0

10

20

30

40

Experimental

Firstdouble support


Rt R

A m

uscl

e ac

tivity

(% s

ub M

VIC

)

1 2 3 40

10

20

30

40

Control

Firstdouble support


0

10

20

30

40

50

60

Experimental

Firstdouble support


Lt R

A m

uscl

e ac

tivity

(% s

ub M

VIC

)

1 2 3 40

10

20

30

40

50

60


Control

Firstdouble support


Figure 8. Comparison of the averaged RA muscle activities during walking between


contraction, RA: rectus abdominis muscle).

- 59 -

0

10

20

30

40

50

60

Experimental

Firstdouble support


Rt E

O m

uscl

e ac

tivity

(% s

ub M

VIC

)

0

10

20

30

40

50

60

Control

Firstdouble support


0

10

20

30

40

50

60

70

Experimental

Firstdouble support


Lt E

O m

uscl

e ac

tivity

(% s

ub M

VIC

)

0

10

20

30

40

50

60

70


Control

Firstdouble support


Figure 9. Comparison of the averaged EO muscle activities during walking between


contraction, EO: abdominal external oblique muscle).

- 60 -

0

20

40

60

80

100

Experimental

Firstdouble support


Rt I

O m

uscl

e ac

tivity

(% s

ub M

VIC

)

0

20

40

60

80

100

Control

Firstdouble support


0

20

40

60

80

100

Experimental

Firstdouble support


Lt I

O m

uscl

e ac

tivity

(% s

ub M

VIC

)

0

20

40

60

80

100 Pre-interventionPost-intervention

Control

Firstdouble support


Figure 10. Comparison of the averaged IO muscle activities during walking between


contraction, IO: abdominal internal oblique muscle).

- 61 -

Discussion

Various interventions to alleviate symptoms and pain in patients with LBP have

been investigated in the clinical and research settings (Hoffman et al. 2011, 2012;

Luomajoki et al. 2010; Van Dillen et al. 2003). Previous studies proposed that

improvements in movement patterns in the lumbopelvic region might help to reduce

the pain intensity and disability due to LBP (Scholtes, Gombatto, and Van Dillen

2009; Van Dillen et al. 2003). Also, it has been reported that specific movement

control exercises can decrease excessive lumbar spine movement during lower

extremity movement. Thus, in this study, the specific movement control exercises

were designed based on previous studies for subjects with the lumbar ExtRot pattern

and a 6–week intervention was applied to investigate whether the specific movement

control exercises for subjects with lumbar ExtRot pattern could alleviate pain

intensity, disability, and fear–avoidance behavior in daily activities. Additionally,

specific movement control exercises could alter the lumbopelvic kinematics and trunk

muscle activities during walking in patients with the lumbar ExtRot pattern. The

results have important implications in that it is the first reported study to (1)

demonstrate an effect of specific movement control exercises on pain intensity,

disability, and fear avoidance behavior in daily activities, and (2) show changes in the

pelvic and lumbar angle in the sagittal plane and ES muscle activities in subjects with

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the lumbar ExtRot pattern during walking after 6 weeks of movement control

exercises.

The exercises performed in this study were intended to change the movement and

alignment in the lumbopelvic region during walking in subjects with the lumbar

ExtRot pattern. Scholtes, Gombatto, and Van Dillen (2009) and Van Dillen et al.

(2003) reported that modifying the patient’s preferred lumbar spine movement or

alignment could improve their symptoms. However, because these studies assessed

the modification of the movement pattern in a single examination session, it is

difficult to demonstrate any long–term effect of modifying the movement pattern of

the lumbar spine on pain or symptoms in patients with LBP. Hoffman et al. (2011)

also demonstrated improvements in LBP through intervention based on the evaluation

of directional movement and alignment of the lumbar spine during a 3–month period,

but this was a single case report. In this study, subjects with the lumbar ExtRot

pattern performed five lumbopelvic control exercises (abdominal control in hook–

lying, hip abduction and lateral rotation in supine position, hip extension with knee

extended, knee flexion, and hip rotation in prone position) over 6 weeks. Improving

the ability to control excessive extension and rotation of the lumbar spine during

lower extremity movement may enable reducing pain–provoking movements of the

lumbar spine in daily activities, resulting in decreased pain intensity, disability, and

fear avoidance behavior in LBP subjects. Thus, the effects of the specific–movement

control exercise could be generalized in patients with a lumbar ExtRot pattern.

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Patients with mechanical LBP can be classified into subgroups according to

movement preferences in the lumbar spine towards a specific direction: flexion,

extension, rotation, or multidirectional (Hoffman et al. 2011). Subjects with the

lumbar ExtRot pattern are characterized by an excessive lordosis curve in standing

alignment and greater rotation and extension of the lumbar spine during lumbar spine

movement or with lower extremity movement (Sahrmann 2002; Van Dillen et al.

2003). In this study, after the 6–week exercise, subjects with the lumbar ExtRot

pattern showed a decreased angle of lumbar extension and pelvic anterior tilting at all

events (p < 0.05). This result could be explained in several ways. First, a change in

perception of the neutral position in the lumbopelvic region could help to maintain a

neutral lumbar position. The 6–week movement control exercise aimed to prevent

excessive lumbar extension and rotation during lower extremity movement as well as

education regarding perception of the neutral lumbar spine position. Thus, improving

the ability to adjust the alignment of the lumbopelvic region may influence changes in

the kinematics in the lumbar and pelvic region during walking. Second, after the 6–

week exercise program, decreased muscle activities in the ES of both sides may

contribute to decreases in lumbar extension and pelvic anterior angle. However, the

ES muscle activates anatomically to extend the lumbar spine, and patients with LBP

show greater activity in the ES by a pain–spasm mechanism, compared with healthy

subjects. After the 6–week exercise program, changes in ES muscle activation may

contribute to the decreased lumbar extension angle, which influences the decreased

intradiscal pressure and excessive loading at facet joint of the lumbar spine. Third,

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changes in the biomechanics may contribute to reduce excessive lumbopelvic

movement in sagittal plane. Unwanted and excessive pelvic anterior tilting and

rotation during lower extremity movement can be due to limitation of the flexibility

or length of the lower extremity muscles (e.g., rectus femoris, tensor fascial

latae/iliotibial, and iliopsoas muscles) (Hoffman et al. 2011; Kim et al. 2013; Park et

al. 2011; Sahrmann 2002). In this study, specific movement control exercises

consisted of lumbopelvic motion control during hip extension, rotation, and knee

flexion; it is possible that these exercises enabled control of the lumbopelvic region

during hip and knee movements through improving the flexibility of the muscles.

Walking is a cyclic and repetitive task, combined with hip and knee movements in the

sagittal plane. Thus, recovery from biomechanical limitation could help to prevent

unnecessary pelvic tilting and lumbar extension movement during walking.

Minimizing excessive directional movement of the lumbar spine could be an

important for rehabilitation and preventative programs for patients with LBP.

In many studies, the changes in muscle activities and motor control in patients with

LBP have been explained using a pain–spasm–pain model (Hodges, and Moseley

2003; van der Hulst et al. 2010a, 2010b). This model suggests that pain induces

continuous muscle activity and made muscle relaxation difficult. The present results

showed that activation of the right ES was decreased significantly at the first and

second double support phase, and the left ES was decreased significantly at the

second double support phase in the experimental group (p < 0.05). However, there

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was no significant difference in the activity of either ES muscle in the control group.

These findings suggest that ES muscle activities in subjects in the experimental group

were decreased by relaxation of muscle guarding with decreased pain after the 6–

week movement control exercise. Another reason for the decreased lumbar ES muscle

activity after the 6–week intervention might be increased activation of the deep

muscles with regard to spinal control. Hodges, and Moseley (2003) demonstrated

reduced muscle activity of the deep paraspinal muscles during functional activity in

patients with LBP, and van der Hulst et al. (2010) reported higher ES muscle activity

in patients with LBP, compared with healthy subjects. These results suggested that

the increased ES muscle activities were induced by compensatory muscle activation

resulting from a loss of deep muscle control, such as from the multifidus. In this study,

the specific movement control exercises were used to maintain lumbar spine stability

during lower extremity movement, which could contribute to activation of deep

muscles for further control of the lumbar spine. Although deep paraspinal muscles,

such as the multifidus muscle, were not examined in walking, the postulated

increased deep muscle control of the lumbar spine may reduce the activities of both

ES muscles.

Abdominal muscles make important contributions to spinal stability (Hanada,

Johnson, and Hubley Kozey 2011). Nevertheless, the abdominal muscles in each

phase showed no difference in either group after the 6–week intervention. High

variability in the IO, EO, and RA has been reported during walking, even with a

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normal gait (Saunders et al. 2005; White, and McNair 2002). Several studies have

reported that the RA, EO, and IO muscles showed mono activation, whereas other

studies demonstrated biphasic activation in walking (Saunders et al. 2005; White, and

McNair 2002). Potential alterations in abdominal muscle activity may result in

different levels of co–activation in the trunk muscle and variable lumbopelvic posture

across a population (Barton, Coyle, and Tinley 2009; White, and McNair 2002). Thus,

because of variability in abdominal muscle activation in walking, the 6–week

intervention did not result in a statistically significant difference in RA, EO, or IO

muscle activity while walking.

In this study, the kinematics of the lumbar spine and pelvic region in the transverse

plane did not change between pre– and post–intervention in either group. One

explanation for this might be the different conditions between the exercise position

and experimental task. In the experimental group, subjects performed all exercises in

a supine or prone position, which are open–chain exercises. However, walking, as the

experimental task, is a closed chain movement. Additionally, a walking task involves

multi–joint movements of the lower extremities, such as the ankle, knee, and hip.

Although movement control exercises for the experimental group were intended to

help control the motion of the lumbopelvic region with lower limb movement (hip

abduction–lateral rotation in supine, hip extension, hip internal/external rotation, and

knee flexion in prone position), it might be difficult for these exercises to control

rotation of the lumbopelvic region and prevent excessive movement in the transverse

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plane during walking. Future study is needed to determine whether specific gait

training to control the rotation of the pelvis and the lumbar spine can reduce motion in

the transverse plane during walking.

In this study, several potential limitations have been raised. First, because the all

participants were in their early and mid–20s, the results cannot be generalized to other

age groups. Second, subjects participating in this study were characterized by the

lumbar ExtRot pattern, so it is also difficult to generalize to other subgroups with

movement impairment, such as patients with lumbar flexion, flexion rotation, rotation,

and extension patterns. Future studies should examine the effects of specific

movement control exercises on the lumbopelvic kinematics and abdominal muscle

activities during walking in the other subgroups and diverse age groups.

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Chapter IV

Summary and Conclusion

Diagnosis and treatment based on a subclassification of the mechanical LBP type

has been emphasized in recent physical therapy practice. However, there has been no

reported study of differences in lumbopelvic motion and trunk muscle activities

during walking according to LBP subclassification and the effects of a specific

movement control intervention on lumbopelvic motion and trunk muscle activity

during walking in subjects with the lumbar ExtRot pattern. Thus, the first purpose of

this study was to compare the lumbopelvic motion and trunk muscle activity during

walking between subjects with and without the lumbar ExtRot pattern. Second, the

effects of a 6–week specific movement control exercise program on lumbopelvic

motion and trunk muscle activity during walking in subjects with the lumbar ExtRot

pattern were investigated. The results of this study showed a greater lumbar and

pelvic angle in the sagittal plane and ES muscle activities at all phases and lower right

IO muscle activity at the second double support phase during walking in subjects with

the lumbar ExtRot pattern, compared with subjects without the lumbar ExtRot pattern.

Additionally, through the 6–week specific movement control intervention, decreased

lumbar and pelvic angles in the sagittal plane and ES muscle activity were

demonstrated during walking in subjects with the lumbar ExtRot pattern. However,

there was no significant change in abdominal muscle activity (RA, EO, and IO) after

- 69 -

the 6–week intervention. Thus, the present study may help to guide clinical

assessments of lumbopelvic motion during walking and provide appropriate education

and rehabilitation programs for patients with LBP related to the lumbar ExtRot

pattern.

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국문 요약

허리 폄 돌림 패턴을 가진 대상자에게 특정 움직임

조절 운동이 걷기 시 허리골반 운동과 몸통 근육의

근활성도에 미치는 영향

연세대학교 대학원

물리치료학과

김 시 현

걷기 시 허리골반 운동과 몸통 근육의 근활성도 변화는 비 특이성 허리

통증을 호소하는 환자를 관리하기 위한 적응증이 될 수 있다. 첫 번째

연구에서는 허리 폄 돌림 패턴을 가진 대상자와 정상인들 사이에서 걷기

시 허리골반 운동과 몸통 근육의 근활성도를 비교하였다. 허리 돌림 폄

패턴을 가진 26 명의 대상자와 18 명의 정상인이 모집되었다. 다리와

허리에 20 개의 반사 마커를 부착하였고 3 차원 동작 분석기를 이용하여

허리골반의 운동을 관찰하였다. 몸통 근육인 척추세움근, 배곧은근,

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배바깥빗근, 배속빗근의 양쪽에 표면 전극을 부착하였고 표면 근전도

시스템을 이용하여 근활성도를 측정하였다. 실험에 참여한 모든 대상자는

편안한 속도로 실험실 내의 8 m 보도를 12 회 걸었다. 운동형상학

데이터는 최초의 발꿈치 딛기(heel strike, HS), 왼쪽 발가락 떼기(toe–off,

TO), 왼쪽 HS, 오른쪽 TO 시점에서 수집되었고, 근전도 데이터는 첫번째

양발 지지(double support), 왼쪽 다리 스윙(leg swing), 두 번째 양발

지지, 오른쪽 다리 스윙 구간에서 수집되었다. 통계분석은 두 집단간의

변수의 차이를 검정하기 위하여 정규분포 여부에 따라 만휘트니 검정 또는

독립 표본 t–검정을 실시하였다. 집단간 유의수준은 0.05 로 하였다.

통계분석 결과, 시상면에서의 골반 및 허리뼈 각도는 허리 폄 돌림 패턴을

가진 대상자에게서 전 구간에 걸쳐 유의하게 증가함을 보였다. 가로면에서

골반 및 허리뼈 각도는 두 집단간 유의한 차이를 보이지 않았다. 또한

허리 폄 돌림 패턴을 가진 대상자는 모든 구간에서 유의하게 증가한 양쪽

척추세움근의 근활성도를 보였고, 두 번째 양발 지지 구간에서 유의하게

감소한 오른쪽 배속빗근 근활성도를 보였다. 두 번째 양발 지지 구간에서

오른쪽 배속빗근의 근활성도를 제외한 양쪽 배근육(배곧은근, 배바깥빗근,

배속빗근)의 근활성도에서는 두 집단간 유의한 차이를 보이지 않았다.

두 번째 연구에서는 허리 폄 돌림 패턴을 가진 대상자에게 6 주간 특정

움직임 조절 운동이 걷기 시 허리골반 운동과 몸통 근육의 근활성도에

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미치는 효과를 보고자 하였다. 39 명의 허리 폄 돌림 패턴을 가진 연구

대상자들이 본 실험에 참여 하였다. 39 명의 연구 대상자는 무작위 할당을

통하여 실험군(19 명)과 통제군(20 명)으로 배정되었다. 실험군의 연구

대상자들은 6 주간 움직임 조절 운동을 시행하였고 점진적으로 운동의

난이도가 조절되었다. 허리 통증의 정도, 통증으로 인한 장애 정도, 두려움

회피반응 정도를 평가하기 위하여 시각 사상 척도, 수정된 Oswestry

허리기능 장애 설문지, Roland–Morris 허리기능 장애 설문지, 두려움–회피

반응 설문지를 사용하였다. 걷는 동안 골반 및 허리뼈의 운동형상학

데이터와 몸통의 근육 활성도 데이터를 수집하기 위하여 실험 실 내의 8

m 보도를 편안한 속도로 걷도록 하였다. 운동형상학 데이터는 최초의

오른쪽 HS, 왼쪽 TO, 왼쪽 HS, 오른쪽 TO 시점에서 수집되었고, 근전도

데이터는 첫 번째 양발 지지, 왼쪽 다리 스윙, 두 번째 양발 지지, 오른쪽

다리 스윙 구간에서 수집되었다. 데이터는 각 집단 내에서 치료 중재

전∙후 변수들 사이에 차이를 검정하기 위하여 정규분포 여부에 따라

윌콕슨 부호 순위 검정 또는 대응 표본 t–검정을 실시하였다. 유의 수준은

0.05 로 하였다. 6 주간 치료 중재 후 실험군에서 모든 구간에서 시상면의

골반 및 허리뼈 각도는 유의하게 감소하였고, 대조군에서는 유의한 차이를

보이지 않았다. 또한 가로면에서의 골반 및 허리뼈 각도는 양쪽 모든

집단에서 유의한 차이를 보이지 않았다. 근전도 데이터에서 실험군은

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오른쪽 척추세움근의 근활성도가 첫 번째와 두 번째의 양발 지지 구간에서,

왼쪽 척추세움근은 두 번째 양발 지지 구간에서 유의하게 감소하였다.

대조군에서 양쪽 척추세움근의 근활성도는 어느 구간에서도 유의한 차이를

보이지 않았으며 배근육(배곧은근, 배바깥빗근, 배속빗근)의 근활성도는

양쪽 모든 집단에서 유의한 차이를 보이지 않았다.

두 연구를 통하여 허리 폄 돌림 패턴을 가진 연구대상자들은 걷기 시

모든 구간에서 시상면의 과도한 허리골반 운동이 증명되었다. 또한 모든

구간에서 유의하게 증가된 척추세움근의 근활성도와 두 번째 양발 지지

구간에서 유의하게 감소한 오른쪽 배속빗근의 근활성도를 증명하였다.

이렇게 변화된 허리골반 운동과 척추세움근의 근활성도는 6 주간의 특정

움직임 조절 운동을 통하여 유의한 영향을 주었지만, 허리골반 돌림과

배근육의 근활성도에는 유의한 영향을 주지 못했다. 이와 같이 특정

움직임 조절 운동이 허리 폄 돌림 패턴을 가진 환자에게 시상면에서

과도한 허리골반 운동과 과도한 척추세움근의 근활성도를 감소시킬 수

있는 효과적인 운동으로 사료된다.

핵심 되는 말: 걷기, 근전도, 배복근, 척추세움근, 허리골반 운동, 허리

통증, 허리 폄 돌림 패턴.

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Appendix 1. Protocol for the movement control exercise

Exercise Position Procedure

Abdominal

control

Hook–lying Level 1. Pulling navel towards the spine.

Level 2. Lifting one leg from the ground with

alternate foot unsupported.

Level 3. Sliding one leg to extend the hip and

knee with other foot unsupported.

Level 4. One foot lifting and then extending

without the leg touching the supporting

surface with other foot unsupported.

Level 5. Both legs extending with the same

method as level 4.

Hip abduction–

lateral rotation

Supine Level 1. Bending one knee with the foot on the

floor and then moving the knee towards

the outside and away from the body.

Level 2. One leg hip abduction–lateral rotation

with straightened knee.

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Appendix 1. (Continued)

Exercise Position Procedure

Hip extension with

knee extended

Prone Lifting one leg off the table.

Progression: Increase of the hip extension

range of motion (only 10° hip extension).

Knee flexion Bending the knee.

Progression: Increase of the knee flexion range

of motion.

Hip internal and

external rotation

Bending the knee to 90° and then rotating the

hip inward and outward.

Progression: Increase of the hip rotation range

of motion.

effects of specific movement control exercises on lumbopelvic … · 2019-06-28 · can be improved...

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