Effects of Abdominal Draw-In Maneuver in

Combination With Ankle Dorsiflexion in

Strengthening the Transverse Abdominal

Muscle in Healthy Young Adults and

Patients With Low Back Pain

Seungchul Chon

The Graduate School

Yonsei University

Department of Rehabilitation Therapy

Effects of Abdominal Draw-In Maneuver in

Combination With Ankle Dorsiflexion in

Strengthening the Transverse Abdominal

Muscle in Healthy Young Adults and

Patients With Low Back Pain

Seungchul Chon

The Graduate School

Yonsei University

Department of Rehabilitation Therapy

Effects of Abdominal Draw-In Maneuver in

Combination With Ankle Dorsiflexion in

Strengthening the Transverse Abdominal

Muscle in Healthy Young Adults and

Patients With Low Back Pain

A Dissertation

Submitted to the Department of Rehabilitation Therapy

and the Graduate School of Yonsei University

in partial fulfillment of the

requirements for the degree of

Doctor of Philosophy

Seungchul Chon

June 2011

This certifies that the doctoral dissertation of

Seungchul Chon is approved.

Thesis Supervisor: Sunghyun (Joshua) You

Suhnyeop Kim

Minye Jung

Hyeson Jeon

Duckwon Oh

The Graduate School

Yonsei University

June 2011

Acknowledgements

First of all, I thank and praise God for preparing and guidance this thesis. This

thesis would not have been possible without individuals who offered their valuable

assistance and strong support to prepare and complete this study. It is great pleasure

to express my sincere gratitude to them in my humble acknowledgement.

First and foremost I would like to convey my gratitude to my advisor, Dr.

Sunghyun (Joshua) You for his excellent guidance, advice and supervision

throughout this research work. He has supported me with his expertise and patiently

encouraged me to bring out my best, allowing me to grow as a researcher and a

scholar. The tireless passion and enthusiasm for his research was an important key

which motivated me to pursue my degree. I would never have productive experience

without his crucial contributions of time and ideas.

I gratefully acknowledge Professor Suhnyeop Kim, Professor Minye Jung,

Professor Hyeson Jeon, and Professor Duckwon Oh for their faith in me to be a good

scholar. Their endless passion and commitment in physical therapy has been driving

force for me to keep moving forward when frustrated. I would like to thank for their

valuable advice and critical comments on my paper. I would also like to thank

Professor Chunghwi Yi, Professor Ohyun Kwon, Professor Sanghyun Cho, and

Professor Heonseock Cynn for being a great mentor with best suggestion and their

willingness to share their valuable insight with me. I believe my intellectual maturity

has been nourished through their sincere advice.

I am indebted to professors at Woosong University for their strong support and

encouragement with their best wishes. My special thanks go to students at Woosong

who help to implement and complete my experiment.

Last but not the least, I would like to show my deepest gratitude to my family. This

dissertation would be impossible without them. I would like to thank my father for

his thoughtful support with love and care. I would also like to thank my mother for

sincerely raising me and standing by me in joy and sorrow. No words can describe

my mother‟s everlasting love to me. Many thanks go to my brother for always

cheering me up.

I owe my loving thanks to my wife. My wife has lost me a lot due to my research

even during her pregnancy. She has been unselfish and dedicated herself to support

my study. Without her understanding and persistent confidence in me, I would never

finish this work. My special thanks to my newborn son for being healthy and showing

me the best smile in the world.

- i -

Table of Contents

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

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

Abstract ···································································································· viii

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

Chapter Ⅱ. Effects of the Abdominal Draw-In Maneuver in Combination

With Ankle Dorsiflexion in Strengthening the Transverse

Abdominal Muscle in Healthy Young Adults

Introduction ··················································································· 4

Method ·························································································· 8

1. Participants ············································································ 8

2. Intervention ········································································· 10

3. Ultrasound Imaging Measurement ······································ 11

4. Electromyographic Measurement ······································· 13

5. Statistical Analysis ······························································ 16

Results ························································································· 17

1. Ultrasound Imaging Data ···················································· 17

2. Test-Retest Reliability ························································ 19

3. Electromyographic Data ····················································· 23

Discussion ··················································································· 24

- ii -

Chapter Ⅲ. Use of Co-contraction of Ankle Dorsiflexors to Increase

Transverse Abdominis Function in Low Back Pain

Introduction ················································································· 28

Method ························································································ 32

1. Participants ·········································································· 32

2. Intervention ········································································· 36

3. Pain and Function Assessment ··········································· 39

4. Ultrasound Imaging Measurement ······································ 41

5. Electromyographic Measurement ······································· 44

6. Statistical Analysis ······························································ 48

Results ························································································· 50

1. Clinical Data ······································································· 50

2. Ultrasound Imaging Data ···················································· 51

3. Test-Retest Reliability ························································ 54

4. Electromyographic Data ····················································· 55

Discussion ··················································································· 58

Chapter IV. Conclusion ············································································ 64

References ································································································· 65

Appendices ································································································ 79

Appendix A. Pain Disability Index ······················································· 80

Appendix B. Pain Rating Scale ····························································· 83

Appendix C. Multivariate tests of ANOVA in SPSS ···························· 88

- iii -

Appendix D. Independent t-test in SPSS ·············································· 89

Appendix E. Review Form Clinical Trial Research Plan ····················· 94

Appendix F. Declaration of Ethical Conduct in Research ···················· 97

Abstract in Korean ···················································································· 98

- iv -

List of Figures

Figure 1. Electromyographic measurement of muscle activity ················ 15

Figure 2. Thickness of the transverse abdominal muscle, internal oblique

muscle and external oblique muscle in the experimental and

control groups ··········································································· 18

Figure 3. Bland and Altman plot showing the reliability of ultrasound

image measurement for the thickness of the transverse

abdominal muscle imaged in two abdominal draw-in

maneuver interventions ····························································· 20

Figure 4. Bland and Altman plot showing the reliability of ultrasound

image measurement for the thickness of the internal oblique

muscle imaged in two abdominal draw-in maneuver

interventions ·············································································· 21

Figure 5. Bland and Altman plot showing the reliability of ultrasound

image measurement for the thickness of the external oblique

muscle imaged in two abdominal draw-in maneuver

interventions ·············································································· 22

Figure 6. Flow diagram for this study ······················································ 35

Figure 7. EMG biofeedback during the resisted dorsiflexion training to

augment transverse abdominis muscle contraction ·················· 37

- v -

Figure 8. Participant positioning during co-contraction biofeedback

training ······················································································ 38

Figure 9. Placement of ultrasound transducer on abdominal muscle ······ 43

Figure 10. Abdominal muscle thickness measurement ······························· 43

Figure 11. Placement of EMG electrodes ··················································· 47

- vi -

List of Tables

Table 1. Demographic data of participants ················································· 9

Table 2. Comparison of muscle thickness (㎝) in the transverse

abdominal, internal oblique and external oblique muscles

between the experimental and control groups ···························· 18

Table 3. Comparison of transverse abdominal electromyographic

amplitudes (root mean square) in the experimental group ········· 23

Table 4. The demographic and clinical characteristics of subjects ·········· 34

Table 5. Comparison of pain data obtained from VAS, PDI, and PRS

measures between the pre-/post-intervention in the LBP group · 50

Table 6. Comparison of the abdominal muscle contraction thickness

(㎜) between the groups ······························································ 52

Table 7. Comparison of baseline muscle rest thickness (㎜) and muscle

contraction thickness of the abdominal muscles between groups

at the pretest ················································································ 53

Table 8. EMG peak amplitude, mean amplitude, and onset time data

(root-mean-square, RMS) between groups during the

co-contraction training ································································ 56

Table 9. Mean EMG latency between groups during the co-contraction

training ························································································ 57

- vii -

ABSTRACT

Effects of Abdominal Draw-In Maneuver in

Combination With Ankle Dorsiflexion in Strengthening

the Transverse Abdominal Muscle in Healthy Young

Adults and Patients With Low Back Pain

Seungchul Chon

Dept. of Rehabilitation Therapy

(Physical Therapy Major)

The Graduate School

Yonsei University

The abdominal draw-in maneuver (ADIM) is the most common in the core

stabilization exercise. However, applying ADIM to the patients with low back pain

(LBP) is not easy due to pain factor and weakness of deep abdominal muscle. These

- viii -

studies were designed to examine the effect of new method of ADIM combined

with resisted ankle dorsiflexion training on the deep abdominal muscle.

In the first study, forty healthy adults were allocated at random to the

experimental group or the control group. The experimental group performed the

ADIM in combination with ankle dorsiflexion, and the control group performed the

ADIM alone, five times a day. Ultrasound (US) image and electromyography

(EMG) were used to determine the intervention-related changes in muscle activity

and the thickness of abdominal muscles during the ADIM or the ADIM in

combination with ankle dorsiflexion. A significant difference was found in the

thickness of the transverse abdominal (TrA) muscle between the groups (mean

difference 0.24 ㎝). A significant difference was demonstrated in the amplitude of

the TrA/internal oblique (IO) muscle contraction between the two techniques in the

experimental group (mean difference 68.76 ㎷ ). The intra-class correlation

coefficient showed excellent test–retest reliability of US image measurement of the

abdominal muscles: 0.96 for the TrA muscle, 0.87 for the IO muscle and 0.77 for

the EO muscle.

In the second study, both the LBP group and the healthy group received ten 30-

minute sessions of ADIM combined with ankle dorsiflexion over a two-week period.

A separate mixed-model analysis of variance was computed for the TrA, IO, and

EO muscle thicknesses. The differences in mean and peak EMG amplitudes, onset

time, and latency were compared between the groups. The visual analog pain scale,

- ix -

pain disability index, and pain rating scale were used to assess pain in the LBP

group before and after the intervention. There was a significant interaction between

the LBP group and the healthy groups and a main effect for pre-/post-test were

obtained for only TrA muscle thickness change. Significant differences in mean and

peak EMG amplitudes, onset time, and latency were achieved between the groups.

Significant reductions in all pain measures were observed after training.

This is the first clinical study to demonstrate that ADIM combined with ankle

dorsiflexion training may result in a morphological change in the TrA muscle and

associated pain management in patients with LBP.

Key Words: Abdominal draw-in maneuver, Ankle dorsiflexion, Electromyography,

Low back pain, Transverse abdominal muscle, Ultrasound image.

- 1 -

Chapter Ⅰ

Introduction

Low back pain (LBP) is common, costly, and leading cause of musculoskeletal

system impairment and disability in sports activities and heavy physical loading

(Cairns, Foster, and Wright 2006; Critchley, and Coutts 2002). Epidemic studies

showed that in the United States alone, as many as 30-50% athletes suffer from LBP

(d'Hemecourt, Gerbino, and Micheli 2000; Dreisinger, and Nelson 1996). The annual

healthcare cost related to LBP is estimated to be nearly 100 billion dollars per year

(Martin et al. 2008). The lumbo-pelvic core instability has been consistently

identified as an important clinical marker for chronic LBP. Core stability exercise

that can effectively improve lumbo-pelvic instability is thus a hallmark of clinical

sports medicine and rehabilitation in athletes with LBP and core instability.

LBP therapeutic techniques are used to optimize spinal stability and reduce pain

(Hides et al. 2006; Hodges, and Richardson 1996; Pengel et al. 2003), but outcome

measures are inconclusive and do not support the superiority of one intervention over

another (Cairns, Foster, and Wright 2006; Ferreira et al. 2007). Chronic LBP is

related to not only discogenic pain but also core instability. Nevertheless, clinical

studies focus on pain reduction and do not target the core instability associated with

transverse abdominis (TrA) dysfunction (Kiesel et al. 2008; Richardson et al. 2004;

- 2 -

Teyhen et al. 2005). There is growing evidence that the ADIM can help in the

selective restoration of the neuromuscular control of the abdominal and mulifidus

muscle groups among individuals with LBP, thereby improving spinal stability.

However, it is often difficult to administer the ADIM and other core exercises to

patients with LBP because of the pain factor and the impaired neuromuscular control

of the core muscles.

The ADIM combined with ankle dorsiflexion training is derived from irradiation,

via the proprioceptive neuromuscular technique (PNF), which has been widely used

to empower the weakened core muscles by selectively stimulating adjacent or

stronger muscles in the lower extremities (Adler, Beckers, and Buck 2008). The

success of this method suggests the potential of a lumbar stabilization exercise for

treating LBP (Chon, Chang, and You 2010). Specifically, irradiation is defined as the

propagation and augmentation of muscle strength in response to resistance, possibly

resulting from stimulus (resistance)-induced temporal or spatial summation in muscle

fibers (Adler, Beckers, and Buck 2008; Eccles, and Sherrington 1930; Shimura K,

and Kasai 2002). It is thus believed to increase the number of motor units activated in

a neuromuscular response. Building on this notion, it is possible that irradiation can

be used to selectively contract the deep target muscle, the TrA, by applying resistance

to the relatively stronger ankle dorsiflexors when combined with the ADIM, thereby

further augmenting lumbar spinal stability. Enhanced TrA neuromuscular control

patterns among individuals with LBP are significantly associated with the reduction

- 3 -

of pain and increase in functional spinal mobility and associated physical activity

(Hides et al. 2006; Hodges, and Richardson 1996).

Work to ascertain the motor control mechanisms that underpin the therapeutic

effects of the ADIM combined with ankle dorsiflexion training has important clinical

ramifications for the prevention of and interventions for mechanical LBP. The

specific aim of this clinical trial was to examine the effect of the ADIM combined

with ankle dorsiflexion training on pain intensity and physical disability among

individuals with mechanical LBP using ultrasound (US) image and electromyography.

In these studies, we hypothesized that the ADIM combined with ankle dorsiflexion

training would lead to greater improvement in core stability, as evidenced by muscle

thickness, electromyographic data, pain reduction, and physical function, than

conventional ADIM alone.

- 4 -

Chapter Ⅱ

Effects of the Abdominal Draw-In

Maneuver in Combination With Ankle

Dorsiflexion in Strengthening the

Transverse Abdominal Muscle in Healthy

Young Adults

(Experimental Study 1)

Introduction

The abdominal draw-in maneuver (ADIM) is commonly used during core

stabilization techniques to restore neuromuscular control in the core stabilization

musculature of athletes with sports injuries. The maneuver has also recently gained

widespread acceptance in reducing symptoms in patients with low back pain (LBP)

(Macedo et al. 2009; von Garnier et al. 2009). Recent evidence on the conservative

- 5 -

management of LBP suggests that the restoration of neuromuscular control in the

transverse abdominal (TrA) muscle, together with minimal contraction of other

superficial oblique, internal and external abdominal muscles, is essential for effective

treatment during the early stages of rehabilitation (Cresswell, Grundström, and

Thorstensson 1992; Hodges 2001; Hodges, and Richardson 1996). Previous studies

have demonstrated that the use of the ADIM, in particular, is far more effective than

the use of general core stabilization techniques in improving the cross-sectional area

of the TrA muscle (Akuthota, and Nadler 2004; Hodges, Cresswell, and Thorstensson

1999; Hodges, and Richardson 1996). Thus, core stabilization techniques that

incorporate the selective motor recruitment of the central core stabilizer, such as the

TrA muscle, may be beneficial in the effective management of LBP.

A variety of core stabilization techniques, including abdominal bracing, curl-ups,

lateral bridges, wall squats and stabilization exercises using a ball (Akuthota, and

Nadler 2004; Standaert, and Herring 2007), are used in conjunction with or without

US image (Mannion et al. 2008; O‟Sullivan et al. 1997; Urquhart et al. 2005),

although outcome studies have failed to provide clinical evidence for the superiority

of any particular technique. In addition, despite the fact that all of these stabilization

exercises have been used in the management of individuals with LBP, it is difficult to

reach a clinical decision about adopting any one of them because their therapeutic

efficacy has yet to be demonstrated. For example, ascertaining the exact or

underpinning therapeutic effect of core stabilization techniques poses a significant

challenge because these techniques are often incorporated into static and dynamic

- 6 -

neuromuscular or strengthening regimens (Hibbs et al. 2008; Hodges 2001; Hodges,

and Richardson 1996). Such combinations can potentially confound the results about

which type of core stabilization technique is more effective for the selective

recruitment of core stabilizers.

The irradiation technique, a form of proprioceptive neuromuscular facilitation, has

been conventionally used to selectively increase the number of active motor unit

recruitments involved or weakened in the neuromuscular response (Moore 1975;

Shimura, and Kasai 2002). Irradiation is defined as the increasing spread and strength

of the response to the stimulation (resistance) (Buchwald 1967; Hopf, Schlegel, and

Lowitzsch 1974; Moore 1975; Shimura, and Kasai 2002), and possibly results from

stimulus (resistance)-induced temporal or spatial summation (Eccles, and Sherrington

1930). It is also possible that the irradiation technique may empower or stimulate the

deep target TrA muscle selectively through the application of resistance to the

relatively stronger ankle dorsiflexors when used in combination with the ADIM, thus

further augmenting lumbar spinal stability. Research is needed to determine the

motor control mechanisms underpinning the therapeutic effects of the irradiation

technique, which has important clinical ramifications for the prevention and

management of lumbar spinal instability. This study was undertaken to determine the

additive effect of a combination of ankle dorsiflexion and the ADIM on lumbar

stabilization and abdominal muscle motor control patterns in healthy young adults.

Lumbar stabilization and the motor control patterns in abdominal muscles were

- 7 -

determined by measuring muscle thickness and muscle activity using US image and

electromyography (EMG), respectively, in experimental and control groups.

The basic hypothesis was that the selective increase in thickness and amplitude in

the TrA muscle would be greater in the experimental group (which performed both

the ADIM and ankle dorsiflexion) compared with the control group (which

performed the ADIM alone).

- 8 -

Method

1. Participants

This study was a cross-sectional study with an experimenter-blinded design. A

convenience sample of 40 healthy young adults was recruited from a local university.

All of the participants gave their informed consent, and the study protocol was

approved by the university ethics and institutional review board. The investigators

responsible for assessing the outcomes were unaware of an individual‟s group

assignment. Random allocation was implemented using the conventional

randomization directory method in which a random number table was used to

produce one code card for each participant, who then picked a card to receive his or

her group assignment. Experimenter blinding success was evaluated by asking the

outcome assessors which intervention they thought had been provided. The

participants, all of whom were free from any known medical problems, were

allocated at random into the experimental group (n1=20) or the control group (n2=20).

Those with any neuro-musculoskeletal pathology or history of spinal surgery were

excluded. The target sample size was estimated based on a power of 87% at α=0.05

to detect large differences in effect size between the groups (Cohen 1977). Table 1

presents the demographic characteristics of the participants.

- 9 -

Table 1. Demographic data of participants

Experimental (n1=20) Control (n2=20)

Age (years) 24.25 ± 1.59a 23.55 ± 1.88

Height (㎝) 168.00 ± 8.89 168.55 ± 7.92

Weight (㎏) 60.65 ± 11.99 58.70 ± 9.14

aMean ± SD

- 10 -

2. Intervention

Both groups performed an US-guided (visual feedback) ADIM for 30 minutes per

day, 5 days per week over a 2-week period, with ankle dorsiflexion added in the

experimental group. The success of the ADIM was assessed by monitoring muscle

thickness using US image, and irradiation was evaluated by monitoring the

recruitment sequence of activation of the tibialis anterior (TA), rectus femoris (RF)

and TrA/internal oblique (IO) muscles of the right lower extremity.

During the ADIM, participants were asked to adopt a crook-lying position, and a

pressure biofeedback unit set to range from 40 to 70 ㎜Hg (Richardson et al. 1992;

Richardson, Hodges, and Hides 2004) was placed beneath their fifth lumbar vertebra

to monitor lumbar movement during the measurement of ADIM performance.

Participants were instructed to draw in their lower abdomen below the navel gently

and gradually without moving their upper abdomen or spine, while maintaining a

neutral pelvic position to attempt to keep the target pressure range (40 to 70 ㎜Hg).

They were then asked to dorsiflex their ankle joint against the resistance (with 50%

maximal voluntary isometric contraction (MVIC) of the TA provided by a fixed-strap

band. The irradiation or propagation order of muscle recruitment or the sequential

activation of the TA, RF and TrA/IO muscles was closely assessed through real-time

EMG.

- 11 -

3. Ultrasound Imaging Measurement

A Logiq US imaging system (α 200, Samsung-GE Medical Systems Inc.,

Seongnam, Korea) with a 7.5-㎒ linear transducer was used to assess muscle

thickness and to provide accurate visual feedback during the intervention. The

thicknesses of the abdominal muscles, including the IO and external oblique (EO)

muscles, were obtained.

The participants were asked to adopt a relaxed crook-lying position (Richardson,

Hodges, and Hides 2004). Their hip and knee joints were positioned between 40 and

80 degrees to reduce the lumbar lordosis. The inferior borders of the rib cage and

iliac crest on the right side were palpated as reference points (Whittaker 2007). US

gel (AQUASONIC® 100, Parker Inc., Orange, NJ) was applied to the transducer

head, which was transversely positioned 25 ㎜ anteromedial to the midway point

between the 12th rib and the iliac crest (McMeeken et al. 2004; Whittaker 2007). The

transducer head was maneuvered until the sharpest images of the lateral abdominal

muscles (EO, IO and TrA muscles) were obtained (Teyhen et al. 2005). Three scans

were taken on the right side of the abdominal muscles in their relaxed state in

reference to a predetermined benchmark. The scanning location at the pretest was

marked on a transparent sheet for the posttest to ensure identical placement

throughout the entire experiment (Rankin, and Stokes 1998). To control for the

potential influence of respiration on muscle thickness, the images were consistently

- 12 -

acquired at the end of expiration, which was determined through visual inspection of

the US image (Whittaker 2007). The image data acquired were stored, and muscle

thickness (㎝) was measured using an on-screen caliper. The thicknesses of all three

muscles were defined by drawing a vertical reference line that was located 2.5 ㎝

from the left edge (the muscle–fascia junction) of the TrA (Whittaker 2007). An

immediate readout of the muscle thickness was displayed on the screen and stored for

further analysis. Data that were unacceptable due to movement artifact were

discarded, and the scan was then repeated. Based on this protocol, a test–retest

reliability study was conducted to determine the degree of reliability between the pre-

and post-tests of US image measurements of abdominal muscle thickness in normal

young adults, including those of the EO, IO and TrA muscles. Intra-class correlation

coefficient (ICC) statistical analysis revealed good to excellent ICCs ranging from

0.77 to 0.97.

- 13 -

4. Electromyographic Measurement

A surface EMG with a WEMG-8-type cable (WEMG-8 System, Laxtha Inc.,

Daejeon, South Korea) was used to record the onset times and amplitudes of the

contractions of the TA, RF and TrA/IO muscles. These measurements were only

collected for the experimental group to determine whether sequential activation of

these muscles occurred during ankle dorsiflexion (Figure 1). During data analysis, the

amplitude data were used to evaluate the meaningful changes in the selective motor

control patterns of the TrA/IO, whereas the onset time data were simply used to

monitor the firing sequence (i.e. TrA/IOTARFaugmented TrA/IO). To reduce

skin impedance, each participant‟s skin was shaved, sanded and cleaned, and

electrode gel was applied. If the measured impedance was greater than 5 ㏀, the

electrode was removed and the skin preparation procedure was repeated. A pair of

active electrodes (inter-electrode distance=2.0 ㎝) was placed over the tested muscle

bellies in parallel (Marshall, and Murphy 2003), and a reference electrode was

positioned over the lateral ankle malleolus. Telescan 2.89 software (Laxtha Inc.) was

used to acquire EMG signals at a sampling frequency of 1024 ㎐ and to process

them with a 60-㎐ notch filter. The root mean square EMG amplitude for the TrA/IO

muscle was calculated for 2 seconds (4 to 6 seconds duration, interval 1) during the

ADIM and for 2 seconds (13 to 15 seconds, interval 4) during the ADIM in

combination with ankle dorsiflexion (Figure 1). The sequential activation of TA, RF

- 14 -

and TrA/IO muscle activities was displayed on a computer monitor. Participants were

instructed to sustain 30% MVIC of the TrA/IO muscle during the ADIM, followed by

50% MVIC of the TA, RF and TrA/IO muscles during ankle dorsiflexion, and then to

rest for 5 seconds. An automatic auditory cue was used to trigger each contraction

event, which lasted for 3 seconds over a 20-seconds period (Figure 1).

- 15 -

Figure 1. Electromyographic (EMG) measurement of muscle activity. Raw EMG data

are shown for a representative subject from the experimental group, who

performed the abdominal draw-in maneuver (ADIM) in combination with

ankle dorsiflexion. The five vertical solid lines indicate the time at which an

automatic auditory cue from the EMG software was sequentially given for

the ADIM, tibialis anterior (TA) contraction, rectus femoris (RF)

contraction, transverse abdominal (TrA)/internal oblique (IO) contraction,

and release (or rest), respectively.

- 16 -

5. Statistical Analysis

Standard statistical analysis included computation of the means and standard

deviations, an independent sample t-test or paired two-tailed t-test, and ICC analysis

(McMeeken et al. 2004). The independent t-test was used to assess the mean

differences in muscle thickness between the experimental and control groups. The

paired t-test was used to examine the mean difference in the EMG amplitude of the

TrA/IO muscle between pre- and post-intervention in the experimental group. ICC

analysis and a Bland and Altman test (Bland, and Altman 1986; von Garnier et al.

2009) were used to examine the test–retest reliability of the US image measurements

of abdominal muscle thickness. Repeated-measures analysis of variance, ICC=(2, 1)

(two-way random, single measure), was undertaken and the 95% confidence interval

(CI) of the difference between the two measurements was calculated (Hopkins 2003;

Shrout, and Fleiss 1979). Bland and Altman plots, including the mean difference and

the limits of agreement, were calculated to provide an estimate of the error between

repeated measurements (Bland, and Altman 1986) using MedCalc for Windows

Version 10.4. (MedCalc Software, Mariakerke, Belgium) Statistical Package for the

Social Sciences Version 12.0 (SPSS release 12.0, SPSS Inc., Chicago, IL, USA) was

used, with statistical significance set at p<0.05.

- 17 -

Results

1. Ultrasound Imaging Data

The independent t-tests consistently revealed a significant difference in the

thickness of the TrA muscle between the groups (mean difference=0.24 ㎝, 95% CI

0.08 to 0.40 ㎝, p=0.01), which indicates that the combination of the ADIM and

ankle dorsiflexion was more effective in improving selective recruitment of the TrA

muscle than the ADIM alone (Table 2). However, no significant difference in the

thickness of the IO muscle (− 0.13 ㎝, 95% CI − 0.29 to 0.02 ㎝, p=0.09) or the

EO muscle (− 0.00 ㎝, 95% CI − 0.09 to 0.09 ㎝, p=0.94) was found between the

two groups. This fi nding suggests that the thickness of the IO muscle in the

experimental group had a tendency to decrease, which in turn further supports the

selective motor control of the core abdominal muscles. The thickness measurements

(㎝) of the TrA, IO and EO muscles in the experimental and control groups are

shown in Figure 2.

- 18 -

Table 2. Comparison of muscle thicknesses (㎝) in TrA, IO, and EO between the

experimental and control groups

Experimental Control p-value Mean 95% difference

aTrA 0.86 ± 0.31 0.62 ± 0.16 0.01

* 0.24 ( 0.08 to 0.40)

bIO 0.79 ± 0.19 0.92 ± 0.29 0.09 –0.13 (–0.29 to 0.02)

cEO 0.42 ± 0.12 0.46 ± 0.16 0.97 –0.00 (–0.09 to 0.09)

The experimental group performed ADIM+irradiation whereas controls performed ADIM only.

*Independent t-test revealed a significant difference between the two groups.

aTransverse abdominis.

bInternal oblique.

cExternal oblique.

Figure 2. Thickness (㎝) of the transverse abdominal (TrA) muscle, internal oblique

(IO) muscle and external oblique (EO) muscle in the experimental and

control groups.

- 19 -

2. Test-Retest Reliability

The test–retest reliability ICC (2, 1) revealed ICCs of 0.96 (95% CI 0.85 to 0.99),

0.87 (95% CI 0.62 to 0.98) and 0.77 (95% CI 0.44 to 0.96) for the TrA, IO and EO

muscles, respectively. The Bland and Altman plots showed that the mean differences

and the 95% limits of agreement in the TrA, IO and EO muscles were 0.24 ㎝

(− 0.52 to 1.00 ㎝: Figure 3), − 0.13 cm (− 0.87 to 0.60 ㎝: Figure 4) and − 0.00

cm (− 0.45 to 0.44 ㎝: Figure 5), respectively.

- 20 -

Figure 3. Bland and Altman plot showing the reliability of ultrasound image

measurement for the thickness of the transverse abdominal (TrA) muscle

imaged in two abdominal draw-in maneuver interventions. The middle

line shows the mean difference. The 95% upper and lower limits of

agreement represent 2 standard deviations above and below the mean

difference.

- 21 -

Figure 4. Bland and Altman plot showing the reliability of ultrasound image

measurement for the thickness of the internal oblique (IO) muscle imaged

in two abdominal draw-in maneuver interventions. The middle line shows

the mean difference. The 95% upper and lower limits of agreement

represent 2 standard deviations above and below the mean difference.

- 22 -

Figure 5. Bland and Altman plot showing the reliability of ultrasound image

measurement for the thickness of the external oblique (EO) muscle

imaged in two abdominal draw-in maneuver interventions. The middle

line shows the mean difference. The 95% upper and lower limits of

agreement represent 2 standard deviations above and below the mean

difference.

- 23 -

3. Electromyographic Data

A paired t-test showed a significant difference in EMG amplitude of the TrA/IO

muscle between the ADIM alone and the ADIM in combination with ankle

dorsiflexion, thus suggesting stronger activation during the latter than the former

(Table 3). The sequential activation pattern of the TA, RF and TrA/IO muscles

during ankle dorsiflexion is illustrated in Figure 1.

Table 3. Comparison of deep abdominal muscle EMG amplitudes (root-mean-square,

RMS) in the experimental group

aADIM ADIM + Irradiation p-value Mean 95% CI

bTrA/IO 71.21 ± 29.73 139.97 ± 48.16 < 0.01

* 68.76 (53.16 to 84.36)

*A paired t-test revealed a significant difference in the experimental group.

aAbdominal draw-in maneuver.

bTransverse abdominis/Internal oblique.

- 24 -

Discussion

This study is the first to investigate the augmented effect of the ADIM and ankle

dorsiflexion on selective motor control and muscle thickness in core muscles. As

anticipated, the data show that a combination of the ADIM and ankle dorsiflexion is

significantly more effective in improving selective motor recruitment and associated

thickness of the TrA muscle than the ADIM alone.

The US imaging data are consistent with previous findings investigating the effect

of core stabilization on muscle thickness during the ADIM. The thickness of the TrA

muscle during the ADIM was approximately 0.77 ㎝ in a previous study (Critchley,

and Coutts 2002), whereas in the present study, the thickness of the TrA muscle

increased by approximately 0.86 ㎝ during the combination of the ADIM and ankle

dorsiflexion, and by 0.62 ㎝ during the ADIM alone (39% increase). In contrast, the

thickness of the IO and EO muscles tended to decrease during the combination of

ADIM and ankle dorsiflexion, although the mean differences failed to reach

statistical significance. These findings further indicate that ankle dorsiflexion in

combination with the ADIM may have produced spatial and temporal summation,

and selectively stimulated the deep target TrA muscle against the resistance, thus

leading to augmented core stability or stiffness.

The present EMG findings show that the amplitude of the root mean square EMG

data during the ADIM in combination with ankle dorsiflexion (139.97 ㎷) increased

- 25 -

by approximately 200% compared with that of the ADIM alone (71.21 ㎷). Recent

research examining the relationship between muscle activity and the change in

thickness of the TrA muscle during the ADIM using fine-wire EMG and US imaging

reported a similarly strong correlation (R²=0.87, p<0.01) (McMeeken et al. 2004).

Neurophysiologically, it can be extrapolated that such augmented and selective

improvement in muscle activity may have been the result of energy overflow or

propagation from the TA (distal) muscle to the TrA/IO (central) muscle via a long

and elastic anterior fascia connection (Buchwald 1967; Hopf, Schlegel, and

Lowitzsch 1974; Moore 1975) when ankle dorsiflexion was added to the ADIM,

which was observed in a sequential EMG activation pattern. In fact, there is a

growing body of evidence to show that core stability can be further strengthened

when the „central‟ core exercise is combined with „distal‟ upper or lower extremity

exercises (i.e. dead bug, one-leg bridging and stability ball bridging) (Hodges 2001;

Hodges, Cresswell, and Thorstensson 1999; Hodges, and Richardson 1997; Moseley,

Hodges, and Gandevia 2002).

Certainly, these results have important clinical implications, as they show that

ADIM training is beneficial for selective recruitment of the TrA muscle and its

central mechanism of action on the lumbopelvic region, and that the mechanism of a

deep musculofascial corset can be further augmented by ankle dorsiflexion. Previous

evidence on the clinical management of LBP suggests that support and protection of

the spine is essential to stiffen the lumbosacroiliac joints during selective core

- 26 -

stabilization training of the TrA muscle, thereby minimizing clinical complaints

about LBP and lumbar spinal instability (Hides et al. 2006).

When considering the ICCs, the test–retest reliability data demonstrate excellent

results, suggesting a good degree of repeatability between the repeated US

measurements. However, the Bland and Altman limits of agreement are wider than

the differences found between groups, which suggests that the measurements may be

subject to consequential error. Previous studies have reported a relatively poor degree

of reliability (Critchley, and Coutts 2002; Hides et al. 2007; Hodges et al. 2003;

O‟Sullivan et al. 1997), although the reliability in this study may have been improved

by the use of a transparent sheet and static position measurement which attempted to

control for error associated with the inconsistent location of US applications and

movement artifacts, where other studies have used washable skin markers and

dynamic conditions. It is tentatively suggested that abdominal muscle thickness

measurements obtained by US image can be reasonably accurate and reliable, within

the limits defined by the Bland and Altman analysis. With further refinement, these

measurements may provide a good measure for the assessment of intervention-related

morphological changes and associated motor control mechanisms.

Several shortcomings were identified in this research, which could be considered

to enhance a more robust and large-scale clinical study in the future. First, this

research represents a preliminary experiment intended to investigate the immediate

effect of the ADIM in combination with ankle dorsiflexion in healthy subjects.

Therefore, it invites future research that examines the long-term effect of the

- 27 -

intervention in both normal and pathological populations, such as those suffering

from LBP. Second, the mechanism of action in the deep multifidus muscles, which is

synchronously orchestrated in harmony with the deep abdominal muscles, the TrA,

for core stability, was not measured. It would be of great interest to probe the

mechanism of action in these muscles (MacDonald, Moseley, and Hodges 2006).

Finally, the results of this study cannot be generalized because the sample was

limited to young, healthy adults. Thus, at this time, the technique discussed here

cannot be said to provide an optimal strategy for training TrA muscle control.

Nevertheless, the findings on the core technique make an important contribution to

the existing body of knowledge on the therapeutic exercise of abdominal muscles in

patients with acute LBP for whom the current ADIM is not easily applicable due to

their severe impairments such as pain and weakness.

- 28 -

Chapter Ⅲ

Use of Co-contraction of Ankle

Dorsiflexors to Increase Transverse

Abdominis Function in Low Back Pain

(Experimental Study 2)

Introduction

Mechanical low back pain (LBP) is a common musculoskeletal impairment. It is

often associated with transverse abdominis (TrA) neuromuscular dysfunction and

spinal instability, thereby affecting ADLs and physical activity (Cairns, Foster, and

Wright 2006; Hides et al. 2006; Standaert, and Herring 2007). Epidemiological

evidence indicates that up to 70% of patients with acute LBP ultimately progress to

chronic LBP (Pengel et al. 2003). Delayed onset time of TrA feedforward activation

during shoulder movement (Hodges, and Richardson 1996) and altered muscle

activation patterns during locomotion (Hall et al. 2009) have been identified in LBP

- 29 -

patients as important pathological markers of abdominal neuromuscular dysfunction.

Normally, the neuromuscular system is believed to maintain lumbar spinal stability

by increasing the stiffness (both active and passive) of the deep abdominal and

multifidus muscles or modulating muscle co-contraction, which increases the

compressive loads (Vera-Garcia et al. 2007). This lumbar spinal stability offsets the

deleterious effects of stress imposed on the spine during lifting (Butler, Hubley-

Kozey, and Kozey 2007; O‟Sullivan et al. 1997; Stanton, and Kawchuk 2008).

Core stabilization exercises including ADIM, lateral bridging, pelvic tilting, and

abdominal bracing (Akuthota, and Nadler 2004; Kavcic, Grenier, and McGill 2004;

Standaert, and Herring 2007) have been widely used to improve lumbopelvic stability

(Hodges, and Richardson 1996; McGill 1997). Core stabilization exercises often

incorporate a low degree of TrA activation loading (less than 30% maximal voluntary

isometric contraction (MVIC) with minimal activity of superficial muscles such as

external oblique (EO) and rectus abdominis during the initial phase of rehabilitation

(Butler, Hubley-Kozey, and Kozey 2007; Ferreira, Ferreira, and Hodges 2004). One

important mechanism by which core stabilization exercise increases the

neuromuscular function of the TrA and associated lumbar spinal stability is the

neuromechanic stiffening of the thoracolumbar fascia (TLF) (Stanton, and Kawchuk

2008). Specifically, the synergistic contraction of the TrA and posterior fibers of the

internal oblique (IO) increases the posterior-lateral lumbar tension on the TLF that

connects to both the spinous and transverse processes of the lumbar spine (Stanton,

and Kawchuk 2008). When the ADIM is performed, the activated TrA draws the

- 30 -

abdominal wall inward while concurrently forcing the viscera upward into the

diaphragm and downward into the pelvic floor. Co-activation of the TrA and IO

together with the TLF generates intra-abdominal pressure, which transforms the

abdomen into a mechanically rigid cylinder, thereby providing spinal stability

(Nordin, and Frankel 2001).

Administering core stabilization exercises to LBP patients with severe pain may

result in a substitution or compensatory movement (e.g., rotation and extension of the

lumbopelvic complex) associated with neuromuscular inefficiency in the deep core

muscles. Therefore, it has been suggested that abdominal or core stabilization

exercise without proper pelvic stabilization may increase intradiscal pressure,

anterior shearing, and compressive forces in the lumbar spine, thereby accentuating

LBP (Hodges, and Richardson 1996; McGill 1997). A method to enhance the

activation of the deep abdominal muscles may be advantageous.

Resisted ankle dorsiflexion to augment the TrA/IO via co-contraction is a

technique for improving the selective activation of deep core muscles such as TrA/IO

in pain-free populations (Chon, Chang, and You 2010). This approach was derived

from the concept of irradiation in the proprioceptive neuromuscular facilitation

(PNF), which emphasizes the important contribution of the relatively stronger distal

muscle group by increasing the number of potential motor unit recruitments involved

or weakened. A recent study demonstrated that the co-activation of the ankle

dorsiflexors and rectus femoris (RF) muscles effectively augmented the selective

activation of TrA muscle as evidenced by an increased mean EMG amplitude of the

- 31 -

TrA/IO muscles after the resisted ankle dorsiflexion (Chon, Chang, and You 2010).

EMG analysis showed that a strong contraction of the dorsiflexion muscles,

specifically the tibialis anterior (TA) improved motor recruitment of the TrA/IO

muscles during the ADIM (Chon, Chang, and You 2010). This finding suggests that

co-contraction of the dorsiflexion muscles increases the recruitment of the active

motor units of TrA/IO muscles (Chon, Chang, and You 2010; Eccles, and

Sherrington 1930; Hall et al. 2009). In fact, enhanced TrA neuromuscular control

patterns in individuals with LBP were found to play an important role in functional

spinal mobility and back pain (O‟Sullivan et al. 1997; Teyhen et al. 2005; Torres-

Oviedo, Macpherson, and Ting 2006).

While there is evidence that core stabilization exercises can contribute to deep

abdominal contraction (O‟Sullivan et al. 1997), there is a dearth of information on

effective ways to improve TrA muscle activation and timing in the LBP population.

Hence, the purpose of this study was to determine the effect of two weeks of ADIM

and co-contraction training on abdominal muscle thickness and activation timing, as

well as to monitor pain and function in subjects with LBP.

- 32 -

Method

1. Participants

This study was a case control study with an experimenter-blind design. A

convenience sample of 40 participants volunteered for this study. Among them,

twenty patients with LBP (age=27.20 ± 6.46 years, height=166.25 ± 8.70 ㎝,

mass=58.10 ± 11.81 ㎏) were recruited from a local orthopedic clinic and 20 healthy

controls (age=24.25 ± 1.59 years, height=168.00 ± 8.89 ㎝, mass=60.65 ± 11.99 ㎏)

from a university community. The independent t-test revealed no significant

differences in age (p=0.06), height (p=0.51), or weight (p=0.50), which confirms the

similar demographic characteristics of the two groups (Table 4). Figure 6 presents the

Consolidated Standards for Reporting of Trials (CONSORT) chart. All of the

participants read and signed an informed consent that was approved by the university

ethics and institutional review board. Data collected pertinent to the LBP patients

included onset time, nature and location of symptoms, aggravating and relieving

factors, medication, surgical history, previous back pain or injury, and pain

measurements. The inclusion criteria for the LBP group were: (1) clinical assessment

of mechanical LBP. (2) presence of periods of LBP within the past six to 12 months.

(3) a current pain level ranging from 4/10 to 8/10 on the self-reported visual analog

scale (VAS). Patients with LBP who had previously received conservative therapy

- 33 -

(i.e., hydrocollator, ultrasound, TENS, interferential current therapy, ROM, and the

William flexion exercises), but with limited therapeutic effects, were observed. None

of the participants had prior knowledge or experience of ADIM training.

The clinical assessment criteria for mechanical LBP were: (1) intermittent pain

during the day that gradually develops later in the day. (2) pain when standing or

sitting for a long time. (3) pain upon trunk flexion (or occasionally extension)

(Brown, and Snyder-Mackler 1999; Walker, and Williamson 2009). (4) pain when

driving long distances or getting in and out of a car. An experienced physical

therapist (10 years) made the diagnosis of mechanical LBP according to the clinical

assessment criteria. Medical diagnosis of LBP was made by an attending orthopedist

or a physician. The exclusion criteria included osteoporosis, structural deformity,

systemic inflammatory disease, nerve root compression, facet osteophytes, prolonged

severe pain, neuro-musculoskeletal system problems, and previous spinal surgery.

These exclusion criteria were confirmed by reviewing each patient‟s medical chart

reported by the physician. The control group comprised healthy young adults with no

known medical problems or a history of LBP.

All assessments were made by researchers who were blinded to the clinical status

(healthy or LBP) and all measurements. Both the healthy and LBP groups underwent

a pretest, followed by a 5 days a week training program (co-contraction treatment) for

2-weeks and a posttest after the training (Figure 6). The dependent variables

measured included the VAS, the pain disability index (PDI), and the pain rating scale

(PRS), muscle thickness for TrA, IO, EO, EMG mean and peak amplitudes, onset

- 34 -

time, and latency for TrA/IO, TA, and RF.

Table 4. The demographic and clinical characteristics of subjects

Variable LBP Group (n1=20) Healthy Group (n2=20) p-value

Age (years) 27.20 ± 6.46a 24.25 ± 1.59 0.06

Height (㎝) 166.25 ± 8.70 168.00 ± 8.89 0.51

Weight (㎏) 58.10 ± 11.81 60.65 ± 11.99 0.50

Gender Male / Female 7 / 13 9 / 11

Onset duration (month) 15.3 ± 9.03 NAb

VASc(0-10 score) 6 / 10 NA

PDId(0-70 score) 30 / 70 NA

PRSe(0-130 score) 70 / 130 NA

aMean ± SD.

bNon application.

cVisual analogue scale.

dPain disability index.

ePain rating scale.

- 35 -

Figure 6. Flow diagram for this study.

- 36 -

2. Intervention

Both the healthy and LBP groups received a combination of US and EMG-guided

visual biofeedback for 30 minutes a day, five days a week over a two-week period.

Determination of the outcomes and performance of the ADIM and co-contraction to

augment TrA/IO was made using visual and tactile feedback. As illustrated in Figures

7 and 8, visual feedback information about EMG co-contraction and change in

muscle thickness were presented in the respective EMG and US computer monitors

and used for augmented feedback during ADIM and co-contraction training. Proper

electrode placement for TrA/IO was ensured with US imaging, which was used to

identify the proper location of these muscles during ADIM.

For the ADIM training, each participant was instructed to lie in a hook-lying

position. A pressure biofeedback unit was placed underneath the fifth lumbar

vertebra and inflated to 40-70 ㎜ Hg (Hodges, Richardson, and Jull 1996; Roussel et

al. 2009). The participant was then asked to draw in his or her navel gradually and

maintain the target pressure without any pelvic motion. For ADIM and added co-

contraction training, the participant was first asked to perform ADIM and co-contract

the TA and RF muscles against static resistance (with 50% MVIC of the TA), which

was induced by a fixed-strap band. If the participant correctly performed ADIM and

co-contraction training without pelvic rotation or compensatory upper chest elevation

with overexertion, the training was considered “successful”. The proper performance

- 37 -

of ADIM and co-contraction was confirmed by visual inspection and concurrent US

and EMG measurements, which were used to carefully monitor changes in TrA/IO

muscle thickness and activity sequence. Additional tactile feedback was provided if

necessary.

Figure 7. EMG biofeedback during the resisted dorsiflexion training to augment

transverse abdominis (TrA) muscle contraction. EMG biofeedback was

used to provide visual feedback about muscle activation of the

corresponding TrA/internal oblique (IO), tibialis anterior (TA), rectus

femoris (RF), and TrA/IO in sequence. The vertical arrow indicate the

time at which automatic auditory cue from EMG software was

sequentially given for initial TrA/IO contraction, co-contraction of TA-

RF-augmented TrA/IO muscles, and release (or rest).

- 38 -

Figure 8. Participant positioning during co-contraction biofeedback training.

- 39 -

3. Pain and Function Assessment

Standardized pain and associated functional activity-based pain measurements

included the VAS, PDI, and PRS for the LBP group only. The VAS incorporates a

10-cm straight line on which the participant scores his or her pain on a scale that

ranges from 0 (“no pain”) to 10 (“pain as bad as it could be”) (Jensen, Chen, and

Brugger 2002; Love, Leboeuf, and Crisp 1989). The test-retest reliability of this scale

ranges from 0.60 to 0.77, and its validity from 0.64 to 0.84 (Boonstra et al. 2008).

The PDI is a brief self-report instrument that provides information that complements

the evaluation of physical functional impairment. It comprises seven sub-items of

physical activities: recreation, occupation, sexual behavior, family and home duties,

social functions, self-care, and life-support functions (Grönblad et al. 1993; Tait, and

Chibnall 2005). The scoring system allows the patient to rate these activities on a

scale that ranges from 0 to 10, with a total possible score of 70 (Tait, and Chibnall

2005). The test-retest reliability of the PDI ranges from 0.73 to 0.91 (Grönblad et al.

1993). The PRS includes the three separate clinical illness components that constitute

LBP in point scales: back and leg pain (0-60 points), disability index (0-30 points),

and physical impairment (0-40 points) (Childs, Piva, and Fritz 2005; Manniche et al.

1994). The scale was designed to monitor outcomes following therapeutic

intervention. The higher the score, the greater the level of disability and impairment,

with a maximum point value of 130. The intra-class correlation coefficient (ICC) of

the PRS is a 0.61 (Childs, Piva, and Fritz 2005), with a high level of inter-rater

- 40 -

reliability (97.7%) (Manniche et al. 1994).

- 41 -

4. Ultrasound Imaging Measurement

A Logiq US imaging system (α 200, Samsung-GE Medical Systems Inc.,

Seongnam, South Korea) with a 7.5-㎒ linear transducer was used to assess muscle

thickness during the test. The thickness of the abdominal wall muscles, including the

TrA, IO and EO muscles, were measured, and changes in the TrA was calculated.

Muscle thickness was an indicator of muscle function or activity. The change in TrA

thickness represents the relative changes in the thickness of the TrA contracted to

TrA rest, which typically involves examination of the relative change in TrA muscle

thickness (Mannion et al. 2008). Participants were asked to assume a relaxed hook-

lying position (Hodges, and Richardson 1996). Their hip and knee joint angles were

maintained at approximately 40-80° to eliminate lumbar lordosis. The inferior

borders of the rib cage and iliac crest on the dominant side were palpated as reference

points (Whittaker 2008). US gel (AQUASONIC® 100, Parker Inc., Orange, NJ) was

then applied to the transducer head, which was transversely positioned 25 ㎜

anteromedial to the midway point between the 12th rib and the iliac crest (Figure 9)

(McMeeken et al. 2004; Whittaker 2008). The transducer head was maneuvered until

the sharpest images of all of the lateral abdominal muscles (EO, IO, and TrA) had

been obtained (Teyhen et al. 2005). Three scans were taken on the dominant side of

the abdominal muscles in their relaxed state (Teyhen et al. 2005). The dominant side

of the normal controls was determined by asking them to kick a ball, whereas the

- 42 -

dominant side of the patients with LBP was determined by asking them which was

the more painful side. The pretest scanning location was marked on a transparent

sheet to ensure identical placement throughout the experiment, including the posttest

(Rankin, and Stokes 1998). Specifically, the anatomical reference locations for the

iliac crest and the 12th rib were first palpated to identify and mark their locations with

a permanent marker. We then superimposed the transparent sheet over these locations

and made corresponding markings on it with the permanent marker for consistent

measure (Figure 9). The images were acquired at the end of the exhalation phase

(Whittaker 2008). The image data were stored, and the measurements of the muscle

thickness dimension (㎜) were determined with an on-screen caliper. The thicknesses

of all three muscles were defined by drawing a vertical reference line that was

located 25 ㎜ from the left edge (muscle-fascia junction) of the TrA (Figure 10)

(Whittaker 2008).

Based on this protocol, we conducted a test-retest reliability study to determine the

degree of reliability between our pre- and posttest use of the US measurements of

abdominal muscle thickness in LBP patients, including those of the TrA, IO, and EO

muscles.

- 43 -

Figure 9. Placement of ultrasound transducer on abdominal muscle.

Figure 10. Abdominal muscle thickness measurement.

- 44 -

5. Electromyographic Measurement

Each subject‟s skin preparation was carefully implemented to reduce skin

impedance to below 5 ㏀ by dry-shaving hair with a disposable razor, abrading the

skin with fine sandpaper, and cleansing it with a 2% alcohol swab. Once the skin was

dry, pairs of circular Ag/AgCl surface electrodes with a contact diameter of 19 mm

were attached at an interelectrode distance of 20 ㎜ to the following locations

(Figure 11). A reference electrode was positioned over the lateral malleolus. The

electrode placement for the TrA/IO was approximately 20 mm medial and inferior to

the anterior superior iliac spine (ASIS) (Marshall, and Murphy 2003). For the TA it

was 20 ㎜ distal and lateral from the tibial tubercle, and for the RF it was halfway

between the ASIS and the superior part of the patella (Figure 11) (Cram, and Kasman

1998).

A surface EMG system (WEMG-8 System, Laxtha Inc., Daejeon, South Korea) is

composed of 8 electrodes, a preamplifier for initial processing, a second amplifier, an

A/D converter of 16-bit resolution, a USB connection, and a WEMG-8-type cable.

This EMG was used to record the onset times and mean and peak amplitudes of the

TA, RF, and TrA/IO muscles. These EMG data were used to provide proper muscle

activation sequence during the co-contraction training.

Because approximately 30% MVIC has been reported to be the best activation

level for the TrA/IO muscles (Butler, Hubley-Kozey, and Kozey 2007), we used this

- 45 -

criterion during our EMG biofeedback training for effective co-contraction of the

target muscles. Once the MVIC for each TA, RF, and TrA/IO muscle was reached,

participants were instructed to sustain 30% MVIC of the TrA/IO (Butler, Hubley-

Kozey, and Kozey 2007), followed by 50% MVIC of the TA, RF, and TrA/IO during

co-contraction training for 3 seconds, and then to rest for 5 seconds. EMG monitoring

was used to ensure consistent muscle activation at each target MVIC for the

corresponding muscle. An automatic auditory cue that lasted for 3 seconds over a 20

seconds period was provided for each participant to start contracting the muscle at

the proper time interval (Figure 7).

The raw EMG signal was processed using Telescan 2.89 software (WEMG-8

System, Laxtha Inc., Daejeon, South Korea) at a sampling frequency of 1024 ㎐

with a 60-㎐ notch filter for noise reduction associated with electrical interference

arising from the usual sources including 60 ㎐ power lines or radio frequencies, and

electric or magnetic devices. The root mean-square EMG amplitude for each TA, RF,

and TrA/IO muscle was calculated for 3 seconds (3-6 seconds duration) during the

ADIM and for 3 seconds (12-15 seconds) during the co-contraction (Figure 7). The

identification of the onset time of EMG for each TrA/IO, TA, and RF muscle was

determined as the onset point at which the mean of 51.2 consecutive samples (50 ㎳)

exceeded the baseline activity (threshold level) by three standard deviations. The raw

EMG signal was full-wave rectified and filtered using a band pass filter at 8-480 ㎐,

with a rejection factor of -3 ㏈. Baseline activity was defined as a period of

- 46 -

approximately 3 seconds before ADIM movement or 6 seconds before ankle

dorsiflexion. Each onset time was visually checked to ensure that EMG onset was

misrepresented or cofounded by motion artifact or environmental interference. Less

than 5% of all trials were discarded following visual inspection due to an inability to

differentiate the muscle onset from environment interference or activity. The latency

between the onset of the TrA/IO and the TA muscles, and the TA and the RF, as well

as the TrA/IO and the RF muscles, was analyzed for both groups.

EMG data for pre-/post-test were not recorded. Initially, we intended to use EMG

primarily to provide visual biofeedback and monitor consistent mean and peak

amplitudes and sequences for the TrA/IO, RF, and TA to maximize our ADIM

training effect during the co-contraction training. EMG activity was recorded in 2

sessions in the first week of the training and another 2 sessions in the second week to

facilitate a proper sequence of muscle activation.

- 47 -

Figure 11. Placement of EMG electrodes.

- 48 -

6. Statistical Analysis

Standard statistical analysis included computations of means and standard

deviations, a mixed 2 × 2 analysis of variance (ANOVA), paired two-tailed t-test,

ICC, and standard error of the measurement (SEM). The independent variables

included group and time factors. The dependent variables included VAS, PDI, PRS,

muscle thickness, EMG peak and mean amplitude, onset time, and latency. Three

separate 2 (group) × 2 (time) mixed-model ANOVAs were performed to evaluate the

effect of co-contraction training on increasing TrA muscle thickness using the

resisted ankle dorsiflexion technique, with time (or intervention) as a within-subject

factor and two independent groups as a between-group factor. Post-hoc comparison

using Tukey‟s honestly significant difference (HSD) test was performed if significant

interactions were obtained. The independent t-tests were used to determine

differences in muscle rest thickness and muscle contraction thickness for TrA, IO,

and EO between groups at the pretest. Additional analysis was implemented using the

independent t-test to assess the differences in mean and peak EMG amplitudes, onset

time, and latency between the healthy and LBP groups. The paired t-test was also

used to assess the differences in mean and peak EMG amplitudes between baseline

TrA/IO and co-contracted TrA/IO. Pre-post differences in the VAS, PDI, and PRS

were used to assess pain in the LBP group using the paired t-test. Significance level

was set at p<0.05 for all analyses.

- 49 -

ICC analysis was used to examine the test-retest reliability of the US

measurements of abdominal muscle thickness (Bland, and Altman 1986). ICC (3, 1)

(two-way mixed, single measure) was performed at a 95% confidence interval (CI) of

the difference between the repeated US measurements of muscle thickness at two

separate occasions (48-72 hours apart) (Hopkins 2000; Shrout, and Fleiss 1979). The

SEM was defined as SEM=standard deviation (SD) (1-ICC)0.5

, where SD is the 1 SD

of all measurements. SPSS for Windows statistical software (SPSS release 12.0,

SPSS Inc., Chicago, IL, USA) was used, with statistical significance set at p<0.05.

- 50 -

Results

1. Clinical Data

Separate paired t-tests showed a statistically significant difference in the pain

measurements, the VAS (p<0.01), PDI (p<0.01), and PRS (p=0.02), between the pre-

and posttests in the LBP group (Table 5).

Table 5. Comparison of pain data obtained from VAS, PDI, and PRS measures

between the pre-/post-intervention in the LBP group (n=40)

Pretest Posttest Mean difference 95% CI p-value

VASb 6.15 0.29a 4.65 0.25 -1.50 ( -2.15, -0.85) 0.00

PDIc 30.95 5.94 23.90 4.77 -7.05 ( -9.63, -4.47) 0.00

PRSd 69.60 4.59 61.60 4.27 -8.00 (-10.07, -5.93) 0.02

aMean ± SD.

bVisual analogue scale.

cPain disability index.

dPain rating scale.

- 51 -

2. Ultrasound Imaging Data

A separate mixed 2 × 2 ANOVA showed a significant group × intervention

interaction and intervention main effect for the TrA muscle contraction thickness

(p=0.01), but this was not the case for IO (p=0.83) and EO (p=0.53) (Table 6).

Further analyses using Tukey post hoc tests showed that the LBP group significantly

improved on muscle contraction thickness after the training compared to the healthy

group. No significant between group effects were observed. Independent t-tests

showed significant differences in baseline (rest) muscle thickness for TrA (p<0.01),

IO (p=0.02), and EO (p=0.00) between groups at the pretest, but no significant

changes in muscle contraction thickness were observed (Table 7).

- 52 -

Table 6. Comparison of the abdominal muscle contraction thickness (㎜) between

groups

LBP Group (n1=20) Healthy Group (n2=20)

Pretest Posttest Pretest Posttest p-value

TrAb 12.0 1.7

a 13.6 12.0 14.7 7.2 15.1 7.5 0.01

IOc 10.2 1.2 9.7 1.0 9.8 2.8 9.5 4.3 0.83

EOd 9.8 0.4 9.0 1.1 9.9 2.4 9.5 2.6 0.53

aMean SD. b

Transverse abdominis. cInternal oblique.

dExternal oblique.

A significant group × intervention interaction and intervention main effects were observed only

for TrA muscle contraction thickness (p<0.05), but did neither IO nor EO show any interaction

effects. Tukey HSD confirmed that the LBP group showed greater improvement in TrA muscle

contraction thickness as compared with the healthy group at the posttest. No between-group

effect was obtained.

- 53 -

Table 7. Comparison of baseline muscle rest thickness (㎜) and muscle contraction

thickness of the abdominal muscles between groups at the pretest

LBP Group (n1=20) Healthy Group (n2=20) p-value

Rest

TrAb 3.0 9.0

a 6.0 1.5 0.00

IOc 7.2 2.6 9.3 2.9 0.02

EOd 6.1 1.7 4.4 1.5 0.00

Contraction

TrA 12.0 11.7 14.7 7.2 0.11

IO 10.2 1.2 9.8 2.8 0.62

EO 9.8 0.4 9.9 2.4 0.86

aMean SD.

bTransverse abdominis.

cInternal oblique.

dExternal oblique.

Independent t-test showed significant difference in baseline (rest) muscle thickness for TrA, IO,

and EO between groups at the pre-test, but no significant changes in muscle contraction

thickness were observed.

- 54 -

3. Test-Retest Reliability

The test-retest reliability (ICC (3, 1), 95% CI, SEM) analysis revealed ICCs of

0.99 (0.98 to 0.10, 0.02), 0.95 (0.82 to 0.99, 0.06), and 0.96 (0.85 to 0.99, 0.03) for

the TrA, IO, and EO muscles, respectively.

- 55 -

4. Electromyographic Data

The independent t-test showed significant differences in the mean peak EMG

amplitudes for TrA/IO (p=0.00), TA (p=0.00), and RF (p=0.00), but not for the co-

contracted TrA/IO (p=0.07) between the healthy and LBP groups (Table 8).

Significant differences in the mean EMG amplitudes were observed for TrA/IO

(p=0.00), TA (p=0.00), and RF (p=0.00), but not for the co-contracted TrA/IO

(p=0.08) between the healthy and LBP groups (Table 8). Significant differences in

the mean onset time were observed for the TrA/IO (p=0.01) and TA (p=0.01), but not

for the RF (p=0.11) between the healthy and LBP groups (Table 8). No significant

difference in the mean latencies for TrA/IO-TA (p=0.48), TA-RF (p=0.14), and

TrA/IO-RF (p=0.06) were found between the groups (Table 9).

- 56 -

Table 8. EMG peak amplitude, mean amplitude, and onset time data (root-mean-

square, RMS) between groups during the co-contraction training

LBP Group (n1=20) Healthy Group (n2=20) p-value

TrA/IOb

Peak amplitude (㎶) 87.27 19.76a 151.23 48.54 0.00

Mean amplitude (㎶) 65.08 20.07 106.71 38.14 0.00

Onset time (s) 4.15 0.69 3.68 0.34 0.01

TAc

Peak amplitude (㎶) 71.20 16.71 89.83 21.55 0.00

Mean amplitude (㎶) 43.79 15.86 63.81 22.99 0.00

Onset time (s) 6.72 0.39 6.39 0.33 0.01

RFd

Peak amplitude (㎶) 76.77 23.41 99.42 22.54 0.00

Mean amplitude (㎶) 44.29 17.71 68.63 19.65 0.00

Onset time (s) 6.89 0.35 6.73 0.25 0.11

Co-contracted TrA/IO

Peak amplitude (㎶) 159.18 30.94* 181.73 43.01

* 0.07

Mean amplitude (㎶) 111.38 37.59* 134.09 41.54

* 0.08

Onset time (s) NAe NA

aMean SD.

bTransverse abdominis/Internal oblique.

cTibialis anterior.

dRectus femoris.

eNot

applicable. *Paired t-test showed statistical significance between TrA/IO and co-contracted

TrA/IO (p<0.05).

Note that TA and RF muscles were co-contracted, followed by the initial onset of TrA/IO

muscle activation. Onset time for the co-contracted TrA/IO was not determined due to additive

contraction.

- 57 -

Table 9. Mean EMG latency between groups during the co-contraction training

Latency (sec) LBP Group (n1=20) Healthy Group (n2=20) p-value

TrA/IOb–TA

c 2.57 0.74

a 2.72 0.52 0.48

TA–RFd 0.16 0.42 0.34 0.28 0.14

TrA/IO–RF 2.73 0.57 3.06 0.45 0.06

aMean SD.

bTransverse abdominis/Internal oblique.

cTibialis anterior.

dRectus femoris.

- 58 -

Discussion

This study presents clinical evidence that demonstrates the potential efficacy of the

combined co-contraction and ADIM technique for sequential motor recruitment and

muscle thickness in the abdominal muscles of healthy adults and those with chronic

LBP. Our data show that treatment with the combined technique (co-contraction) was

effective in the LBP group in increasing TrA muscle thickness. Our findings suggest

that the ADIM followed by co-contraction technique is useful in stimulating the

selective recruitment of the TrA. Previously, the co-contraction technique had only

been studied in normal subjects rather than a pathological group (Chon, Chang, and

You 2010).

We used US imaging to determine a subject‟s ability to activate or contract the

TrA using changes in the muscle thickness. McKeeken et al. (2004) investigated the

relationship between muscle activity and thickness changes of the TrA during the

ADIM using fine-wire EMG and US imaging techniques and reported a strong

correlation of the two measures (R2=0.87, p<0.01). Our US imaging data are

consistent with the findings of a previous study investigating the effect of core

stabilization on muscle thickness during ADIM combined with resisted ankle

dorsiflexion treatment (Chon, Chang, and You 2010). In the present study, the TrA

muscle thickness increased by approximately 31% (from 3.5 ㎜ to 4.6 ㎜) while the

TrA muscle contraction thickness increased 13% (from 12 to 13.6) for the LBP

- 59 -

patients. The TrA muscle thickness increased 6% (from 8.1 ㎜ to 8.6 ㎜) while the

muscle contraction thickness increased 3% (from 14.7 to 15.1) for the healthy

controls. Independent t-tests showed significant differences in baseline (rest) muscle

thickness for TrA, IO, and EO between groups at the pretest, but no significant

changes in muscle contraction thickness were observed. The pretest differences in

baseline (rest) muscle thickness between the groups imply a pathological condition,

either atrophy or a neuromuscular inhibition in the abdominal muscles of patients

with LBP. However, increased activation of the previously inhibited TrA after

training suggests the positive benefits of ADIM and the co-contraction technique in

patients with LBP (Cairns, Foster, and Wright 2006; Hodges, and Richardson 1996;

Kumar, Sharma, and Negi 2009; O‟Sullivan et al. 1997). Moreover, the additive

effect of co-contraction to ADIM training seems to be more advantageous for LBP

patient population than for the healthy controls. As shown in Figure 7, the second

TrA/IO EMG peak amplitude was amplified after the co-contraction was applied.

This finding suggests that the co-contraction was associated with improvements in

the TrA activation, supporting a potential therapeutic efficacy of this novel technique.

Previous studies showed that increases in TrA muscle thickness were associated with

improved lumbar stiffness or spinal stability, contributing to pain reduction in

individuals with LBP (Chon, Chang, and You 2010; O‟Sullivan et al. 1997).

Previous studies proposed that the recurrence of LBP is associated with a delayed

timing dysfunction of the TrA (Butler, Hubley-Kozey, and Kozey 2007; Ferreira,

Ferreira, and Hodges 2004; Hall et al. 2009; Hodges 2001). Our EMG onset time data

- 60 -

confirmed that initial TrA/IO, TA, and RF onset times in the LBP group were

significantly slower than those in the healthy group. Similarly, LBP patients had

delayed EMG latency. The mean EMG amplitudes of the LBP patients were smaller

than those of the healthy controls. These findings suggest that LBP patients had

altered motor activation patterns compared to those of normal controls. This altered

neuromuscular response has been identified as an important marker or a pathological

characteristic associated with mechanical LBP (Hall et al. 2009; Hodges 2001;

Hodges, and Richardson 1996; Roussel et al. 2009). However, this assumption needs

to be validated. In our study, after co-contraction with ADIM, the impaired

neuromuscular responses (peak amplitude and mean amplitude) improved more in the

co-contracted TrA/IO than in the initial TrA/IO, suggesting that the co-contraction

may be useful in treating activation timing factors. Our findings are consistent with

those of previous studies that demonstrated increased EMG amplitude following co-

contraction training (Chon, Chang, and You 2010; Hall et al. 2009).

Neurophysiologically, co-contraction involves motor synergies or coordinative

structures whereby groups of muscles are recruited to work together as a functional

unit (Torres-Oviedo, Macpherson, and Ting 2006). Hence, a facilitation of the

impaired TrA function in LBP patients can be achieved by integrating the TA,

quadriceps, and abdominal groups to work together as a functional core. When co-

contraction was added to the ADIM, as observed by the improved sequencing of the

EMG activation pattern during the co-contraction training, the lumbopelvic unit was

trained to demonstrate a motor pattern more similar to healthy individuals. Previous

- 61 -

studies demonstrated that a combination of the isolated training of delayed TrA

activation and non-isolated functional training (involving abdominal curl ups, side

bridges, and birddogs) was beneficial for pain and functional improvement in LBP

patients (O‟Sullivan et al. 1997; Stuge et al. 2004). One study found that delayed

feedforward activation of the medial quadriceps muscle in individuals with

patellofemoral pain was enhanced with comprehensive isolated and non-isolated

contraction training (Cowan et al. 2003). A combination of isolated training (initial

ADIM of delayed TrA/IO) and non-isolated training involving co-contraction of the

TA and RF helped to restore delayed TrA activation, which is a consistent pro-

marker of abdominal neuromuscular dysfunction in LBP. Hence, earlier activation of

the TrA during the co-contraction training as reflected in our EMG onset time data

can be considered an important indicator of improved neuromuscular control. This

improved neuromuscular response has greater force-generating potential and an

enhanced ability to increase spinal stiffness, resulting improvements in pain, function,

and recurrence rates in LBP patients (Cholewicki, and McGill 1996; Kavcic, Grenier,

and McGill 2004; O‟Sullivan et al. 1997). Perhaps EMG could be used to provide

accurate information about motor activation pattern and sequence.

The LBP group targeted potential subjects with recurrent mechanical back pain

who had failed previous conservative treatments. In those subjects, we observed a

reduction of pain and improvement in function in LBP subjects, specifically with

significant improvements in VAS, PDI, and PRS following the intervention. Our

findings are consistent with O‟Sullivan et al. (1997) who showed that engaging in

- 62 -

ADIM exercise for 15 minutes a day for 10 weeks significantly reduced the VAS

scores of patients with spondylolysis or spondylolisthesis from 6 to 2. Kumar et al.

(2009) reported that the administration of the ADIM in combination with various

core exercise for 5 weeks in patients with chronic LBP resulted from 7 to 1 on the

VAS.

The results of the present study have a number of important clinical implications.

They show that ADIM training is beneficial for the selective recruitment of the TrA

and its central mechanism of action on the lumbopelvic region, and that the

mechanism of the deep musculofascial corset may be further augmented by the co-

contraction technique. Previous evidence of the clinical management of LBP suggests

that the support and protection of the spine is essential to stiffening the lumbo-

sacroiliac joints during selective core stabilization training of the TrA, thereby

minimizing clinical complaints of LBP and lumbar spinal instability (Hides et al.

2006).

Our test-retest reliability data suggest a good degree of reliability in our repeated

US measurements, which is in contrast to a number of earlier studies that reported a

relatively poor degree of reliability (Hodges et al. 2003; Mannion et al. 2008). Others

have demonstrated a good to high degree of reliability (Hebert et al. 2009; Hides et al.

2007; McMeeken et al. 2004). Our higher degree of test-retest reliability may be due

to our consistent use of a transparent sheet and static position measurement to control

for potential errors associated with the inconsistent location of US applications and

movement artifacts. Our findings corroborate existing evidence showing that the

- 63 -

abdominal thickness measurements obtained from US imaging are accurate and

reliable. Hence, such measurements are a good indicator of intervention-related

morphological changes and associated motor control mechanisms.

Notwithstanding its significant results, this study had several shortcomings that

should be addressed in a more robust and large-scale clinical study. First, it is

possible that US-guided visual feedback at pretest may have affected outcome results

in muscle thickness measures. Hence, in future visual feedback should be excluded in

the pretest. Second, the ephemeral changes in muscle thickness are unlikely to occur

within such a short duration of strength training. The motor learning literature has

shown that corticospinal excitability occurs within the first 2 weeks of training when

the main improvement in motor performance is achieved, and reaches a significant

level after 4 weeks of training (Abe et al. 2000; Jensen, Marstrand, and Nielsen 2005;

Legg 1981; MacDougall et al. 1995). The long-term effect of such intervention needs

further exploration. Third, the function of the multifidus, which provides segmental

stability, was not measured. It would be of great interest to further probe the

mechanism of action in these muscles (MacDonald, Moseley, and Hodges 2006).

Lastly, the results of this study cannot be generalized due to limited sample size and

our case control study design. A larger clinical trial with a true control group with

LBP is needed to investigate the therapeutic effects of the resisted dorsiflexion

contraction training to augment TrA/IO in clinical practice.

- 64 -

Chapter IV

Conclusion

This series of two studies were designed to examine the effect of new method of

ADIM combined with resisted ankle dorsiflexion training on the deep abdominal

muscle in healthy adults and patients with LBP.

Experimental study 1 provided empirical evidence to show that the ADIM

combined with ankle dorsiflexion is useful in enhancing muscle activity and

associated morphological changes in the TrA muscle. It offers clinical insights into

the additive effect of ankle dorsiflexion in selectively stimulating the TrA muscle,

and suggests that it may be used as an alternative core stabilization technique for the

management of patients with LBP.

Experimental study 2 highlighted the potential application of ADIM along with

ankle dorsiflexion in normal and LBP groups. We demonstrated increased muscle

thickness and the associated reduction of LBP after the intervention. The additive

ADIM combined with ankle dorsiflexion training could be integrated as a part of a

core stabilization regimen for the management of patients with LBP, but further study

is needed to validate its therapeutic efficacy.

- 65 -

References

Abe T, DeHoyos DV, Pollock ML, and Garzarella L. Time course for strength and

muscle thickness changes following upper and lower body resistance training in

men and women. Eur J Appl Physiol. 2000;81(3):174–180.

Adler SS, Beckers D, and Buck M. PNF in Practice: An illustrated guide. 3rd ed.

Berlin: Springer, 2008.

Akuthota V, and Nadler SF. Core strengthening. Arch Phys Med Rehabil. 2004;85(3

Suppl 1):S86–92.

Bland JM, and Altman DG. Statistical methods for assessing agreement between two

methods of clinical measurement. Lancet. 1986;1(8476):307–310.

Boonstra AM, Schiphorst Preuper HR, Reneman MF, Posthumus JB, and Stewart RE.

Reliability and validity of the visual analogue scale for disability in patients with

chronic musculoskeletal pain. Int J Rehabil Res. 2008;31(2):165–169.

Brown A, and Snyder-Mackler L. Diagnosis of mechanical low back pain in a laborer.

J Orthop Sports Phys Ther. 1999;29(9):534–539.

- 66 -

Buchwald JS. Exteroceptive reflexes and movement. Am J Phys Med.

1967;46(1):121–128.

Butler HL, Hubley-Kozey CL, and Kozey JW. Changes in trunk muscle activation

and lumbar-pelvic position associated with abdominal hollowing and reach during

a simulated manual material handling task. Ergonomics. 2007;50(3):410–425.

Cairns MC, Foster NE, and Wright C. Randomized controlled trial of specific spinal

stabilization exercises and conventional physiotherapy for recurrent low back pain.

Spine. 2006;31(19):E670–681.

Childs JD, Piva SR, and Fritz JM. Responsiveness of the numeric pain rating scale in

patients with low back pain. Spine. 2005;30(11):1331–1334.

Cholewicki J, and McGill SM. Mechanical stability of the in vivo lumbar spine:

implications for injury and chronic low back pain. Clin Biomech. 1996;11(1):1–15.

Chon SC, Chang KY, and You SH. Effect of the abdominal draw-in manoeuver in

combination with ankle dorsiflexion in strengthening transverse abdominal muscle

in healthy young adults: A preliminary, randomized, controlled study.

Physiotherapy. 2010;96(2):130–136.

- 67 -

Cohen J. Statistical Power Analysis for Behavioral Science. New York: Academic

Press, 1977.

Cram JR, and Kasman GS. Introduction to Surface Electromyography. Gaithersburg,

MD: Aspen Publishers, 1998.

Cresswell AG, Grundström H, and Thorstensson A. Observations on intra-abdominal

pressure and patterns of abdominal intra-muscular activity in man. Acta Physiol

Scand. 1992;144(4):409–418.

Critchley DJ, and Coutts FJ. Abdominal muscle function in chronic low back pain

patients: measurement with real-time ultrasound scanning. Physiotherapy.

2002;88(6):322–332.

Cowan SM, Bennell KL, Hodges PW, Crossley KM, and McConnell J. Simultaneous

feedforward recruitment of the vasti in untrained postural tasks can be restored by

physical therapy. J Orthopaed Res. 2003;21(3):553–558.

d'Hemecourt PA, Gerbino PG 2nd, and Micheli LJ. Back injuries in the young athlete.

Clin Sports Med. 2000;19(4):663–679.

- 68 -

Dreisinger TE, and Nelson B. Management of back pain in athletes. Sports Med.

1996;21(4):313–320.

Eccles JC, Sherrington CS. Reflex summation in the ipsilateral spinal flexion reflex.

J Physiol. 1930;69(1):1–28.

Ferreira ML, Ferreira PH, Latimer J, Herbert RD, Hodges PW, Jennings MD, Maher

CG, and Refshauge KM. Comparison of general exercise, motor control exercise

and spinal manipulative therapy for chronic low back pain: A randomized trial.

Pain. 2007;131(1-2):31–37.

Ferreira PH, Ferreira ML, and Hodges PW. Changes in recruitment of the abdominal

muscles in people with low back pain: Ultrasound measurement of muscle activity.

Spine. 2004;29(22):2560–2566.

Grönblad M, Hupli M, Wennerstrand P, Järvinen E, Lukinmaa A, Kouri JP, and

Karaharju EO. Intercorrelation and test-retest reliability of the Pain Disability

Index (PDI) and the Oswestry Disability Questionnaire (ODQ) and their

correlation with pain intensity in low back pain patients. Clin J Pain.

1993;9(3):189–195.

- 69 -

Hall L, Tsao H, MacDonald D, Coppieters M, and Hodges PW. Immediate effects of

co-contraction training on motor control of the trunk muscles in people with

recurrent low back pain. J Electromyogr Kinesiol. 2009;19(5):763–773.

Hebert JJ, Koppenhaver SL, Parent EC, and Fritz JM. A systematic review of the

reliability of rehabilitative ultrasound imaging for the quantitative assessment of

the abdominal and lumbar trunk muscles. Spine. 2009;34(23):E848–856.

Hibbs AE, Thompson KG, French D, Wrigley A, and Spears I. Optimizing

performance by improving core stability and core strength. Sports Med.

2008;38(12):995–1008.

Hides J, Wilson S, Stanton W, McMahon S, Keto H, McMahon K, Bryant M, and

Richardson C. An MRI investigation into the function of the transversus abdominis

muscle during “drawing-in” of the abdominal wall. Spine. 2006;31(6):E175–178.

Hides JA, Miokovic T, Belav y DL, Stanton WR, and Richardson CA. Ultrasound

imaging assessment of abdominal muscle function during drawing-in of the

abdominal wall: An intrarater reliability study. J Orthop Sports Phys Ther.

2007;37(8):480–486.

- 70 -

Hodges P, Cresswell A, and Thorstensson A. Preparatory trunk motion accompanies

rapid upper limb movement. Exp Brain Res. 1999;124(1):69–79.

Hodges P, Richardson C, and Jull G. Evaluation of the relationship between

laboratory and clinical tests of transversus abdominis function. Physiother Res Int.

1996;1(1):30–40.

Hodges PW. Changes in motor planning of feedforward postural responses of the

trunk muscles in low back pain. Exp Brain Res. 2001;141(2):261–266.

Hodges PW, Pengel LH, Herbert RD, and Gandevia SC. Measurement of muscle

contraction with ultrasound imaging. Muscle Nerve. 2003;27(6):682–692.

Hodges PW, and Richardson CA. Contraction of the abdominal muscles associated

with movement of the lower limb. Phys Ther. 1997;77(2):132–142.

Hodges PW, and Richardson CA. Inefficient muscular stabilization of the lumbar

spine associated with low back pain. A motor control evaluation of transversus

abdominis. Spine. 1996;21(22):2640–2650.

- 71 -

Hopf HC, Schlegel HJ, and Lowitzsch K. Irradiation of voluntary activity to the

contralateral side in movements of normal subjects and patients with central motor

disturbances. Eur Neurol. 1974;12(3):142–147.

Hopkins WG. Measures of reliability in sports medicine and science. Sports Med.

2000;30(1):1–15.

Jensen JL, Marstrand PC, and Nielsen JB. Motor skill training and strength training

are associated with different plastic changes in the central nervous system. J Appl

Physiol. 2005;99(4):1558–1568.

Jensen MP, Chen C, and Brugger AM. Postsurgical pain outcome assessment. Pain.

2002;99(1-2):101–109.

Kavcic N, Grenier S, and McGill SM. Quantifying tissue loads and spine stability

while performing commonly prescribed low back stabilization exercises. Spine.

2004;29(20):2319–2329.

Kiesel KB, Uhl T, Underwood FB, and Nitz AJ. Rehabilitative ultrasound

measurement of select trunk muscle activation during induced pain. Man Ther.

2008;13(2):132–138.

- 72 -

Kumar S, Sharma VP, and Negi MP. Efficacy of dynamic muscular stabilization

techniques (DMST) over conventional techniques in rehabilitation of chronic low

back pain. J Strength Cond Res. 2009;23(9):2651–2659.

Legg SJ. The effect of abdominal muscle fatigue and training on the intra-abdominal

pressure developed during lifting. Ergonomics. 1981;24(3):191–195.

Love A, Leboeuf C, and Crisp TC. Chiropractic chronic low back pain sufferers and

self-report assessment methods. Part I. A reliability study of the Visual Analogue

Scale, the Pain Drawing and the McGill Pain Questionnaire. J Manipulative

Physio Ther. 1989;12(1):21–25.

MacDonald DA, Moseley GL, and Hodges PW. The lumbar multifidus: does the

evidence support clinical beliefs? Man Ther. 2006;11(4):254–263.

MacDougall JD, Gibala MJ, Tarnopolsky MA, MacDonald JR, Interisano SA, and

Yarasheski KE. The time course for elevated muscle protein synthesis following

heavy resistance exercise. Can J Appl Physiol. 1995;20(4):480–486.

Macedo LG, Maher CG, Latimer J, and McAuley JH. Motor control exercise for

persistent, nonspecific low back pain: A systematic review. Phys Ther.

2009;89(1):9–25.

- 73 -

Manniche C, Asmussen K, Lauritsen B, Vinterberg H, Kreiner S, and Jordan A. Low

back pain rating scale: validation of a tool for assessment of low back pain. Pain.

1994;57(3):317–326.

Mannion AF, Pulkovski N, Gubler D, Gorelick M, O‟Riordan D, Loupas T, Schenk P,

Gerber H, and Sprott H. Muscle thickness changes during abdominal hollowing: an

assessment of between-day measurement error in controls and patients with

chronic low back pain. Eur Spine J. 2008;17(4):494–501.

Mannion AF, Pulkovski N, Toma V, and Sprott H. Abdominal muscle size and

symmetry at rest and during abdominal hollowing exercises in healthy control

subjects. J Anat. 2008;213(2):173–182.

Marshall P, and Murphy B. The validity and reliability of surface EMG to assess the

neuromuscular response of the abdominal muscles to rapid limb movement. J

Electromyogr Kinesiol. 2003;13(5):477–489.

Martin BI, Deyo R, Mirza SK, Turner JA, Comstock BA, Hollingworth W, and

Sullivan SD. Expenditures and health status among adults with back and neck

problems. JAMA. 2008;299(6):656–664.

- 74 -

McGill SM. The biomechanics of low back injury: implications on current practice in

industry and the clinic. J Biomech. 1997; 30(5):465–475.

McMeeken JM, Beith ID, Newham DJ, Milligan P, and Critchley DJ. The

relationship between EMG and change in thickness of transversus abdominis. Clin

Biomech. 2004;19(4):337–342.

Moore JC. Excitation overflow: An electromyographic investigation. Arch Phys Med

Rehabil. 1975;56(3):115–120.

Moseley GL, Hodges PW, and Gandevia SC. Deep and superficial fibers of the

lumbar multifidus muscle are differentially active during voluntary arm

movements. Spine. 2002;27(2):E29–36.

Nordin M, and Frankel VH. Basic Biomechanics of the Musculoskeletal System. 3rd

ed. Philadelphia: Lippincott & Williams, 2001.

O‟Sullivan PB, Phyty GD, Twomey LT, and Allison GT. Evaluation of specific

stabilizing exercise in the treatment of chronic low back pain with radiologic

diagnosis of spondylolysis or spondylolisthesis. Spine. 1997;22(24):2959–2967.

- 75 -

Pengel LH, Herbert RD, Maher CG, and Refshauge KM. Acute low back pain:

Systematic review of its prognosis. BMJ. 2003;327(7410):323.

Rankin G, and Stokes M. Reliability of assessment tools in rehabilitation: An

illustration of appropriate statistical analyses. Clin Rehabil. 1998;12(3):187–199.

Richardson CA, Hodges PW, and Hides JA. Therapeutic Exercise for Lumbopelvic

Stabilization: A motor control approach for the treatment and prevention of low

back pain. 2nd ed. Edinburgh: Churchill Livingstone, 2004.

Richardson CA, Jull GA, Toppenberg R, and Commerford M. Techniques for active

lumbar spine stabilisation for spinal protection: a pilot study. Aust J Physiother.

1992;38:105–112.

Roussel N, Nijs J, Truijen S, Vervecken L, Mottram S, and Stassijns G. Altered

breathing patterns during lumbopelvic motor control tests in chronic low back

pain: A case-control study. Eur Spine J. 2009;18(7):1066–1073.

Shimura K, and Kasai T. Effects of proprioceptive neuromuscular facilitation on the

initiation of voluntary movement and motor evoked potentials in upper limb

muscles. Hum Mov Sci. 2002;21(1):101–113.

- 76 -

Shrout PE, and Fleiss JL. Intraclass correlations: Uses in assessing rater reliability.

Psychol Bull. 1979;86(2):420–428.

Standaert CJ, and Herring SA. Expert opinion and controversies in musculoskeletal

and sports medicine: core stabilization as a treatment for low back pain. Arch Phys

Med Rehabil. 2007;88(12):1734–1736.

Stanton T, and Kawchuk G. The effect of abdominal stabilization contractions on

posteroanterior spinal stiffness. Spine. 2008;33(6):694–701.

Stuge B, Veierod MB, Laerum E, Bragelian M, and Vollestad N. The efficacy of a

treatment program focusing on specific stabilizing exercises for pelvic girdle pain

after pregnancy: a two-year follow-up of a randomized clinical trial. Spine.

2004;29(10):E197– 203.

Tait RC, and Chibnall JT. Factor structure of the pain disability index in workers‟

compensation claimants with low back injuries. Arch Phys Med Rehabil.

2005;86(6):1141–1146.

Teyhen DS, Miltenberger CE, Deiters HM, Del Toro YM, Pulliam JN, Childs JD,

Boyles RE, and Flynn TW. The use of ultrasound imaging of the abdominal

- 77 -

drawing-in maneuver in subjects with low back pain. J Orthop Sports Phys Ther.

2005;35(6):346–355.

Torres-Oviedo G, Macpherson JM, and Ting LH. Muscle synergy organization is

robust across a variety of postural perturbations. J Neurophysiol.

2006;96(3):1530–1546.

Urquhart DM, Hodges PW, Allen TJ, and Story IH. Abdominal muscle recruitment

during a range of voluntary exercises. Man Ther. 2005;10(2):144–153.

Vera-Garcia FJ, Elvira JL, Brown SH, and McGill SM. Effects of abdominal

stabilization maneuvers on the control of spine motion and stability against sudden

trunk perturbations. J Electromyogr Kinesiol. 2007;17(5):556-567.

von Garnier K, Köveker K, Rackwitz B, Kober U,Wilke S, Ewert T, and Stucki G.

Reliability of a test measuring transversus abdominis muscle recruitment with a

pressure biofeedback unit. Physiotherapy. 2009;95(1):8–14.

Walker BF, and Williamson OD. Mechanical or inflammatory low back pain. What

are the potential signs and symptoms? Man Ther. 2009;14(3):314–320.

- 78 -

Whittaker JL. Ultrasound imaging of the lateral abdominal wall muscles in

individuals with lumbopelvic pain and signs of concurrent hypocapnia. Man Ther.

2008;13(5):404–410.

- 79 -

Appendices

- 80 -

Appendix A. Pain Disability Index

The rating scales below are designed to measure the degree to which several aspects

of your life are presently disrupted by chronic pain. In other words, we would like to

know how much your pain is preventing you from doing what you would normally do,

or from doing it as well as you normally would. Respond to each category by

indicating the overall impact of pain in your life, not just when the pain is at its worst.

For each of the 7 categories of life activity Listed, please circle the number on the

scale which describes the level of disability you typically experience. A score of 0

means no disability at all, and a score of 10 signifies that all of the activities in which

you would normally be involved have been totally disrupted or prevented by your

pain.

(1) Family/home responsibilities

This category refers to activities related to the home or family. It includes chores or

duties performed around the house (e.g., yard work) and errands or favors for other

family members (e.g., driving the children to school).

0 1 2 3 4 5 6 7 8 9 10

No disability Total disability

(2) Recreation

- 81 -

This category includes hobbies, sports, and other similar leisure time activities.

0 1 2 3 4 5 6 7 8 9 10

No disability Total disability

(3) Social activity

This category refers to activities which involve participation with friends and

acquaintances other than family members. It includes parties, theater, concerts,

dining out, and other social functions.

0 1 2 3 4 5 6 7 8 9 10

No disability Total disability

(4) Occupation

This category refers to activities that are a part of or directly related to one‟s job.

This includes non-paying jobs as well, such as that of a housewife or volunteer

worker.

0 1 2 3 4 5 6 7 8 9 10

No disability Total disability

(5) Sexual behavior

This category refers to the frequency and quality of one‟s sex life.

0 1 2 3 4 5 6 7 8 9 10

No disability Total disability

- 82 -

(6) Self-care

This category includes activities which involve personal maintenance and

independent daily living (e.g., taking a shower, driving, getting dressed, etc.).

0 1 2 3 4 5 6 7 8 9 10

No disability Total disability

(7) Life-support activity

This category refers to basic life-supporting behaviors such as eating, sleeping, and

breathing.

0 1 2 3 4 5 6 7 8 9 10

No disability Total disability

- 83 -

Appendix B. Pain Rating Scale

Manniche et al developed rating scale to evaluate patients with low back pain. The

scale covers the 4 manifest components of back pain and was designed for

monitoring outcome following therapeutic interventions. The authors are from

several hospitals in Denmark.

Measures in rating scale:

(1) Back and leg pain (60 points)

(2) Disability index (30 points)

(3) Physical impairment (40 points)

Back and Leg Pain

Visual analogue scales (VAS) ranging from 0 (no pain) to 10 (worst imaginable

pain):

(1) Back pain at the time of the examination

(2) Leg pain at the time of the examination

(3) The worst back pain within the last 2 weeks

(4) The worst leg pain within the last 2 weeks

(5) Average level of back pain during the last 2 weeks

(6) Average level of leg pain during the past 2 weeks

Pain index=SUM (points for all 6 visual analogue scales)

- 84 -

Disability Index

Questions

(1) Can you sleep at night without low back pain interfering?

(2) Can you do your daily work without low back pain reducing your activities?

(3) Can you do the easy chores at home such as watering flowers or cleaning the

table?

(4) Can you put on shoes and stockings by yourself?

(5) Can you carry two full shopping bags (10 kilograms total)?

(6) Can you get up from a low armchair without difficulty?

(7) Can you bend over the wash basin to brush your teeth?

(8) Can you climb stairs from one floor to another without resting because of low

back pain?

(9) Can you walk 400 meters without resting because of low back pain?

(10) Can you run 100 meters without resting because of low back pain?

(11) Can you ride a bike or drive a car without feeling any low back pain?

(12) Does low back pain influence your emotional relationship to your nearest

family?

(13) Did you have to give up contact with other people within the last 2 weeks

because of low back pain?

(14) If it was a present interest do you think that there are certain jobs which you

would not be able to manage because of your back trouble?

(15) Do you think that the low back pain will influence your future?

- 85 -

Responses Points Forward Reverse

Not a problem 0 Yes No

Can be a problem 1 Can Can be

Is a problem 2 No Yes

Forward questions: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11

Reverse questions: 12, 13, 14, 15

NOTE: In the paper scoring is given as yes = 0; can be problem = 1; no = 2.

However these responses for the last 4 questions reverse the general trend of the first

11 questions. It makes more sense to me to reverse the scoring for the last 4 questions.

Disability index=SUM (points for all 15 questions)

Physical Impairment

(1) Endurance of back muscles: length of time that the patient can lie horizontal

above the floor with the legs strapped to a bench and the trunk unsupported from the

level of the iliac crest

(2) Back mobility: modified Schober's test (a) draw a line between the posterior iliac

spines then (b) identify a point 10 ㎝ above the midpoint of the line then (c) with

the person bending forward measure the distance from that point to the midpoint of

the line connecting the posterior iliac spines and (d) determine the distraction =

increase in measurement while bending forward.

(3) Overall mobility: fastest time taken to go from (a) lying supine on a flat couch 80

cm above the floor to (b) standing beside the couch then (c) walking to the end of the

couch where (d) a deep knee bend is done and then (e) return to the starting position.

- 86 -

(4) Use of analgesics: based on the frequency of use for non-narcotic and narcotic

analgesics

Measures Finding Points

back muscle endurance

≥ 270 seconds 0

240 – 269 seconds 1

210 – 239 seconds 2

180 – 209 seconds 3

150 – 179 seconds 4

120 – 149 seconds 5

90 – 119 seconds 6

60 – 89 seconds 7

30 – 59 seconds 8

1 – 29 seconds 9

0 seconds 10

back mobility

(modified Schober's test)

≥ 60 ㎜ 0

50 – 59 ㎜ 2

40 – 49 ㎜ 4

30 – 39 ㎜ 6

20 – 29 ㎜ 8

0 – 19 ㎜ 10

overall mobility test

< 10 seconds 0

10 – 19 seconds 2

20 – 29 seconds 4

30 – 39 seconds 6

40 – 49 seconds 8

≥ 50 seconds 10

analgesic use

none during past week 0

use NSAID or non-narcotic analgesic 1– 4 times a week

2

use of NSAID or non-narcotic analgesic 5+ times a week

4

use of morphine or analogues 1– 4 times a week

8

use of morphine or analogues 5+ times a week

10

Impairment index=SUM (points for all 4 measures)

- 87 -

Interpretation:

• minimum score for sub-scores and total: 0

• maximum pain index: 60

• maximum disability index: 30

• maximum physical impairment: 40

• maximum total points: 130

• The higher the score the greater the level of disability and impairment.

Performance:

• The scale was found to be reliable based on comparisons with the Global

Assessments reported by an experienced clinician and the patient.

• Inter-rater agreement is high.

- 88 -

Appendix C. Multivariate tests of ANOVA in SPSS

Multivariate tests of ANOVA in SPSS program for comparison of the abdominal

muscle contraction thickness between groups

- 89 -

Appendix D. Independent t-test in SPSS

Figure 1. Independent t-test in SPSS program for comparison of baseline muscle rest

thickness and muscle contraction thickness of the abdominal muscles between groups

at the pretest

- 90 -

Figure 2. Independent t-test in SPSS program for EMG peak amplitude between

groups during the co-contraction training

- 91 -

Figure 3. Independent t-test in SPSS program for EMG mean amplitude between

groups during the co-contraction training

- 92 -

Figure 4. Independent t-test in SPSS program for EMG onset time data between

groups during the co-contraction training

- 93 -

Figure 5. Independent t-test in SPSS program for Mean EMG latency between groups

during the co-contraction training

- 94 -

Appendix E. Clinical Trial Research Plan

Review Form

Clinical Trial Research Plan Woosong University

Application Date: March 25, 2009

Name Seung-Chul Chon

Title

Effects of abdominal draw-in maneuver in combination with

ankle dorsiflexion in strengthening the transverse abdominal

muscle in healthy young adults and patients with low back pain

Kind of Research

Experimental study 1:

Effect of the abdominal draw-in maneuver in combination with

ankle dorsiflexion in strengthening the transverse abdominal

muscle in healthy young adults

Experimental study 2:

Use of co-contraction of ankle dorsiflexors to increase

transverse abdominis function in low back pain

The researchers named below respectfully submit the following research proposal

for consideration by the Committee for Clinical Trials of the Graduate School of

Public Health and Welfare, Woosong University, Daejeon, South Korea

- 95 -

Researcher Information

Name Seung-Chul Chon Experimental period Start: April 25, 2009 Finish: December 25, 2009

Address #405 Information-Science Building, 17-2 Jayang-Dong, Dong-Gu, Daejeon, Republic of S. Korea, 300-718

E-mail Biomechanic1@hotmail.com Office phone number 042-630-9824 Fax 042-630-9828

The following co-researchers each reviewed this research proposal and agreed to

participate in the described research project

Name Academic

background Affiliation

Phone

number E-mail

Ki-Yeon

Chang

Doctor of

Philosophy

Department of

Occupational Therapy,

Woosong University

042-630-

9821

kiyeon@

lion.woosong.ac.kr

Sung-Hyun

You

Doctor of

Philosophy

Department of Physical

Therapy, Yonsei

University

033-760-

2476

neurorehab@

yonsei.ac.kr

Susan

Saliba

Doctor of

Philosophy

Department of

Kinesiology, Virginia

University

434-243-

4033

saf8u@

virginia.edu

- 96 -

Approval considerations:

1 What facilities will be used for this project?

Laboratory, Graduate School of

Public Health and Welfare,

Woosong University

Daejeon Woori Hospital

2 Will minors participate in this study?

(0~17 years) NO

3 Will pregnant women participate in this

study? NO

4 When performing this study, will you need to

use voice, video, or photographic recording? YES

5 Will the study use human tissue or blood? NO

6 Will the study target people who cause harm? NO

7

Will the participants in this study be exposed

to radiation therapy, radiation diagnostics,

clinical trials, nuclear radiation or

experimental drugs?

NO

8

Will the principal investigator, the co-workers

or any of the subjects benefit financially from

this study?

NO

9 Will this study require interviews or

questionnaires? NO

10 Is this study a criminal or crime-related

research? NO

11 Are there potential risks to the research

participants? NO

Approved: Committee Signature (or Stamp) date: April 10, 2009

- 97 -

Appendix F. Declaration of Ethical Conduct in

Research

I, as a lecturer of Department of Occupational therapy in Woosong University,

hereby declare that I abide by the following Code of Research Ethics while writing

this experimental study with “Effects of abdominal draw-in maneuver in combination

with ankle dorsiflexion in strengthening the transverse abdominal muscle in healthy

young adults and patients with low back pain”.

“First, I strive to be honest in my conduct, to produce valid and reliable research

conforming. I affirm that my experimental study contains honest, fair and reasonable

conclusions based on my own careful research.

Second, I do not commit any acts that may discredit or damage the credibility of my

research. These include, but are not limited to: falsification, distortion of research

findings or plagiarism”.

Date: April 10, 2009

Address: #405 Information-Science Building, 17-2 Jayang-Dong, Dong-Gu,

Daejeon, Republic of S. Korea, 300-718

Name: Seung-Chul Chon

- 98 -

국문 요약

발목 배측굴곡을 결합한 복부 당기기 방법이 건강한

젊은 성인과 요통환자의 복횡근 강화에 미치는 영향

연세대학교 대학원

재활학과(물리치료학 전공)

천 승 철

복부 당기기 방법은 척추 안정화 운동 중 가장 많이 사용되는 방법이다.

그러나 임상적으로 요통환자들에게 복부 당기기 방법을 적용하는 것은

통증과 심부 복부근육의 약화로 인하여 쉽지 않다. 본 연구에서는 발목

배측굴곡근에 저항을 제공하여 복부 당기기 방법과 결합된 새로운 척추

안정화 방법이 심부 복부근육인 복횡근에 미치는 영향을 알아보았다.

실험연구 1은 40명의 대상자를 실험군 20명과 대조군 20명으로

무작위 배정하였다. 실험군은 발목 배측굴곡이 결합된 복부 당기기 방법을

시행하였고, 대조군은 복부 당기기 방법을 실시하였다. 초음파와

- 99 -

근전도기를 사용하여 발목 배측굴곡이 결합된 복부 당기기 방법과 복부

당기기 방법을 실시하는 동안 복부 근육의 두께와 근 활성도를

측정하였다. 연구 결과, 실험군과 대조군 사이에 복횡근의 두께에서 0.24

㎝ 유의한 차이를 보였고, 실험군에서 복부 당기기 방법과 발목

배측굴곡이 결합된 방법을 비교한 결과 68.76 ㎷ 유의한 차이를 보였다.

복부 두께 측정에 대한 초음파 검사-재검사 신뢰도인 급간내 상관계수는

복횡근이 0.96, 내복사근이 0.87, 그리고 외복사근이 0.77로 높게

나타났다.

실험연구 2는 요통환자 20명과 건강한 성인 20명이 발목 배측굴곡이

결합된 복부 당기기 방법을 2주간 동일하게 실시하였다.

분산분석방법으로 복횡근, 내복사근 및 외복사근의 두께를 계산하였고,

그룹 사이에 평균 및 정점 진폭 값, 근 수축 및 잠복기 시간을 비교하였고,

요통환자 그룹에서 실험 전후에 통증시각척도, 통증장애지수 및

통증등급척도로 통증을 측정하였다. 연구 결과, 요통환자 그룹과 건강한

성인 그룹 사이에 유의한 차이가 있었고, 실험 전후에 복횡근 두께에서

유의한 차이를 보였다. 평균 및 정점 진폭 값, 근 수축 및 잠복기 시간도

그룹 사이에서 유의한 차이를 보였다. 요통환자 그룹에서 모든 통증

척도는 실험 후 유의하게 감소되었다.

- 100 -

이와 같은 연구 결과들은 발목 배측굴곡을 결합한 복부 당기기 방법이

요통환자들의 복횡근 두께와 이와 관련된 통증 관리에 효과적임을

보여주고 있다.

핵심 되는 말: 근전도, 발목 배측굴곡, 복부 당기기 방법, 복횡근, 요통,

초음파 영상.