Differential Effects of Abdominal Drawing-

in Maneuver, Abdominal Bracing, and

Dynamic Neuromuscular Stabilization on

Core Stability and Motor Control in Adults

With Core Instability

Jaejin Lee

The Graduate School

Yonsei University

Department of Physical Therapy

Differential Effects of Abdominal Drawing-

in Maneuver, Abdominal Bracing, and

Dynamic Neuromuscular Stabilization on

Core Stability and Motor Control in Adults

With Core Instability

Jaejin Lee

The Graduate School

Yonsei University

Department of Physical Therapy

Differential Effects of Abdominal Drawing-

in Maneuver, Abdominal Bracing, and

Dynamic Neuromuscular Stabilization on

Core Stability and Motor Control in Adults

With Core Instability

A Master Thesis

Submitted to the Department of Physical Therapy

and the Graduate School of Yonsei University

in partial fulfillment of therequirements

for the degree of Master of Science

Jaejin Lee

December 2013

This certifies that the masters thesis of

Jaejin Lee is approved.

______________________________________________________

Thesis Supervisor: Sunghyun You

______________________________________________________

Chunghwi Yi: Thesis Committee Member #1

______________________________________________________

Hyeseon Jeon: Thesis Committee Member #2

The Graduate School

Yonsei University

December 2013

Acknowledgements

First of all, I would like to thank Professor Sunghyun You for his unwavering

support, patience, and confidence in my abilities, and the numerous opportunities he

provided for my professional growth. I will always remember and appreciate his

encouragement and support. I would also like to thank Professor Chunghwi Yi for his

sincere encouragement and for sharing his academic flair. I would like to express my

gratitude to Professor Hyeseon Jeon who was a spiritual counselor and adviser. I

sincerely thank Professor Ohyun Kwon, Professor Sanghyun Cho, and Professor

Heonseok Cynn for their help in broadening my knowledge and perspective.

Thanks also to the 41 research subjects who generously donated their time.

I would like to offer my appreciation to members of the Movement Healing

Laboratory - Dongryul Lee, Namgi Lee, Dongkoog Noh, Dohyeon Kim, Jiwon Yoo,

and Jeongjae Lee - who always paid attention to my grumbling and answered my

questions. I also want to give my appreciation to all members of the Department of

Physical Therapy at the Graduate School.

I offer sincere thanks to the Professors of Catholic University of Busan (Department

of Physical Therapy) for their support and encouragement.

Finally, I want to express my gratitude to my family, who always encouraged me,

especially my parents and maternal grandmother, who provided endless love and

support.

-i-

Table of Contents

List of Figures ····································································· iii

List of Tables ········································································ iv

Abstract ············································································· v

Introduction ··········································································· 1

Methods ··············································································· 4

1. Subjects ········································································· 4

2. Instrumentation ·································································· 5

2.1. Ultrasound ································································· 5

2.2. Surface Electromyography················································ 5

2.3. Pressure Biofeedback Unit ················································ 5

2.4. Simi Aktisys ································································ 5

3. Experimental Procedures ··················································· 6

3.1. Clinical tests ································································ 6

3.2. Intervention ································································· 7

3.3. Experimental testing ······················································· 9

3.3.1. Core Stability Using PBU and Simi Aktisys ···················· 11

3.3.2. Diaphragm Movement and Abdominal Muscle Thickness

Using Real-time Ultrasound Imaging ···························· 12

3.3.3. EO Amplitude Using EMG ········································ 16

-ii-

4. Statistical Analysis ························································· 17

Results ·············································································· 18

1. General Subject Characteristics ············································ 18

2. Hip Joint Angle During the BLES Test ··································· 20

3. Diaphragm Movement ······················································· 22

4. Abdominal Muscle Thickness ·············································· 24

5. EO EMG Amplitude ························································· 27

Discussion ·········································································· 29

Conclusion ··········································································· 33

References ········································································· 34

Abstract in Korean ································································· 40

-iii-

List of Figures

Figure 1. Experimental testing····················································· 10

Figure 2. Measurement of diaphragm movement ······························· 13

Figure 3. Representative composite illustration of diaphragm movement

during three core stabilization techniques ··························· 14

Figure 4. Measurement of abdominal muscles thickness ······················ 15

Figure 5. Core stability during the four test conditions ························ 21

Figure 6. Diaphragm movement during the three test conditions ············· 23

Figure 7. The TrA, IO, and EO thickness during the four conditions ········ 26

Figure 8. EO amplitude during the three exercises ····························· 28

-iv-

List of Tables

Table 1. Demographical characteristics of the subjects ······················· 19

Table 2. Hip joint angle during the (bilateral lower extremity sliding)

BLES test ································································· 21

Table 3. Diaphragm movement during the three test conditions ············· 23

Table 4. Abdominal muscle thickness during the four conditions ··········· 25

Table 5. EO EMG amplitude during the four exercise conditions ··········· 28

-v-

ABSTRACT

Differential Effects of Abdominal Drawing-in Maneuver,

Abdominal Bracing, and Dynamic Neuromuscular

Stabilization on Core Stability and Motor Control in

Adults With Core Instability

Jaejin Lee

Dept. of Physical Therapy

The Graduate School

Yonsei University

The purpose of this study was to compare the effects of the abdominal drawing-in

maneuver (ADIM), abdominal bracing (AB), and dynamic neuromuscular

stabilization (DNS) on core stability, diaphragm movement, abdominal muscle

thickness, and external oblique (EO) electromyography (EMG) amplitude in adults

with core instability. Forty-one subjects (male = 34; mean age ± standard deviation =

21.07 ± 2.34) with core instability participated in this study. The subjects performed

ADIM, AB, and DNS in random order. A Simi Aktisys and Pressure Biofeedback

-vi-

Unit (PBU) were utilized to measure core stability, an ultrasound with 3.5㎒ was

utilized to measure diaphragm movement and ultrasound with 10㎒ was utilized to

measure abdominal muscles thickness and surface EMG was utilized to measure EO

amplitude. A one-way repeated measures analysis of variance (ANOVA) was used to

determine the statistical significance of the core stability, diaphragm movement,

abdominal muscles thickness, and EO amplitude across the four test conditions (rest,

ADIM, AB, DNS). The significance level was set at α = 0.05. Core stability was

significantly increased in DNS and AB compared to ADIM and rest (p < 0.05). Core

stability tended to increase more in DNS than AB but the change was not statistically

significant. Diaphragm descending movement was significantly increased in DNS

compared to ADIM and AB (p < 0.05). TrA and IO thickness were significantly

increased in DNS and ADIM compared to rest and AB (p < 0.05). EO amplitude was

significantly increased in AB compared to rest, ADIM, and DNS. Therefore, the

results of this study suggest that DNS was the most effective technique to provide

core stabilization via balanced coactivation of the diaphragm and TrA with relatively

less contraction of EO.

Key Words: Abdominal bracing, Abdominal drawing-in maneuver, Core

stabilization, Dynamic neuromuscular stabilization, Muscle imbalance.

Introduction

The integrated dynamic spinal stabilization (IDSS) is essential for optimal

movement and performance, which is achieved via precise coordination or synkinesis

of diaphragmatic, spinal, pelvic, and hip muscles and intra-abdominal pressure (IAP)

mediated by the central nervous system (Frank, Kobesova, and Kolar 2013;

Liebenson 2007). Anatomically, the IDSS is a ‘virtual balanced coactivation

cylinder,’ which is primarily encapsulated by the local muscles [transversus

abdominis (TrA), deep cervical flexors (longus colli), and diaphragm], and global

muscles [external oblique (EO) and spinal extensors (erector spinae)] in the cervical-

hip regions (Frank, Kobesova, and Kolar 2013; Liebenson 2007).

Neuromechanically, the synkinetic activation of the inner core muscular chain of

TrA, the pelvic floor, and the diaphragm regulates IAP, providing anterior

stabilization of the lumbopelvic region (Frank, Kobesova, and Kolar 2013; Gardner-

Morse, and Stokes 1998; Hodges, and Gandevia 2000). In coordination with IAP, this

local muscular chain provides spinal stiffness, which serves to provide dynamic core

stability of the spine (Frank, Kobesova, and Kolar 2013; Hodges, and Richardson

1997). This IDSS modulates deep core stabilization via the automatic and

subconscious ‘feed-forward control mechanism,’ which precedes any cortical,

purposeful movement (Frank, Kobesova, and Kolar 2013).

- 2 -

Pathologically, core instability is a common pathomarker for low back pain (LBP)

(Ferreira, Ferreira, and Hodges 2004; Hodges, and Richardson 1999; Page, Frank, and

Lardner 2010). Recently, local muscle motor control deficit was proven to be crucial

for core instability (Faries, and Greenwood 2007; Kolar et al. 2012). Diaphragm

movement was significantly decreased during upper and lower extremity isometric

flexion against resistance (Kolar et al. 2012) and TrA activation was delayed during

shoulder movement in low back patients (Faries, and Greenwood 2007). These

findings suggest that synkinectic dynamic neuromuscular stabilization is essential for

effective management of the LBP population with core instability.

Contemporary core stabilization techniques including the abdominal drawing-in

maneuver (ADIM), abdominal bracing (AB), and dynamic neuromuscular

stabilization (DNS) have been employed to optimize spinal stability and reduce

associated LBP, but outcome measures were variable and do not conform to the

superiority of one intervention over another (Grenier, and McGill 2007; Hodges, and

Richardson 1996; Junginger et al. 2010; Lee et al. 2011; Liebenson 2007). ADIM has

shown to be effective in lumbar spinal instability and associated LBP because it

selectively activates TrA and creates a ‘sandglass-like cylinder,’ thereby providing

the localized segmental stabilization to the ventral region of the lower lumbar spinal

column (Cholewicki, Juluru, and McGill 1999; Cresswell, Oddsson, and Thorstensson

1994; Hodges, and Richardson 1996). However, such a sandglass-like cylinder may

inhibit natural descending movement of the diaphragm and can interfere with IAP

regulation and IDSS as is evident in LBP. AB is another core stabilization exercise; it

- 3 -

synchronously activates both local and global muscles to produce a greater IAP and

stabilize the spine (Grenier, and McGill 2007; Junginger et al. 2010; Vera-Garcia et al.

2006). The balanced activation of local and global muscles may not be possible in a

majority of LBP patients due to inherent neuromuscular imbalance between the local

and global muscles (Page, Frank, and Lardner 2010; Elphinston 2008). For example,

the overactivation of global muscles and underactivation of local muscles may result

in mechanical stress and strain on the lumbar spine and further accentuate LBP

(Comerford, and Mottram 2001; Page, Frank, and Lardner 2010). Recently, DNS was

developed to effectively create optimal IAP via the synkinetic activation of the inner

core muscular chain, thus mitigating anterior stabilization of the lumbopelvic region

(Liebenson 2007).

Despite the important clinical and therapeutic ramifications of the contemporary

core stabilization techniques, the superiority of these techniques on effective

neuromuscular stabilization is unknown in individuals with core instability. Therefore,

the purpose of this study was to compare the differential effects of ADIM, AB, and

DNS on core stability, diaphragm movement, abdominal muscle thickness, and EO

EMG amplitude in core instability. It was hypothesized that DNS would show

superior core stabilization via coordinated neuromuscular activation of the diaphragm

and TrA muscle than other techniques.

- 4 -

Method

1. Subjects

A convenience sample of 41 young adults with core instability (male = 34; mean

age ± standard deviation = 21.1 ± 2.3) was recruited from Yonsei University. The

experimental procedure was approved by Yonsei University Wonju Campus Human

Studies Committee (2013-03). An informed consent form was obtained from all

subjects prior to participation in this study.

Inclusion criterion entailed subjects with core instability who were unable to

perform the bilateral lower extremity sliding (BLES) test while maintaining the target

pressure level (40 ± 10 mmHg) recorded from the pressure biofeedback unit (PBU)

(Faries, and Greenwood 2007; Ferreira, Ferreira, and Hodges 2004; Stanton, Reaburn,

and Humphries 2004).

Exclusion criteria were: (1) any known neurological or cardiopulmonary disease;

(2) history of abdominal surgery; (3) pain or injury to the low back or lower

extremities.

- 5 -

2. Instrumentation

2.1 Ultrasound

The SonoAce (X8, Medison Co., Ltd, Korea) in B-mode with a 10 ㎒ linear

transducer (L5-12EC) was used to measure the muscle thickness of the TrA, IO, and

EO muscles. The SonoAce (6000, Medison Co., Ltd, Korea) in M-mode with a 3.5

㎒ curved transducer (HC2-5) was used to measure diaphragm movement.

2.2 Surface Electromyography

Surface electromyography (EMG) with a WEMG-8-type cable (Laxtha Inc.,

Daejeon, Korea) was used to monitor and record the muscle activity of EO.

2.3 Pressure Biofeedback Unit

A PBU (Chattanooga Group, Hixon, TN, USA), which contains a 3-chamber

pressure bag connected to a pressure gauge and inflation device, was used to detect

the core instability (von Garnier et al. 2009).

2.4 Simi Aktisys

The Simi Aktisys (Simi Reality Motion Systems GmbH, Unterschleissheim,

Germany) was used to check the hip joint angle in real-time.

- 6 -

3. Experimental Procedures

3.1 Clinical tests

All subjects underwent a physical health screening and BLES test. The physical

health screening included neurological and cardiopulmonary disease, history of

abdominal surgery, and pain or injury to the low back or lower extremities. The

BLES test was conducted to check subjects’ core instability (Faries, and Greenwood

2007; Ferreira, Ferreira, and Hodges 2004; Stanton, Reaburn, and Humphries 2004).

A rater instructed a subject to lay in the crook lying position with 70° of hip flexion

(Richardson et al. 1992). PBU was placed under the subject’s lumbar spine at L5 and

inflated to 40 mmHg. The subject was instructed to pull his or her navel up and

toward the spine to activate TrA and then slowly slide out both legs by fully

extending his/her hip and knee joints. If a subject performed this test without change

in pressure of more than 10 mmHg, he or she was classified as having enough core

stability and excluded from this study (Faries, and Greenwood 2007; Ferreira,

Ferreira, and Hodges 2004; Stanton, Reaburn, and Humphries 2004).

- 7 -

3.2 Intervention

Three different core stabilization techniques including ADIM, AB, and DNS were

instructed. Muscle thickness and diaphragm movement using ultrasound and EO

activity using EMG during the BLES test were used to monitor the successful

performance. The core stabilization techniques were as follows. For ADIM the

subject was instructed to breathe in and out and to pull his or her navel up and toward

the spine (Lee et al. 2011). The successful or accurate performance of ADIM was

ensured or monitored by selective activation of TrA with minimal activity of global

muscles (Urquhart et al. 2005). For AB the subject was instructed to breathe in and

out and to swell out his or her waist gently and slowly without pulling the abdomen

inwards (Urquhart et al. 2005). AB involves the general contraction of local and

global muscles around the abdominal region (Grenier, and McGill 2007; Junginger et

al. 2010; Vera-Garcia et al. 2006). DNS involves a synergistic descending action of

the diaphragm during inspiration, which coactivates with all the abdominal muscles

(increased TrA activation, but minimal activation of RA and EO) and the pelvic floor,

and controls IAP to provide anterior stabilization of the lumbar spine. Successful or

corrective steps for DNS include: (1). The patient was asked to exhale and centrate

(or neutralize) the thorax and rib cage in a caudal position; (2). While maintaining this

neutral caudal alignment, the subject was then asked to inhale to make and his or her

diaphragm descend and coactivate TrA and the pelvic floor; (3). The therapist

palpated anteriorly the xiphoid process; laterally 10~12 ribs; and posteriorly angulus

costae to ensure the symmetrical activation against the therapist’s fingers while

- 8 -

expanding the lower ribs (10~12th ribs) in a lateral direction; (4). The corrective

movement involves caudal movement and widening of the intercostal spaces, and

relatively stable rib motion (no cranial motion) in a transverse plane (Liebenson

2007).

The subject practiced the three core stabilization techniques until they could

perform the techniques with normal breathing without external feedback (Richardson

et al. 1999). All the core stabilization techniques regime was standardized and the

subject was instructed to perform the techniques and maintained them for 10 seconds

with normal breathing. One session consisted of 5 times of each technique and the

subject repeated 10 sessions. Between each session, the subject took a rest for 5

minutes. The subjects who could not perform these techniques accurately after this

intervention were excluded from this study.

- 9 -

3.3 Experimental testing

The experimental tests included the BLES test using PBU and Simi Aktisys,

abdominal muscles thickness and diaphragm movement using ultrasound, and EO

activity using EMG during four testing conditions including ADIM, AB, DNS, and

rest (Figure 1).

- 10 -

Figure 1. Experimental testing.

- 11 -

3.3.1 Core Stability Using PBU and Simi Aktisys

To measure core stability the PBU was placed under the lumbar spine at L5 to

detect pressure change (Prentice, 2004.) Simi Aktisys markers were placed on the

lateral abdominal wall of the L3 level and greater trochanter, and lateral femoral

epicondyle. A Basler acA640 camera (Basler Ahrensburg, Germany) with a sampling

rate of 60 ㎐ was set a distance of 1 m away from the subject.

The subject laid in the crook lying position with 70° of hip flexion (Richardson et

al. 1992). PBU was placed under the subject’s L5 and inflated to 40 mmHg, and the

subject was instructed to perform one of the four test conditions in random order.

Next, the subject was instructed to slide out both legs slowly by fully extending

his/her hip and knee joints. The rater checked the hip joint extension angle when the

PBU pressure changed more than 10 mmHg by using Simi Aktisys (Faries, and

Greenwood 2007; Ferreira, Ferreira, and Hodges 2004; Stanton, Reaburn, and

Humphries 2004). The lower hip joint angle means higher core stability capacity.

- 12 -

3.3.2 Diaphragm Movement and Abdominal Muscle Thickness Using Real-

time Ultrasound Imaging

An ultrasound with a 3.5 ㎒ curved transducer was used to measure diaphragm

movement. The transducer was placed between the midclavicular and anterior axillary

lines in the subcostal area, and applied to the medial, cranial, and dorsal direction

(Boussuges, Gole, and Blanc 2009). Diaphragm movement was measured by caliper.

The first reference line was placed at the rest condition slope and the second reference

line was placed at the core stabilization technique condition slope on the diaphragm

echoic line (Figure 2) (Figure 3) (Ayoub et al. 1997). A 10 ㎒ linear transducer was

used to measure abdominal muscle thickness and the transducer was placed on the

anterolateral abdominal wall between the 12th rib and the iliac crest (Arab, and

Chehrehrazi 2011). The TrA, IO, and EO muscles were measured along the horizontal

reference line located 1cm from the medial boundary of the TrA (Figure 4) (Lee et al.

2011; Whittaker 2008). The subject was positioned in the crook lying position with

70° of hip flexion and the four test conditions were performed three times in random

order (Richardson et al. 1992). The rater measured the subject’s abdominal muscle

thickness and diaphragm movement while the subject performed the test condition.

- 13 -

A B

Diaphragm

Diaphragm movement

Figure 2. Measurement of diaphragm movement A: B-mode for detecting diaphragm,

B: M-mode for measuring diaphragm movement.

- 14 -

Rest Core stabilization

AB DNS

ADIM

ADIM: -6.4㎜

AB: 8.4㎜

DNS: 13.4㎜

Figure 3. Representative composite illustration of diaphragm movement during three

core stabilization techniques (ADIM: Abdominal drawing-in maneuver,

AB: Abdominal bracing, DNS: Dynamic neuromuscular stabilization).

- 15 -

Rest ADIM

AB DNS

Figure 4. Measurement of abdominal muscle thickness (EO: External oblique, IO:

Internal oblique, TrA: Transversus abdominis, D1: Horizontal reference

line, D2: TrA thickness, D3: IO thickness, D4: EO thickness).

EO

IO

TrA

EO

IO

TrA

EO

IO

TrA

EO

IO

TrA

D1

D1

D1 D1

- 16 -

3.3.3 EO Amplitude Using EMG

EMG was used to measure the EO amplitude at a sampling rate of 1024 ㎐ along

with the 60 ㎐ notch filter; the band-pass filtered was between 20 and 450 ㎐ and

analyzed using Telescan 3.06 software. The EMG data was expressed as a percentage

of maximum voluntary isometric contraction (MVIC). Before the data collection the

skin sites for electrode attachment were prepared to reduce skin impedance by dry-

shaving, abrading with 70% ethyl alcohol. A pair of active electrodes was attached on

the muscle zone in parallel and a reference electrode was attached on the anterior

superior iliac spine (ASIS). The pair of active electrode sites for EO were 2 ㎝ apart,

lateral to the rectus abdominis and directly above the ASIS (Criswell, and Cram

2011).The subject was positioned in the crook lying position with 70° of hip flexion

and the four test conditions were performed three times in random order (Richardson

et al. 1992). The rater measured the subject’s EO amplitude while the subject

performed the test condition.

- 17 -

4. Statistical Analysis

PASW Statistics ver. 18.0 software (SPSS, Inc., Chicago, IL, USA) was used for

all statistical analyses. The descriptive statistics include the mean ± standard deviation

(SD). A one-way repeated measures analysis of variance (ANOVA) with three core

stabilization technique conditions (ADIM, AB, DNS) was used to determine the

statistical significance of the diaphragm movement. A one-way repeated measures

analysis of variance (ANOVA) with four test conditions (rest, ADIM, AB, and DNS)

was used to determine the statistical significance of the abdominal muscle thickness,

and EO EMG amplitude, and hip joint angle of the BLES test. If statistical

significance was found for the main effect, Fisher's least-significant-difference (LSD)

was applied as a post hoc test. The level of statistical significance was set at 0.05.

- 18 -

Results

1. General Subject Characteristics

The general characteristics of the 41 adult subjects with core instability are shown

in Table 1.

- 19 -

Table 1. Demographical characteristics of the subjects (N = 41)

Parameters Subject (n = 41)

Age (years) 21.1 ± 2.4a

Height (㎝) 173.0 ± 6.5

Weight (㎏) 64.6 ± 10.7

aMean ± standard deviation.

- 20 -

2. Hip Joint Angle During the BLES Test

Repeated measures ANOVA revealed a significant main effect in the hip joint

angle during the BLES test across four conditions: rest, ADIM, AB, DNS (p < 0.05)

(Table 2). A LSD post hoc comparison revealed that all three core stabilization

conditions showed a significantly lower hip joint angle than the rest condition (p <

0.05). Among the core stabilization techniques, DNS (51.72°) showed the a lower hip

joint angle than ADIM (58.89°) and AB (52.01°), which indicates that DNS increased

core stability than ADIM and AB. There was a significant difference between DNS

and ADIM (p < 0.05). AB showed a significantly lower hip joint angle than ADIM

(Figure 5) (p < 0.05).

- 21 -

Table 2. Hip joint angle during the BLES test

Conditions

F p

Rest ADIMa ABb DNSc

Hip angle

(°) 60.81 ±

6.44d

58.89 ±

6.67

52.01 ±

8.85

51.72 ±

9.16 42.571 p < 0.01

aADIM: Abdominal drawing-in maneuver bAB: Abdominal bracing cDNS: Dynamic neuromuscular stabilization dMean ± standard deviation.

0

20

40

60

80

Rest ADIM AB DNS

Bilateral lower extremity sliding test

* **

**

Hip

an

gle

(d

eg

ree)

Figure 5. Core stability during the four test conditions (ADIM: Abdominal drawing-in

maneuver, AB: Abdominal bracing, DNS: Dynamic Neuromuscular Stabilization).

*p < 0.05

- 22 -

3. Diaphragm Movement

Repeated measures ANOVA revealed a significant main effect in diaphragm

movement across the three conditions: ADIM, AB, and DNS (p < 0.05) (Table 3). A

LSD post hoc comparison revealed that DNS (10.8 mm) showed a significantly

increased diaphragm descending movement, greater than that of ADIM (-1.54 mm)

and AB (8.17 mm) (p < 0.05). AB showed a significantly increased diaphragm

descending movement compared with that of ADIM, which showed an ascending

movement (p < 0.05) (Figure 6).

- 23 -

Table 3. Diaphragm movement during the three test conditions

Conditions

F p

ADIMb ABc DNSd

Diaphragm

movementa

(mm) -1.54 ± 3.55e 8.17 ± 5.99 10.80 ± 6.65 91.953 p < 0.01

aDiaphragm movement: Diaphragm position during core stabilization technique -Diaphragm

position during rest bADIM: Abdominal drawing-in maneuver cAB: Abdominal bracing dDNS: Dynamic neuromuscular stabilization eMean ± standard deviation.

-10

-5

0

5

10

15

20

ADIM AB DNS

Diaphragm movement

**Caudal direction

Cranial direction

*

Dia

ph

rag

m m

ovem

en

t (m

m)

Figure 6. Diaphragm movement during the three test conditions (ADIM: Abdominal

drawing-in maneuver, AB: Abdominal bracing, DNS: Dynamic Neuromuscular Stabilization).

*p < 0.05

- 24 -

4. Abdominal Muscle Thickness

Repeated measures ANOVA revealed a significant main effect in TrA thickness

across four conditions: rest, ADIM, AB, DNS (p < 0.05) (Table 4). A LSD post hoc

comparison revealed that all three core stabilization conditions showed significantly

increased TrA thickness, greater than that of the rest condition (p < 0.05). DNS (6.35

mm) and ADIM (6.44 mm) showed a significantly increased TrA thickness, greater

than that of AB (5.18 mm) (p < 0.05). There was no significant difference between

DNS and ADIM (Figure 7).

Repeated measures ANOVA revealed a significant main effect in IO thickness

across four conditions: rest, ADIM, AB, DNS (p < 0.05) (Table 4). A LSD post hoc

comparison revealed that all three core stabilization conditions showed significantly

increased IO thickness, greater than that of the rest condition (p < 0.05). DNS (10.83

mm) and ADIM (11.06 mm) showed significantly increased TrA thickness, greater

than that of AB (9.63 mm) (p < 0.05). There was no significant difference between

DNS and ADIM (Figure 7).

Repeated measures ANOVA revealed a significant main effect in EO thickness

across four conditions: rest, ADIM, AB, DNS (p < 0.05) (Table 4). However, the

LSD post hoc comparison did not reveal a significant difference between each

condition (Figure 7).

Table 4. Abdominal muscle thickness during the four conditions

Conditions

F p

Rest ADIMa ABb DNSc

TrAd (mm) 4.19 ± 1.28g 6.44 ± 1.85 5.18 ± 1.74 6.35 ± 1.96 56.370 p < 0.01

IOe (mm) 8.71 ± 2.24 11.06 ± 2.60 9.63 ± 2.99 10.83 ± 3.01 69.733 p < 0.01

EOf (mm) 6.74 ± 2.16 7.97 ± 3.53 6.67 ± 2.23 6.93 ± 2.20 5.590 p < 0.01

aADIM: Abdominal drawing-in maneuver bAB: Abdominal bracing cDNS: Dynamic neuromuscular stabilization dTrA: Transversus abdominis eIO: Internal oblique cEO: External oblique gMean ± standard deviation.

0

2

4

6

8

10

Rest ADIM AB DNS

Transversus abdominis

* * **

*

Th

ick

ne

ss

(m

m)

0

3

6

9

12

15

Rest ADIM AB DNS

Internal oblique

* * **

*

Th

ick

ne

ss

(m

m)

0

5

10

15

Rest ADIM AB DNS

External oblique

Th

ick

ne

ss

(m

m)

Figure 7. The TrA, IO, and EO thickness during the four conditions (ADIM:

Abdominal drawing-in maneuver, AB: Abdominal bracing, DNS: Dynamic Neuromuscular Stabilization).

*p < 0.05

- 27 -

5. EO EMG Amplitude

Repeated measures ANOVA revealed a significant main effect in EO amplitude

across four conditions: rest, ADIM, AB, DNS (p < 0.05) (Table 5). A LSD post hoc

comparison revealed that all AB showed significantly higher EO amplitude

(8.57 %MVIC) than rest (2.35 %MVIC), ADIM (4.77 %MVIC), and DNS

(6.07 %MVIC) (p < 0.05). DNS showed significantly higher EO amplitude, greater

than that of rest and ADIM (Figure 8) (p < 0.05).

- 28 -

Table 5. EO EMG amplitude during the four exercise conditions

Exercises

F p

Rest ADIMa ABb DNSc

EOd

(%MVIC) 2.35 ±

1.33e

4.77 ±

2.08

8.57 ±

4.76

6.07 ±

3.33 37.711 p < 0.01

aADIM: Abdominal drawing-in maneuver bAB: Abdominal bracing cDNS: Dynamic neuromuscular stabilization dEO: External oblique eMean ± standard deviation.

0

5

10

15

Rest ADIM AB DNS

External Oblique

* * **

**

EM

G a

mp

litu

de (

% M

VIC

)

Figure 8. EO amplitude during the three exercises (ADIM: Abdominal drawing-in

maneuver, AB: Abdominal bracing, DNS: Dynamic Neuromuscular Stabilization).

*p < 0.05

- 29 -

Discussion

This is the first study demonstrating the differential effects of ADIM, AB, and

DNS on core stability, diaphragm movement, abdominal muscles thickness, and EO

EMG amplitude in individuals with core instability. As anticipated, DNS produced

the most effective core stabilization by means of synchronous activation of the

diaphragm and TrA while inhibiting excessive EO when compared with AB and

ADIM techniques. Most importantly, this finding suggests that DNS is beneficial for

improving core stabilization in adults with core instability.

Core stability data showed greater improvements in both DNS (51.72 °) and AB

(52.01 °) than in ADIM (58.89 °). It was difficult to compare novel findings of this

study with previous studies because no current core stability data related with DNS,

AB, and ADIM are available. Core stabilization during dynamic distal segmental

movement (e.g, hip flexion) is orchestrated by synergistic coactivation of the deep

neck flexors, spinal extensors, diaphragm, abdominal muscles, and the pelvic floor,

which regulates IAP and stabilizes the anterior lumbopelvic system (Frank, Kobesova,

and Kolar 2013; Gardner-Morse, and Stokes 1998; Hodges PW, and Gandevia SC

2000; Liebenson 2007). Particularly, in DNS, the diaphragm is the important intrinsic

spinal stabilizing muscle in coordination with other deep core muscles such as TrA,

IO, and multifidus that contributes to the IAP modulation and serves to maximize

dynamic spinal stability (Frank, Kobesova, and Kolar 2013; Liebenson 2007). In fact,

- 30 -

the present ultrasound measurement of the diaphragm descending movement showed

the greatest excursion during DNS (10.80 mm) when compared with that of ADIM (-

1.54 mm) and AB (8.17 mm). The present finding was consistent with Noh et al.’s

(2014 in press) radiographic data (22 mm) and Kolar et al.’s (2009) dynamic MRI

measurement of the diaphragm descending movement excursion (27.3 mm). AB also

showed more significantly increased core stability than ADIM. However, concurrent

EMG and ultrasound data in the present study demonstrated that AB mitigates core

stability by means of maximizing EO activation as well as the diaphragm.

Specifically, the present EMG results showed significantly higher EO amplitude

during AB (8.57 %MVIC) than ADIM (4.77 %MVIC) and DNS (6.07 %MVIC). This

finding supports a previous study which reported that AB generated more IAP for

core stabilization than ADIM (Junginger et al. 2010). This finding suggests that AB

may be a challenging exercise in individuals with core instability secondary to

overactive EO because of inherent neuromuscular imbalance between the deep and

superficial core muscles (Elphinston 2008; Page, Frank, and Lardner 2010). For these

reasons, AB should be exercised with special consideration in individuals with core

instability and associated lumbar pathology due to its superior core stabilization effect.

A concurrent ultrasound measurement of abdominal muscles and diaphragm

descending movement showed the most balanced coactivation of local muscles (TrA,

IO) and diaphragm to provide core stabilization during DNS (TrA: 6.35 mm, IO:

10.83 mm, diaphragm: 10.80 mm) when compared to ADIM (TrA: 6.44 mm, IO:

11.06 mm, diaphragm: -1.54 mm) and AB (TrA: 5.18 mm, IO: 9.63 mm, diaphragm:

- 31 -

8.17 mm). TrA was more significantly activated during ADIM than AB, but was

similar to DNS. Previous studies showed that TrA activation is more increased during

ADIM than AB which involves co-contraction of overall abdominal muscles (Arab,

and Chehrehrazi 2011; Richardson et al. 2002). ADIM may be an effective technique

to provide segmental lumbar stabilization because it creates a ‘sandglass-like

cylinder’ that provides the localized pressure to the lumbar spinal region (Jull, and

Richardson 2000; Marshall, and Murphy 2005; Richardson et al. 1992). However, the

‘sandglass-like cylinder’ may be relatively unstable compared to that of AB and DNS

because of less activation of other local muscles such as the diaphragm and IO. This

corresponds with the BLES test result which showed significantly lower core stability

of ADIM than DNS and AB.

Taken together with previous findings, DNS was the most effective strategy for

core stabilization via synchronous activation of TrA and the diaphragm when

compared to ADIM and AB. Most importantly, the present study has a clinical

implication that DNS can be incorporated into the current core stabilization exercises

for prevention and intervention of individuals with core instability.

Three main limitations exist in the present study. The first shortcoming is that the

current study validated an immediate effect of three different core stabilization

techniques on core stability, diaphragm movement, and abdominal muscle activity. A

prospective study is needed to determine long-term therapeutic effects on core

stability. Second, core stabilization is comprised of the diaphragm, pelvic floor and

transversus abdominis kinetic chain, which regulate IAP to provide anterior

- 32 -

lumbopelvic stability. The influence of the pelvic floor on core stabilization was not

evaluated in the present study. It may be of interest to concurrently measure all

sections of the abdominals and spinal extensors in the cervical, thoracic, and lumbo-

pelvic region. Finally, further studies were warranted to validate if this finding is

generalizable to other LBP populations.

- 33 -

Conclusion

This is the first clinical research to compare ADIM, AB, and DNS. The present

results demonstrated that DNS was the most effective technique to provide core

stabilization via balanced coactivation of diaphragm and TrA with relatively less

contraction of EO in coordination with IAP. Clinically, this study provides important

conceptual and therapeutic evidence for clinicians when designing and implementing

effective core stabilization techniques for individuals with core instability.

- 34 -

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국문 요약

체간 중심의 불안정을 가진 성인에게 복부당김 기법과

복부 브레이싱, 그리고 다이나믹 근신경 안정성 훈련이

체간 중심의 안정성과 운동조절에 미치는 영향 비교

연세대학교 대학원

물리치료학과

이 재 진

본 연구의 목적은 체간 중심의 불안정이 있는 성인 대상자에게 세 가지

가지 체간 중심 안정성 훈련 방법(복부당김 기법, 복부 브레이싱, 다이나

믹 근신경 안정성 훈련)을 적용하였을 때 체간 중심의 안정성, 가로막 위

치의 변화, 복부 근육의 두께, 배바깥경사근 근활성도를 비교하는 것이다.

41명의 체간 중심 불안정이 있는 성인이 본 연구에 참여하였으며, 체간

- 41 -

중심의 안정성을 측정하기 위해 시미 엑티시스 동작분석 장비와 압력바이

오피드백 기기를 사용하였고, 가로막 위치 변화를 측정하기 위해 영상 초

음파(3.5MHz) 장비를 사용하였고, 복근 두께를 측정 하기 위해 영상 초음

파(10MHz) 장비를 사용하였고, 배바깥경사근 근활성도를 측정 하기 위해

표면 근전도 장비를 사용하였다. 4가지 검사 조건(휴식, 복부당김 기법, 복

부 브레이싱, 그리고 다이나믹 근신경 안정성 훈련)에서 체간 중심 안정성,

횡격막 위치의 변화, 그리고 복부 두께 변화를 비교하기 위해 반복측정 분

산분석을 실시하였으며 유의수준은 α = 0.05로 정하였다. 다이나믹 근신경

안정성 훈련과 복부 브레이싱에서 체간 중심 안정성이 휴식과 복부당김 기

법에서보다 통계학적으로 유의하게 증가하였고(p < 0.05), 다이나믹 근신

경 안정성 훈련이 복부 브레이싱보다 체간 중심의 안정성을 증가시키는 경

향을 보였으나 통계학적으로 유의하지는 않았다. 다이나믹 근신경 안정성

훈련에서 횡격막의 아래방향 이동이 복부당김 기법과 복부 브레이싱에서보

다 통계학적으로 유의하게 증가하였다(p < 0.05). 다이나믹 근신경 안정성

훈련과 복부당김 기법에서 가로배근과 배속경사근의 두께가 휴식과 복부

브레이싱에서보다 통계학적으로 유의하게 증가하였다(p < 0.05). 복부 브

레이싱에서 배바깥경사근 근활성도가 휴식, 복부당김 기법, 그리고 다이나

믹 근신경 안정성 훈련에서보다 통계학적으로 유의하게 증가하였다(p <

0.05). 따라서 본 연구의 결과는 다이나믹 근신경 안정성 훈련이 체간 중

- 42 -

심의 불안정이 있는 성인의 횡격막과 가로배근, 그리고 배속경사근의 활성

의 증가시켜 체간 중심의 안정성을 향상시키는 것으로 생각된다.

핵심 되는 말: 근육 불균형, 다이나믹 근신경 안정성 훈련, 복부 브레이싱,

복부당김 기법, 체간 중심 안정성.