J Korean Soc Phys Ther Vol. 24, No. 5, October, 2012 pissn 1229-0475 eissn 2287-156X The Journal of Korean Society of Physical Therapy Original Article 교각운동시복부넣기가큰볼기근과척추세움근의활성도에미치는영향 고은경 1, 장진호 2, 정도영 2 1 마산대학교물리치료과, 2 중부대학교관광보건대학물리치료학과 Effect of Abdominal Hollowing on Muscle Activity of Gluteus Maximus and Erector Spinae during Bridging Exercise Eun-Kyung Koh 1, Jin-Ho Jang 2, Do-Young Jung 2 1 Department of Physical Therapy, Masan University, 2 Department of Physical Therapy, College of Tourism & Health Science, Joongbu University Purpose: This study examined the muscle activities of the erector spinae (ES) and gluteus maximus (GM) during bridging exercises with and without abdominal-hollowing. Methods: Nineteen healthy subjects with no medical history of low back pain or hip flexion contracture were enrolled in this study. The subjects performed bridging exercises with and without abdominal hollowing or with and without a one-leg lift. The muscle activities of the ES and GM were measured by surface electromyography during bridging exercises under each condition. A 2 (abdominal hollowing)x2 (one-leg lift) repeated ANOVA was used to compare the normalized muscle activities of the ES and GM. Results: The muscle activity of the ES during bridging exercise with abdominal-hollowing was significantly smaller than that without abdominal-hollowing (p=0.00). The muscle activities of the GM during bridging exercise with abdominal-hollowing were significantly greater than those without abdominal-hollowing (p=0.00). In addition, the muscle activities of the GM during bridging exercise with one-leg lifting was significantly greater than that without one-leg lifting (p=0.00). Conclusion: Bridging exercise with abdominal-hollowing appears to be more effective on activating the GM muscle than that without abdominal-hollowing minimizing the activation of the ES muscle. Keywords: Abdominal hollowing, Bridging exercise, Erector spinae, Gluteus maximus I. 서론 Received September 18, 2012 Revised October 12, 2012 Accepted October 15, 2012 Corresponding author Do-Young Jung, ptsports@joongbu.ac,kr Copyright 2012 by The Korean Society of Physical Therapy This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. 요통 (low back pain) 은인간이살아가면서일생에 80% 이상경험하는인류의대표적인질환중에하나이다. 1 그중요통환자의 85% 는질환의손상기전이명확하지않는 비특이성 (nonspecific) 으로인해고생한다. 2 다양한환자-대조군연구들에서특이성과비특이성인요통환자군간의신경-근육계차이점들을발견하였다. 3-5 이러한연구들에서흔히수행된기능적인움직임은선자세에서몸통굽힘과폄움직임이다. 이런움직임을수행하는동안몸통과엉덩관절의운동형상학적움직임과근육의동원전략이요통환자와정상인간에차이가있었다. 1,4 McClure 등 6 은정상인들은몸통굽힘상태에서폄시움직임의처음 75% 동안에는엉덩관절의움직임이우세하다고보고하였다. 이전다른연구에서는요통환자군이정상군에비해우세적인척추움직임전략을보이며허리주위근 (lumbar paraspinals) 의이른근수축이일어난다고보고하였다. 1,4 또한 J Korean Soc Phys Ther 2012:24(5):319-324 319
Eun-Kyung Koh, et al: Effect of Abdominal Hollowing on Muscle Activity of Gluteus Maximus and Erector Spinae 몇몇연구자들은엉덩관절폄근의약화와요통과관련이있다고하였다. 7-9 따라서재활분야에서요통환자들을위해엉덩관절의폄근인큰볼기근 (gluteus maximus) 의근력강화운동은흔히처방되고시행된다. 큰볼기근을강화시키기위한방법으로볼기근세트운동 (gluteal muscle setting), 앞으로구부린자세에서다리들기 (forward-bending leg lift), 네발기기자세에서다리들기 (quadruped leg lifts), 교각운동 (bridging exercise) 등이있다. 10 비록많은연구에서몸통안정화를위해교각운동시복부근육들에대한근활성도를알아보았지만 11-13 아직까지엉덩관절폄근을강화시키는데중점을둔큰볼기근과척추세움근의근활성도를알아본연구는없는실정이다. 또한교각운동시큰볼기근의근력강화를가중화 (progression) 시키기위해골반의도수저항혹은무거운벨트착용, 발아래에짐볼 (gym ball) 놓기, 그리고한쪽다리들기등다양한방법을이용하지만, 10 아직까지교각운동시진전을위한한쪽다리들기시엉덩관절폄근의근활성도를알아본연구는없었다. 따라서본연구에서는교각운동시한쪽다리들기가큰볼기근과척추세움근의근활성도를알아보고자하였다. 많은연구자들은사지의기능적인움직임동안원치않은허리와골반의보상적인움직임을막기위해허리안정화 (lumbar stabilization) 를강조하였다. 14,15 허리는내적혹은외적으로안정화시킬수있는데, 사지의움직임시복부근육들의등척성수축으로허리를내적으로안정화시킬수있고, 치료사의손, 치료용벨트혹은스트랩을이용하여외적으로허리를안정시킬수있다. 엉덩관절의폄운동을수행하는요통환자들은골반앞기울림 (anterior pelvic tilt) 과허리앞굽음 (lumbar lordorsis) 과같은과도한허리척추움직임을보인다. 이러한허리척추움직임을막기위해치료사들은환자들에게복부넣기 (abdominal-hollowing) 방법을사용하여척추를안정화시키게한다. 16,17 하지만아직까지교각운동시복부넣기방법이큰볼기근과척추세움근의근활성도에미치는영향에대한정량적인연구는없는실정이다. 따라서본연구에서는교각운동시복부넣기와한쪽다리들기유무에따른큰볼기근과척추세움근의근활성도를비교하고자하였다. 본연구에서는다음과같은연구가설을설정하였다. 첫째, 교각운동시복부넣기가복부넣기없이수행했을때보다척추세움근의근활성도는줄어들것이며, 큰볼기근의근활성도는증가할것이다. 둘째, 교각운동시한쪽다리들기가한쪽다리들기없이하는것보다큰볼기근의근활성도는증가할것이다. II. 연구방법 1. 연구대상본연구의대상자는성인남성 19명을대상으로실시하였다. 대상자의평균연령은 21.5±2.2 세, 신장은 173.6±6.1 cm 그리고체중은 65.5±8.9 kg이었다. 과거혹은현재요통의과거력이있거나신경학적문제, 엉덩관절굽힘구축, 큰볼기근의약화그리고상지혹은하지의통증및기능적제한이있는대상자는제외시켰다. 각각의대상자들에게실험전실험동의서의내용을알려주고연구참여에동의를얻은후에실시하였다. 실험자는대상자들에게직접교각운동과복부넣기방법을알려주고대상자들은실험전익숙해지도록실험전날 15분정도연습하였다. 또한실험당일복부넣기를수행하지못하거나교각운동시골반앞기울림이발생되는자는대상자에서제외시켰다. 2. 실험방법 1) 실험도구각조건에서의교각운동과각근육의최대수의적등척성수축 (maximal voluntary isometric contraction, MVIC) 시근활성도를측정하기위해무선표면근전도시스템인 TeleMyo DTS (Noraxon, Scottsdale, AZ, USA) 를사용하였다. 표본수집률은 1500 Hz로하였으며원신호 (raw signal) 를주파수대역필터인 20~250 Hz를사용하였고각근육별근전도신호를 root mean square (RMS) 로처리하였다. 근전도자료는 MyoResearch Master Edition 1.07 XP software (Noraxon, Scottsdale, AZ, USA) 를사용하여분석하였다. 복부넣기방법을실행하기위해생체되먹임압력계 (pressure biofeedback unit) (Stabilizer TM ; Chattanooga Group, Hixson, TN, USA) 를이용하였다. 2) 실험절차본실험을실행하기전에대상자에게실험절차를설명하였다. 교각운동시복부넣기가큰볼기근과척추세움근의근활성도를측정하기위해무선근전도전극을우세측근육에부착하였다. 전극을부착하기전에표면근전도신호에대한피부저항을감소시키기위해부착부위의털을제거하고, 가는사포로 3~4회문질러피부각질층을제거하고소독용알코올로피부지방을제거하였다. 표면전극부착위치는다음과같았다. 척추세움근 (erector spinae) 의전극은네번째허리뼈 (L4) 의가시돌기 (spinous process) 2 cm 옆에부착하였다. 큰볼기근의 320 J Korean Soc Phys Ther 2012:24(5):319-324
고은경외 : 교각운동시복부넣기가큰볼기근과척추세움근의근활성도에미치는영향 전극은큰돌기 (greater trochanter) 와두번째엉치뼈 (S2) 의중간지점에사선방향으로부착하였다. 18 두개의근육들의최대수의적등척성수축시근활성도를측정하기위해도수근력검사 (manual muscle testing) 자세를이용하였다. 척추세움근은대상자에게양손을머리뒤에깍지끼우고엎드린자세에서가슴전체가검사대에서들어올릴때까지허리를펴게하였다. 큰볼기근은대상자에게엎드린자세에서무릎을 90도이상굽힘한상태에서종아리후면의발목위에위치시켜저항을주며엉덩관절폄을하도록하였다. 19 교각운동의시작자세는무릎관절 90 o 굽힘상태에서무릎과양발은어깨넓이로벌리고발바닥은지면에평행하게놓게하였다. 머리와몸통은똑바로유지하였으며, 시선은천장을바라보게하였다. 무작위로복부넣기와한쪽다리들기유무에따른각각의교각운동을실시하였다 (Figure 1). 복부넣기방법은교각운동의시작자세에서생체되먹임압력계의중앙이대상자의세번째허리뼈에위치시켜 40 mmhg 되도록팽창시키고복근을수축시켜 60 mmhg 까지올리도록하였다. 이자세를유지한상태에서교각운동을실시하였다. 이때실 험자가복부넣기시처음자세가계속유지되는것을모니터링하기위해실험자는위앞엉덩뼈가시를촉진하여골반뒤기울림이유지되는지확인하였다. 실험중골반앞기울림이발생되면실험을다시하였다. 또한각조건에서의넙다리뼈의높이를동일하게하기위해넙다리뼈중앙에목표막대를설치하였다. 높이는각대상자의신장에맞게조절하였다. 각운동시근활성도는운동마지막자세에서 5초동안 3번반복측정하였으며, 근육의피로를예방하기위해각조건마다 5분간의휴식을취하도록하였다. 3) 자료분석및통계방법각근육의 3번반복측정된근활성도값의신뢰도는급간내상관계수 (intraclass correlation coefficient; ICC 3,1 ) 를사용하여알아보았다. 각운동방법에따른큰볼기근과척추세움근의근활성도를정규화 (normalization) 하기위해최대등척성수의적수축시근활성도를측정하여평균평방근 (RMS) 으로처리된각근육의근활성도를백분율 (%MVIC) 로분석하였다. Figure 1. Bridging exercise combined with one-leg lift (A) and abdominal hollowing (B). J Korean Soc Phys Ther 2012:24(5):319-324 321
Eun-Kyung Koh, et al: Effect of Abdominal Hollowing on Muscle Activity of Gluteus Maximus and Erector Spinae 통계프로그램은 SPSS version 12.0 (SPSS Inc., Chicago, IL, USA) 을이용하여반복측정된개체내이요인분산분석 (repeated-measures ANOVAs with 2 within-subject factors) 을통계처리하였다. 큰볼기근과척추세움근의근활성도는복부넣기와한쪽다리들기유무에따라 4개의수준 (2X2) 으로분석하였다. 이때유의성수준은 p<0.05 에서검증하였다. 분산분석에서유의한효과가발견되면본훼로니 t-검정교정 (paired sample t-tests with Bonferroni correction) 을이용한사후검정을실시하였다. 유의수준은 α=0.012 (0.05/4) 로하였다. III. 결과 각근육의측정된근활성도의급간내상관계수 (ICC 3,1 ) 는큰볼기근의근활성도의경우 0.95 (95% CI=0.89~0.98) 그리고척추세움근의근활성도는 0.91 (95% CI=0.83~0.96) 이었다. 따라서, 본연구에서측정된각근육의근활성도는매우신뢰도가높아결과를일반화할수가있었다. 교각운동시복부넣기와한쪽다리들기유무에따른큰볼기근과척추세움근의근활성도는 Table 1에제시하였다. 복부넣기유무에따른큰볼기근의근활성도는통계학적으로유의한차이가있었으며 (p<0.05), 또한한쪽다리들기유 무에따른근활성도는통계학적으로유의한차이가있었으며 (p<0.05), 교호작용은통계학적으로유의한차이가없었다 (p>0.05) (Table 2). 사후분석결과, 큰볼기근은한쪽다리들기유무에상관없이교각운동시복부넣기가복부넣기없이했을때보다유의하게증가하였다 (p<0.01). 또한복부넣기유무에상관없이교각운동시한쪽다리들기가한쪽다리들기없이했을때보다유의하게증가하였다 (p<0.01) (Figure 2A). 복부넣기유무에따른척추세움근의근활성도는통계학적으로유의한차이가있었으며 (p<0.05), 또한한쪽다리들기유무에따른근활성도는통계학적으로유의한차이가없었으며 (p=0.66), 교호작용은통계학적으로유의한차이가있었다 (p<0.05) (Table 2). 사후분석결과, 척추세움근은한쪽다리들기유무에상관없이교각운동시복부넣기가복부넣기없이했을때보다유의하게감소하였다 (p<0.01) (Figure 2B). IV. 고찰 본연구에서는교각운동시복부넣기와한쪽다리들기유무에따른큰볼기근과척추세움근의근활성도를비교하고자하였다. 교각운동은재활분야에서요통환자에게몸통의안정성을향상시키고엉덩관절폄근을강화시키기위해처방되 Table 1. Muscle activities of GM and ES during bridging exercise (unit: %MVIC) Muscle Source Without one-leg lift With one-leg lift GM ES Without abdominal hallowing With abdominal hallowing Without abdominal hallowing With abdominal hallowing 16.24±10.09 30.23±16.75 65.11±23.31 36.53±28.08 41.21±15.75 57.58±25.20 62.39±21.51 41.41±27.79 Values are presented as mean±standard deviation. GM: gluteus maximus, ES: erector spinae, MVIC: maximal voluntary isometric contraction. Table 2. Two-way ANOVA results with exercise condition as factors in each muscle Muscle Source F Effect size p GM ES Abdominal hallowing One-leg lift Abdominal hallowing X One-leg lift Abdominal hallowing One-leg lift Abdominal hallowing X One-leg lift 21.68 45.18 0.46 27.77 0.20 7.38 0.72 0.55 0.03 0.01 0.61 0.29 0.00 0.00 0.51 0.00 0.66 0.01 Statistically significant at the level of p<0.05. GM: gluteus maximus, ES: erector spinae. 322 J Korean Soc Phys Ther 2012:24(5):319-324
고은경외 : 교각운동시복부넣기가큰볼기근과척추세움근의근활성도에미치는영향 Figure 2. Result of post-hoc test in GM (A) and ES (B). Statistically significact at the level of p<0.01, GM: gluteus maximus, ES: erector spinae, MVIC: maximal voluntary isometric contraction. 고수행된다. 하지만교각운동과같은엉덩관절의폄운동시허리의과도한폄과골반의앞기울림움직임이자주발생된다. 엉덩관절의굽힘근의굳음 (stiffness), 큰볼기근의약화, 복근조절의결핍그리고척추세움근의우세한근활성도는엉덩관절의폄운동시과도한허리의폄과골반앞기울림에기여한다. 20 Sahrmann 21 은엉덩관절의폄운동시골반앞기울림을막아주는복근의조절의결핍은과도한허리폄과허리-골반의기능장애를야기시키기때문에과도한골반앞기울림이일어나지않도록손을이용하여골반의움직임을모니터링해야한다고주장하였다. 따라서많은저자들이엉덩관절폄운동시허리와골반의보상움직임을막기위해복근의근수축을추천하였다. 7,14,22 그러나아직까지큰볼기근의근력강화를위한교각운동시복부넣기가큰볼기근과척추세움근의근활성도에미치는영향에대한연구는없는실정이다. 본연구결과, 교각운동시척추세움근의근활성도는교각운동시복부넣기가복부넣기없이했을때보다유의하게감소하였다. 또한한쪽다리들기시에도복부넣기가복부넣기없이했을때 ( 평균 =41.41% MVIC) 보다유의하게감소하였다. Oh 등 23 은엎드린자세에서복부넣기를한엉덩관절폄운동시복부넣기를하지않았을때보다골반의앞기울림각 (10 o vs. 3 o ) 과척추세움근의근활성도 (17% MVIC vs. 49% MVIC) 모두감소하였다고보고하였다. 비록본연구에서는이전연구처럼허리폄각혹은골반앞기울림각을측정하지않았으나, 교각운동시복부넣기가골반뒤기울림을일으켜척추세움근의근활성도가작아졌다고사료된다. 교각운동시큰볼기 근의근활성도는교각운동시복부넣기가복부넣기없이했을때보다유의하게증가하였다. 또한한발들기시에도복부넣기가복부넣기없이했을때보다유의하게증가하였다. 따라서, 본연구에서는교각운동시복부넣기가척추세움근의근활성도를줄이면서큰볼기근을강화시키는데유용하다고제안한다. 교각운동시복부넣기가큰볼기근의근활성도를증가시키는몇가지기전을생각해볼수있다. 첫째, 본연구에서교각운동시복부넣기유무에상관없이엉덩관절폄각 0 o 를유지하기위해넙다리뼈의높이를동일하도록목표막대를설치하였다. 따라서복부넣기시허리폄각과골반앞기울림각이줄어들고교각운동시같은높이에넙다리뼈가도달하기위해서는큰볼기근의수축력이커져야하기때문이다. 둘째, 본연구에서대상자의대부분이넙다리곧은근이신장되는느낌을받았다고하였다. 복부넣기시골반뒤기울림이일어나고교각운동시엉덩관절폄이되면넙다리곧은근 (rectus femoris) 의스트레칭이일어난다. 따라서교각운동의마지막자세에서넙다리곧은근의신장력 (stretching forece) 이큰볼기근의저항으로작용되기때문에큰볼기근의근활성도가증가되었다고사료된다. 셋째, 척추세움근과큰볼기근의근육길이-장력관계를가지고설명할수있다. 교각운동시복부넣기는허리폄각과골반앞기울림각을줄이기때문에상대적으로척추세움근은큰볼기근에비해근육길이가덜짧아지고큰볼기근은척추세움근에비해상대적으로더짧아지기때문에큰볼기근의근활성도가커졌을것이다. J Korean Soc Phys Ther 2012:24(5):319-324 323
Eun-Kyung Koh, et al: Effect of Abdominal Hollowing on Muscle Activity of Gluteus Maximus and Erector Spinae 본연구결과, 교각운동시한쪽다리들기는복부넣기와 상관없이큰볼기근의근활성도가유의하게증가하였다. 한쪽 다리를들게되면반대측다리로하중이더가해지기때문에 큰볼기근의근활성도가커졌다. 따라서교각운동시체간의 안정성의진전을위해한쪽다리들기를하는것처럼큰볼기 근의근력강화진전을위해한쪽다리들기방법은유용하다. 본연구의제한점은몇가지가있다. 첫째, 각운동시허리 폄각과골반앞기울림각을측정하지못했다는것이다. 하지 만본연구에서는실험자가복부넣기시교각운동을하는동 안대상자의골반뒤기울림이유지되는지모니터링을하였다. 둘째, 복부넣기시복부근육들의근활성도를측정하지못했 다는것이다. 셋째, 본연구의대상자는정상인성인남성을대 상으로하였기때문에본연구결과를모든대상자들에게일 반화시킬수없다. 따라서, 향후연구에서요통환자를대상으 로교각운동시복부넣기가큰볼기근과척추세움근의근활 성도에미치는영향에대해알아볼필요가있다. 참고문헌 1. Wong TK, Lee RY. Effects of low back pain on the relationship between the movements of the lumbar spine and hip. Hum Mov Sci. 2004;23(1):21-34. 2. Waddell G. The back pain revolution. New York, Churchill Livingstone, 2004. 3. Brumagne S, Janssens L, Janssens E et al. Altered postural control in anticipation of postural instability in persons with recurrent low back pain. Gait Posture. 2008;28(4):657-62. 4. Esola MA, McClure PW, Fitzgerald GK et al. Analysis of lumbar spine and hip motion during forward bending in subjects with and without a history of low back pain. Spine (Phila Pa 1976). 1996; 21(1):71-8. 5. van Dieën JH, Selen LP, Cholewicki J. Trunk muscle activation in low-back pain patients, an analysis of the literature. J Electromyogr Kinesiol. 2003;13(4):333-51. 6. McClure PW, Esola M, Schreier R, Siegler S. Kinematic analysis of lumbar and hip motion while rising from a forward, flexed position in patients with and without a history of low back pain. Spine (Phila Pa 1976). 1997;22(5):552-8. 7. Leinonen V, Kankaanpää M, Airaksinen O et al. Back and hip extensor activities during trunk flexion/extension: effects of low back pain and rehabilitation. Arch Phys Med Rehabil. 2000;81(1): 32-7. 8. Nadler SF, Malanga GA, Bartoli LA et al. Hip muscle imbalance and low back pain in athletes: influence of core strengthening. Med Sci Sports Exerc. 2002;34(1):9-16. 9. Nadler SF, Malanga GA, Feinberg JH et al. Relationship between hip muscle imbalance and occurrence of low back pain in collegiate athletes: a prospective study. Am J Phys Med Rehabil. 2001;80(8):572-7. 10. Kisner C, Colby LA. Therapeutic Exercise, 5th ed. PA, Davis Company, 2007:678-9. 11. Bjerkefors A, Ekblom MM, Josefsson K et al. Deep and superficial abdominal muscle activation during trunk stabilization exercises with and without instruction to hollow. Man Ther. 2010;15(5):502-7. 12. Guthrie RJ, Grindstaff TL, Croy T et al. The effect of traditional bridging or suspension-exercise bridging on lateral abdominal thickness in individuals with low back pain. J Sport Rehabil. 2012; 21(2):151-60. 13. Konrad P, Schmitz K, Denner A. Neuromuscular evaluation of trunk-training exercises. J Athl Train. 2001;36(2):109-18. 14. Hodges PW, Richardson CA. Relationship between limb movement speed and associated contraction of the trunk muscles. Ergonomics. 1997;40(11):1220-30. 15. Vogt L, Banzer W. Dynamic testing of the motor stereotype in prone hip extension from neutral position. Clin Biomech (Bristol, Avon). 1997;12(2):122-7. 16. Park DJ. The effect of real-time ultrasound imaging feedback during abdominal hollowing in four point kneeling to healthy men. J Korean Soc Phys Ther. 2010;22(6):1-6. 17. Park DJ. Changes of thickness in abdominal muscles between crook lying and wall support standing during abdominal hollowing in healthy men. J Korean Soc Phys Ther. 2010;22(6):7-12. 18. Cram JR, Kasman GS, Holtz J. Introduction to surface electromyography. 2nd ed. Ontario, Jones and Bartlett Publisher Inc., 2010:355. 19. Kendall FP, McCreary EK, Provance PG et al. Muscle: testing &function, with posture and pain. 5th ed. Baltimore, Williams and Wilkins, 2005:418-36. 20. Comerford MJ, Mottram SL. Movement and stability dysfunction-- contemporary developments. Man Ther. 2001;6(1):15-26. 21. Sahrmann SA. Diagnosis and treatment of movement impairment syndrome. St. Louis, Mosby, 2002:430. 22. Mills JD, Taunton JE, Mills WA. The effect of a 10-week training regimen on lumbopelvic stability and athletic performance in female athletes: a randomized controlled trial. Phys Ther Sport. 2005;6:60-6. 23. Oh JS, Cynn HS, Won JH et al. Effects of performing an abdominal drawing-in maneuver during prone hip extension exercises on hip and back extensor muscle activity and amount of anterior pelvic tilt. J Orthop Sports Phys Ther. 2007;37(6):320-4. 324 J Korean Soc Phys Ther 2012:24(5):319-324