KJS B Korean Journal of Sport Biomechanics 2020; 30(1): 103-109 http://dx.doi.org/10.5103/kjsb.2020.30.1.103 http://e-kjsb.org eissn 2093-9752 Surface EMG Verification according to the Electrode Location in Biceps Brachii during Arm Curl Isometric Exercise ORIGINAL 암컬등척성운동시상완이두근에서의 EMG 전극위치에따른근활성검증 Hyo Eun Park 1, Ah Reum Hong 1, Jae Moo So 2 1 Department of Physical Education, Graduate School of Konkuk University, Seoul, South Korea 2 Department of Physical Education, College of Education, Konkuk University, Seoul, South Korea Received : 19 February 2020 Revised : 06 March 2020 Accepted : 09 March 2020 Objective: The purpose of this study is to compare the muscle activity by electrode location in the biceps brachii during the arm curl isometric exercise and to provide the basic data needed to develop the proper electrode location of the biceps brachii based on the study results comparing the muscle activity by the angle of the elbow. Method: 17 adult males (Age: 21.50±4.63 yrs, height: 175.29±5.97 cm, weight: 63.79±15.31 kg, upper-arm length: 30.10±1.22 cm) participated in the study. In the arm curls isometric exercise, the experiment was divided into 1st and 2nd steps to compare muscle activity according to electrode location in the biceps brachii and muscle activity according to elbow angle change. In the first experiment, the surface electrode was attached at one-third point on the line from medial acromion to cubital fossa, according to the measurement method indicated by SENIAM. The elbow angle was set to 90. In the second experiment, according to the proposed method of this study, the electrodes were separated at one finger's width in the left and right direction at onethird point on the line from medial acromion to cubital fossa, attached at the long head and short head. From the long head electrode, in about a width of two fingers in proximal direction, a total of three electrodes were attached at the myotendinal junction of the long head. The elbow angles were set as 70, 90, and 110, and the isometric exercise (100% MVC) for 5 seconds was maintained with keeping the forearm and the rope to be 90 for the first and second experiments. Corresponding Author Jae Moo So Department of Physical Education, College of Education, Konkuk University, 120, Neungdong-ro, Gwangjin-go, Seoul, 05029, South Korea Tel : +82-10-3202-3828 Fax : +82-2-453-6326 Email : human@konkuk.ac.kr Results: During the arm curl isometric exercise, there was no significant difference in SH and SENIAM proposition location proposed by this researcher. LH was shown to be lower than the muscle activity of the location proposed by SENIAM and there were significant (p<.01) differences. MJ appeared lower than the muscle activity of the location proposed by SENIAM and there were significant (p<.001) differences. The muscle activity by the elbow angle of SH in the biceps brachii was shown in large order of 70 <90 <110, but there was no significant difference. The muscle activity by the elbow angle of LH was shown in large order of 90 <70 <110, but there was no significant difference. The muscle activity by the elbow angle of MJ was shown in large order of 110 <90 <70, but there was no significant difference. Conclusion: During the arm curl isometric exercise of the biceps brachii, it is judged appropriate to attach surface electrodes to the location proposed by SENIAM. Keywords: Arm curl, EMG, Electrodes, Biceps brachii Copyright C 2020 Korean Journal of Sport Biomechanics This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/bync/3.0/) which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
104 Hyo Eun Park, et al. KJSB INTRODUCTION 현대사회는기계화되고자동화된편리한생활로인해신체활동이줄어들면서건강증진을위한신체운동을중요하게생각하는사람들이늘고있다. 건강증진을위한저항운동기구를이용한근력운동은근육의수축, 팽창을반복하여근육을발달시킬수있고날씨와시간적제약이적어많은사람들이이용하고있다. 그중암컬운동기구 (Arm Curl Machine) 는팔꿈치를회전축으로전완을끌어당기는구조로서상완이두근 (Biceps Brachii) 을발달시킬수있는운동기구이다 (Vella, 2012). 상완이두근은근섬유가방추형으로생긴방추형근 (Fusiform muscle) 으로장두 (Long head: LH) 와단두 (Short head: SH), 두갈래를가진근육이다. 일상생활에서는물건집어들기, 입으로음식가져오기와스포츠에서는권투, 노젓기, 카누경기등에서이근육을많이사용한다. 근육의활동은근전도 (Electromyography: EMG) 를이용하여측정할수있는데근전도기술은근육평가를위한도구로서높은잠재력을지니고있어다양한스포츠활동의평가와의료임상분야에서사용되고있다. 근전도는바늘전극법 (Needle Electromyography: NEMG) 과표면전극법 (Surface Electromyography: SEMG) 이있는데표면근전도가비침습적용이성으로인해운동역학연구에더욱폭넓게사용되고있다. 표면근전도는두개의전극을한근육에부착하여근섬유막을따라전도되는운동단위활동전위 (Motor Unit Action Potential: MUAP) 를차동증폭원리로얻는방식이기 (Jeong & Sin, 2005) 때문에전극이적절한위치에배치되는것이중요하다 (Ganesh, 2012). 표면근전도전극위치에대한선행연구들에서 Bilodeau, Cincera, Arsenault & Gravel (1997) 은단두위에장축으로배치하였고 Orizio, Gobbo, Diemont, Esposito & Veicsteinas (2003) 은근복 (Muscle of Belly) 위에배치하였으며 Lange, Weerden & Hoeven (2002) 은신경분포구역과원위힘줄사이에근섬유방향과평행하게배치하는등연구자들마다전극의위치를다르게배치하고있었다. 이렇게다양한전극위치에대한표준화를위해유럽에서 SENIAM (Surface Electromyography for the Non-Invasive Assessment of Muscle) 연합을만들어프로젝트연구를진행하였고현재까지많은연구자들이 SENIAM 에서제시하는근전도실험방법을따르고있다. SENIAM 프로젝트연구 (Hermens, Freriks, Disselhorst-klug & Rau, 2000) 에따르면 SEMG 표면전극의배치방법은실험대상자의자세를전극위치를적절하게결정할수있도록준비시키고해부학적지점을결정한후연결해서운동종판 (endplate) 과원위힘줄 (Distal Tendon) 사이에두개의전극을근섬유방향과장축으로배열해야하며단축으로배열할경우에는힘줄이나근육가장자리 (edge of the muscle) 에서떨어져야한다고했다. 상완이두근의근활성도를측정할경우의자에앉 고팔꿈치를 90 로구부린후견봉내측 (Medial acromion) 부터팔오금 (Cubital fossa) 까지의선상에서 1/3 지점에위치해야한다고했다. 그러나이것은권장사항일뿐완성되지않았고새로운지식에근거하여정기적으로갱신되어야한다고하였다. 따라서전극배치에따른세밀한연구가뒷받침되어야한다. 또한생역학적인관점에서보면관절각도의변화는지레팔 (lever arm) 의길이와근육의길이를변화시키고이러한변화는근수축력을변화시킨다 (An, Kaufman & Chao, 1989). 이점과관련하여 Baltzopoulos & Brodie (1989) 는신체의각관절에서는최적의역학적이점이있는관절각도가존재한다고하였고 Kim et al. (2005) 도하지분절각도에따른수의등척성수축 (MVIC) 시근전도를비교한연구에서관절의각도변화에따라근육의활성도가변한다고하였으며최대의활동전위값을발생시키는특정관절각도혹은분절의상대적위치를밝혀내는것이근전도정량화연구에서가장우선적으로이루어져야한다고하였다. Kang (2013) 은주관절각도변화가주관절굴곡근의근활성도에미치는영향을알아보고자한연구에서주관절 55 에서가장근활성도가높았고, 반면가장강한힘을낸다는 90 굴곡에서가장작은근활성도를보임으로주관절굴곡근이 20% 늘어난위치에서가장큰힘을낸다고하였다. 또한견관절의휴면자세 (Loose-packed position) 와액와슬링을사용한자세에서주관절굴곡 55 일때가장높게나타났으며, 두번째로 70, 90 에서근활성도가가장낮게나타났다. 견관절을체간에붙인자세에서는일관된결과는보이지않았지만다른자세에서보다근활성도가커진다고하였다. 이렇듯여러연구마다각도에따라상완이두근의근활성의차이를보이고있어, 이부분을측정비교해보는연구가필요하다고할수있다. 이에본연구는암컬등척성운동시상완이두근에서의전극위치별근활성도를비교하고주관절각도별근활성을비교한연구결과를근거로상완이두근의적절한전극위치와주관절자세를개발하는데필요한기초자료를제공하고자한다. METHOD 1. 연구대상 본연구의대상자는상지근골격계에이상이없고우세팔이우측인남자성인 17명을대상으로선정하였다. 피험자들마다비교가능하도록내측견봉부터팔오금까지의길이를측정하였고신체적인특성은 (Table 1) 과같다. 실험에참여하기전모든피험자들은실험과정에대한설명을듣고참여의사와동의서를작성하였다. Korean Journal of Sport Biomechanics
KJSB Surface EMG Verification according to the Electrode Location in Biceps Brachii during Arm Curl Isometric Exercise 105 Table 1. Characteristics or the subjects Height (cm) Weight (kg) Age (year) Upper arm length (cm) M ± SD (n=17) 175.29±5.97 63.79±15.31 21.50±2.63 30.10±1.22 2. 실험도구 암컬등척성운동시상완이두근에서의전극위치에따른 근활성을비교하기위한구체적인장비는 (Table 2) 과같다. Table 2. Experimental equipment Equipment Experimental equipment Manufacturer EMG Telemyo DTS Noraxon Arm curl machine Arm curl machine Cybex 3. 실험방법 Figure 1. Arm curl machine 암컬머신을이용한등척성운동시상완이두근에서의전극위치와주관절의각도변화에따른근활성도를비교하기위해 1차와 2차로나누어실험하였다. 근전도측정전피험자들은민소매티셔츠를입고준비운동을실시한후근육의측정오류를방지하기위해털을면도기로제거하고알코올솜으로닦아내었다. 상완이두근에서의전극위치변화에따른근활성도차이를알아보기위해 SENIAM 에서제시하는측정방법에따라견봉내측부터팔오금까지선상에서 1/3 지점에표면전극 (HEX Dual Electrodes, Noraxon) 을장축으로부착하고 1차실험을진행했다. 이때주관절의굴곡각도는 90 로설정하였다. 2차실험은본연구자가제시하는방법에따라견봉내측부터팔오금까지선상의 1/3 지점에서좌우로손가락 1개너비로띄어장두와단두에부착하고장두전극위치에서근위방향으로손가락 2개너비로띄어장두의근건접합부 (Myotendinal Junction: MJ) 에전극을장축으로부착하였다. 전극부착위치는 (Figure 2) 와같다. 주관절각도변화에따른근활성도차이를알아보기위해주관절의각도는 70, 90, 110 로설정하였고상완이두근외의근육사용을제어하기위해암컬머신에몸통을밀착하고의자높이를실험자마다앉은키에맞게설정하였다. 실험자세는 (Figure 1) 과같다. 1, 2차실험모두본실험은로프를손목에감아전완과로프가 90 가되도록고정한후에최대힘 (100% MVC) 으로로프를잡아당기는등척성운동을 5초동안유지하였다. Figure 2. EMG Electrode placement 4. 자료분석본연구에서는암컬등척성운동수행시 5초동안얻어진자료에서처음과끝의 1초를제외한안정화된 3초의근활성을분석하였다. EMG 신호의주파수대역폭 (Bandwidth) 범위는 20~350 Hz 사이로설정하였고절대값을구하기위하여전파정류 (Full-Wave Rectification) 한다음이어서 Smoothing 하였다. 5. 통계처리본연구의통계처리는 SPSS 24.0 (IBM, USA) 을이용하였고, 전극의위치에따른근활성도비교와주관절각도에따른 http://e-kjsb.org
106 Hyo Eun Park, et al. KJSB 근활성도비교를위해 independent t-test와반복측정분석 (ANOVA with repeated measure) 을사용하였다. 유의차이에따른상호작용은단순사후검증을실시하였으며모든통계치의유의수준은 p<.05로설정하였다. RESULTS 본연구는암컬등척성운동시상완이두근의 SENIAM에서제시하는전극위치의근활성도와본연구자가제시하는전극위치의근활성도를비교하고본연구자가제시하는전극위치의주관절각도별근활성도를비교하였다. 총 2회의실험데이터를가지고독립표본검정과일원배치반복측정을통하여비교분석하였다. 1. 주관절각도 90 에서 SH와 SENIAM 의근활성도 이높은차이로나타났으나, 유의미한차이는없었다. 2. 주관절각도 90 에서 LH 와 SENIAM 의근활성도 암컬등척성운동시 LH 와 SENIAM 의근활성도를살펴보면 (Table 4, Figure 4) 과같다. LH 와 SENIAM 의근활성도는 649.94 ±253.45 μⅤ 와 620.82±178.23 μⅤ 로유의한차이를보였다 (p<.01). Table 4. Muscle activity of LH and SENIAM at 90 of elbow LH SENIAM t p 90 443.00±185.70 620.82±178.23 2.484.008 ** LH: Long Head, SENIAM: electrode location by SENIAM 암컬등척성운동시 SH 와 SENIAM 의근활성도를살펴보 면 (Table 3, Figure 3) 과같다. SH 와 SENIAM 의근활성도는 649.94±253.45 μⅤ 와 620.82±178.23 μⅤ 로 SH 의근활성도값 Table 3. Muscle activity of SH and SENIAM at 90 of elbow SH SENIAM t p 90 649.94±253.45 620.82±178.23 -.387.701 SH: Short Head, SENIAM: electrode location by SENIAM Figure 4. Muscle activity of LH and SENIAM at 90 of elbow 3. 주관절각도 90 에서 MJ 와 SENIAM 의근활성도 암컬등척성운동시 MJ와 SENIAM의근활성도를살펴보면 (Table 5, Figure 5) 과같다. MJ와 SENIAM의근활성도는 283.79±134.01 μⅤ와 620.82±178.23 μⅤ로유의한차이를보였다 (p<.001). 4. 주관절각도별근활성도 Figure 3. Muscle activity of SH and SENIAM at 90 of elbow 암컬등척성운동시상완이두근에서의전극각도별전극 Korean Journal of Sport Biomechanics
KJSB Surface EMG Verification according to the Electrode Location in Biceps Brachii during Arm Curl Isometric Exercise 107 Table 5. Muscle activity of MJ and SENIAM at 90 of elbow MJ SENIAM t p 90 283.79±134.01 620.82±178.23 6.232.000 *** MJ: Myotendinal Junction, SENIAM: electrode location by SENIAM Figure 6. Muscle activity with varying elbow angles Figure 5. Muscle activity of MJ and SENIAM at 90 of elbow 위치에따른근활성을살펴보면 (Table 6, Figure 6) 와같다. SH 의각도별근활성도는 70 <90 <110 순으로크게나타났지만유의미한차이는없었다. LH 의각도별근활성도는 90 <70 <110 순으로크게나타났지만유의미한차이는없었다. MJ 의각도별근활성도는 110 <90 <70 순으로크게나타났 지만유의미한차이는없었다. DISCUSSION 근육의수축과이완은신경계로부터흥분이운동신경을통 해운동종판 (end-plate) 에전달되면운동단위활동전위 (Motor Unit Action Potential: MUAP) 가근섬유막을따라전도되면서이루어진다 (Lee, 2018). 이에따라 SENIAM 의연구 (Hermens et al., 2000) 에서전통적으로표면전극은 ' 큰 (Large)' 신호를기록할수있는근복 (Muscle Belly) 또는운동종판 (end-plate) 영역위에배치되었다. 그러나현재는운동종판영역이 SEMG 신호의진폭에큰영향을미친다고하였고 (Blok & Stegeman, 1997), Mathiassen & Hägg (1997) 은근섬유의길이방향으로전극위치마다진폭이다르다고보고되었다. 상완이두근에서의전극위치변화에따른근활성도비교시 SH 근활성도가 SENIAM 근활성도보다높게나타났지만유의미한차이는없었고 LH와 MJ는 SENIAM 근활성도보다낮게나타났고유의미한차이가있었다. 이는암컬의최대동작수행시주관절굴곡외에견관절굴곡시모음하고전완을회외한상태로힘을작용하여단두의힘이많이요구되어높은근활성도를보인것으로판단된다. 상완이두근의단두는오훼돌기 (coracoid process) 에서힘줄로시작하고장두는견갑골상관절와결절 (supraglenoid) 에서시작해, 상완골의절반위치쯤내려가다가합쳐지는모양이다. 상완이두근의단두는 Table 6. Muscle activity with varying elbow angles 70 90 110 F (p) Post-hoc SH 581.05±252.26 649.94±253.45 662.59±146.47.658 (.523) - LH 469.06±183.62 443.00±185.70 499.47±155.18.441 (.646) - MJ 343.47±95.24 283.79±134.01 274.00±148.18 1.472 (.240) - SH: Short Head, LH: Long Head, MJ: Myotendinal Junction http://e-kjsb.org
108 Hyo Eun Park, et al. KJSB 견관절굴곡, 주관절굴곡, 전완회외, 팔의모음작용을하고장두는견관절굴곡, 팔의벌림, 어깨탈구방지기능을한다 (Calais-Germain, 2009). 상완이두근에서 SH의주관절각도별근활성도는 70 <90 <110 순으로더크게나타났지만유의미한차이는없었고, LH의주관절각도별근활성도는 90 <70 <110 순으로더크게나타났지만유의미한차이는없었으며 MJ의각도별근활성도는 110 <90 <70 각도순으로크게나타났지만유의미한차이는없었다. 최대힘은주관절 90 굽힘과뒤침 (supination) 상태일때발생한다 (Palastanga, Field & Soames, 2009) 고보고한것과다른결과가나타났다. 유의미한차이는없었지만관절각도와근활성도사이에관련성이있음을확인하였다. Kendall & McCreary (1983) 은관절의각도변화가근활성도에영향을미친다는주장을근육의길이와장력의관계에의한설명으로이론적근거를마련했다. 힘또는장력은근육의길이에따라다양하게발휘되는데, 최대장력은근-선 (Z-line) 간격이느슨한길이일때발휘된다. 반면근절의길이가이상적인길이보다짧아질경우능동장력은감소된다 (Nordin & Frankel, 2001). 따라서근육길이의변화는장력의변화를초래하기때문에관절각도의변화로인한근육길이의변화는근육의활성과수축력의변화를가져올수있다 (Kendall & McCreary, 1983; Kim et al., 2005). 결국근력의결정요인은관절각도, 근육의길이, 관절축으로부터힘이작용하는거리등이있으며 (Kim & Lee, 1996), 그중에서근육의길이는근육의수축력을결정하는중요한인자라고할수있다 (Basmajian, 1962). CONCLUSION 본연구에서는표면근전도를이용하여상완이두근에서의적절한전극위치를제안하고자근활성을검증하였다. 머리가두갈래인상완이두근을대상으로 SENIAM에서제안한전극위치와본연구자가제안하는전극위치의근활성을비교한결과, 암컬등척성운동시본연구자가제안하는 SH와 SENIAM 제안위치는유의한차이가없었고 LH, MJ은 SENIAM 에서제안하는위치의근활성도보다더낮게나타났고유의한차이가있었다 (p<.01, p<.001). 따라서상완이두근의등척성운동시표면전극은 SENIAM 에서제안하는위치에부착하는것이적절하다고판단되어진다. 또표면근전도를다양한측면에서측정할수있는방법을마련하였다는점에서그의의가있으며표면근전도를이용한연구를활성화하는데기여할것으로기대된다. 그러나본연구는정상성인남성 17명을대상으로하여일반화하기에무리가있으며많은근육의종류중에서대표적으로두갈래방추형모양인상완이두근의근활성만알아보았기때문에추후에는대상자를더확대하여다양 한근육종류의근활성을파악하는지속적인연구가필요하다고판단된다. 또한우세팔이우측인연구대상자를통하여얻은결과이기때문에추후연구에서는비우세팔과우세팔의비교연구도이루어져야할것으로사료된다. ACKNOWLEDGEMENT This study was supported by the 2018 Research Foundation of University of Konkuk. REFERENCES An, K. N., Kaufman, K. R. & Chao, E. Y. S. (1989). Physiological considerations of muscle force through the elbow. Journal of Biomechanics, 22(11-12), 1249-1256. Baltzopoulos, V. & Brodie, D. A. (1989). Isokinetic Dynamometry Applications and Limitations. Sports Medicine, 8(2), 101-116. Basmajian, J. V. (1962). Muscle Alive, Their functions revealed by electromyography. Journal of Medical Education, 37(8), 802. Bilodeau, M., Cincera, M., Arsenault, A. B. & Gravel, D. (1997). Normality and Stationarity of EMG Signals of Elbow Flexor Muscle during Ramp and Step Isometric Contractions. Journal of Electromyography and Kinesiology, 7(2), 87-96. Blok, J. H. & Stegeman, D. F. (1997). Simulated bipolar SEMG characteristics. In: Hermens HJ, Freriks B (Eds.). SENIAM 5: The state of the art on sensors and sensor placement procedures for surface electromyography: a proposal for sensor placement procedures. Enschede: Roessingh Research and Development. Calais-Germain, B. (2009). Anatomy of Movement. Seoul: yeongmunsa. Ganesh, R. N. (Ed.) (2012). Computational Intelligence in Electromyography Analysis - A Perspective on Current Applications and Future Challenges. Croatia: IntechOpen. Hermens, H. J., Freriks, B., Disselhorst-klug, C. & Rau, G. (2000). Development of recommendations for SEMG sensors and sensor placement procedures. Journal of Electromyography and Kinesiology, 10(5), 361-374. Jeong, C. S. & Sin, I. S. (2005). Introduction to Sports Biomechanics. Seoul: Daehanmedia. Kang, T. W. (2013). The effects of changing shoulder and elbow Angle on the muscle activity of the upper extremity during pulley with weight exercises. Graduate School, Silla University. Korean Journal of Sport Biomechanics
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