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1 PNF and Movement, 2019; 17(1): Print ISSN: Online ISSN: Original Article Open Access VR-HMD 를활용한불안정지지면운동이기능적발목불안정성에미치는영향 백종수 김용준 김형주 박주환 이누리 이보라 임보배 정다송 최지예 김민희 1) 을지대학교물리치료학과 The Effect of Unstable Supporting Exercise in Young Adults with Functional Ankle Instability when Training with a Virtual Reality-Head Mounted Display System Jong-Soo Baek Yong-Joon Kim Hyung-Joo Kim Joo-Hwan Park Noo-Ri Lee Bo-Ra Lee Bo-Bae Lim Da-Song Jung Ji-Ye Choi Min-Hee Kim The Department of Physical Therapy, Eulji university Received: January 9, 2019 / Revised: February 15, 2019 / Accepted: February 15, 2019 c 2019 Journal of Korea Proprioceptive Neuromuscular Facilitation Association This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract Purpose: This study was an investigation of the effect of unstable supporting exercise in young adults with functional ankle instability. The study tested the use of a jumper and virtual reality (VR) training via a VR-head mounted display (HMD) system to provide functional improvement in proprioception, range of motion (ROM), ankle muscle strength, agility, and balance. Methods: The subjects comprised 61 young adults (in their twenties) with functional ankle instability to decide as less than 24 points using Cumberland ankle instability tool. The subjects were divided into three groups: VUS (VR-HMD and unstable supporting exercise, n = 20), VSS (VR-HMD and stable supporting exercise, n = 19), and NUS (non-vr-hmd and unstable supporting exercise, n = 22). The exercise program was conducted three times per week for three weeks. VR training via a VR-HMD system and a VR application on a smart mobile device were used with the VUS and VSS groups, and unstable supporting exercise was used in the VUS and NUS groups for 30 minutes. Proprioception, ROM, ankle muscle strength, agility, and balance were measured before and after training. Results: The VUS group showed significant differences in most results, including proprioception, ROM, ankle muscle strength, agility, and balance to compare before and after, and the VSS and NUS groups partially. Moreover, the VUS group had significant differences in most results when compared with the other groups. Conclusion: Unstable supporting exercise and VR training via a VR-HMD system improved functional ankle instability in terms of proprioception, ROM, ankle muscle strength, agility, and balance. Key Words: Virtual reality program training, Functional ankle instability, Unstable supporting exercise Corresponding Author : Min-Hee Kim (kmh12@eulji.ac.kr)

2 82 PNF and Movement Vol. 17, No. 1 Ⅰ. 서론발목관절은일상생활과스포츠활동에서가장흔하게손상받을수있는신체부위중하나이며발목손상은일상생활과스포츠활동에서지속적인제한을발생시키고 (Fong et al., 2007), 불안정성보행과불안감을초래한다 (Yeung et al., 1994). 특히, 발목의가쪽인대가반복적으로손상되고재손상비율은 80% 에달한다 (Hertel, 2000). 이는만성발목불안정성 (chronic ankle instability) 에이르게되고 (Hertel, 2002) 고유수용성감각의저하, 정강종아리뼈삠, 정강뼈의약화및자세조절의결함등이나타나게된다 (Gauffin et al., 1988). 만성발목불안정성은크게기계적 (mechanical) 발목불안정성과기능적 (functional) 발목불안정성으로나눌수있다 (Hiller et al., 2011). 특히, Freeman (1964) 은반복적인발목삠의결과로일상생활동안에발목이휘청거리는주관적인느낌을기능적발목불안정성으로정의하였다. 이러한기능적발목불안정성은환자에게통증과발목이빠지는듯한느낌이나반복적인손상이나타나는등의만성적인문제를발생시킨다. 또한, 발목의고유수용감각정확성이감소됨에따라발목삠이재발하게되며 (Hertel, 2000) 환측엉덩관절벌림근의근력약화 (Friel et al., 2006) 와발목관절의안정근약화로인해자세조절동요의증가로이어지게된다 (Yaggie & McGregor, 2002). 이러한기능적발목불안정성은위에서언급한발목삠의재발 (Hadadi et al., 2014), 자세조절및기능적인문제들과직접적인연관이있기때문에이를해결하기위해여러치료방법들이국내외에서개발되었다. 밸런스보드를이용한고유수용감각훈련 (Hupperets et al., 2008), 체중부하운동및탄성밴드운동 (Choi & Han, 2014), 외발수행 (single leg performance) 을통한자세안정성 (Moussa et al., 2009) 등의치료가보고되었다. 그중불안정한지지면에서의운동은근력, 균형능력의증가효과적이며 (Verhagen et al., 2014), 인체의심부안정성을향상시켜기능적발목불안정성감소 에효과적이다 (Verhagen et al., 2014). 이러한불안정지지면운동은 심부근육 의움직임에중점을두고있어신체의균형을잡는동작들을통해근육의활성도가높아지고자세안정성을향상시킨다. 이운동프로그램은균형능력과고유감각을증진시켜기능적발목안정성에효과적이지만대부분의운동프로그램은지루하며동기유발을시키지못한다는단점이있다 (Vernadakis et al., 2012). 이러한문제를해결하기위해가상현실을활용한운동프로그램이제안되고있으며대상자의운동수용기제와동기유발에효과적인것으로보고되었다 (Kim, 2005). 가상현실 (virtual reality, VR) 프로그램이란, 대상자가컴퓨터스마트폰등과같은기기를통해만들어낸특정한공간및상황에서상호작용을하는것을말한다. 또한, 가상현실에서사용되는시각적피드백은물체의운동에관한정보와자신의운동에대한정보를제공받아환경의요구에맞도록행동을조절한다 (Ma, 1996). 이는자세동요를감소시켜자세균형에중요한역할을한다 (Loughlin & Redfem, 2001). 이러한가상현실프로그램은여러가지방법으로대상자에게제공될수있는데그중에서도 4차산업혁명의핵심기술인 VR-Head Mount Display (HMD) 를통해서효과적으로제공될수있다 (Lee, 2007). VR-HMD 는머리에착용하는디스플레이장치로기존의디스플레이와달리대상자를보다가상현실에몰입할수있다는장점이있다. 과거에는 VR-HMD 가고가의장비로서전문적인제작을요구하여콘텐츠제작에비용및시간이많이들어활용이되지않았다. 하지만스마트폰의대중화및저가형 VR-HMD 의보급으로 VR-HMD 를이용한가상현실프로그램이다시주목받기시작하였다 (Choi, 2016). 가상현실을이용한치료는뇌졸중환자의상지기능, 균형능력, 보행능력을향상시키기위한재활에이용되고있으며 (Jang et al., 2013), 다양한환경을경험하기힘든발달장애아동들의치료에도사용되는등의학분야에서다양하게이용되고있다 (Yu et al., 2018). 따라서 VR-HMD를이용한시청각적자극을동반

3 VR-HMD 를활용한불안정지지면운동이기능적발목불안정성에미치는영향 83 한불안정지지면에서의운동이기능적발목불안정성에어떠한영향을미치는지알아보자하였다. Ⅱ. 연구방법 1. 연구대상본연구의대상은 S시 E대학교에재학중인 20대성인대학생중과거병력, 문진, 이학적검사, 설문조사를통해 300여명의학생중기능적발목관절불안정성으로판단되고실험에동의한 61명을대상으로탈락된대상자없이연구가시행되었다. 연구대상자는체중을지탱하지어려울정도의발목삠을과거에한번이상경험하였고, 발목수술병력이없는자, 발목관절에휘청거림을느끼는자, Cumberland 발목불안정성설문지점수가 24점이하인자, 중재나일상생활을통증증가없이수행할수있는자, 현재재활운동프로그램에참여하고있지않은자로선정하였고, 발목에외과적변형, 부종 (edema) 이나혈관등의구조이상이있는자, 실험에영향을미치는시, 청각장애및정신또는인지적장애가있는자, 발목삠을경험하지못한자, 발목삠외에다른근골격계손상이있는자는연구대상에서제외하였다. 2. 연구절차모집된연구대상자총 61명에게사전평가로한발서기검사, Y-balance 검사, 균형감각측정검사, 발목근력측정검사, 발목고유감각측정검사, 관절가동범위 (range of movement, ROM) 검사를실시하였다. 선정된대상자들을 VR-HMD (VR box, Max, China) 를착용하고불안정지지면에서운동하는 VR-HMD+unstable surface (VUS) 군 20명, VR-HMD 를착용하고안정지지면에서운동하는 VR-HMD+stable surface (VSS) 군 19 명, VR-HMD 를착용하지않고불안정지지면에서운동하는 none VR-HMD+unstable surface (NUS) 군 22명으로각집단에무작위로배정하였다. VUS군과 VSS 군, NUS군모두주 3회 3주간총 9회에걸쳐운동프로그램을적용한후사전검사와같은방법으로사후검사를실시하여전, 후차이를알아보았다. 3개의군모두준비운동 5분, 본운동 20분, 마무리운동 5분으로구성하였다. 준비운동과마무리운동은간단한스트레칭을실시하였다. 3. 연구중재 1) VR-HMD 기능적발목불안정성을가진환자의균형능력을향상시키기위한 VR-HMD (VR box, Max, China) 기기는총 12대로각각바이온회사제품을사용하였다. 실험에서사용된애플리케이션으로는 VR 줄타기 (Yi Wang, China), VR 교통자전거경주 (Babloo Games, United Arab Emirates), Subway Surf Race VR 2017 (Daisy Daisy, USA) 을사용하였다. VR 줄타기는 VR에서와이어워킹의경험을제공하는게임으로구성됨으로써균형감각을증진시킨다. VR 교통자전거경주는 VR 기반의자전거경주게임으로써, 순발력과균형감각, 근력, 근지구력등을향상시켜준다. Subway Surf Race VR 2017은가상현실에서지하철서핑레이스를즐길수있는게임으로써, 균형감각, 근력, 조정력등을향상시켜준다. 이실험에서사용된핸드폰은피실험자의개인핸드폰을사용하였다. 2) 불안정지지면운동불안정지지면운동은점퍼 (JUMPER, TOGU, Germany) 를이용하였다. 본연구에사용된점퍼는약 24cm 높이로된에어공간으로구성되어있고공기가들어있으며, 이러한특성으로인해탄성이있는무른지면을제공할수있다. 이는서서균형을이루는노력자체만으로도초당, 단위면적당다양한반작용력을갖게하며, 건, 인대, 관절고유수용기를모두활성화시킬수있는장비이다. 적용방법은점퍼위에서두

4 84 PNF and Movement Vol. 17, No. 1 발로균형을잡고서있는형태로적용하였다. 사이에 10 초의휴식을취하게하였다 (Kim, 2012). 4. 측정방법 1) 발목고유감각측정발목의고유수용성감각을측정하기위해실험자는먼저서있는상태에서무릎관절과발목관절을중립자세로유지하였다. 그후실험자는측정자의보조에의해천천히발목관절을수동적으로움직여 30 에이르도록한후 5초간자세위치를인식하도록하고다시시작자세로위치시켰다. 시각을차단한상태에서측정자의구령에의해실험자가능동적으로같은각도를재현하도록실시하였으며, 실험자가인지하던관절의위치에도달했다고하면, 그때의각도를측정하여자극지점에서의각도와의오차각도를측정하여평균값을측정하였다. 각각 3회측정하여평균값을산출하여자료화하였다 (Akbari & Ghiasi, 2007; Jan et al., 2009). 2) 근력측정발목의등속성근기능의측정을위하여 Biodex 등속성힘측정계 (Biodex medical systems, shirley, USA) 를사용하였다. (1) 발목관절의발등굽힘및발바닥굽힘대상자는신발을신은상태에서의자를뒤로 30 젖히고, 발은측정판위에 0 로설정하였고무릎관절을 로굽힘을한위치에서무릎뼈와발목의중심이나란히정렬될수있도록자세를취하게하였다. 보상작용을통한오차의범위를최소화할수있도록스트랩 (strap) 을이용하여몸통, 넙다리, 발목을고정시켰다. 발바닥굽힘및발등굽힘의측정은 40 발바닥굽힘된상태에서시작하여 20 발등굽힘을한다음발바닥굽힘으로되돌아오는것으로총 3회측정하였다. 각속도는 60 로설정하였으며, 각각속도 (2) 발목관절의안쪽번짐및가쪽번짐안쪽번짐및가쪽번짐은위와같은자세로 30 안쪽번짐상태에서시작하여 20 가쪽번짐하였다가안쪽번짐상태로되돌아오는것으로 3회측정하였다. 각속도는 60 로설정하였으며, 각각속도사이에 1분의휴식을취하게하였다 (Kim, 2012). 3) 균형 (1) Y-균형테스트 Y-균형테스트는 1.5inch 테이프를이용하여전방향의선에기준하여양쪽으로 135 지점에뒤안쪽과뒤바깥쪽방향의선을표시하였으며, 중앙선에서대상자가다리를뻗은지점까지의거리를cm단위로측정하였다 (Plisky et al., 2009). 맨발로측정하였으며, 두번째발가락을기준으로측정하였다. 학습효과를최소화하기위해 3회의연습후측정하도록하였으며 (Hertel et al., 2000), 총 3회측정하여평균값을기록하였다. 지지하는발이지면에서떨어지거나, 균형을잡기위해뻗은발이바닥에닿는경우, 또는발을뻗은후다시시작자세로돌아오지못할경우에는실패로간주하고다시측정하였다. 다리길이의차이를보상하기위하여표준화공식을이용하였다. 좌우측다리를각각측정하여표준화된수치의평균과표준편차를계산하였으며, 표준화된수치는백분율로나타내었다 (Plisky et al., 2006). 통계분석에는좌우를구분하지않고수치를계산하였다. Star Excursion Balance Test (SEBT) 는 Hertel 등 (2006) 과 Plisky 등 (2006) 에의해 의신뢰도를가진다고보고되었으며, 반복측정을통한숙달로인해측정에오류가생기는것에대하여반복측정신뢰도검사를한결과 의신뢰도를가진다고보고되었다 (Munro et al., 2010). (2) 균형감각측정균형감각측정도구로 Bio Rescue (Bio rescue, RM

5 VR-HMD 를활용한불안정지지면운동이기능적발목불안정성에미치는영향 85 INGENIERIE, France) 를사용하였다. Bio Rescue는화면과플랫폼 (platform) 으로이루어져있으며, 12개의스트레인게이지 (strain gauges) 를가지고있어서플랫폼의각도가측정되어진다. 실험자가눈을뜬상태로지지판정중앙부분에다리를편상태로체중을지지하고반대측무릎은 90 굽힘하며, 프로그램지시에따라발의위치를입력하여측정을실시하였다 (Alonso et al., 2011). 지지판안정도는 1-8단계이며, 전체 (overall), 앞-뒤 (anterior-posterior), 안쪽-가쪽 (medial-lateral) 방향으로측정이가능하다. 균형감각이좋을수록수치적으로낮은값을보인다. 측정은 30초간실시후 10초휴식하였고, 총 3번측정하여평균값을산출하였다 (Lee et al., 2006). 정적균형감각측정후동적균형감각을측정하였고, 동적균형의단계는안정도가낮은수준 (level 2) 에서실시되었다 (Kim et al., 2013). 롬버그검사는플랫폼에선상태에서두발을모으고움직이지않고 1분동안유지하게한뒤이동거리를측정하였다. 5. 자료처리본연구를통해수집된자료는 SPSS ver for win 프로그램 (SPSS, SPSS Inc, USA) 을이용해서분석하였다. 대상자의일반적특성은일원배치분산분석 (one-way ANOVA) 을이용하여동질성을확인하였다. 각군내에서의전 후비교는대응표본 t 검정 (paired t-test) 를이용하였고, 군간에서의전과후의변화비율의비교는일원배치분산분석을이용하였다. 사후검정은 Bonferroni 다중비교테스트를사용하였다. 통계 학적유의수준은 0.05로설정하였다. Ⅲ. 연구결과 1. 대상자의일반적특성본연구에참여한대상자는 VUS군 20명, VSS군 19명, NUS군 22명인전체 61명을대상으로실험을하였다. 본연구에참여한대상자의일반적특성은아래의표와같으며, 세군간비교한결과유의한차이가있지않았다 (p>0.05)(table 1). 2. 고유수용성감각 VUS군의운동프로그램적용전 후고유수용성감각의기록은군내평균비교에서통계학적으로유의한차이가있었다 (p<0.05). VSS군의운동프로그램적용전 후고유수용성감각의기록은군내평균비교에서통계학적으로유의한차이가있었다 (p<0.05). VSS군의운동프로그램적용전 후고유수용성감각의기록은군내평균비교에서좌측발에서만통계학적으로유의한차이가있었다 (p<0.05). 또한, 세군간의차이를알아보기위해변화율을비교한결과 VUS군과 VSS군, VUS 군과 NUS군은통계적으로유의한차이가있었지만 (p<0.05), VSS군과 NUS군은유의한차이가있지않았다 (p>0.05)(table 2). Table 1. General characteristics VUS(N=20) VSS(N=19) NUS(N=22) p Height (cm) ± ± ± Weight (kg) 60.60± ± ± Right leg length (cm) 83.85± ± ± Left leg length (cm) 83.63± ± ± Mean±Standard deviation *p<0.05

6 86 PNF and Movement Vol. 17, No. 1 Table 2. Comparision of after and before group of Proprioceptive sense Lt. Rt. VUS VSS NUS F p Pre 5.87± ± ±3.29 Post 2.56± ± ±2.13 Ratio 80.33± ± ± ** t p 0.00* 0.05* 0.00* Pre 4.76± ± ±3.41 Post 2.86± ± ±3.42 Ratio 96.95± ± ± ** t p 0.05* 0.00* 0.07 Mean±Standard deviation, *: paired t-test p<0.05, **: ANOVA p< 근력 Biodex 등속성힘측정계를사용하여각군의근력을비교한결과 VUS군의운동프로그램적용전 후결과는군내평균비교에서통계학적으로유의한차이가있었다 (p<0.05). VSS 군의운동프로그램적용전 후결과는군내평균비교에서좌, 우측발바닥굽힘에서만통계학적으로유의한차이가있었다 (p<0.05). NUS군의운동프로그램적용전 후결과는군내평균비교에서우측안쪽번짐과좌측발바닥굽힘에서만통계학적으로유의한차이가있었다 (p<0.05). 또한, Biodex 등속성힘측정계를사용하여각군의근력변화율을비교한결과 VUS군의운동프로그램적용후 Biodex 의최대토크비값은 VUS군과 VSS군, VUS 군과 NUS군은군간평균의비값비교에서통계학적으로유의하였으나 VSS군과 NUS군은통계학적으로유의한차이가있지않았다 (p>0.05)(table 3). 4. 균형능력 1) Y-균형테스트 Y-균형테스트를통해측정한각군의운동프로그 램적용전 후의 Y-균형테스트점수를비교한결과 VUS군의 Y-균형테스트점수의변화는좌, 우측모두통계학적으로유의한차이가있었으나 (p<0.05), VSS 군과 NUS군의운동프로그램적용전 후 Y-균형테스트점수의변화는좌, 우측모두통계학적으로유의한차이가있지않았다 (p>0.05). 세군간의차이를알아보기위해 Y-균형테스트점수의변화율을비교한결과 VUS군과 VSS군, VUS 군과 NUS군은통계학적으로유의한차이가있었으나 (p<0.05), VSS군과 NUS군은유의한차이가있지않았다 (p>0.05)(table 4). 2) 균형감각운동프로그램적용전 후 BioRescue 결과의변화중안정성한계 (limit of stability) 는 VUS군과 VSS군내평균비교에서통계학적으로유의한차이가있었으나 (p<0.05), NUS 군내평균비교에서통계학적으로유의한차이가있지않았다 (p>0.05). 롬버그검사는 VUS군내평균비교에서통계학적으로유의한차이가있었고 (p<0.05), VSS 군내평균비교중눈을뜬상태 (eyes open) 에서는통계학적으로유의한차이가있었으나 (p<0.05), 눈을감은상태 (eyes close) 에서는통계학적으로유의한차이가있지않았다 (p>0.05). NUS 군

7 VR-HMD 를활용한불안정지지면운동이기능적발목불안정성에미치는영향 87 Table 3. Intra and intergroup comparisons of muscle strength Inversion Eversion Plantar flexion Dorsi flxeion Lt. Rt. Lt. Rt. Lt. Rt. Lt. Rt. VUS VSS NUS F p Pre 4.94± ± ±3.03 Post 7.63± ± ±3.00 Ratio ± ± ± ** t p 0.00* Pre 5.09± ± ±3.00 Post 8.57± ± ±4.38 Ratio ± ± ± ** t p 0.00* * Pre 5.12± ± ±4.70 Post 7.900± ± ±2.30 Ratio ± ± ± ** t p 0.00* Pre 5.31± ± ±2.72 Post 7.55± ± ±2.52 Ratio ± ± ± ** t p 0.00* Pre 22.57± ± ±14.07 Post 31.12± ± ±12.33 Ratio ± ± ± ** t p 0.01* 0.03* 0.03* Pre 22.86± ± ±12.02 Post 34.48± ± ±12.46 Ratio ± ± ± ** t p 0.01* 0.00* 0.09 Pre 13.51± ± ±5.38 Post 15.68± ± ±4.11 Ratio ± ± ± ** t p 0.05* Pre 13.80± ± ±6.31 Post 17.30± ± ±4.56 Ratio ± ± ± ** t p 0.04* Mean±Standard deviation, *: paired t-test p<0.05, **: ANOVA p<0.05

8 88 PNF and Movement Vol. 17, No. 1 Table 4. Intra and intergroup comparisons of dynamic or static balance (Y-balance test) Lt Rt VUS VSS NUS F p Pre ± ± ±19.63 Post ± ± ±17.59 Ratio ± ± ± ** t p 0.00* 0.02* 0.10 Pre ± ± ±17.77 Post ± ± ±16.55 Ratio ± ± ± ** t p 0.00* Mean±Standard deviation, *: paired t-test p<0.05, **: ANOVA p<0.05 Table 5. Intra and intergroup comparisons of dynamic or static balance (Romberg test) Eye open Eye close VUS VSS NUS F p Pre 57.15± ± ±15.12 Post 35.96± ± ±17.32 Ratio ± ± ± ** t p 0.02* 0.00* 0.40 Pre ± ± ±36.67 Post 51.90± ± ±48.91 Ratio ± ± ± ** t p 0.02* Mean±Standard deviation, *: paired t-test p<0.05, **: ANOVA p<0.05 에서는통계학적으로유의한차이가있지않았다 (p<0.05). 또한, BioRescue를이용한안정성의한계, 롬버그검사의비값의결과는군간비교에서 VUS 군과 VSS군, VSS 군과 NUS군사이에서통계학적으로유의한차이가있었으나 (p<0.05) VSS군과 NUS군은통계학적으로유의한차이가있지않았다 (p>0.05)(table 5). Ⅳ. 고찰삠으로인한발목관절의급성손상은현대인들에게서빈번하게발견될수있는손상중하나이다 (Kaminski & Morrison, 2007). 특히남녀노소를가리지않고누구에게나닥칠수있는손상이라는점에서중요하다. 발목관절의손상은신체활동중의작은부주의로쉽게상해가발생할수있음에도불구하고, 통증의정도가심하지않으며적절한치료없이도일상생활을영위하는데에큰어려움이없기때문에그대로

9 VR-HMD 를활용한불안정지지면운동이기능적발목불안정성에미치는영향 89 방치하는등손상을가볍게보는경향이있다. 이러한손상후적절한치료적처치의부재는증상을만성적발목불안정성으로확대시킬위험이있다 (Chan et al., 2011). 만성적발목불안정성은반복적인발목손상을야기함으로써발목주변의연부조직과근골격을약화시키며, 이로인해신체전체의안정감을감소시키고, 고유수용성감각을저하시키는등기능적장애에노출시킨다. 따라서본연구에서는불안정지지면을적용한균형운동시 VR-HMD 를활용한과제지향적접근을통해, 동기를유발시키고운동집중력을향상시켜기능적발목불안정성을개선시키고자하였다. 발목손상의경우고유수용성감각의결손이발목불안정성의원인이된다 (Han et al., 2006; Willems et al., 2002). 이에따라본연구에서는불안정한지지면위에서 VR-HMD 를이용한운동을통한고유수용감각향상이기능적발목불안정성에어떠한영향을미치는지알아보기위해각도계를사용하여관절내위치감각을측정하였다. 세군모두전후비교에서유의한차이가있었으며, VUS군에서관절내위치감각의오차범위가가장크게줄어든것으로나타났다. 군간비교에서는 VUS군과 NUS군사이에서유의한차이가있었다. 시각적자극이자세동요를유발하여인체의발목전략을많이사용하게한다는선행연구의결과로보아 (Horak & Nashner, 1986), VUS군에서는 VR-HMD 에의한과제지향적시각적자극으로인해더많은관절내위치감각의자극을받게된것으로보인다. 또한, VUS군과 VSS군사이에서도유의한차이가있었는데, 이는 VSS 군에서시각적자극에의해유발되는움직임들은안정지지면의적용으로신체균형유지보다는단순한시각적자극에대응하는움직임으로써관절내위치감각에미치는영향이적었던것으로생각된다. 따라서단일한시각적자극이나불안정지지면에서의운동보다불안정지지면과함께 VR-HMD 를이용하여운동을진행하는것이고유수용감각의향상에도움이될것이라생각된다. 근력은발목불안정성과관련이있으며, 가쪽번짐 근육의근력이충분히강하지못하면가쪽인대의신장력이증가하여상해를입게된다 (Kwon & Park, 2016). 본연구에서는등속성장비를이용하여최대근력을측정하였으며, 근력을가장잘측정할수있는각속도 60 에서최대근력을측정하였다 (Kim, 2012). VR-HMD 를이용한가상현실프로그램과더불어불안정지지면운동을이용하여균형훈련을실시한결과 VUS군에서운동전후에오른발과왼발의발바닥굽힘, 발등굽힘, 안쪽번짐, 가쪽번짐모두의최대근력이유의한증가를보였다. VSS 군은운동전후에오른발과왼발의발바닥굽힘에서만유의한증가를보였고, NUS 군은운동전후에오른발의안쪽번짐과왼발의발바닥굽힘에서만유의한증가를보였다. 이것은시각적자극이없는불안정지지면에서의훈련과근력훈련을병행한선행연구에서는가쪽번짐의최대근력이유의한증가가나타나지않았으나 (Kim, 2012), 본연구에서는불안정지지면에서 VR-HMD 를통한과제지향적시각적자극을적용하였기때문에가쪽번짐이유발되어가쪽번짐의최대근력이향상된것으로생각된다. 이는발목불안정성의원인중하나인종아리근의약화 (Bernier & Perrin, 1998) 를보완해주어발목의안정성향상에기여한다고볼수있다. 또한모든군의전후비교에서발바닥굽힘의최대근력이유의하게증가하였고, 군간비교에서 VUS군의발바닥굽힘의최대근력은다른두군에비해유의한차이가있었다. 이는불안정지지면위에서균형훈련과 VR-HMD 를활용한다양한시각적자극이모든방향에서힘줄, 인대, 관절, 고유수용기를활성화시켜발목의최대근력을향상시키고, 최대근력의향상이신체를더안정적으로지탱하게할것으로생각된다. 균형능력은많은활동에기초적인역할을하고성공적인운동수행과신체적활동을위해서는꼭필요한요소 (Hrysomallis, 2011) 이므로발목불안정성을가진사람들에게발목균형은필수요소이다. 본연구의중재로균형의증진이있는지알아보기위해정적균형과동적균형을측정하였다.

10 90 PNF and Movement Vol. 17, No. 1 동적균형에서의전후결과는모든군에서유의한차이가있다. 이는기능적발목불안정성을가진대상군에서가상현실을운동프로그램에적용한경우균형능력이향상되었다는연구 (Kim & Heo, 2015) 와불안정지지면에서의훈련이발목관절에서의움직임을통해균형능력을향상시켰다는연구 (Han, 2006) 와연구결과가유사하다. 군간비교에서도 VUS군은나머지두군과유의한차이가있다. 이로인해 VR-HMD 를통한목표지향적인시각적자극과불안정지지면을함께적용한경우다른여러기능과밀접하게연관되어균형증진에도영향을준것으로판단된다. 정적균형에서전후결과는 VUS군과 VSS군에서는유의하였지만 NUS군에서는유의하지않았다. 이는시각적인지과제를병행한훈련이균형변화에있어서유의한차이가있다는연구결과 (Gouglidis et al., 2011) 처럼시각적자극이없었던 NUS군만유의하지않았던것으로생각된다. 따라서시각적자극을동반한불안정지지면에서의운동이동적및정적균형증진에효과가있다는것을알수있었다. 본연구에서는불안정지지면위에서 VR-HMD 를이용한가상현실의시각적자극을제공함으로써운동을진행했을때발목불안정성의주요원인이되는고유수용감각, 근력, 균형능력이모두유의하게증가하였다. 이는발목불안정성으로인한신체기능을향상시켜기능적발목불안정성을완화시킬것으로생각된다. 이실험이 3주간의짧은기간이었고실험대상자가모두 20대학생이라는점과개인의일상생활속의운동을완전히차단하지못했다는제한점이있다. 차후에중재기간을늘리고, 다양한연령대를대상으로한연구가필요할것으로본다. 또한 VR-HMD 의부작용인가상멀미의원인으로알려진디스플레이구현속도가개인스마트폰의성능에따라다르게나타나는점은고려하지못하였다. 본연구결과를통해, 다양한환자를치료할때단순한동작으로유발하는훈련을적용하기보다, 기존치료에가상현실등을복합적으로활용하여흥미와동기를유발시키고과제지향적 접근을활용한치료프로그램을활용하는것이보다나은치료결과를가져올수있을것으로생각된다. Ⅴ. 결론본연구는 2017년 8월 28일부터 9월 29일까지성남소재 E 대학교에서기능적발목불안정성을가진대상자를선별하여 VR-HMD 를착용하고불안정지지면에서운동하는 20명, VR-HMD 를착용하고안정지지면에서운동하는 19명, VR-HMD 를착용하지않고불안정지지면에서운동하는 22명으로나누고중재전 후로고유수용감각, 근력, 균형능력을측정하였다. 본연구의내용을종합해볼때, 가상현실의시각적자극을제공한운동은고유수용감각, 근력, 균형능력을보다향상시켜기능적발목불안정성에긍정적효과를가지는것으로생각된다. 따라서기존치료에가상현실등을활용한치료프로그램은보다나은결과를가져올수있을것으로생각된다. References Akbari A, Ghiasi F. Comparison of the effects of open and closed kinematic chain and different target position on the kknee joint position sense. Journal of Medical Sciences. 2007;7(6): Bernier JN, Perrin DH. Effect of coordination training on proprioception of the functionally unstable ankle. The Journal of Orthopaedic and Sports Physical Therapy. 1998;27(4): Braham RA, Hale SA, Hertel J, et al. Simplifying the star excursion balance test: analyses of subjects with and without chronic ankle instability. Journal of Orthopaedic & Sports Physical Therapy. 2006;36(3): Butler RJ, Gorman PP, Plisky PJ, et al. The reliability of

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012임수진

012임수진 Received : 2012. 11. 27 Reviewed : 2012. 12. 10 Accepted : 2012. 12. 12 A Clinical Study on Effect of Electro-acupuncture Treatment for Low Back Pain and Radicular Pain in Patients Diagnosed with Lumbar