J Korean Soc Phys Med, 2015; 10(4): 25-31 http://dx.doi.org/10.13066/kspm.2015.10.4.25 Online ISSN: 2287-7215 Print ISSN: 1975-311X Research Article Open Access 휴대전화사용이젊은성인의보행에미치는영향 : 문자메시지보내기와음악감상하며문자메시지보내기 유경훈 1,2 심재훈 1 정성대 1 전혜선 3,4 1 백석대학교보건학부물리치료학과, 21 연세대학교대학원물리치료학과 3 연세대학교보건과학대학물리치료학과, 4 연세대학교보건환경대학원인간공학치료학과 Effect of using a Cell Phone on Gait Parameters in Healthy Young Adults: Texting and Texting while Listening to Music Kyung-Hoon Yu, MSc, PT 1,2 Jae-Hun Shim, PhD, PT 1 Sung-Dae Choung, PhD, PT 1 Hye-Seon Jeon, PhD, PT 3,4 1 Dept. of Physical Therapy, Division of Health Science, Baekseok University 2 Dept. of Physical Therapy, The Graduate School, Yonsei University 3 Dept. of Physical Therapy, College of Health Science, Yonsei University 4 Dept. of Ergonomic Therapy, The Graduate School of Health and Environment, Yonsei University Received: August 30, 2015 / Revised: August 31, 2015 / Accepted: September 3, 2015 c 2015 J Korean Soc Phys Med Abstract 1) PURPOSE: Previous studies have shown that healthy young adults reduced gait velocity during texting or talking while walking. It was reported that increasing number of pedestrian accidents were related to distract the environmental attention. The purpose of this study was to compare the effects of texting and texting while listening to music on gait parameters. METHODS: Texting and listening to music while walking were assessed in two dual-task condition using 35 healthy young adults. The outcome measurements were Corresponding Author : yukh@bu.ac.kr 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. assessed in terms of spatiotemporal gait parameters in three walking conditions, namely, comfortable walking speed, walking while texting, and walking while texting and listening to music. To avoid learning effect, subjects were individually blinded to assessment schedule and space. The changes between the three walking conditions were analyzed using repeated measures ANOVA. RESULTS: When comparing the two dual-task conditions with the single-task condition, it was found that dual-task interference was increased in almost gait velocity, cadence, stride length, step time, double limb support, and single limb support. In addition, walking while texting and listening to music condition negatively was affected gait speed, stride length, and step time more than the texting only condition. CONCLUSION: Walking while texting and listening to music as well as waling while texting may decrease pedestrian safety when crossing streets by diverting the person s
attention away from the street environment. Key Words: Texting, Music, Cell phone, Dual-task, Walking Ⅰ. 서론대부분의연령대에서보행중에휴대폰을사용한경험이있으며, 보행중에문자메시지보내기, 인터넷검색이나음악감상과같은휴대전화사용은스마트폰이사용이보편화된이후일반적인모습이되었다 (Schabrun 등. 2014). 휴대전화를이용하여운전하며통화하는것은위험한행동이라는것은인식되어있으며, 특히운전중문자보내는행동은운전자의주위를산만하게하여교통사고의위험을더욱증가시키는것으로보고되었다 (Atchley 등, 2011). 따라서많은나라에선운전중에휴대폰사용은교통법규의위반으로정해져있으며, 최근들어보행자들의휴대전화사용은운전중휴대전화사용과마찬가지로낙상이나부주의로인한사고의위험성이점차늘어나고있어사회적인문제로나타나고있다 (Nasar와 Troyer, 2013). 보행은중추패턴발생기 (central pattern generator) 로잘프로그램화된운동기술로미리예측된환경에서자동발생하는기본적인움직임으로기존에알려져있으나 (Nielsen, 2003), 보행자들은높은수준의인지과정과운동기능을동시에사용하여보행을자동적이며안전하게수행하게된다. 일상생활환경에서보행중추가과제가주어질경우다른인지과제의처리과정을통해보행이조절된다고알려져있다 (Yogev-Seligmann 등, 2008). 예를들어, 휴대전화에서문자메시지보내기와같이손으로휴대전화다루기및문자를작성하는인지적과제들은주변환경의시각적이용능력의감소하며휴대전화의조작과관련된신체적인변화가동반하게된다 (Schabrun 등, 2014). 보행자들은휴대전화를사용중보행과통화또는문자메시지보내기와같은과제사이에적절한주의력을분배하기어려우며, 정확한공간적정보를파악할수없게되고보행속도또한 유지하지못하게된다 (Lamberg 와 Muratori, 2012; Hyman 등, 2010). 휴대전화이용이자세조절의변화에영향을주며, 특히문자메시지를보내며균형을잡는과제에서현저히자세조절능력을감소시킨다했으며 (Won, 2012), 젊은학생들을대상으로휴대전화로전자우편을사용하는것은일반보행에비해보행속도와보폭 (stride length) 의감소를보고했다 (Demura와 Uchiyama, 2009). 다른연구에서는 33명의젊은성인들을대상으로통화를하면서걷는집단은편하게걷는집단에비해보행속도가 16% 감소, 문자메시지를보내며걷는집단을편히걷는집단과비교했을때 33% 의보행속도의감소와목표물에비해 10 벗어났음을알수있었다 (Lamberg와 Muratori, 2012). 이와같이변화된보행변수의결과로휴대전화를사용하는보행자들이사람들과장애물에부딪히거나넘어질수있는안전성의문제가지속적으로증가하고있음을보고했다 (Nasar와 Troyer, 2013). 운전시음악을듣는것이스트레스와긴장을줄여주는긍정적부분과브레이크반응시간에영향이적다는결과를보여주고있으며, 휴대전화로통화하는것만큼안전을주의력을산만하게하지않다고했다 (Bellinger 등, 2009). 하지만 Schwebel 등 (2012) 연구에서는보행중에통화, 문자메시지보내기와음악감상모두횡단보도와같은외부환경에서보행시안전을위협할수있다고하였다. 최근에젊은성인들이보행시스마트폰으로문자메시지와통화뿐아니라음악감상및인터넷이용등의모습을쉽게볼수있다. 따라서보행자들의안전을위해문자메시지보내기와음악감상시보행의변화를알아보는것이중요하며, 아직까지문자메시지를보내며걷기와음악감상과문자메시지를보내며걷기를비교한연구는없었다. 본연구의목적은젊은성인에게평소보행속도로편하게걷기, 문자메시지를보내며걷기와음악감상과문자메시지를보내며걷기, 총 3 조건에서시공간보행변수의변화의차이를알아보기위한것이다. 본연구에서는평소보행속도로편하게걷기에비해문자메시지를보내며걷기와음악감상과문자메시지를보내며걷기조건에서보행변수들의수행정도가감소할것이
며, 음악감상과문자메시지를보내며걷는조건에서보행의수행이더욱감소할것으로가설을설정했다. Ⅱ. 연구방법 1. 연구대상자 35명의건강한젊은성인을대상으로연구에참여하기전에실험방법과절차들을자세히설명하였으며, 실험동의서를서명한 35명의대상을 3가지의보행조건에서반복측정하였다. 대상자선정기준은균형의문제가없는자, 휴대전화를사용하여문자전송이가능한자, 시각적문제가없는자, 스마트폰을사용하는자로정하였다. 신경학적진단을받은자, 전정기관문제를가진자, 보행이어려운정형외과학적수술을받은자, 통증으로다른기능장애로보행이나휴대전화사용이어려운자는제외하였다. 대상자의일반적특성은다음과같다 (Table 1) 의반복과학습효과를방지하기위해 5분의간격을두었다. 대상자간의간섭효과를최소화하기위해실험시간을사전에약속을하여실시하였다. 또한휴대전화사용자세를일치시키기위해두손을사용하여가슴높이에서휴대전화를위치시키고문자메시지를쓸수있도록모든대상자들을설정하였다 1) 문자메시지를보내며걷기 (walking while texting) 대상자는평소보행속도로편하게걸으면서휴대전화기를들고두손으로문자메시지를보내는상황을연출하게된다. 보행측정전에대상자는실제상황과비슷한설정으로휴대전화에문자메시지를정확히입력하며걷게하였다. 문자입력은스마트폰에서사용하는타자연습기를사용하였으며, 한문장이끝나면자동으로다른문장으로넘어가는프로그램이었다. 대상자들이사용하고있는휴대전화기가다양하므로실험에사용된휴대전화기는즐겨쓰는문자입력방식으로미리바꾸어연습을하였으며, 총 3번을측정하였다. Table 1. General characteristics of participants General characteristics Subjects Gender (male/female) 17 / 18 Age (years) 22.09±1.63 a Height ( cm ) 166.69±6.78 Weight ( kg ) 63.57±9.60 Length of legs (right/left) 86.23±5.17/86.46±5.00 a Mean ± SD 2. 연구절차본연구는대상자에게단일과제와두가지의이중과제실험조건에서보행변수의측정을실시하였고, 일상생활과최대한비슷한환경으로수행하였다. 각대상자들은평소보행속도로편하게걷기 ( 단일과제조건 ), 문자메시지를보내며걷기 ( 이중과제조건 ) 와음악감상과문자메시지를보내며걷기 ( 이중과제조건 ), 총 3가지보행조건을수행하였다. 대상자마다각조건은무작위순서로실시하고 3번씩반복하여보행변수들의평균값으로변수들의결과값으로사용하였으며, 조건간 2) 음악감상과문자메시지를보내며걷기 (walking while texting and listening to music) 대상자는평소보행속도로편하게걸으며동시에이어폰으로음악을듣게하였다. 주위환경의소음이들리지않고불편하지않은범위내의음량으로대상자들은자신이좋아하는음악을선택하여들으면서문자메시지를보내는과제를하게된다. 사전에설명한보행중에문자메시지를쓰는것과동일한방법으로대상자들에게설명을하고측정을하였다. 3. 측정도구및변수본연구에서는시공간보행변수 (spatiotemporal parameters) 로각조건에서보행의객관적인차이를알아보고자하였다. 휴대용보행분석시스템인 GAITRite (GAITRite interface CIR system Inc., NY, USA) 는길이 3.7미터와폭 0.6미터의매트로컴퓨터에서발자국을감지하여시간, 공간데이터를보여주게된다. 이보행분석시스템은젊은성인에게높은측정- 재측정신뢰도 (Menz et al., 2004) 와 3D 동작분석기와높은동시타당도
를보고하였다 (Stokic 등, 2009). 측정변수로보행속도 (velocity), 보행률 (cadence), 보폭 (stride length), 걸음시간 (step time), 두다리지지기 (double limb support; % 보행주기 ) 와한쪽다리지지기 (single limb support; % 보행주기 ), 보행너비 (step width) 를선택하였다. 3가지조건에서대상자에게평소에걷는속도로 10미터를걷게하며, 중간에 GAITRite를위치시켰고각조건을 3번씩측정하였다. 4. 분석방법본연구에서수집된자료들은 SPSS ver 18.0(SPSS Inc. Chicago, IL, USA) 프로그램을이용하여자료를분석하였다. 대상자들의일반적인특성 ( 나이, 다리길이, 키, 체중 ) 은기술통계를이용하여제시하였다. 평소보행속도로편하게걷기, 문자메시지를보내며걷기와음악감상과문자메시지를보내며걷기, 3가지의보행조건에서대상자들의보행의차이를알아보고자시공간변수들의변화를비교하기위해반복측정된분산분석 (repeated measures ANOVA) 통계방법을이용하여분석을실시하였으며, 대상자들이보행조건간에유의한차이가있다면보행조건별차이의다중비교로 Bonferroni 조정을사용하였고, 통계학적유의수준은 α=.05로하였다. Ⅲ. 연구결과대상자들의일반적인특성은 Table 1과같다. 3가지보행조건 ( 평소보행속도로편하게걷기, 문자메시지를보내며걷기, 음악감상과문자메시지를보내며걷기 ) 에서시공간보행변수들의변화의차이를알아보았다 (Table 2). 각보행과제조건간에보행속도 (F= 101.70, p<.01), 보행률 (F=55.064, p<.01), 보폭 (F=90.403, p<.01), 걸음시간 (F=25.149, p=.03), 두다리지지기 (F=23.024, p<.01), 한쪽다리지지기 (F=25.807, p<.01), 보행너비 (F=3.283, p=.04) 의보행변수들이통계적으로유의한차이를보였다. 문자메시지를보내며걷기조건은평소보행속도로편하게걷기조건에비해보행너비 (p=.85) 를제외하고모든보행변수에서유의한차이를보였다 (p<.05). 음악감상과문자메시지를보내며걷기조건에서는모든보행변수에서평소보행속도로편하게걷기조건에비해유의한차이가있었다 (p<.05). 보행속도 (p=.02), 보폭 (p=.030) 과걸음시간 (p=.02) 은문자메시지를보내며걷기와음악감상과문자메시지를보내며걷기조건사이에유의한차이가있었다. Ⅳ. 고찰 본연구는주요목적은건강한성인들이음악감상과 Table 2. Comparison of spatiotemporal gait parameters in 3 walking task conditions Variables Walk a Texting b Listening&texting c F p Velocity ( cm /s) 112.99±16.92 d 95.36±18.40 91.30±17.04, 101.704 <.01 * Cadence (step/min) 115.76±9.21 103.41±22.00 103.61±12.73 55.064 <.01 * Stride length ( cm ) 118.15±12.56 107.47±12.61 105.32±11.61, 90.403 <.01 * Step time (sec) 0.53±0.06 0.58±0.08 0.59±0.09, 25.149.03 * Double limb support (%) 21.81±2.80 23.50±3.71 23.93±3.57 23.024 <.01 * Single limb support (%) 39.06±1.65 38.21±2.03 37.89±1.99 25.807 <.01 * Step width ( cm ) 13.40±1.57 13.25±1.55 13.10±1.42 3.283.04 * a Walking at a comfortable speed, b walking while texting, c walking while texting and listening to music d mean ± SD, * p<0.05, p value is comparison of spatiotemporal data using repeated measures ANOVA in 3 walking conditions, significant differences when compared walking at a comfortable speed condition. significant differences between walking condition (texting and listening& texting).
문자메시지를보내며걷기조건이문자메시지를보내며걷기조건에비해시공간보행변수들의변화를확인하기위함이다. 평소보행속도로편하게걷기와비교할때, 문자메시지를보내며걷는조건과음악감상과문자메시지를보내며걷는조건에서보행속도와보행률, 보폭, 한쪽다리지지기에서유의하게감소를하였으며, 보행시간과두다리지지기는유의하게증가를보였다. 이런변수들의변화로복잡한이중과제조건이보행자들의보행안전수준을감소시킨다고볼수있다. 문자메시지를보내며걷기조건에서는주의력이두과제에분배되어문자메시지보내기와보행의정보를동시에처리하게된다. 또한문자메시지를보내는과제로인한주의력의산만으로보행속도가감소하며, 직선보행이어려워져측면으로벗어나는정도가증가하게된다 (Woollacott과 Shumway-Cook, 2002; Schabrun 등, 2014). 본연구에서도문자메시지를보내며걷기조건에서평소보행속도로편하게걷기조건과비해보행속도, 보행률과보폭에뚜렷한감소와걸음시간은더욱증가하는양상을보였으며, 기존의문자메시지보내며걷기연구와동일한변화를보여주었다 (Demura와 Uchiyama, 2009; Schabrun 등, 2014). 이것은대상자들이문자메시지를보내는과제에주의력의증가로보행의수행능력이감소된것이라할수있다. 젊은성인들은보행중에문자메시지를보내기와같은이차과제를수행할때, 사전에두과제에동일하게주의력을분배할것을계획하더라도문자메시지보내기와같은이차과제에주의력을우선하게된다 (Lopresti-Goodman 등, 2012). 하지만좀더노력이필요한보행상황에서는주로이차과제보다보행을우선시하여보행의안정화에주의력을우선시하게된다 (Kelly 등, 2013). 사람들이많은환경이나복잡한환경에서는오히려보행을멈추고문자를보내며다시걷게되는데, 이는젊은성인들이모든상황에서주의력을적절하게분배하며동시에수행할수없음을알수있다 (Plummer 등, 2015). 양손으로문자메시지를보내는동작은팔젓기 (arm swing) 가사라져보행의속도와다른보행변수들의변화에영향을주게되고, 보행자들의안전에문제를 일으킬것이다 (Bruijn 등, 2008). 또한문자를보내는과제를위해휴대전화에집중하여목과머리의움직임이제한되고, 전정기관의정보를정확하게사용할수있는기회가줄어들게된다. 결국주위환경에대한시각적인피드백의사용의감소로직선보행의어려움과장애물을피하기어려워충돌하게될것이다 (St George와 Fitzpatrick, 2011; Schabrun 등, 2014). 대부분의이전연구에서운전과보행중에음악감상을하는것은문자메시지를보내거나통화를하는것만큼주의력산만을일으킬만한과제가아니며오히려도움을줄수있다고했다 (Bellinger 등, 2009; Neider 등, 2011; Stavrinos 등, 2011). 하지만횡단보도를건너는가상현실을이용하여보행자들에게음악감상과문자메시지를보내는과제를실시한 Schwebel 등 (2012) 의연구에서, 단지보행만하는것에비해음악감상하며걷는조건이문자를보내는과제를수행하는대상자들과비슷하게자동차에부딪히는경우가증가하였고, 주의력을산만하게만드는과제였다고보고했다. 이전연구들과는대조적인결과이지만본연구와는동일한결과를보였다. 우리연구에서음악감상과문자메시지를보내며걷기는문자메시지를보내며걷기과제에비해보행속도와보폭이의감소와걸음시간이더욱증가하였으며, 이를통해음악감상은보행변수를변화시킬수있는주요한과제임을알수있었다. 이어폰을사용한음악감상은실제환경에서청각신호를차단시키며위험신호를파악하지못하고보행중에안전을판단하는부분에주의력이줄어들어보행에영향을미치게되었을것이다 (Pfeffer와 Barnecutt, 1996). 따라서젊은성인들에게위와같은보행변수의변화를인식시켜주며개선시킬수있는교육이필요할것이다. 본연구는시공간보행변수만으로측정했고, 정해진폭에서걸어야하는실험실적조건으로일상생활환경에서보행으로예측할수없었다. 또한문자메시지를보내는과제는작업기억 (working memory) 과다양한인지기능을수행하는복잡한과정이므로본실험조건의단순하고주어진문장으로일반화하기에는한계가있었다.
Ⅴ. 결론본연구는젊은성인들의보행시문자메시지보내며음악감상을하는과제들이보행안전에영향을미칠수있다는점을알고자하였다. 문자메시지를보내며걷기조건과음악감상과문자메시지를보내며걷기조건은평소보행속도로편하게걷기조건에비해보행속도와보행률의감소, 보폭과한쪽다리지지기의감소, 걸음시간과두다리지지기의증가를나타냈다. 또한음악감상과문자메시지를보내며걷기는문자메시지를보내며걷기에비해보행속도와보폭의감소, 걸음시간의증가를보여줬다. 보행자들이음악감상과문자메시지를보내는행동은보행의변화를일으키며, 주변환경의부주의로인해사람들과장애물에부딪히거나사고의위험이증가할수있을것이다. Acknowledgements 이논문또는저서는정부 ( 교육부 ) 의재원으로한국연구재단의지원을받아수행된연구임 (NRF-2013S1A5B8A01055336). References Atchley P, Atwood S, Boulton A. The choice to text and drive in younger drivers: behavior may shape attitude. Accid Anal Prev. 2011;43(1):134-42. Bellinger DB, Budde BM, Machida M, et al.. The effect of cellular telephone conversation and music listening on response time in braking. Transportation Research Part F: Traffic Psychology and Behaviour. 2009;12(6): 441-51. Bruijn SM, Meijer OG, van DJH, et al. Coordination of leg swing, thorax rotations, and pelvis rotations during gait: the organisation of total body angular momentum. Gait and Posture. 2008;27:455 62. Demura S, Uchiyama M. Influence of cell phone email use on characteristics of gait. European Journal of Sport Science. 2009;9(5):303-09. Hyman IE, Boss SM, Wise BM, et al. Did you see the unicycling clown? Inattentional blindness while walking and talking on a cell phone. Appl Cognit Psychol. 2010;24:597 607. Kelly V, Eusterbrock AJ, Shumway-Cook A. Factors influencing dynamic prioritization during dual-task walking in healthy young adults. Gait Posture. 2013; 37:131 4. Lamberg EM, Muratori LM. Cell phones change the way we walk. Gait and Posture. 2012;35:688-90. Lopresti-Goodman SM, Rivera A, Dressel C. Practicing safe text: the impact of texting on walking behavior. Appl Cogn Psychol. 2012;26:644 8. Menz HB, Latt MD, Tiedemann A, et al. Reliability of the GAITRite walkway system for the quantification of temporo-spatial parameters of gait in young and older people. Gait Posture. 2004;20(1):20-5. Nasar JL, Troyer D. Pedestrian injuries due to mobile phone use in public places. Accid Anal Prev. 2013;57:91 5. Neider MB, Gaspar JG, McCarley JS, et al. Walking and talking: dual-task effects on street crossing behavior in older adults. Psychology and Aging. 2011;26:260 8. Nielsen JB. How we walk: central control of muscle activity during human walking, Neuroscientist. 2003;9:195 204. Pfeffer K, Barnecutt P. Children s auditory perception of movement of traffic sounds. Child: Care, Health, and Development. 1996;22:129 37. Plummer P, Apple S, Dowd C, et al. Texting and walking: effect of environmental setting and task prioritization on dual-task interference in healthy young adults. Gait Posture. 2015;41(1):46-51. Schabrun SM, van den Hoorn W, Moorcroft A, et al. Texting and Walking: Strategies for Postural Control and Impli cations for Safety. PLoS ONE. 2014;9(1):e84312. Schwebel DC, Stavrinos D, Byington KW, et al. Distraction
and pedestrian safety: How talking on the phone, texting and listening to music impact crossing the street. Accid Anal Prev. 2012;45:266-71. St George RJ, Fitzpatrick RC. The sense of self-motion, orientation and balance explored by vestibular stimulation. J Physiol. 2011;589(4):807-13. Stavrinos D, Byington KW, Schwebel DC. Distracted walking: cell phones increase injury risk for college pedestrians. J Saf Res. 2011;42:101 7. Stokic DS, Horn TS, Ramshur JM, et al. Agreement between temporospatial gait parameters of an electronic walkway and a motion capture system in healthy and chronic stroke populations. Am J Phys Med Rehabil. 2009;88(6):437-44. Won JI. Effects of using a mobile phone on postural control. Phys Ther Kor. 2012;19(3):61-71. Woollacott M, Shumway-Cook A. Attention and the control of posture and gait: a review of an emerging area of research. Gait Posture. 2002;16:1 14. Yogev-Seligmann G, Hausdorff JM, Giladi N. The role of executive function and attention in gait. Mov Disord. 2008;23(3):329-42.