many stroke patients with stroke have a balance problems while standing because they tend 
 to put their weight on their non - paralyzed lower limb to increase swing of their upper 
 body1 .
falling accidents due to such 
 decline in balance ability is on the increase annually .
even when there is no injury from falling , frequent 
 falling can sufficiently disrupt physical and social activities2 . because deterioration of muscular strength and balance 
 ability increases the risk of falling , it is significantly important to perform exercises to 
 promote upper limb muscular strength and training for balance3 .
regular exercise of walking and for muscular strength and balance 
 may increase muscular strength and balance to prevent falling of patients4 . walking , in particular ,
is known to be a 
 safe type of aerobic exercise for patients , having the merit that it can be performed 
 gradually by considering appropriate intensity , frequency , period , and phases of exercise 
 for abilities of each patient5 .
recently 
 efficiency of walking training using a treadmill has attracted more attention as when such 
 training has been reported to have better effects than walking on even ground .
some 
 researchers reported that walking on a treadmill is effective in improving balance and 
 walking ability6 , 7 . with recent developments of relevant computer programs , new methods of rehabilitation 
 exercise
such exercises can increase interest and participation of 
 patients in treatment and improve their significant functions by enabling them to perform 
 various forms of tasks appropriate for goals of individual patients in virtual reality . 

virtual reality indicates a type of interactive simulation using computer hardware and 
 software , in which users can have close - to - reality experiences8 .
virtual reality training using visual feedback enables the 
 participants to undergo the training while seeing their movements with their own eyes , a 
 feature that helps them adjust their inaccurate body center caused by body image damage 
 suffered by most stroke patients .
in addition , training serves as a catalyst in active 
 participation and performance of tasks by inducing interest and pleasure , providing 
 immediately visual feedback on the result to enhance motor education ability9 .
many recent researches of virtual reality 
 games with higher accessibility reported that such games showed significant effects on 
 voluntary control and coordination of children with cerebral palsy and increases in the 
 motor ability of patients with parkinson disease10 .
those types of games were also effective on recovery of upper limb 
 functions and induced significant improvement in balance and walking of stroke patients , 
 showing that the games can be used as an effective method of intervention11 , 12 . as a means of overcoming limitations of the existing intervention methods , virtual
reality 
 shows an availability it has to being applied in the rehabilitation of stroke patients . 

however , devices of virtual reality in previous studies are so large that they are difficult 
 to be used in general social institutes or homes in terms of scale and cost .
furthermore , 
 they are targeted to a small number of patients . in this context , the purpose of this study 
 was to perform treadmill exercise and virtual reality training exercise using nintendo wii , 
 a device that can be easily used without regard to place or facility , in order to 
 investigate the effects on balance and walking of stroke patients .
all of the subjects were sufficiently 
 explained of this study and voluntarily consented to their participation in the experiment . 

this study was approved by the research agency , and all participants provided written 
 informed consent .
those who could perform communication , comply with instructions in this 
 study , perform balancing and walking independently , had no pain limiting execution of 
 exercise , and had no disability in sight , hearing , and the vestibular organs were selected 
 to be the subjects of this study .
the forty stroke patients were randomly divided into two 
 exercise program groups with one group using virtual reality training ( n=20 ) and another 
 group using a walking exercise program using a treadmill ( n=20 ) . age for the virtual reality 
 group , the age was 62.2  7.2  years old , the height was 162.8  6.7  cm , the weight was 58.1 
  5.4  kg , and the onset period was 30.4  5.4 months .
age for the treadmill group , the age 
 was 63.2  5.4  years old , the height was 164.7  7.5  cm , the weight was 60.2  4.5  kg , and 
 the onset period was 31.6  7.4 months .
the virtual 
 reality group underwent training using the wii - fit software by nintendo , japan . when playing 
 the nintento wii , the participants used wireless controllers to interact with the avatars on 
 the screen via the virtual reality motion detection system .
the controllers were attached by 
 acceleration detecting sensors responding to changes in direction and speed . due to the 
 detector being installed on the television ,
the screen showed the movements of the 
 controller just as the player performed the movements13 .
the virtual reality system used in this study was the wii board 
 balance system , in which users played games while the balancing board sensed weight shift 
 and distribution .
the subjects of the virtual reality group performed yoga , muscular 
 strength exercise , aerobic exercise , and balancing exercise , all for 10 minutes each for a 
 total of 40 minutes .
the treadmill group used low - speed treadmills for patients to directly 
 control their speed based on their walking ability while walking for 40 minutes .
the 
 treadmills were equipped with handles on the front and on both sides , which the users could 
 grip when they lost balance walking .
we used a pedoscan ( rsscan 1 m , germany ) to measure balance of the subjects .
the device 
 consisted of 4,096 sensors for measuring pressures on both feet in static standing , 
 computerizing left / right weight - bearing and anterior / posterior weight - bearing by separating 
 each area .
the patients were asked to stand up straight on the device without any movement 
 for 30 seconds .
the device was 
 attached to the dominant foot of a subject , measuring the anterior and posterior pressures 
 of the foot by the pressure detecting sensors on its insole .
the insole between the foot and 
 the board sensed the vertical reaction force to measure the stance phase , swing phase , 
 cadence of the dominant foot .
the measured signals were temporarily saved by the portable 
 compact controller attached to the ankle by receiving the walking data of the subject and 
 then were computerized and calculated . before the walking exercise
, the smart step insoles 
 were inserted in the shoes and were injected with air to maintain appropriate pressure . 
 after putting on the shoes and being attached to the controller on their ankles , the 
 subjects walked along a straight footpath for 10 meters , looking straight ahead .
a paired t - test was used for before and 
 after comparisons , and an independent t - test was used for a between group comparison with a 
 significance level of =0.05 .
for balance , there were significant differences in both the virtual reality group and the 
 treadmill group after completing of the exercise program .
for walking , the virtual reality 
 group showed significant differences after completing of the exercise program .
significant 
 differences between the groups were shown in balance after completing of the exercise 
 program ( table 
 1table 1.the comparison of balance and gait in virtual reality and treadmillperiodvirtual reality group ( n=20 ) treadmill group ( n=20)m  sdm  sdleft / right weight - bearing ( % ) pre17.1  5.516.9  6.5post10.6
 4.8**13.1  5.8*anterior / posterior weight - bearing ( % ) pre15.4  6.715.7  4.6post10.3  4.7**12.9  5.1*affected side stance phase ( % ) pre53.7  6.454.2  7.6post57.5  5.7 * 55.3  6.4affected side swing phase ( % ) pre46.2  6.445.7  7.6post42.4  5.7 * 44.6  6.4cadence ( steps / min)pre44.2  5.443.7  6.4post48.1  6.1 * 45.2  6.1*paired t - test , independent t - test , * p<0.05 , 
 * * p<0.01 ) . * paired t - test , independent t - test , * p<0.05 , 
 * * p<0.01
falling can occur in all age groups , but older people and patients show higher frequency of 
 falling . planned and consistent exercise is needed to prevent falling and strengthen 
 muscles , and exercises promoting weight bearing , resistance , and aerobic process are known 
 to be effective for such purposes14 . 

exercises for 
 lower limb muscular strength and balancing exercises are effective for the prevention of 
 falling and improvement of stamina of patients , but such exercises have some demerits 
 because the content is simple and thus boring .
to supplement the demerits , new methods of 
 exercise owing to development of scientific techniques have been recently introduced where 
 patients can perform various tasks in virtual reality15 , 16 .
therapeutic 
 intervention via virtual reality is more advantageous than other intervention methods in 
 that it can provide relatively easy environmental control , availability in selecting 
 environments , training based on patients abilities via phase - in task difficulty , rapid and 
 precise feedback on performing tasks , and self - learning in safe environment17,18,19 .
we applied an eight - week exercise program to stroke patients who were divided into a 
 virtual reality exercise group and a treadmill walking group , in order to investigate 
 effects of each exercise on balance and walking .
the results of measuring balance and walking effects as the purpose of the virtual reality 
 exercise program showed that significant differences were shown in all the domains of the 
 left / right and anterior / posterior weight - bearing in balancing and the stance phase , the 
 swing phase , and the cadence in walking . for the treadmill group
, significant differences 
 were displayed in the left / right and anterior / posterior weight - bearing in balancing . 
 although the walking exercise program using a treadmill showed significant differences in 
 balancing ability , the exercise program using virtual reality training displayed significant 
 differences in balancing and walking because the patients could directly adjust their weight 
 center and shift due to visual feedback .
in addition , various similar programs such as 
 jogging may further influence their balancing and walking .
the results of this study suggest 
 that virtual reality training may be appropriate to provide planned and consistent exercises 
 for stroke patients who need improved balance and walking ability by giving visual feedback 
 to induce their interest . meanwhile , the results of this study are consistent with those reporting increases in 
 left / right , anterior / posterior stability of stroke patients who performed of virtual reality 
 training , or reporting significant improvement in the berg balance test for the elderly who 
 underwent a training using virtual reality games20 .
in addition , there were researches in which significant 
 differences were observed in balancing ability of the elderly with their eyes open after 
 they underwent a virtual reality exercise program , or in which significant differences were 
 found in balancing ability of the elderly after an eight - week virtual reality exercise 
 program .
meanwhile , the increase in walking ability shown in this study was consistent with 
 the results of studies in which electrotherapy based on virtual reality significantly 
 increased walking speed of stroke patients , or in which exercise using visual feedback was 
 effective on the walking ability of stroke patients8 , 
 14 , 21 . in this study also , virtual reality training was effective in 
 producing positive improvements in balance and walking of stroke patients .
however , there remains insufficient research related to virtual reality because the 
 technology has not been fully commercialized yet .
further studies are needed to deal with 
 virtual reality for many patients to use it in performing various indoor exercise programs 
 and developing their abilities .
the results of this study may indicate that virtual reality training providing visual 
 feedback enables stroke patients to directly adjust their wrong weight center and shift 
 visually , and that it is appropriate for the patients who need improved balance and walking 
 ability by inducing their interest for them to perform planned exercise on a consistent 
 basis .
 [ purpose ] the purpose of this study is to investigate the effects of virtual reality 
 training using nintendo wii on balance and walking for stroke patients . 
 [ subjects and 
 methods ] forty stroke patients with stroke were randomly divided into two exercise program 
 groups : virtual reality training ( n=20 ) and treadmill ( n=20 ) . 
 the subjects underwent their 
 40-minute exercise program three times a week for eight weeks . 
 their balance and walking 
 were measured before and after the complete program . 
 we measured the left / right 
 weight - bearing and the anterior / posterior weight - bearing for balance , as well as stance 
 phase , swing phase , and cadence for walking . 
 [ results ] for balance , both groups showed 
 significant differences in the left / right and anterior / posterior weight - bearing , with 
 significant post - program differences between the groups . for walking , 
 there were 
 significant differences in the stance phase , swing phase , and cadence of the virtual 
 reality training group . 
 [ conclusion ] the results of this study suggest that virtual 
 reality training providing visual feedback may enable stroke patients to directly adjust 
 their incorrect weight center and shift visually . 
 virtual reality training may be 
 appropriate for patients who need improved balance and walking ability by inducing their 
 interest for them to perform planned exercises on a consistent basis . 
INTRODUCTION
SUBJECTS AND METHODS
RESULTS
DISCUSSION