falls occur more often in women than in men , and the rate of falls in people older than 
 65  years is greater than 33%1 . falls are 
 affected by many causes ; for example , culture , sex , social services regarding health , 
 physical activities , healthy intake , drug intake , behavior that increases dangerous causes , 
 attitudes , fear of falls , treatment after falls , and personal factors , like race , social 
 environment , and economic strength , are factors affecting personal life and are taken as 
 having a negative effect on quality of life2 . however , these fall factors can be good prevention factors that 
 decrease danger of falls in the elderly3,4,5 . loss of muscle 
 strength in the weak elderly occurs more on the upper part of the body than the lower part ; 
 special knee supporting muscle strength shows a decrease , so that the body sways even when 
 standing with two feet supported on a bearing surface6 . in addition , gait is also affected , so that decrease in step 
 length , stride length , gait speed , and toe off and double support time increase . therefore , 
 elderly persons should increase muscle and maintain balance , and prevent falls through 
 experimental factors like exercise7 . research on fall prevention exercise for the elderly has been proposed , which includes 
 balancing exercise while standing on a hard and soft surface8 , resistive exercise that increases muscle strengthening exercise 
 using a thera - band9 , endurance exercise 
 riding on a stationary exercise bike10 , 
 and maintenance of a maintain static body posture that can improve flexibility , like 
 yoga11 and tai chi chuan , which is 
 effective for balance and motor sensation12 . however , all these studies suggest different methods , and there is 
 no typical method . the otago exercise program is composed of muscle strengthening , balance training , and 
 walking , which suggests a specific training method13 ; in an experiment using this training program , males and females 
 aged older than 70 were randomly divided into an experimental group and control group ; the 
 results showed an increase in balance , muscle strength , and falls percentage , and the danger 
 rate of falls was decreased14 . on the other hand , recent rehabilitation research has introduced a new rehabilitation 
 training method using various forms of tasks that fit the patient s personal purpose and is 
 performed using virtual reality and augmented reality ; the results showed significant 
 functional improvement15 , 16 . augmented reality provides reality and additional 
 information using external projection equipment17 combined with an imagine target , which turn increases the reality 
 effects , which increases feedback , making flexible imagined changes become reality and vice 
 versa18 . therefore , the treatment 
 environment when using augmented reality increases task complication gradually and also 
 helps in increasing the effects of the education19 . thus , this study was conducted in order to investigate the effect of application of 
 augmented reality - based otago exercise on the elderly for fall prevention and to provide 
 basal information . bmi , body mass index a total of 21 elderly women who voluntarily agreed to active participation were included in 
 this study . the selection criteria were sufficient cognitive ability to participate , as 
 indicated by a mini - mental state examination score of 24 or higher . the exclusion criteria 
 were 1 ) disabilities in visual , auditory sensation , and vestibular organs ; 2 ) defects in 
 extremities ; and 3 ) fracture in the past year . all of the subjects received an explanation 
 of this study and agreed to participate . a total of 21 elderly women were selected and 
 divided into an augmented reality - based otago exercise group , which included 10 subjects , 
 and an otago exercise group , which included 11 subjects ; exercise was performed for 12 
 weeks . general characteristics of the augmented reality - based otago exercise group and otago 
 exercise group are shown in table 1 . this study was conducted in order to provide an augmented reality environment for training 
 of elderly women , provide the graphic and vision - based web - camera recognition handling 
 technique , provide the vision and auditory expression technique for emotional feedback , 
 build up vision and auditory models and a recognition information database , and provide a 
 handling technique for situational perception and its reactions as a way of improving 
 balance , gait , and physical factors in falls ; in particular , real - time motion recognition 
 was performed using a preserved modeled movement for measurement of speed of the movement 
 and its accuracy . the first week of research started with a moderate intensity exercise 
 program that subjects could perform five times . subjects stood in front of a computer with a 
 web camera , which had an svga resolution ( 800  600 ) head - mounted display ( i - visor fx601 , 
 dae - yang e&c co , korea , 2008 ) and followed the movement displayed . the computer sensed 
 the movement of the subjects and sent the information to the head - mounted display in order 
 to repeat the task and move to the next level , which increased the speed . the muscle strengthening exercises 
 include knee extension exercise for front knee strengthening , knee flexion for back knee 
 strengthening , hip joint abduction for side hip strengthening , plantar flexion for calf 
 raises of the ankle , and dorsiflexion for toe raises of the ankle ; the balance training 
 includes backward walking , walking and turning around , heel to toe walking , one leg stand , 
 heel walking , toe walk , heel to toe walking backward , sit to stand , and stair walking . muscle training and balance training are performed for a period of 40 minutes each , three 
 times per week , according to the level of the subjects , and after the exercise , there was a 
 10-minute cooling down period13 . the bbs is a valid and 
 reliable instrument for measuring both the static and dynamic aspects of balance in elderly 
 people with stroke20 . bbs scores range 
 from 0 to 56 points , and the higher the score , the better the balance . gait function was measured using a gaitrite system ( gaitrite , cir systems inc . , the gaitrite system was used to measure spatiotemporal parameters , including gait 
 velocity , cadence , step length , and stride length . subjects were asked to walk at a 
 comfortable speed , without the use of an assistive device , along a 10  m hallway21 . fall efficacy was measured using the short falls efficacy scale - international ( fes - i ) 
 version , which is a tool for measuring confidence regarding prevention of falls . kempen et 
 al.22 selected seven items for the 
 short fes - i out of the 16 items of the fes - i . the spss statistical package , version 18.0 , was used in performance of all statistical 
 analyses . the 
 paired t - test was used to determine changes between before and after the balance test , gait 
 function , and falls efficacy test . the independent t - test p<0.001 differences in balance , gait , and falls efficacy after training are shown in table 2 . the bbs score showed a significant 
 increase , from a score of 47.605.36 before to a score of 53.702.50 ( p=0.000 ) after in the 
 augmented reality - based otago exercise group ; a significant difference , from a score of 
 48.914.53 to a score of 52.452.91 , was observed in the otago exercise group ( p=0.001 ) . gait parameters in the augmented reality - based otago exercise group showed significantly 
 increased gait velocity ( from 79.8313.22  cm / s to 99.1811.56  cm / s , p=0.001 ) , cadence ( from 
 100.799.92 steps / min to 116.738.81 steps / min , p=0.000 ) , left side stride length ( from 
 93.8810.18  cm to 100.259.91  cm , p=0.041 ) , right side step length ( from 46.784.67  cm to 
 50.555.13  cm , p=0.011 ) , and right side stride length ( from 93.6410.48  cm to 
 100.3910.07  cm , p=0.019 ) . the otago exercise group showed significantly increased gait 
 velocity ( from 90.2212.22  cm / s to 103.7612.83  cm / s , p=.001 ) , cadence ( from 107.928.69 
 steps / min to 118.557.67 steps / min , p=0.022 ) , left side step length ( from 51.125.68  cm to 
 53.436.84  cm , p=0.023 ) , and right side stride length ( from 100.6412.79  cm to 
 105.0514.02  cm , p=0.028 ) . the falls efficacy score for the augmented reality - based otago exercise group showed a 
 significant difference , from a score of 14.504.58 to a score of 11.803.71 ( p=0.019 ) ; 
 however , the otago exercise group showed no significant difference ( from a score of 
 12.366.23 before to a score of 11.184.53 after ) . this study examined the effect of augmented reality - based otago exercise on balance , gait 
 functions , and falls efficacy of elderly women . as one grows older , anatomically , 
 physiological aging and degeneration of proprioception and the vestibular system occurs . in 
 addition , muscle mass decreases and postural sway increases , so the reaction time of the 
 motor nerve becomes slower until changes ultimately occur in balance control , which 
 increases the frequency of falls24 . liu - ambrose et al.14 randomly divided 74 
 elderly people older than 70  years of age into an experimental group , which included 36 
 subjects , and a control group , which included 38 subjects . otago exercise was performed in 
 the experimental group for six months ; for static balance , postural sway showed a decrease , 
 from 360.3  mm to 305  mm , and dynamic balance , which was tested using the timed up and go 
 test , decreased from 14.2  s to 13.6 s. in addition , campbell et al.25 divided 233 elderly women into an experimental group , 
 which included 116 subjects , and a control group , which included 117 subjects . otago 
 exercise was performed for six months ; the 4-test balance score showed a significant 
 difference , from 0.42 to 0.01 ( p<0.05 ) . in this study , the bbs score for the augmented 
 reality- based otago exercise group showed a significant increase , from 47.60 to 53.70 
 ( p=0.000 ) ; a significant increase , from 48.91 to 52.45 ( p=0.001 ) , was observed in the otago 
 exercise group , corresponding to findings of previous research . this means that otago 
 exercise might affect improvement in the ankle strategy and hip strategy . in the ankle 
 strategy , the body can move as a single entity about the ankle when the foot muscle is 
 activated on the ground26 ; otago exercise 
 was helpful in walking , standing erect , control of the body when it moves in a small range 
 of area , and regaining balance when moving unconsciously . the hip strategy is used when the 
 body moves faster as the velocity increases along with the distance26 ; otago exercise helped walking posture with regard to 
 movement correction and muscle activation pattern and the helped with balance control with 
 regard to the base of support . finally , we assume that augmented reality is a medium for 
 helping the ankle and hip strategy by allowing individuals to visually compare the modeled 
 motion and self motion . an independent gait makes life productive , and is the most efficient method of moving from 
 one place to another27 . as the elderly 
 age , aerobic capacity , joint flexibility , muscle strength , and bone mass decrease , so that 
 gait velocity and cadence decrease , step length and stride length decrease , double leg 
 support time increases , and heel off and arm swing decrease , resulting in an unstable gait 
 pattern28 . binns29 divided women older than 80  years into an experimental 
 group , which included 19 subjects , and an control group , which included 18 subjects ; otago 
 exercise was performed in the experimental group for six months ; gait velocity increased 
 from 0.80 m / s to 1.10 m / s . in this study , the augmented reality - based otago exercise group 
 showed a significant increase , from 0.79.8 m / s to 0.99.2 m / s ( p=0.001 ) , which corresponded 
 with results of previous research . we assume that this is affected by backward walk , walking 
 and turning around , heel to toe walking , and stair walking in the otago exercise program . the subjects worked on speed , distance , direction , rhythm and muscle tone , and strength 
 while walking . in addition , through stair walking , the subjects practiced with a fixed foot 
 support , acceleration , balance control , extension and contraction of the lower limb , and 
 ankle dorsiflexion to move the center of gravity to control the afferent , efferent , and 
 contraction of the lower limb muscles . as a result , coordination and weight shifting were 
 learned through movement of the lower limbs , and this improvement resulted in an increase in 
 step length of the right lower limb and stride length of both lower limbs , thereby improving 
 gait velocity and cadence . self - efficacy is the self - belief or capability to create a plan and implement it . this 
 efficacy also affects elderly , and decreases as people grow older , and it can be a hazardous 
 factor for falls5 ; in addition , fear , 
 which is the most significant complication of falls , should be regarded as an important 
 matter30 . campbell et al.31 divided 233 women older than 80  years of 
 age randomly into an experimental group , which included 116 subjects , and a control group , 
 which included 117 subjects ; otago exercise was performed in the experimental group for six 
 months ; fall efficacy showed a significant difference , from 93.3 to 91.9 ( p=0.009 ) . two 
 years later , campbell et al.31 traced 41 
 subjects in the experimental group , and 61 subjects in the control group and found that the 
 falls efficacy changed from 91.0 to 89.4 , which was statistically significant ( p=0.03 ) . in 
 this research , the falls efficacy in the augmented reality - based otago exercise group showed 
 a significant difference ( p=0.019 ) , from 14.50 to 11.80 , which corresponded with the 
 previous research . this was the result of repeated training with the augmented reality 
 program and the head - mounted display , which isolated the subjects from the external 
 environment in order to increase concentration . thornton et al.32 have shown that virtual reality participants had greater 
 improvements in quantitative measures and made more comments expressing enjoyment and 
 improved confidence . an augmented reality environment can provide users with direct visual 
 feedback to control their movement and watch their own movement at the same time33 . it implies that otago exercise based on 
 augmented reality can draw a user s interest and influence the falls efficacy . in addition , 
 the improved gait of subjects in the augmented reality - based otago exercise group resulted 
 in increased mobility , which helped in performance of activities of daily living and social 
 activities and was also related to positive physical activity . in this study , we assume that 
 the augmented reality program represented repeated feedback , and the otago training 
 represented a goal of the subjects , which they could achieve by succeeding at each level , 
 and that self - pride increased . the increase in self - pride was related to self - efficacy , 
 which leads to an increase in falls efficacy . therefore , repetitive training using the 
 augmented reality - based otago exercise for fall prevention leads to a decrease in the fear 
 of falls in elderly women and even changes their behaviors . this research showed that augmented reality - based otago exercise is effective for improving 
 balance , gait , and falls efficacy of elderly women and that application of augmented 
 reality - based otago exercise is meaningful . we expect that this augmented reality - based 
 otago exercise will be used in elderly care centers as a physical therapy for effective 
 training for balance , gait , and falls efficacy , and it could be used as a database for 
 rehabilitation . we also hope that augmented reality - based rehabilitation research will be 
 conducted continuously .
[ purpose ] the purpose of this study was to determine the effects of augmented 
 reality - based otago exercise on balance , gait , and falls efficacy of elderly women . 
 [ subjects ] the subjects were 21 elderly women , who were randomly divided into two groups : 
 an augmented reality - based otago exercise group of 10 subjects and an otago exercise group 
 of 11 subjects . [ methods ] all subjects were evaluated for balance ( berg balance scale , 
 bbs ) , gait parameters ( velocity , cadence , step length , and stride length ) , and falls 
 efficacy . within 12 weeks , 
 otago exercise for muscle strengthening and balance training 
 was conducted three times , for a period of 60 minutes each , and subjects in the 
 experimental group performed augmented reality - based otago exercise . [ results ] following 
 intervention 
 , the augmented reality - based otago exercise group showed significant 
 increases in bbs , velocity , cadence , step length ( right side ) , stride length ( right side 
 and left side ) and falls efficacy . [ conclusion ] 
 the results of this study suggest the 
 feasibility and suitability of this augmented reality - based otago exercise for elderly 
 women .