stroke patients have characteristic walking patterns showing long gait cycles , low walking 
 speeds , differences in stride length between the affected side step length and the 
 unaffected side step length , and short stance phases and relatively long swing phases on the 
 affected side1 .
the recovery of walking 
 ability is an important element for the improvement of quality of life and the achievement 
 of functional independence in daily life , and is one of the most important goals not only 
 for patients , but also for therapists2 . for the walking rehabilitation training of stroke patients , body weight supported treadmill 
 walking training
previous studies have stated that body weight supported treadmill training is more helpful 
 for walking ability than walking training on the ground , because it extends the affected 
 side lower extremity s body weight support periods , enhances symmetric postures , and induces 
 constant activity patterns in the calf muscles4 , 5 .
body weight supported treadmill walking 
 training helps maintain proper postures , and these postures play a role in increasing body 
 weight support by the damaged lower extremity while providing more proprioceptive sense 
 information input6 . in general ,
although forward walking is widely performed as a method of walking training , 
 some studies have recently investigated the effects on stroke patients of backward 
 walking7 . in an exercise physiological 
 study , nadeau et al.8 reported that 
 backward walking and forward walking had different exercise physiological characteristics 
 and that the temporospatial characteristics of backward walking could increase the frequency 
 of , and endurance for walking . among the stroke patient - related studies of body weight supported treadmill walking 
 training , clinical studies have been conducted comparing treadmill walking training and 
 walking on the ground1 , 4 , 9 , increasing walking 
 speeds10 , intervention methods that 
 gradually increase the gradients of the treadmill to increase the intensity of training11 , whether treadmills should be used or 
 not12 , and speed - dependent treadmill 
 training methods13 .
however , studies of body weight support , walking speeds , and walking directions 
 related to body weight supported treadmill walking training for improving stroke patients 
 walking are still insufficient . to improve the effects of body weight supported treadmill 
 walking training , gradual increases in the degree of body weight support14 and walking directions7 , 15 
 are important .
in particular , with regard to the improvement of stroke patients walking , 
 existing body weight supported treadmill walking training is conducted with uniform training 
 parameters , such as forward walking and speed , making it difficult to change the stroke 
 patients walking patterns , and no studies have conducted body weight supported treadmill 
 training and forward and backward walking training simultaneously to investigate the 
 improvement of walking ability .
therefore , the purpose of this study was to examine the effects of progressive body weight 
 supported treadmill forward and backward walking training on changes in the stroke patients 
 affected side lower extremity s walking ability , and to examine the differences between 
 progressive body weight supported treadmill forward and backward walking training groups in 
 order to present diverse therapeutic protocols for improving stroke patients walking and 
 enhancing their functionality .
this study was conducted with 36 stroke patients in the rehabilitation center of a general 
 hospital located in korea as subjects . to minimize selection bias ,
the selection criteria were : patients who medically had 
 had stroke for at least six months ; had no joint contracture , pain , or fractures in their 
 musculoskeletal system , or hemianopia based on their medical records ; and had functional 
 gait index scores exceeding three points .
all subjects understood the content of the study 
 and voluntarily participated in the study .
walking tests were conducted using a walking analyzer ( optogait , microgates.r.l , italy , 
 2010 ) to collect data for the quantitative walking analysis of the patients walking 
 characteristics .
the temporospatial characteristics of walking that comprise affected side 
 step length , affected side stance phase , affected side swing phase , and affected side 
 walking time were analyzed . to remove inter - tester differences ,
the temporal symmetry index was calculated 
 using the formula : 2[(affected single - limb support  unaffected single - limb support ) / 
 ( affected single - limb support + unaffected single - limb support)]1007 , 16 , 17 the study was conducted over of six weeks from june to august 2013 .
progressive body weight 
 supported treadmill walking training was performed for three weeks , and the subjects were 
 evaluated after the three weeks of training . as a follow - up test , the subjects were 
 evaluated six weeks after the beginning of the training to examine the persistency of the 
 exercise effects .
the subjects were randomly divided into a pbwstfbwt group of 12 subjects , 
 a pbwstfwt group of 12 subjects , and a pbwstbwt group of 12 subjects , which performed their 
 respective regimes 30 minutes , six times per week .
the pbwstfbwt group performed forward and backward walking on treadmill while wearing a 
 suspension system , the degree of body weight support was progressively decreased from 40% of 
 body weight in the first week of the training program to 30% in the second week and 20% in 
 the third week4 , 18 , 19 .
the participants 
 average forward walking speeds ranged from 0.6 to 1.0  km / hr , and their average backward 
 walking speeds ranged from 0.4 to 0.9  km / hr .
the mean walking speeds of the pbwstfwt , 
 pbwstbwt , and pbwstfbwt groups were 0.710.20 , 0.750.31 , and 0.670.16  km / h , respectively , 
 and there were no significant differences among the groups .
the mean speed of forward 
 walking in the pbwstfwt group started at 0.710.20  km / h and ended at 0.850.22  km / h , and in 
 pbwstbwt group the mean speed of backward walking started at 0.570.17  km / h and ended at 
 0.670.16  km / h , and in pbwstfbwt group the mean speed of forward and backward walking 
 started at 0.670.16 and 0.530.09  km / h , respectively , and ended at 0.860.22 and 
 0.630.09  km / h , respectively .
the mean weight support during the intervention was 
 progressively reduced from 40 to 20% , decreasing 10% weekly . for the exercise intensity
, 
 individual gait speeds were changed at the same changes of body weight support .
the patients 
 initially selected a treadmill walking speeds that they considered appropriate while walking 
 on the ground , and when each patient could stably walk for 20 seconds or longer20 , the treadmill walking speed was increased 
 by 0.1  km / hr each time21 .
two physical 
 therapists participated in the training to help the subjects with the walking training .
one 
 physical therapist took a position right behind the subject to help the subject with proper 
 body weight support , and the other physical therapist took a position on the side of the 
 subject s affected leg to assist the subject s steps and control the lower extremity 
 movements during the swing and stance phases .
they manually corrected the subject s forward 
 walking patterns for 15 minutes and backward walking patterns for 15 minutes .
when a patient 
 showed fatigue , signs of pain , abnormality of breathing , or change in complexion after 
 beginning the walking training , a rest of five minutes was allowed22 .
the pbwstfwt group and the pbwstbwt group performed forward walking training for 30 minutes 
 and backward walking training for 30 minutes , respectively , and the other parts of their 
 training were implemented in the same way as for the pbwstfbwt group . all statistical analyses in this study were conducted using pasw statistics 18.0 for 
 windows . among the general characteristics of the three groups , sex , diagnoses , paretic 
 side , ankylosis , and
the homogeneity of the dependent variables , such as age , height , weight , and korean 
 mini - mental state examination scores , among the three groups were tested using one - way 
 analysis of variance ( anovas ) before the training .
repeated measures anova was conducted to 
 compare the differences between the first three weeks of the training and the three weeks of 
 follow up within each of the groups , and to compare the differences between pairs of groups 
 before the training , three weeks after the beginning of training , and six weeks after the 
 beginning of training .
the bonferroni test was used as a post - hoc test of the differences 
 between the groups , as analyses of covariance ( ancovas ) for the variables that showed 
 significant differences during the treatment period .
the general characteristics of the study subjects are shown in table 1table 1.the general characteristics of the subjects ( n=36)pbwstfbwt(n=12)pbwstfwt(n=12)pbwstbwt(n=12)age ( year)51.00  14.6052.75  9.2150.25  16.69onset ( months)11.33  3.7611.00  4.2211.83  3.46gendermale8 ( 66.7%)8 ( 66.7%)9 ( 75.0%)brain lesion locationcortex level1 ( 8.3%)1 ( 8.3%)subcortex level6 ( 50.0%)7 ( 58.3%)7 ( 58.3%)mixed5 ( 41.7%)4 ( 33.3%)5 ( 41.7%)affected sideleft6 ( 50.0%)6 ( 50.0%)4 ( 33.3%)right6 ( 50.0%)6 ( 50.0%)8 ( 66.7%)values are n ( % ) or mean  sd , ns = not significant , pbwstfbwt : 
 progressive body weight supported treadmill forward and backward walking training , 
 pbwstfwt : progressive body weight supported treadmill forward walking training , 
 pbwstbwt : progressive body weight supported treadmill backward walking training , 
 mixed= cortex level + subcortex level .
values are n ( % ) or mean  sd , ns = not significant , pbwstfbwt : 
 progressive body weight supported treadmill forward and backward walking training , 
 pbwstfwt : progressive body weight supported treadmill forward walking training , 
 pbwstbwt : progressive body weight supported treadmill backward walking training , 
 mixed= cortex level + subcortex level according to the results of this study , all three groups showed significant changes in the 
 characteristics of the affected side lower extremity after the 3 weeks of training 
 ( p<0.05 ) . in the comparison of the three groups , while the affected side stance phase , 
 affected side swing phase , affected side single support , and symmetry index did not show 
 significant differences , the affected side step length and affected side step time of the 
 pbwstfbwp group showed significant differences compared with the pbwstfwt and the pbwstbwt 
 group after the 3 weeks of training ( p<0.05 ) .
additionally , there were only significant 
 improvement of the affected side step length for all three groups during the follow - up 
 period and was a significant difference between the pbwstfbwtp and the pbwstbwt groups 
 ( table 2table 2.comparison of walking ability among the three groups ( n=36)grouppbwstfbwtppbwstfwtpbwstbwtmean  sdmean  sdmean  sdasl ( cm)0 week41.67  5.9741.44  8.5741.72  7.813 weeks48.64  5.0644.33  8.7044.88  9.726 weeks50.33  5.2546.62  7.9548.88  10.25astp ( % ) 0 week68.43  5.5368.56  4.7668.60  6.793 weeks65.93  3.5864.96  5.1165.19  6.476 weeks65.02  4.2964.87  5.3164.69  8.65aswp ( % ) 0 week31.58  5.5331.44  4.7631.39  6.793 weeks34.07  3.5835.04  5.1134.81  6.476 weeks34.98  4.2935.13  5.3135.31  8.65ass ( % ) 0 week32.23  7.2133.61  7.1932.66
 5.913 weeks36.10  4.4136.76  7.1837.19  3.986 weeks39.26  5.8537.37  6.3638.74  4.80ast ( sec)0 week1.26  0.331.25  0.281.27  0.313 weeks0.91  0.121.10  0.301.07  0.176 weeks0.90  0.091.09  0.291.05  0.16symmetry index0 week16.26  13.5016.06  12.0916.40  9.363 weeks8.51 
5.1010.77  5.0910.73  11.376 weeks7.56  7.219.05  3.159.02  11.53p<0.05 , significantly different from 03 weeks , 
 significantly different from 36 weeks , asl : affected side step length , 
 astp : affected side stance phase , aswp : affected side swing phase , ass : affected side 
 single support , ast : affected side step time .
post - hoc tests comparison was calculated 
 using bonferronis method .   significantly different from pbwstfbwt . 
  significantly different from pbwstfwt .   significantly 
 different from pbwstbwt .
p<0.05 , significantly different from 03 weeks , 
 significantly different from 36 weeks , asl : affected side step length , 
 astp : affected side stance phase , aswp : affected side swing phase , ass : affected side 
 single support , ast : affected side step time .
post - hoc tests comparison was calculated 
 using bonferronis method .   significantly different from pbwstfbwt . 
  significantly different from pbwstfwt .   significantly 
 different from pbwstbwt .
in this study , progressive body weight supported forward walking training and backward 
 walking training were performed by stroke patients , and we examined the effects of the 
 training programs on the patients walking abilities . according to the results , all three 
 groups showed significant changes at the end of the training period , and comparisons among 
 the three groups showed significant differences in the affected side step length and 
 affected side walking time . the affected side step length increased in all three groups . in the comparisons of the 
 three groups , the pbwstfbwt group showed more significant improvement than the other two 
 groups at the end of the three weeks of the treadmill training , and the pbwstfbwt and the 
 pbwstbwt groups showed more significant improvements than the pbwstfwt group at the end of 
 the follow - up period , six weeks after the beginning of the experiment .
these results are 
 consistent with the results of a study conducted by verma et al.23 who reported that 30 stroke patients , divided into two 
 groups for circuit task - oriented gait training , showed improvements in walking - related 
 parameters , such as stride length .
our results are also consistent with those of the study 
 conducted by yang et al.7 , in which 25 
 stroke patients were divided into an experimental group that performed general walking 
 training plus backward walking training for 30 minutes at a time , three times per week for 
 three weeks , and a control group that performed only general walking training .
the 
 experimental group s stride length increased from 0.78  m before the intervention to 0.88  m 
 after the intervention .
sousa et al.14 
 reported that when 12 chronic stroke patients performed walking training on the ground 
 without any body weight support or partial body weight support at self - selected speeds , the 
 walking speeds and symmetric stride length of the individual patients increased , a result 
 which is agreement with the results of our present study .
we think patients walking speeds 
 increased , because the patients muscle activities were increased by the movements of their 
 affected side lower extremity , and their mental states or self - confidence in walking 
 improved as a result the repeated walking training on a treadmill in a stable walking 
 environment .
also , we found a significant difference in affected side step length at the end 
 of the follow - up phase , possibly because a variety of tasks on the treadmill induced a 
 higher activation of the cortex .
accordingly , we think that the activation of the flexors 
 and extensors of lower limb through pbwstfbwt would elicit a higher center of gravity , which 
 would improve the step length . although the affected side stance phase , affected side swing 
 phase , and affected side single support increased in all three groups , comparisons among the 
 three groups showed there were no significant differences .
these results are consistent with 
 the results of the study conducted by devita and stribling24 who was reported that when the quadriceps muscles of the thigh 
 undergo eccentric contractions they require relatively more metabolism during backward 
 walking because of longer stance phase duration compared to forward walking .
also , in the 
 study conducted by lam et al.25 , stroke 
 patients performed body weight supported treadmill walking training with sandbags attached 
 to the affected side ankle weighing 5% of the patients body weight for 30 minutes per day 
 for 4 weeks .
the swing phase ratio of the affected side lower extremity increased from 34.2 
 to 39.4% and the ratio of the unaffected side stance phases improved from 75.4 to 69% .
the 
 repeated performance of body weight supported treadmill walking training increased 
 proprioceptive feedback through the sensory receptors on the sole , thereby improving lower 
 extremity extensor muscle strength and the central pattern generators .
the affected side walking time showed significant improvement at the end of the 3 weeks of 
 training in each of the three groups . in comparisons among the three groups , the pbwstfbwt 
 group showed a more significant improvement than the other two groups at the end of the 
 three weeks of training .
these results are consistent with the results of a study conducted 
 by roerdink et al.26 who reported that 
 when the frequency of auditory stimuli was increased during treadmill walking , stride time 
 and walking time decreased . in the study of yang
et al.7 , 25 stroke patients were divided into an experimental group that 
 performed general walking training plus backward walking training for 30 minutes at a time , 
 three times per week for three weeks , and a control group that performed only general 
 walking training .
the experimental group s stride time decreased from 1.96 sec before the 
 experiment to 1.62 sec after the experiment .
therefore , we consider that progressive body 
 weight supported walking training is an appropriate method for improving motor control 
 ability and reinforcing newly learned walking training , because it reduces the phenomenon of 
 foot dragging during the swing phase , thereby reducing the time that the affected side of 
 the lower extremity needs to stay in the air for the body weight to be moved , and it induces 
 repeated use of the muscles necessary for walking while the body s weight is supported .
the symmetry indexes increased in all three groups , but comparisons among the three groups 
 did not find any significant differences .
these results are consistent with the results of a 
 study conducted by combs et al.27 who 
 reported that when nine stroke patients and 22 healthy individuals performed body weight 
 supported treadmill walking training for eight weeks , the stroke patients group showed 
 larger changes in walking symmetry after the training . based on these results ,
we consider 
 that body weight supported treadmill walking training is a meaningful training method for 
 improving walking ability , because it reduces and adjusts the weight that must be borne by 
 the patient and supports the patient s trunk , so the patients can feel less fear while 
 trying to improve their ability to control their lower extremity movements .
the limitations of this study include the fact that the experimental groups daily lives 
 could not be completely controlled , the size of the experimental sample was small , and the 
 subjects were limited to stroke patients who could walk , making it difficult to generalize 
 the results . in summary , this study demonstrated that progressive body weight supported treadmill 
 walking training had a positive effect on stroke patients walking abilities , and that 
 implementing progressive body weight supported forward and backward walking training is more 
 effective at improving stroke patients affected side lower extremity walking abilities .
 [ purpose ] the purpose of the present study was to examine the effects of progressive body 
 weight supported treadmill forward and backward walking training ( pbwstfbwt ) , progressive 
 body weight supported treadmill forward walking training ( pbwstfwt ) , progressive body 
 weight supported treadmill backward walking training ( pbwstbwt ) , on stroke patients 
 affected side lower extremity s walking ability . 
 [ subjects and methods ] a total of 36 
 chronic stroke patients were divided into three groups with 12 subjects in each group . 
 
 each of the groups performed one of the progressive body weight supported treadmill 
 training methods for 30 minute , six times per week for three weeks , and then received 
 general physical therapy without any other intervention until the follow - up tests . 
 for the 
 assessment of the affected side lower extremity s walking ability , step length of the 
 affected side , stance phase of the affected side , swing phase of the affected side , single 
 support of the affected side , and step time of the affected side were measured using 
 optogait and the symmetry index . 
 [ results ] in the within group comparisons , all the three 
 groups showed significant differences between before and after the intervention and in the 
 comparison of the three groups , the pbwstfbwt group showed more significant differences in 
 all of the assessed items than the other two groups . 
 [ conclusion ] in the present study 
 progressive body weight supported treadmill training was performed in an environment in 
 which the subjects were actually walked , and pbwstfbwt was more effective at efficiently 
 training stroke patients affected side lower extremity s walking ability . 
INTRODUCTION
SUBJECTS AND METHODS
RESULTS
DISCUSSION