stroke generally leads to greater postural instability , a shift of balance to the 
 non - paralyzed side , an asymmetrical posture , and muscle weakening compared with healthy 
 individuals1 .
this is usually a result 
 of neurological damage to the sensory and motor processes of the postural control system , 
 which leads to a decline in the awareness of physical balance required to maintain a precise 
 orientation of the trunk2 .
such postural 
 control deficits following stroke impair walking ability and interfere with a functionally 
 independent lifestyle ; furthermore , they cause a high risk of falling , because of 
 impairments in voluntarily shifting the center of mass during the performance of activities 
 of daily living and everyday tasks3,4,5 .
neurological damage to sensory and motor processes has a negative effect on activities of 
 daily living . in order to minimize this ,
stroke patients receive diverse rehabilitation 
 therapies to improve their ability to lead a functionally independent lifestyle6,7,8 .
in particular , the loss of balance control 
 in stroke patients resulting from loss of trunk control leads to declining motor function in 
 the upper and lower limbs on the paralyzed side , leading to secondary impairments , such as 
 in walking9 , 10 , thereby requiring recuperative training to increase trunk control 
 and improve balance and walking ability .
the movement of bending the trunk forwards while keeping the arms extended has been used in 
 clinical rehabilitation as postural control training for tasks , and clinical therapists have 
 attempted to develop  reach for taget activities to help stroke patients adapt their 
 posture after paralysis .
this can promote postural movements in stroke patients according to 
 the position of the target to be reached and the distance and direction , and so it is 
 assumed to improve the ability to solve daily postural difficulties11 . in stroke patients , performing external tasks , such as 
 reaching for a target while considering direction and distance , promotes sensory and motor 
 performance , and by finding ways to adapt to changes in posture , these exercises can improve 
 posture and prevent falling12,13,14 .
several researchers have studied the effect of target distance ( near vs. far in the 
 sagittal plane ) when performing the action of bending forwards and extending the arms in 
 postural activities14,15,16 .
functional movements , 
 such as moving the torso while extending the arms , require movements of the trunk17 , so they can help to develop the trunk 
 muscles in hemiparesis patients18 , 19 , while actions that require extending the 
 arms to touch external targets in different directions and distances have been found to 
 improve sensory processes and adaptation to postural changes12,13,14 .
the aims of this study were to implement training in chronic stroke patients involving 
 extending the arm in a seated or standing position while varying the direction and distance 
 of the target in relation to the frontal and sagittal planes and to investigate the effects 
 of this training on trunk control , dynamic balance , and walking .
the subjects in this study were 23 patients who were diagnosed with hemiparesis resulting 
 from chronic stroke , and were receiving physical therapy at e hospital in seoul , republic of 
 korea ( table 1table 1.general characteristics of the subjects ( n=26)fbr ( n=10)control ( n=13)age ( yrs)59.87.959.110.4height ( cm)165.49.9166.910.4weight ( kg)64.012.261.911.0paretic side ( right / left)4/67/6duration ( months)16.37.317.010.0meanstandard deviation ) . the study was performed in 
 accordance with international ethical guidelines and declaration of helsinki and was 
 approved by a local institutional review board .
the selection criteria were as follows : more 
 than six months since stroke , so as to minimize the effects of natural recovery ; ability to 
 follow and understand the researcher s instructions and sufficient cognitive ability as 
 demonstrated by a score of over 24 points on the mini - mental state examination - korean 
 ( mmse - k ) ; ability to walk at least 10 m , irrespective of the use of assistive tools ; and 
 sufficient eyesight to perform the exercises .
meanstandard deviation the subjects were divided randomly into a forward bending of the trunk and reaching ( fbr ) 
 group and a control group .
pre - testing was conducted before training and post - testing was 
 conducted after training .
the fbr group and control group both underwent the same ordinary 
 rehabilitation therapy of five 30-minute sessions a week for four weeks , while the fbr group 
 additionally underwent fbr training , which involved four sets of pressing a button 35 times 
 for a total of 140 presses per session , five sessions a week , for four weeks .
for the fbr training group , we adapted the movements from the experiment of chern et al . 
 with modifications .
using superlap 2.04 ( cedrus , san pedro , ca , usa ) , the patients performed 
 random button pressing training by watching a laptop screen and pressing six buttons ( 3 
 directions  2 distances ) on a table set at knee - height .
the laptop was placed on top of the 
 table at an adjustable height , so that the exercise could be performed while watching the 
 laptop screen . after setting the height of the table to the subject s knee height , the 
 distances to the buttons
were set at 10% and 30% of the subject s height , and the directions 
 were set at straight ahead and 45 to either side of the midline .
the buttons were connected 
 to the laptop running superlap program , and each button was fixed to the table at one of the 
 six locations ( 2 distances  3 directions ) .
the laptop screen depicted six circles on a white background , with the positions of the 
 circles corresponding to those of the buttons on the table .
when a button turned red , the 
 subject was to press the corresponding button on the table and then stand upright . each time 
 circle turned red , which occurred in random order , the subject was to press the 
 corresponding button on the table and then stand upright .
the training program was conducted 
 for four weeks , five sessions a week , with each session consisting of four sets of 35 button 
 presses , for a total of 140 button presses per day .
the experiment was conducted for a total 
 of six weeks , with both groups undergoing assessment three days before and after 
 training . in order to assess the stroke patients trunk impairments
, we used the trunk impairment 
 scale ( tis ) , which has proven reliability and validity7 .
it is composed of 17 items , and is a tool used to assess static and 
 dynamic control and coordination of the trunk in a seated position , in which posture can be 
 assessed for trunk movement disorders .
static balance consists of three items and has a max 
 score of 7 points , dynamic stability consists of ten items and has a max score of 10 points , 
 and coordination consists of four items and has a max score of 6 points ; the max total score 
 is 23 points .
, we used the berg balance scale ( bbs ) , which has high 
 intra - rater and inter - rater reliability20 .
the assessment items consist of three domains , sitting , standing , 
 and postural change . with a minimum of 0 points and a maximum of 4 points for each of the 14 
 items ,
the timed up and 
 go ( tug ) test is an instrument with proven intra - rater and inter - rater reliability and can 
 quickly measure functional mobility , movement capability , and balance .
it involves measuring 
 the time to get up from a chair with armrests , walk forward 3 m , turn around , walk back to 
 the chair and then sit back down in the chair21 .
this study performed the six - minute walking test to evaluate the level of movements and 
 endurance whilst walking .
in the six - minute walking test , subjects repeat walking 30  m in a 
 straight line to cover the greatest distance possible in six minutes . walking speed and
rest 
 time were left for the individual to control in keeping with their own ability . in order to 
 eliminate confounding errors from motivational stimulation during walking ,
the only words 
 spoken were the remaining time and a phrase allowed by the guidelines : 
the subjects walked a total of 13  m at the speed that 
 they felt was most stable and comfortable , and the time required to traverse the middle 10  m 
 was measured , excluding the 1.5  m at the start and end - points . to analyze the collected data , this study used spss ver .
for 
 the subjects general characteristics , we used descriptive statistics . in order to 
 investigate intergroup differences
, we performed a mann - whitney u test , and in order to 
 compare pre - afe training and post - training results in both groups , we performed a wilcoxon 
 signed - rank test .
in the tis , the fbr group showed a significant improvement after training ( p<0.05 ) , 
 whereas the improvement in the control group was not significant .
after the experiment , the 
 amount of change in the tis between the two groups was significant ( p<0.05 ) . in the bbs 
 and tug examinations ,
the fbr group showed a significant improvement in the bbs after 
 training ( p<0.05 ) , and a significant decrease in time in the tug examination ( p<0.05 ) . 

the difference 
 in change between the two groups was significant for the bbs but not for the tug .
for the 
 six - minute walking test and the 10-meter walking test , the fbr group only showed a 
 significant improvement in the six - minute walking test .
after the experiment , the amount of 
 change in the six - minute walking test between the two groups was significant ( p<0.05 ) . 

the control group showed no significant difference in either test , and the difference in 
 change between the two groups after the experiment was not significant for the 10-meter 
 walking test ( table 2table 2.comparison of tis , bbs , tug , six - minute walk and 10-meter walk results within 
 groups and between groups ( n=23)valueschange valuesfbr ( n=10)control ( n=13)fbrcontrolbeforeafterbeforeaftertis11.73.815.64.0 * 14.02.613.73.13.92.50.32.1bbs37.36.544.46.3 * 36.28.136.38.07.13.90.11.4tug34.322.130.018.0 * 26.713.127.515.84.85.50.87.86mwt134.377.2152.381.7 * 184.7107.8186.3104.818.19.51.619.610mwt29.620.428.917.226.514.026.913.30.76.90.45.3meanstandard deviation tis : trunk impairment scale ; bbs : berg balance 
 scale ; tug : timed up and go test ; 6mwt : 6 minute walk test ; 10mwt : 10-minute walk 
 test*significantly different from before ( p<0.05)significantly different from control ( p<0.05 ) ) .
meanstandard deviation tis : trunk impairment scale ; bbs : berg balance 
 scale ; tug : timed up and go test ; 6mwt : 6 minute walk test ; 10mwt : 10-minute walk 
 test * significantly different from before ( p<0.05 ) significantly different from control ( p<0.05 )
in stroke patients , the decline in balance and control of posture causes difficulties in 
 maintaining stability and in motor functions9 , 25 .
accordingly , rehabilitation therapy is 
 required for improving balance and postural control in patients with hemiparesis following a 
 stroke . in this study
, we divided stroke hemiparesis patients into a group performing 
 ordinary physiotherapy and fbr training five times a week for four weeks and a group 
 performing only ordinary physiotherapy , to investigate the effects of fbr training on trunk 
 control , dynamic balance , and walking .
the movement of reaching out an arm towards a target varying in distance and direction 
 during the performance of everyday tasks requires adaptation of postural changes through the 
 action of the nervous and musculoskeletal systems in order to maintain a stable dynamic 
 posture12,13,14 .
voluntary movement of 
 the upper limb when sitting or standing provides stability to the center of the trunk26 . according to the results of this study , the group that underwent fbr training showed a 
 significant increase of 3.9 points in the tis , from 11.703.77 points before training to 
 15.604.01 points after training , meaning that trunk control improved significantly .
the 
 control group that only underwent ordinary physiotherapy did not show a significant 
 increase , and when the before - after change was compared between the two groups , the fbr 
 training group showed a significantly greater change .
regarding dynamic balance , the fbr 
 training group showed a significant increase in the bbs from 37.306.53 points before 
 training to 44.406.26 points after training , while it showed a significant decrease in the 
 tug test , from 34.2922.05 point before training to 30.017.95 points after training .
the difference in 
 before - after change between the training and control groups was significant only for the 
 bbs .
activation and strengthening of the trunk muscles is required for functional recovery of 
 impaired trunk control in stroke patients27 .
functional movements , such as extending the arm , have been shown 
 in previous studies to improve trunk movements and muscle strength in hemiparesis patients 
 because they require movement of the trunk17,18,19 . 
 among assessments of trunk control ,
the tis consists of items evaluating coordination when 
 emphasizing lateral rotation of the pectoral girdle and the pelvis , and the separate upper 
 and lower limb movements that follow from this8 .
the training in this study , bending the trunk forwards and reaching 
 out the arm straight ahead , 45 to the right or 45 to the left , to press a button in a 
 horizontal plane , involved lateral movements of the trunk through rotation of the pelvis and 
 pectoral girdle and simultaneous separate movements of the upper and lower limbs , such as 
 reaching out with the upper limb and squatting with the lower limbs .
this is similar to the 
 items in the tis examining at coordination , and the significant improvement that the fbr 
 training group showed in the tis before and after training is thought to indicate 
 improvement in trunk control resulting from improved movement and strength of the trunk 
 muscles .
the movement of extending the arm while using the whole trunk is similar to the movement of 
 extending the arm forwards from a squat position15 .
this is a position that requires dynamic balance , like postures 
 commonly required in everyday life , such as using the toilet , sitting on a chair , walking 
 down stairs , and picking up an object from the top of a shelf28 . in a study by yao29 , stroke patients with large movements in center of pressure 
 trajectory were reported to have higher bbs scores , and in a study by chern et al .
, bbs 
 scores were also reported to be higher for stroke patients performing dynamic movements that 
 used the whole trunk , such as arm extension , compared with maintaining a static posture . 
 with similar training movements to those used in this study ,
there was no significant 
 increase in bbs in the control group before and after training , but in the fbr group showed 
 a significant increase in bbs and a significantly greater before - after change compared with 
 the control group , demonstrating that dynamic balance improved .
there was no significant 
 decrease in the tug test in the control group before and after training , but there was a 
 significant decrease in the fbr training group .
this is similar to the results of a study by 
 karatas et al.30 , in which dynamic 
 balance improved with improved strength of the trunk flexion muscles . in the training for 
 this study , when bending forwards and extending the arm , movement of the trunk flexion 
 muscles was required , and in the tug test31 , abdominal and trunk rotation muscles were required to walk 3 m , 
 turn around , return to the original position , and sit down . in the training for the current 
 study , bending forward and extending the arm for each of the 140 presses required flexion 
 and rotation of the trunk .
the significant decrease of the fbr training group in the tug 
 test , which assesses dynamic balance , demonstrates an improvement in dynamic balance . in the walking tests , the fbr training group showed a significant improvement in the 
 six - minute walk test from 134.30  m before training to 152.30  m after training , but the 
 control group did not show any significant difference . in 10-meter walk test , neither the 
 fbr training group nor the control group showed a significant difference , but the time 
 required to walk 10  m decreased in the fbr training group .
the six - minute walk test reflects 
 endurance in walking and is used to assess patients with limited walking ability due to 
 stroke , including that resulting from muscular weakness , stiffness , and impaired control and 
 balance in the lower limb22 , 32 .
the movement of extending the arm forwards from a 
 squatting position , like in this study , requires simultaneous movement of the trunk and 
 lower limbs , so it can increase trunk movements and lower limb muscle strength in stroke 
 patients , making symmetrical movements of the body easier17,18,19 .
hausdorff et al.33 reported that asymmetrical movements when walking can increase 
 energy consumption and that increases in symmetrical movements in stroke patients reduce the 
 effort required to walk , so these movements can improve walking ability . in relation to 
 this , after training , patients showed a significant increase in endurance during walking , 
 and walking speed also increased , although this increase was not significant . because this study was conducted on only a limited group of hemiparesis patients , it has 
 limitations in terms of generalization to all hemiparesis patients .
the small number of 
 patients and the lack of sufficient control for other movements in the subjects daily lives 
 outside of training are also possible confounding factors of this study . in the future , more 
 research will be required to investigate the clinical improvement effects of fbr on trunk 
 control , dynamic balance , and walking .
 [ purpose ] the objective of this study was to perform forward bending of the trunk and 
 reaching training in chronic stroke patients and to investigate subsequent changes in 
 trunk control , dynamic balance , and gait . 
 [ subject ] twenty - three chronic stroke patients 
 were randomly divided into two groups , with 10 patients in the forward bending of the 
 trunk and reaching group and 13 patients in the control group . 
 [ methods ] both groups 
 underwent 30 minutes of rehabilitation therapy , five days a week , for four weeks . 
 the 
 forward bending of the trunk and reaching group additionally performed forward bending of 
 the trunk and reaching training five times a week for four weeks , which involved four sets 
 of pressing buttons 35 times , for a total of 140 button presses per session . 
 the subjects 
 were tested before and after training using the trunk impairment scale , berg balance 
 scale , timed up and go test , six - minute walking test , and 10-meter walking test . 
 trunk 
 control , dynamic balance , and walking ability were compared between the two groups . 
 
 [ result ] the results of the study showed that the results of the trunk impairment scale , 
 berg balance scale , timed up and go test , six - minute walking test improved significantly 
 in the fbr group , while there were no significant differences in the control group . 
 
 [ conclusion ] this study results suggest that forward bending of the trunk and reaching 
 training can be an effective exercise method for chronic stroke patients . 
INTRODUCTION
SUBJECTS AND METHODS
RESULTS
DISCUSSION