due to the loss of the central nervous system s ability to control the paretic side , stroke 
 patients show excessive muscle tone , such as spasticity and loss of proprioceptive and 
 equilibrium senses1 . in particular , carr 
 and shepherd2 reported that stroke 
 patients have disorders in standing and gait due to asymmetric postures , abnormal body 
 balance , and the loss of certain motor abilities . in the human body , in particular , the hip joints mainly act when the range of body sway is large , 
 and the ankle joints mainly act when the range of body sway is small3 . the most important roles of the ankle joints and the feet 
 are in controlling body sway and forward movements of the lower extremities , and these roles 
 require a sufficient range of motion , muscle strength , and proprioceptive sense in the ankle 
 joints4 . regarding the effects of functional electrical stimulation treatment , achache et al.5 reported that when functional electrical 
 stimulation was applied to the dorsal flexor muscle of the ankle joints , increased muscle 
 activity improved muscle strength . this led to the enhancement of the stability of the knee 
 joints , which had positive effects on balance . in addition , sabut et al.6 reported that when functional electrical 
 stimulation was applied for 12 weeks , the activity of the anterior tibial muscle increased 
 and energy consumption decreased by 34.6% . regarding the reason that ankle muscle strength is necessary to maintain balance , macrae et 
 al.7 stated that according to the 
 results of tests of seven lower extremity muscles , the ankle dorsal flexor muscle was the 
 best predictive factor for the prediction of falls . in addition , lord et al.8 advised that one of differences between 
 no - fall groups and those who experienced falls was the muscle strength of the ankle dorsal 
 flexor muscle . the retraining of the movements of the ankle joints that control body balance plays as 
 important role in solutions to problems in balance control , and it mitigates problems such 
 as abnormal forms of muscle control of the ankle joint , joint contracture over a long 
 period , and proprioceptive sense disorders9 . to improve stroke patients balance ability that has deteriorated 
 due to ankle instability and proprioceptive sense declines , the stability of the ankles 
 needs to be restored through ankle muscle strengthening10 . studies that have simultaneously applied functional 
 electrical stimulation treatment , proprioceptive sense treatment , and ankle muscle 
 strengthening exercises in an ankle training program for stroke patients are rare . as noted above , to improve stroke patients balance ability , the ankle muscles need to be 
 strengthened and the proprioceptive sense needs to be recovered . therefore , the purpose of 
 the present study was to examine the effects of approaches to ankle joint treatment on 
 balance ability . the study focused on that the factors affecting stroke patients balance , 
 the loss of the ankles proprioceptive sense , and ankle muscle weakening , in order to 
 determine diverse protocols for stroke patients balance improvement and functional 
 enhancement . the subjects were 22 stroke patients in the rehabilitation center of a general hospital 
 located in korea . the selection criteria were : first - time stroke , at least 6 weeks 
 post - stroke , a mini - mental state examination score 24 , and no serious visual disorder , 
 visual field defect , or hearing impairment based on the opinion of the doctor in charge , all 
 subjects understood the content of the study and voluntarily participated in the study . the 
 exclusion criteria were : severe hemineglect , pregnancy , or prior adverse reaction to 
 functional electrical stimulation ( fes ) . this study was approved by the institutional human 
 research review board of sahmyook university . to minimize the selection bias of group division , the subjects drew ox lots and those who drew o were assigned to the group 
 receiving the application of fes , ankle muscle strengthening exercises , and ankle 
 proprioceptive exercises , the fps group , while those who drew x were assigned to the fp 
 group . a preliminary evaluation was conducted before the experiment and an ex post facto 
 evaluation was conducted at three weeks and six weeks after the start of the experiment . fps group received fes for 30  min , and performed ankle proprioceptive exercises for 15  min , 
 and an ankle muscle strengthening exercise program for 15  min in 60-minute sessions , five 
 times per week for six weeks . fes was applied as a square waveform with a pulse width of 400 s and a stimulation 
 frequency of 40  hz . to induce accurate movements of the muscles , the stimulation intensity 
 was adjusted to 3070 ma at the common peroneal nerve through observations by the therapist . the subjects performed ankle dorsiflexion movement during functional electrical stimulation 
 producing muscle contraction delivered via surface electrodes . the stimulation increase and 
 decrease times were set to 0.3  s , and to minimize muscle contraction and fatigue due to the 
 subjects excessive efforts , the electrical stimulation given to patients was restricted to 
 below the threshold value11 . the ankle 
 proprioception exercise program was designed by modifying and supplementing the method 
 proposed by lynch and grison12 and the 
 details are as follows : ankle joint mobility was promoted in a sitting position , an exercise 
 to move the weight toward the paretic side and get up was repeatedly performed , the weight 
 was moved in various directions in a standing position , and upper extremity task training 
 was performed in a standing position . the subjects lay in a supine position on 
 a bed and performed dorsal flexion of the ankle joint with 2030% of the total muscle 
 strength that could be mobilized by the subject . in addition , the therapist provided 
 counter - pressure equal to the pressure of the subject s ankle joint dorsal flexion using 
 manual resistance so isometric contraction could occur in the muscle anterior to the tibia . this exercise was performed three 
 times repeatedly with a rest of 10  s after each trial . during the trials , the therapist 
 helped the subject so that accurate movements could be made without the occurrence of 
 compensation by the ankle joint14 . ankle 
 dorsiflexion , ankle plantarflexion , ankle eversion , and ankle inversion were performed for a 
 total of 15  min . the fs group received fes for 30  min and performed ankle stretching exercises for 30  min in 
 60-minute sessions , five times per week for six weeks . for the stretching exercises , the subjects were instructed to apply force toward the sole 
 in a prone position and the therapist applied the same level of force in the opposite 
 direction to maintain isometric contraction for 6 s. while the subject relaxed the muscle 
 for 23  s after the contraction , the therapist extended the length of the muscle for further 
 stretching . at this time , the therapist s hands moved to the point where the hands were 
 stopped by the muscle , and the position was maintained for 1516 seconds . the subjects were 
 instructed to maintain the relaxed state and to take a rest for 10 s. this exercise was 
 performed repeatedly for a total of 15  min15 . thereafter , the subjects held the therapist s hand in a standing 
 position , leaned against a wall , stood on a tripod , and performed stretching for 15  min with 
 the ankle joints at 1520. a rest was allowed when the patient felt pain or needed a rest 
 and the exercise was performed again thereafter . in the present study , a balance ability measuring and training system ( analysis systems by 
 biofeedback , ap1153 biorescue , france ) was used to measure subjects balance ability . the 
 measuring method was demonstrated to the subjects before measuring their balance ability . 
 with their eyes open and eyes closed , the romberg test , the measured the migration length of 
 the center of gravity ( cog ) and the surface area while standing on the force plate with both 
 feet was measured for 60 s. the unit of the migration length of the cop was  cm and that of 
 the unit of surface area was mm . in this evaluation , smaller values mean less 
 sway , which indicates a better balance ability . in the limit of stability ( los ) test , the 
 cop was moved in eight directions ( forward , backward , leftward , rightward , and diagonally ) 
 using a biorescue software program , and the movement area was recorded in  cm in 
 this test , direction arrows randomly appear on the computer screen and subjects move their 
 cop in the arrow direction . both feet have to be placed on the force plate at all times , and 
 when subjects lifted a foot off the force plate , the measurement was conducted again from 
 the beginning . the forward and 
 backward ( fb ) test measures the length of migration of the cop while subjects move the 
 non - paretic side foot to the front of the force plate in a standing position supported by 
 two feet and then move it back to the original position ; smaller measured values indicate 
 better balance ability . the fb test was conducted three times for each study subject and the 
 average values were used in the analysis . for the functional reach test ( frt ) , the subjects adopted a standing position on a fixed 
 surface with the feet shoulder width apart and maximally stretched out an arm while 
 maintaining the arm horizontal to a bar ruler installed horizontally . with the first 
 clenched and the elbow joint extended subjects bent forward as far as they could without 
 losing balance . then , the distance between the first point and the last point of the distal 
 part of the third metacarpal bone was measured . the measurement was conducted three times 
 for each study subject and the average values were used in the analysis . for this test an 
 intra - rater reliability of r = 0.98 and an inter - rater reliability of r = 0.99 have been 
 reported16 . the berg balance scale ( bbs ) is a tool for measuring the balance of elderly persons with 
 damaged balance functions . it evaluates their ability to perform functional tasks and the 
 tasks are largely divided into three areas : sitting , standing , and postural changes . fourteen items are scored from 0 to 4 and thus , the maximum possible score is 56 points . this test is used to measure the ability to maintain dynamic balance and it is widely used 
 to measure the balance ability in movements or standing positions of patients with 
 hemiplegia due to a senile disease or stroke . this test is highly reliable for the 
 measurement of balance and it has been reported to have an intra - rater reliability of r = 
 0.98 and an inter - rater reliability of r = 0.9717 . the timed up - and - go ( tug ) test is used to evaluate simple functions by measuring the time 
 it takes to get up from a chair , walk to a turning point at a distance of 3  m from the 
 chair , and return , and sit on the chair . each subject completed the tug test three times , 
 and the average value was calculated . the test - retest reliability of the tug test for stroke 
 patients is reported to be high , r = 0.9518 . all statistical analyses in this study were conducted using pasw 18.0 for windows . for the 
 general characteristics of the two groups , the  test was used to analyze 
 ankylosis , sex , diagnoses , and the side of brain lesions . the patients heights , weights , 
 mini - mental state examination scores , and time since the onset of stroke were analyzed using 
 the independent samples t - test . normality was tested using the shapiro - wilk test . repeated 
 measures anova was conducted to examine differences within the two groups among the 
 treatment times ( zero , three , and six weeks of training ) and to examine differences between 
 the two groups resulting from the therapeutic exercise methods before the training , after 
 three weeks training , and after six weeks training . a statistical significance level of  
 = 0.05 was used in all tests the general characteristics of the study subjects are shown in table 1table 1.the general characteristics of the subjects ( n=22)group variablefs ( n=11)fps ( n=11)age ( years)54.9  14.049.0  13.1height ( cm)165.2  5.2166.3  2.8weight ( kg)70.0  11.066.1  9.6mmse - k ( score)27.1  1.627.5  1.9gendermale8 ( 72.7%)6 ( 54.5%)female3 ( 27.3%)5 ( 45.5%)brain lesion locationcortex level2 ( 18.2%)2 ( 18.2%)subcortex level5 ( 45.5%)4 ( 36.4%)mixed4 ( 36.4%)5 ( 45.5%)diagnosisinfarction7 ( 63.6%)7 ( 63.6%)hemmorhage4 ( 36.4%)4 ( 36.4%)affected sideleft6 ( 54.5%)8 ( 72.7%)right5 ( 45.5%)3 ( 27.3%)values are n ( % ) or mean  standard deviation , ns : not significant , fs : fes with 
 stretching exercise group , fps : fes with proprioception and strengthening exercise 
 group , mmse - k : mini - mental state examination - korea , mas : modified ashworth scale . 
 general characteristics and dependent variables were calculated using the 
  test and the independent t - test . values are n ( % ) or mean  standard deviation , ns : not significant , fs : fes with 
 stretching exercise group , fps : fes with proprioception and strengthening exercise 
 group , mmse - k : mini - mental state examination - korea , mas : modified ashworth scale . general characteristics and dependent variables were calculated using the 
  test and the independent t - test in the balance ability test , cop migration lengths and surface areas showed significant 
 differences from before the training , at three and six weeks after the beginning of the 
 training in both groups ( p<0.05 ) . los tests showed significant increases from before the 
 training at three and six weeks after the start of the training in both groups ( p<0.05 ) . the fb tests showed significant increases from before the training at three and six weeks 
 after the start of the training in both groups ( p<0.05 ) . the bbs results showed 
 significant increases from before the training at three and six weeks after the start of the 
 training in both groups . the frt results also showed significant increases from before the 
 training at three and six weeks after the start of the training in both groups . the fps 
 group showed significantly greater improvements in all variables of balance ability than the 
 fp group ( p<0.05 ) ( table 2table 2.comparison of the test results between the two groups ( n=22)group variablefs ( n=11)fps ( n=11)reo ( cm)pre-55.4  16.857.3  18.73 weeks50.0  16.8 * 46.0  14.1*,6 weeks46.3  16.3 * 38.6  14.0*,rec ( cm)pre-82.1  19.984.5  16.23 weeks78.2  18.6 * 74.6  10.8*,6 weeks74.9  19.6 * 68.2  11.3*,sa ( cm)pre-97.7  22.3111.6  26.33 weeks89.0  20.4 * 95.5  24.4*,6 weeks72.5  16.5 * 72.9  18.3*,los ( mm)pre-4,165.5  1,016.04,199.7  1,289.23 weeks4,333.5  992.0 * 5,216.5  1,879.4*,6 weeks4,564.9  1,088.1 * 6,286.5  2,201.0*,fb ( cm)pre-50.7  5.049.9  5.003 weeks49.0  4.6 * 47.3 4.9*,6 weeks48.9  5.3 * 45.1  4.9*,frt ( cm)pre-18.6  5.318.0  7.93 weeks22.5  4.8 * 23.6  7.5*,6 weeks24.1  4.6 * 26.6  7.0*,bbs ( score)pre-48.9  4.147.3  3.03 weeks49.8  3.7 * 49.4  2.4*,6 weeks50.8  3.5 * 52.2  2.1*,tug ( sec)pre-19.2  4.119.3  4.33 weeks15.2  1.9 * 12.9  2.5*,6 weeks12.8  2.7 * 11.7  2.7*,*p<0.05 , values are mean  standard deviation , significantly different between 
 03 weeks between the two groups , significantly different between 36 weeks between 
 the two groups by repeated anova , fs : fes with stretching exercise group , fps : fes 
 with proprioception and strengthening exercise group , reo : romberg s eyes open test , 
 rec : romberg s eyes closed test , sa : eyes open surface area , los : limit of stability 
 test , fb : forward and back test , frt : functional reach test , bbs : berg balance scale , 
 tug : timed up and go test ) . * p<0.05 , values are mean  standard deviation , significantly different between 
 03 weeks between the two groups , significantly different between 36 weeks between 
 the two groups by repeated anova , fs : fes with stretching exercise group , fps : fes 
 with proprioception and strengthening exercise group , reo : romberg s eyes open test , 
 rec : romberg s eyes closed test , sa : eyes open surface area , los : limit of stability 
 test , fb : forward and back test , frt : functional reach test , bbs : berg balance scale , 
 tug : timed up and go test in the present study , the effects of ankle joint muscle strengthening and proprioceptive 
 exercise programs on stroke patients balance ability were examined . according to the 
 results , balance ability improved in both groups and in the comparison of the two groups , 
 the fps group was revealed to have improved more . regarding the changes in balance ability of the two groups , the fps group showed 
 significant differences in the cop migration length , surface area , los test , and fb test . 
 though the results were inconsistent with the results of a previous study indicating that 
 ankle strengthening training did not have any effect on stroke patients postural sway19 , in a study conducted by niam et al.20 of 13 stroke patients , it was reported 
 that compared to subjects with intact ankle proprioceptive sense , subjects with damaged 
 ankle proprioceptive sense showed increased sway speed and decreased balance ability . the 
 results of the present study are consistent with the results of the study conducted by 
 lisinski et al.21 , who divided 26 stroke 
 patients into a balance training group and a no training group , and examined the effects of 
 balance training on motor skills . the group that received balance training showed reductions 
 in the asymmetry of bilateral weight - bearing and could perform selective movements . the 
 results of the present study are also consistent with the results of a study conducted of 16 
 stroke patients which examined the effects of task - oriented exercise programs on postural 
 stability , the study reported that the experimental group that performed task - oriented 
 exercises and received ankle joint proprioceptive sense inputs showed significant 
 improvements in cop movements22 . therefore , to improve balance ability , the muscles around the ankles need to be activated 
 and ankle joint proprioceptive sense inputs should accompany the activation . the diverse 
 inputs derived from ankle joint muscle strengthening and functional electrical stimulation 
 applied together with repetitive ankle movements appeared to have great effects on the 
 promotion of motor learning , and balance control ability improved because the body 
 perception regarding changes in the position of the body increased in an environment in 
 which these elements were provided , so the environment and proprioceptive sense interacted 
 with each other and they were integrated . in the present study , bbs , frt , tug , and balance ability tests showed significant 
 differences after the intervention in both groups and in the comparison of the groups , and 
 improvements the fps group were significantly greater than in the fs group . these results 
 are consistent with the study conducted by geiger et al.23 of 13 stroke patients . they reported that the tug result improved 
 from 23.08  s to 14.62  s in the group that performed an additional exercise program using a 
 balance master . out present results are also consistent with a study conducted by park et 
 al.24 who reported that when an ankle 
 joint proprioceptive movement control program was conducted for 13 stroke patients , sway 
 speed and distance decreased , balance ability improved , and tug values decreased from 20.5  s 
 before the experiment to 17.9  s four weeks after the start of the experiment and to 15.3  s 
 eight weeks after the start of the experiment . given these results , it can be seen that the 
 rom was increased by the ankle muscle strengthening exercises , so the stability limit 
 increase and the feed - back and feed - forward control mechanisms were improved thanks to 
 proprioceptive sense inputs . thus , the ability to establish and maintain correct posture 
 improved through the provision of information on the movement and location of individual 
 parts of the body . in addition , the ability to appropriately control balance during sway was 
 improved through better coordination and mobilization of the senses and muscle 
 functions . limitations of the present study include the possibility of interference of balance factors 
 could not be excluded because the subjects daily lives could not be completely controlled , 
 and whether or not ankle muscle strengthening exercises and proprioceptive sense training 
 have continuous effects was not determined through follow - up . in conclusion , the two groups showed differences in balance ability between each other at 
 three and six weeks after the start of the experiment , and the fes , ankle proprioception 
 exercise , and ankle muscle strengthening group showed greater improvements . the treatment 
 method that added a program centered on ankle muscle strengthening to fes and ankle 
 proprioceptive exercises was more effective at enhancing balance ability .
[ purpose ] the purpose of the present study was to examine the effects of ankle joint 
 muscle strengthening and proprioceptive exercises accompanied by functional electrical 
 stimulation on stroke patients balance ability . 
 [ methods ] for six weeks beginning in 
 april 2015 , 22 stroke patients receiving physical therapy at k hospital located in 
 gyeonggi - do were divided into a functional electrical stimulation ( fes ) , ankle 
 proprioceptive exercise and ankle joint muscle strengthening exercise group ( fps group ) of 
 11 patients and an fes and stretching exercise group ( fs group ) of 11 patients . 
 the 
 stimulation and exercises were conducted for 30  min per day , five days per week for six 
 weeks . 
 balance ability was measured using a biorescue and the berg balance scale , 
 functional reach test , and the timed up - and - go test were also used as clinical evaluation 
 indices . 
 repeated measures anova was conducted to examine differences between before the 
 exercises and at three and six weeks after beginning the exercises within each group , and 
 the amounts of change between the two groups were compared . [ results ] in the comparison 
 within each group , both groups showed significant differences between before and after the 
 experiment in all the tests and comparison between the groups showed that greater 
 improvement was seen in all values in the fps group . 
 [ conclusion ] in the present study , 
 implementing fes and stretching exercises plus ankle joint muscle strengthening and 
 proprioceptive exercises was more effective at improving stroke patients balance ability 
 than implementing only fes and stretching exercises .