stroke patients are characterized by an asymmetric posture due to decreased movement , and 
 this asymmetric posture makes balance control in a standing posture difficult , as a result 
 of the center of pressure moving toward the lower limb of the unaffected side , triggering 
 problems with postural control ability1 . 

loss of balance ability in stroke patients may cause increased postural sway , reduction of 
 weight on the lower limb of the affected side , and increased fall risk2
. in general , balance or postural stability refers to maintaining the center of mass within 
 the support surface to maintain static action and to perform desired motions .
balance 
 ability is essential for functional activities , as well as for actions such as sitting , 
 standing , and walking3 . to maintain and 
 adjust balance , the proprioceptive , visual , and vestibular senses must interact4 . however , 65% of stroke patients experience 
 loss of tactile and proprioceptive senses , largely because of impaired in proprioception 
 resulting from lowered muscle tone5 .
these include 
 therapeutic exercises , such as weight shifting to the lower limb of the affected side , 
 proprioceptive neuromuscular facilitation techniques , bobath techniques , neurodevelopmental 
 facilitation techniques , and task - oriented exercises6 , 
 7 .
repetitive exercise is necessary to 
 improve balance , and ankle - foot orthoses are used for hours when there is excessive 
 spasticity or deformity .
ankle orthoses stabilize the ankle joint and compensate for 
 insufficient ankle dorsiflexion and mediolateral instability of the subtalar joint , 
 increasing balance ability .
they also facilitate medial shift of the center of mass and 
 weight shift toward the foot of the affected side , reducing asymmetric body posture8 .
dysfunction of the foot and the ankle joint of stroke patients are closely associated with 
 functional and kinetic aspects of the lumbar region and lower limbs , inevitably triggering 
 overall body imbalance9 .
the ankle joint 
 and the hip joint play important roles in providing body stability during stroke patients 
 balance training .
the first type of postural control strategy is the ankle joint strategy , 
 which primarily improves standing balance through muscle contraction of the ankle joint10 . while walking with an ankle - foot orthosis
, the moment of the dorsiflexion angle during the 
 stance phase and plantarflexion during the terminal stance may increase11 . in a static standing position ,
the ankle joint is used 
 frequently12 , and according to 
 comparisons of muscular strength between those who have experienced falls and those who have 
 not , the extensors of the hip joint and the plantar flexor of the ankle joint show 
 significant differences13 , indicating 
 that loss of balance ability is closely related to the weakening of ankle strength14 .
therefore , the purpose of this study was 
 to examine the effects of balance training with an ankle - foot orthosis on stroke patients 
 lower limb muscle activities and static balance maintenance .
the subjects of this study were 25 stroke patients , and they were randomly assigned to a 
 group with ankle - foot orthosis shoes ( afo , n=13 ) and a group with shoes ( n=12 ) ( table 1table 1 .
the general characteristics of the subjectsvariablesgroupafo group ( n=13)shoes group ( n=12)sexmale5 ( 38.5%)4 ( 33.3%)female8 ( 61.5%)8 ( 66.7%)diagnosisinfarction5 ( 38.5%)3 ( 25%)hemorrhage8 ( 61.5%)9 ( 75%)affected sideleft10 ( 76.9%)7 ( 58.3%)right3 ( 23.1%)5 ( 41.7%)onset time ( months)9.0  1.29.9  1.0age ( years)58.9  5.557.2  4.4height ( cm)160.8  8.5159.2  7.4weight ( kg)56.6 
8.557.2  8.2ashworth scalegastrocnemius2  12  1values are number ( % ) or mean  sd ) .
prior to participation in this study , the purpose was explained to the 
 subjects and their guardians , and they consented to participate voluntarily .
the research 
 and development review board for human subjects of hallym university approved this study . 

inclusion 
 criteria were : a diagnosis of stroke within the previous 612 months ; no evidence of 
 vestibular system disorders , neurological deficits in the bilateral lower limbs , or visual 
 or auditory disorders ; a mini 
mental state examination - korean score of 23 or higher ; a berg 
 balance scale score of 40 or higher without any musculoskeletal deficit that affected 
 standing balance ; and agreement to wear a plastic ankle - foot orthosis of the plantar flexion 
 90 ankle stop - type .
values are number ( % ) or mean  sd a tele myo 2400 t dynamic electromyograph ( emg , noraxon inc .
arizona , usa ) was employed to 
 measure muscle activities of the lower limbs .
the electrodes were attached to the affected 
 side over the tibialis anterior muscle at one - third of the distance from the proximal 
 tibialis anterior muscle , and the muscle belly of the medial gastrocnemius muscle 2  cm 
 proximal from where the achilles tendon encounters the medial gastrocnemius muscle .
the 
 collected surface emg signals were digitized using myoresearch - xp 1.07 software : emg signals 
 were sampled at 1000  hz , bandpass - filtered between 20 to 500  hz , and processed with a 60  hz 
 notch filter .
a tetrax portable multiple system ( tetrax , tetrax ltd , ramat gan , israel ) was used to 
 measure balance ability15 .
when a subject 
 places a foot on the force plate , the data of the pressure on the force plate is amplified 
 and filtered before being delivered to a computer .
for the measurement of static balance ability , the stability index was 
 obtained , and the collected data were recorded as percentages of the subjects body 
 weights .
the ankle - foot orthosis used in this study was a joint type , and it was appended and raised 
 by 1/8 of an inch so that the medial malleolus and the lateral malleolus did not meet , and 
 the arch support maintained or supported the longitudinal arch when it was worn .
the medial 
 and lateral sides of the caput metatarsals tend to widen when they support weight ; 
 therefore , each of the medial sides and the lateral sides were widened by 1/16 inch and the 
 orthosis was made to be a plantar flexion 90 ankle stop - type using a 5  mm thick 
 thermoplastic material that melted at 170  c .
bands wrapped around the top of the shoes so that they were not easy to remove , and 
 they were made lightweight so that they could be used indoors .
prior to and after the balance training , muscle activities and balance ability were 
 measured .
four balance exercises were conducted , two on flat ground and two on a balance pad 
 ( balance pad , airex , switzerland ) for a total of 20 minutes ( table 2table 2 .
program for balance trainingperiodcompositiontraining methodstimerest06 weekson the floor standing on two feet 1 m15 sstanding with both knees flexed1 m15 sstanding on the affected leg while holding a chair with the 
 unaffected arm1 m15 salternate leg raise : standing on a foothold 20 cm high 1 m15 s06 weekson a balance pad standing on two feet 1 m15 sstanding with both knees flexed1 m15 sstanding on the affected leg while holding a chair with the 
 unaffected arm1 m15 salternate leg raise : standing on a foothold 20 cm high 1 m15 s)16 , 17 .
to measure the muscle activities in a standing position , the subject maintained a standing 
 position in bare feet for five seconds .
data were recorded for three seconds from the 
 tibialis anterior muscle and the medial gastrocnemius muscle of the affected side ; the first 
 and the last one seconds were excluded from the data analysis .
muscle activity signals of 
 each muscle were converted to root mean square values , and expressed as % maximum voluntary 
 isometric contraction ( % mvic ) . for the measurement of balance ability
, the subjects stood on a hard surface with their 
 eyes open and with their eyes closed and on a soft pillow with their eyes open and with 
 their eyes closed .
measurements were made three times in each position , and the average values were used the 
 analysis .
we used the 
 independent t - test to compare differences between the two groups , and the paired t - test to 
 compare within - group differences , before and after the intervention .
muscle activity prior to and after the balance training was compared between the afo and 
 shoes group .
muscle activity of the tibialis anterior muscle of the affected side of the afo 
 group decreased from 19.93  4.85% prior to the balance training to 16.71  3.88% after the 
 balance training and muscle activity of the medial gastrocnemius muscle of the affected side 
 increased from 23.65  8.10% prior to the balance training to 26.64  5.83% after the 
 balance training , and both differences were significant ( p<0.05 ) .
muscle activity of the 
 tibialis anterior muscle of the affected side of the shoes group decreased from 20.26  
 3.83% prior to the balance training to 20.23  3.49% after the balance training and muscle 
 activity of the medial gastrocnemius muscle of the affected side increased from 24.87  
 4.59% prior to the balance training to 25.51  5.11% after the balance training ; neither of 
 the differences was significantly different .
there was a significant difference in the 
 muscle activities of the tibialis anterior muscle of the affected side between the afo and 
 shoes groups ( p<0.05 ) ( table 3table 3 .
comparison of muscle activities between the two groupsvariablesgroupafo group ( n=13)mean  sdshoes group ( n=12 ) mean  sdpta ( % ) pre-19.93  4.8520.26  3.83post-16.71  3.8820.23  3.49change3.22  0.570.03  0.49pmg ( % ) pre-23.65  8.1024.87  4.59post-26.64  5.8325.51 
5.11change3.00  0.810.63  0.59*indicates a significant difference between before and after , * * indicates a 
 significant difference between the two groups , p<0.05 .
pta : paralyzed side tibialis 
 anterior muscle , pmg : paralyzed side medial gastrocnemius , afo : ankle foot orthosis . 

comparison within the group and comparison between the groups were made using the 
 paired sample t - test and the independent sample t - test , respectively . ) .
stability indexes prior to and after the balance training between the afo 
 and shoes group were compared .
for the afo group , the stability index in a standing position 
 with eyes open ( no ) decreased from 25.72  2.98 prior to the balance training to 24.07  
 2.90 after the balance training , the stability index in a standing position with eyes closed 
 ( nc ) decreased from 35.37  7.19 prior to the balance training to 34.08  6.93 after the 
 balance training , the stability index in a standing position on the pillow with eyes open 
 ( po ) decreased from 30.13  5.64 prior to the balance training to 29.57  5.95 after the 
 balance training , and the stability index in a standing position on the pillow with their 
 eyes closed ( pc ) decreased from 38.80  6.70 prior to the balance exercise to 35.76  6.38 
 after the balance exercise .
for the shoes 
 group , the stability index showed significant decreases from 22.45  4.31 to 21.05  4.19 in 
 no , and from 28.03  6.01 to 27.01  6.03 in po ( p<0.05 ) .
regarding changes in stability 
 index resulting from balance training , there was a significant difference in no between the 
 afo group and the shoes group ( p<0.05 ) ( table 
 4table 4 .
comparison of the stability index between the two groupscondition groupafo group ( n=13)mean  sdshoes group ( n=12)mean  sdnopre-25.72  2.9822.45  4.31post-24.07  2.9021.05  4.19change1.65  0.741.40  0.80ncpre-35.37  7.1931.57  9.28post-34.08  6.9330.52  10.04change1.29  1.351.05  3.22popre-30.13  5.6428.03  6.01post-29.57  5.9527.01  6.03change0.56  0.591.02  1.20pcpre-38.80  6.7032.37  7.51post-35.76  6.3832.25  7.26change3.05  1.750.13  1.40*indicates a significant difference between before and after , * * indicates a 
 significant difference between the two groups , p<0.05 .
no : normal open , nc : normal 
 close , po : pillow open , pc : pillow close , afo : ankle foot orthosis .
comparison within 
 the group and comparison between the groups were made using the paired sample t - test 
 and the independent sample t - test , respectively . ) .
* indicates a significant difference between before and after , * * indicates a 
 significant difference between the two groups , p<0.05 .
pta : paralyzed side tibialis 
 anterior muscle , pmg : paralyzed side medial gastrocnemius , afo : ankle foot orthosis . 

comparison within the group and comparison between the groups were made using the 
 paired sample t - test and the independent sample t - test , respectively .
* indicates a significant difference between before and after , * * indicates a 
 significant difference between the two groups , p<0.05 .
no : normal open , nc : normal 
 close , po : pillow open , pc : pillow close , afo : ankle foot orthosis .
comparison within 
 the group and comparison between the groups were made using the paired sample t - test 
 and the independent sample t - test , respectively .
this study examined the effects of ankle - foot orthosis during balance training of chronic 
 stroke patients on muscle activities and static balance of the lower limbs of stroke 
 patients .
after the six weeks of balance training , the data of the two groups were compared 
 to examine muscle activities and static balance around the ankles related to wearing of the 
 ankle - foot orthosis .
the stability index was significantly different in the no condition 
 between the groups , and the afo group showed statistically significant differences in all 
 conditions between prior to and after the balance training .
the changes in afo group muscle 
 activities were significantly greater than those of the shoes group .
after balance training with the ankle - foot orthosis , there was no significant difference in 
 the medial gastrocnemius muscle activity of the affected side , but there was a significant 
 difference in the tibialis anterior muscle activity of the affected side . during balance 
 training with the ankle - foot orthosis ,
the muscle activity of the tibialis anterior muscle 
 of the affected side decreased and the muscle activity of the medial gastrocnemius muscle 
 increased .
however , in the group without the ankle - foot orthosis , there was no pre - post 
 statistically significant difference in either the muscle activity of the tibialis anterior 
 muscle or the medial gastrocnemius muscle of the affected side .
this result is consistent 
 with a study in which the ankle muscle activities of nine males and one female in a static 
 standing posture were examined , and the use of the ankle plantar flexor was predominant18 .
it is also in agreement with a study in 
 which the anterior - posterior center of pressure of six multiple sclerosis patients and four 
 ordinary subjects were examined in a standing position and the use of the gastrocnemius was 
 predominant19 .
however , an ankle - foot 
 orthosis used postural adjustment by 42 stroke patients whose onset of a stroke was 6 months 
 prior or earlier , and 61 stroke patients whose onset of a stroke was 12 months ago or 
 longer , was effective at providing stability for the ankle of early phase stroke patients 
 but not chronic phase stroke patients , as structural changes has occurred , including changes 
 in alignment and muscle shortening20 .
there was a statistically significant difference in the stability index of no between the 
 afo and shoes group , but there were no statistically significant differences in nc , po , and 
 pc between the two groups . in the group who wore the ankle - foot orthosis ,
there were 
 significant differences in the stability indexes of no , nc , po , and pc , and in the group who 
 wore only shoes , there were significant differences in no and po .
this result is similar to 
 that of study in which postural sway of 28 stroke and traumatic brain injury patients was 
 measured with and without an ankle - foot orthosis ; when the ankle - foot orthosis was worn , 
 postural sway was small2 .
our results are 
 also consistent with those of a study in which balance maintenance of 11 stroke patients and 
 10 ordinary subjects wearing an ankle - foot orthosis was examined : weight shift to the 
 lateral side and an increase in weight bearing on the affected side resulted in more use of 
 an ankle strategy than a hip strategy for stability4 . in the rehabilitation process of stroke patients ,
improvement of 
 balance ability is important . in prescribing orthoses , improvement in balance ability and 
 gait
use of an ankle - foot orthosis may be helpful for some 
 stroke patients balance , but stroke patients differ in degree and area of anatomical 
 damage .
balance training variables appropriate for patients should be selected , and effective 
 treatment methods should be utilized to maximize patients potential capabilities
. 
 generalization of this study is limited , as only those patients meeting the selection 
 criteria were examined .
future research that includes the same kind of patients with 
 classification of etiology and brain lesions is necessary .
   [ purpose ] this study examined the effects of an ankle - foot orthosis worn during balance 
 training on lower limb muscle activity and static balance of chronic stroke patients . 
 [ subjects ] the subjects were twenty - five inpatients receiving physical therapy for chronic 
 stroke . 
 [ methods ] the chronic stroke patients were divided into two groups : thirteen 
 patients were assigned to the ankle - foot orthosis group , while the remaining twelve 
 patients wore only their shoes . 
 each group performed balance training for 20 minutes , 
 twice per day , 5 days per week , for 6 weeks . 
 the lower limb muscle activities of the 
 paralyzed side tibialis anterior , medial gastrocnemius , and the stability index were 
 measured before and after the 6-week intervention . [ results ] 
 comparison of the groups 
 indicated a significant difference in the muscle activity of the paralyzed side tibialis 
 anterior and the stability index of the eyes - open standing position . 
 after the 
 intervention , the ankle - foot orthosis group evidenced a significant difference in the 
 muscle activities of the paralyzed side tibialis anterior and paralyzed side medial 
 gastrocnemius as well as the stability index of the eyes - open standing position , 
 eyes - closed standing position , eyes - open standing position on a sponge , and eyes - closed 
 standing position on a sponge . 
 the group that only wore their shoes showed significant 
 differences in the stability indexes of eyes - open standing and eyes - open standing on a 
 sponge . 
 [ conclusion ] using the ankle - foot orthosis was effective during the initial 
 training of lower limb muscle activities and the static balance training of chronic stroke 
 patients . 
 however , it was not effective for a variety of dynamic situations . 
INTRODUCTION
SUBJECTS AND METHODS
RESULTS
DISCUSSION