a stroke is a cerebrovascular event in which the supply of blood delivered to the brain is 
 significantly altered1,2,3 .
the resulting deficits or 
 impairments following stroke vary according to the location and extent of the lesion , but 
 often include hemiparesis , communication disorders , and cognitive deficits4 . in isolation or combined
, these deficits 
 often lead to significant difficulty completing activities of daily living . even after 
 extensive rehabilitation , up to 50% of stroke survivors experience lingering motor 
 deficits4 , 5 .
although the majority of stroke patients are able to walk 
 independently , most do not reach a walking level that enables them to perform all of their 
 daily activities . impaired walking function , including reduced gait stability and asymmetric 
 walking , is a common neurological deficit following stroke4 .
for example , laufer et al . reported that the nonparetic lower limb 
 assumes 6180% of the full body weight during normal walking in patients with 
 hemiparesis5 .
asymmetric walking caused 
 by hemiparalysis can become a cause of instability during daily activities , and these 
 patients have a higher rate of falls than elderly individuals in the general population4 .
thus , gait recovery is a major objective of 
 rehabilitation programs for patients with stroke .
studies have focused especially on the musculoskeletal effects of stroke , such as 
 strength and muscle density , which are implicated in gait and balance problems6,7,8 .
diminished muscle activity has been identified as a factor contributing to balance 
 impairment in patients with hemiplegia , and as such , treatment to increase muscle activity 
 has been attempted as a method to improve balance capacity9 .
trunk muscles are activated during the rhythmic movement that is part of the execution of 
 gait .
core strengthening exercises are used to specifically strengthen the trunk muscles and 
 have become a specialty area in the field of rehabilitation10 .
recently , in the united states and europe , pilates has become a target of interest as a 
 useful exercise .
pilates exercises were developed by joseph h. pilates ( 18801967 ) as an 
 exercise method to relax and strengthen the body .
the exercises have a scientific , rational 
 system for adjusting the center of the body11 .
pilates training is based on 8 principles : control , breathing , flowing movement , precision , 
 centering , stability , range of motion , and opposition .
mat - based pilates exercises have been 
 developed that use equipment for those who can not exercise more vigorously due to injury or 
 poor health .
as strength - based exercises are directly connected to health , they can be an effective 
 method to improve balance ability and can also be used to correct postural deviations for a 
 flexible and balanced body11 , 12 . a recent study on balance and pilates demonstrated that pilates can be effective for 
 enhancing both static and dynamic equilibrium capacity in university students in a 16-week 
 mat exercise course13 . in another study , 
 by changgiun14 ,
based on these findings , we hypothesized that pilates exercise training could be an 
 effective post - stroke rehabilitation method to address impairments frequently encountered by 
 patients with stroke , such as flexibility , somatosensory loss , muscular strength , and 
 balance15,16,17,18 .
currently , most of the studies on pilates training programs have focused on orthopedic 
 remedial exercise19,20,21 or balance improvement in 
 the elderly16 , 21 , 22 .
reported 
 that patients with low back pain described a lower level of functional disability after 4 
 weeks of pilates intervention21 .
bird et 
 al . reported that a 5-week pilates training course for the elderly contributed to greater 
 benefits in static and dynamic balance compared to usual activity16 .
of these , the majority have focused on patients with 
 multiple sclerosis22,23,24,25,26 , and no studies have been 
 conducted on the rehabilitation of patients with chronic stroke .
therefore , the purpose of this study was to investigate the effects of an 8-week mat - based 
 pilates exercise training program on the static and dynamic balance abilities of patients 
 with chronic stroke .
thirty participants were initially recruited from the rehabilitation center for the 
 disabled located in uijeongbu , gyeonggi province , korea .
the inclusion criteria stated that 
 each participant must be at least 2  years post stroke , medically stable with a physician 
 release granting approval to initiate and complete an exercise program , able to walk 
 independently without an assistive device , and willing to participate in a pilates exercise 
 class .
participants were excluded if they had visual impairment , hearing damage , 
 uncontrolled high blood pressure , or were unable to understand the nature of the experiment . 

participants who were receiving physical therapy separately were also excluded from this 
 study . in total , 10 participants were excluded because they were participating in individual 
 physical therapy sessions , and one participant dropped out of the control group due to 
 hospital admission during the intervention period . finally , nineteen individuals with 
 chronic hemiparetic stroke participated in the study ( age , 64.7  6.9  years ; height , 161.7  
 7.9 ; and weight , 67.0  11.1 ) .
the research protocol was approved by the institutional review 
 board of sahmyook university . following participant selection ,
they were randomized into two groups , a pilates exercise 
 training group ( pg ) and a control group ( cg ) . during the intervention period ,
the pg was 
 given pilates exercise training , while the cg was not given any exercises or treatment at 
 the center for the disabled .
the pilates training program was based on mat classes lasting one hour per class , three 
 times a week for 8 weeks . in this study ,
two certified pilates instructors and one physical 
 therapist were in charge of the class .
one instructor demonstrated movements for patients to 
 follow and the other instructor and the physical therapist assisted patients with the 
 exercise .
all movements included in the pilates training was based on 8 1 set of 8 
 repetitions per exercise .
to improve core stability , breathing exercises were conducted in a 
 sitting position before and after all training sessions .
the mat based pilates training was 
 composed of spine mobility exercises , upper limb exercises , and lower limb strengthening 
 exercises .
the exercises were composed of the following detailed movements : 1 ) spine 
 mobility- chin up and down , forward spine stretch , and side spine stretch in sitting with 
 theraband ; 2 ) upper limb exercise- draw a sword , and deltoid lift in sitting with theraband ; 
 and 3 ) lower limb strengthening exercise- top leg pulse - down and bottom leg pulse - up in 
 sidelying using the magic circle , and foot and ankle strengthening in sitting with 
 theraband .
unlike general pilates training , lower limb strengthening exercises help to 
 strengthen the quadriceps , gluteus medius , adductor magnus , gastrocnemius , and anterior 
 tibialis .
additionally , for gluteal activation , a gluteal series including charlie chaplin 
 exercises , swimming , and a heel squeeze in prone with a ball under the chest were performed , 
 along with a prone bridge . to verify the effects of the 8-week pilates training course on the static and dynamic 
 balance of patients with chronic stroke , two data collection protocols were conducted one 
 week before and after the training .
the variables assessed were center of pressure ( cop ) 
 sway and velocity . to measure static balance , participants wore familiar shoes , and were asked to stand on an 
 instrumented treadmill ( fit , bertec corp . , usa)with their eyes open and arms at their sides 
 comfortably for 30 seconds .
each foot was placed on a separate force plate located under the 
 treadmill belts and foot position was measured and maintained for each evaluation . to measure dynamic balance ,
participants were asked to walk on the instrumented treadmill 
 at their self - selected velocity .
the over - ground self - selected velocity was determined for 
 each participant beforehand and the treadmill belt speed was set to match that velocity 
 during the evaluation . when it was determined that subjects were exhibiting natural walking 
 movements ( after about 35 seconds ) ,
a total of 5 static and dynamic trials were conducted for each subject , and average values 
 from the trials were used for data analysis .
and anterior - posterior ( a - p ) and medial - lateral ( m - l ) directional cop sway , as well as 
 velocity with time series , were computed and evaluated .
the 8-week pilates training effects were assessed using a paired t - test , and an independent 
 samples t - test was conducted to compare the differences in subordinate variables between the 
 groups .
no significant differences in general characteristics were noted between the groups 
 ( p>0.05 , table 1table 1.general characteristics of subjectspg ( n=10)cg ( n=9)gender ( male / female ) 10 ( 5/5 ) 9 ( 5/4)age ( years)66.80  5.761.11  6.6height ( cm)159.75  8.9163.57  10.4weight ( kg ) 65.01  12.6 66.43  10.9duration ( years)12.80  3.013.20  6.3stroke type ( hemorrhage / infarction)10 ( 4/6)9 ( 5/4)paretic side ( left / right)10 ( 6/4)9 ( 5/4)pg : pilates training group ; cg : control group .
for static balance , cop sway significantly decreased in the pg in both the 
 a - p and m - l directions ( p<0.05 , table 
 2table 2.changes in static balance abilityvariablespg ( n=10)cg ( n=9)m - l cop range ( mm)pre10.85  5.011.72  5.4post7.11  2.216.10  6.1pre - post3.74  3.3 * 1.61  3.0a - p cop range ( mm)pre14.75  8.016.10  6.1post10.47  3.716.82  5.0pre - post4.28  4.9 * 0.72  4.6m - l cop velocity ( mm / s)pre83.94  42.184.24  45.0post66.48  26.686.69  41.9pre - post17.46  24.4 * 2.45  4.8a - p cop velocity ( mm / s)pre122.00  47.6130.48  45.8post104.55  42.0135.78  43.2pre - post17.45  11.9 * 5.30  7.2a - p cop : anterior - posterior center of pressure ; m - l cop : medial - lateral center of 
 pressure .
all dynamic balance parameters for both legs improved significantly in the 
 pg after training ( p<0.05 , tables 3table 3.changes in dynamic balance ability on the paretic side in stance phasevariablespg ( n=10)cg ( n=9)m - l cop range ( mm)pre15.0  2.116.0  2.4post12.0  1.416.3  2.4pre - post3.0  2.4**0.4  1.0a - p cop range ( mm)pre27.0  3.226.2  3.7post22.4  2.726.5  2.9pre - post4.6  1.2***0.3  1.2m
- l cop velocity ( mm / s)pre88.6  33.591.8  39.8post76.5  25.692.6  38.8pre - post12.1  8.4 * 0.7  2.2a - p cop velocity ( mm / s)pre114.8  31.2117.0  30.6post98.3  25.2117.1  29.1pre - post16.5  6.6**0.1  2.7a - p cop : anterior - posterior center of pressure ; m - l cop : medio - lateral center of 
 pressure .
* means significant 
 difference within group ; means significant difference between groups and 4table 4 .
changes in dynamic balance ability on the non - paretic side in 
 stance phasevariablespg ( n=10)cg ( n=9)m - l cop range ( mm)pre12.7  1.213.7  2.2post10.4  0.814.2  1.9pre - post2.4  0.6***0.44  0.62a - p cop range ( mm)pre23.2  2.422.1  3.6post18.2  1.222.9  3.3pre - post5.0  1.6***0.77  1.1m
21.287.16  26.3pre - post12.5  7.5 * 1.12  2.6a - p cop velocity ( mm / s)pre89.7  28.896.9  27.5post73.2  17.997.0  25.1pre - post16.6  11.3 * 0.1  3.3a - p cop : anterior - posterior center of pressure ; m - l cop : medial - lateral center of 
 pressure .
* means significant 
 difference within group ; means significant difference between groups ) . for all static and dynamic balance parameters , significant differences after 
 training were found between the pg and the cg , although there were no significance 
 differences at baseline ( p<0.05 , tables 3 
 and 4 ) .
a - p cop : anterior - posterior center of pressure ; m - l cop : medial - lateral center of 
 pressure .
* means significant 
 difference within group ; means significant difference between groups a - p cop : anterior - posterior center of pressure ; m - l cop : medio - lateral center of 
 pressure .
* means significant 
 difference within group ; means significant difference between groups a - p cop : anterior - posterior center of pressure ; m - l cop : medial - lateral center of 
 pressure .
we examined the effects of pilates exercise training on static and dynamic balance in 
 patients with chronic stroke .
to our knowledge , this investigation is the first to show 
 improvements in static and dynamic balance following pilates training in this population . 

one of the important purposes of this study was to determine whether training that had been 
 performed for balance improvement in the elderly could be effectively applied to patients 
 with chronic stroke16 , 18 , 22 , 23 , 27 , 28 . in this study ,
the pg demonstrated 26% and 34% improvement in static balance in the a - p and 
 m - l directions , respectively ( table 2 , 
 p<0.05 ) .
the results of this study support the findings of studies conducted on the 
 effects of pilates training in the elderly . in a study by newell et al .
, an 8-week pilates 
 training course contributed to a 40% improvement in a - p cop sway in the elderly28 . further ,
bird et al . reported that a 
 5-week pilates training course led to a 1622% improvement in m - l cop sway ( p<0.001 ) 
 during challenging balance tasks16 . in 
 our study , the improvement in static balance was attributed to the 8-week pilates training 
 course that improved muscle control of the deeper abdominal muscles ( i.e. , transversus 
 abdominis , lumbar multifidus , and the respiratory and pelvic diaphragms ) .
conversely , bird 
 et al . found no significant training effects on balance performance while standing on a firm 
 surface16 .
the reason our results 
 differ may be due to the difference in training period and frequency . in the present study , 

stroke survivors were trained for 3 times / week for 8 weeks , while patients in the study by 
 bird et al .
this suggests that there may be a dose response effect that should 
 be verified in future studies . in this study ,
the pg demonstrated significant improvements ( 1522% ) in dynamic stability 
 in the a - p and m - l directions for both the paretic and nonparetic foot after training ( tables 3 and 
 4 , p<0.05 ) .
sator et al . reported that polyneuropathy patients demonstrated a 20% reduction in cop 
 velocity of the midfoot during walking after a 12-week ankle strengthening program 
 ( p<0.05)29 and lim and yoon revealed 
 that the elderly exhibited a 32% decrease in cop sway during obstacle walking as a result of 
 a 12-week underwater training program ( p<0.05)30 .
it has been reported that in dynamic situations ( i.e. , walking ) , 
 cop velocity is directly related to center of mass ( com ) acceleration , which represents 
 human movement along with cop sway , and that the reduction of cop variables represents 
 increased balance during walking31 . 
 unlike general pilates training , lower limb strengthening exercises
this could help patients increase muscles force production and subsequently 
 improve their dynamic balance .
given that cop variables in the m - l direction are closely 
 related to the risk of falls32 , 33 , the improvement of cop variables in this direction 
 increases the expectation that pilates training may have an influence on the reduction of 
 fall risk in patients with chronic stroke . to our knowledge , this is the first study using pilates training as an intervention to 
 improve static and dynamic balance in patients with chronic stroke . despite the documented 
 effects on balance , pilates training has not yet been applied to the rehabilitation of 
 patients with chronic stroke . however , as a result of this study , the 8-week pilates 
 training program has been proven fully effective for the treatment of static and dynamic 
 balance in patients with chronic stroke . however , in using this intervention for the rehabilitation of patients with chronic stroke , 
 careful attention will be needed on several points .
first , unlike general muscular strength 
 training or aerobic exercises , maintaining the correct posture is very important in pilates 
 training , and it should only be carried out by qualified instructors supervising a small 
 number of participants per session . in this study , the number of participants in a class was 
 restricted to 811 , and the same class was 
 offered 6 times a week so that patients would not be inconvenienced by attending classes 3 
 days a week .
second , given the previous finding that a 5-week pilates training program for 
 the elderly did not influence balance on firm surfaces15 , a minimum of 8-weeks is suggested as a suitable training 
 period .
as pilates training for patients with chronic stroke has not been reported , this study 
 could only be compared to studies of pilates training for the elderly . moreover
, this study 
 did not include other variables ( e.g. , gait parameters or emg activity ) that may be used to 
 assess static and dynamic balance improvements after pilates training .
therefore , follow - up 
 studies should be performed to investigate the impact of pilates training on gait parameters 
 or lower limb emg activity related to balance measures .
this study proved that an 8-week pilates training program improved the static and dynamic 
 balance of patients with chronic stroke .
if pilates training that strengthens the deeper 
 abdominal muscles is sustained for this duration , than these results can be obtained . 

therefore , if these training parameters are used in the clinic when it becomes appropriate 
 for the patient , a pilates program can be an effective treatment for the recovery of walking 
 ability , which is the highest objective of rehabilitation for patients with chronic stroke . 

given these results , pilates training should be considered as a rehabilitation intervention 
 for balance improvement in patients with chronic stroke .
 [ purpose ] the purpose of this study was to analyze the effects of pilates exercise on 
 static and dynamic balance in chronic stroke patients . [ subjects and methods ] nineteen 
 individuals with unilateral chronic hemiparetic stroke ( age , 64.7  6.9  years ; height , 
 161.7  7.9  cm ; weight , 67.0  11.1  kg ) 
 were randomly allocated to either a pilates 
 exercise group ( pg , n=10 ) or a control group ( cg , n=9 ) . 
 the pg attended 24 exercise 
 sessions conducted over an 8-week period ( 3 sessions / week ) . 
 center of pressure ( cop ) sway 
 and cop velocity were measured one week before and after the exercise program and compared 
 to assess training effects . 
 [ results ] pilates exercise positively affected both static and 
 dynamic balance in patients with chronic stroke . 
 for static balance , cop sway and velocity 
 in the medial - lateral ( m - l ) and anterior - posterior ( a - p ) directions were significantly 
 decreased in the pg after training while no significant differences were found in the cg . 
 for dynamic balance , measured during treadmill walking , 
 the pg showed significantly 
 reduced cop sway and velocity in the m - l and a - p directions for both the paretic and 
 non - paretic leg . 
 [ conclusions ] the findings provide initial evidence that pilates exercise 
 can enhance static and dynamic balance in patients with chronic stroke . 
INTRODUCTION
SUBJECTS AND METHODS
RESULTS
DISCUSSION