stroke is a neurological disease caused by the cutoff of normal blood supply due to vessel 
 rupture or thrombosis , and it causes brain tissue damage . motor , sense , recognition , 
 language , and perception deficits are typical symptoms of the disease , depending on the 
 affected areas , size , and the cause of damage1 . stroke patients mainly experience motor disorders and degeneration 
 of balancing ability due to unbalanced posture ; this is caused by asymmetric arrangement and 
 hemiplegia , and this disrupts independent activities of daily living ( adl)2 . the ability to balance is an individual s ability to maintain the center of gravity within 
 a base region , keeping the body in a balanced state3 . stroke patients lack balancing ability and show degeneration of 
 physical function due to a reduction in walking and activity caused by an inappropriate 
 posture , proprioception malfunction , and abnormal muscle tension4 . to resolve balance problems caused by stroke , the 
 brunnstrom approach , bobath approach , or proprioceptive neuromuscular facilitation ( pnf ) is 
 used ; such methods focus on enhancing physical functions and balance by improving active 
 motor control5 . pnf utilizes a typical helical or diagonal pattern to stimulate proprioceptive sensation 
 promote a nerve root response , enhancing functional movement5 , 6 . it improves muscle 
 strength , flexibility , and balance ; by applying it on the non - paretic side , force is 
 transferred to the paretic side , effectively promoting muscle activity6 . davis7 suggested aquatic pnf lower 
 extremity patterns for reinforcing muscular strength and enhancing muscle reeducation . song 
 and kim8 applied aquatic pnf lower 
 extremity patterns to patients who had a stroke , which stimulated proprioceptors , thus 
 improving control and function of the nerve roots while enhancing balance . in an aquatic environment , the buoyancy allows limbs to be moved more easily with little 
 strength , enhancing coordination of motion9 . water resistance also enables the body to move , helping increase 
 muscle strength , joint movement , and balance10 . multiple studies had reported pnf lower extremity patterns during 
 ground - based exercise for stroke patients , but few had reported aquatic pnf . this study aimed to investigate the effects of aquatic pnf lower extremity patterns on 
 balance and adl of stroke patients . six months after receiving a stroke diagnosis via either computed tomography or magnetic 
 resonance imaging , 20 patients were randomly assigned to a control group ( n = 10 ; 5 males 
 and 5 females ) or an experimental group ( n = 10 ; 5 males and 5 females ) ; the control group 
 was assigned to conduct pnf lower extremity patterns on the ground , and the experimental 
 group was assigned to conduct pnf lower extremity patterns in water . all participants scored 
 > 24 points on the mini - mental status examination ( mmse ) , could perform assignments , were 
 capable of walking 10  m independently , and were classified as > 4 on the brunnstrom scale . the 
 protocol was approved by the institutional review board of nambu university and was 
 conducted in accordance with the ethical standards of the declaration of helsinki . the 
 general features of the participants are listed in table 1table 1.general characteristics of subjectseg ( n=10)cg ( n=10)gender ( male / female)5 / 55 / 5age ( years)69.1  3.268.0  3.1height ( cm)167.6  8.2165.9  6.9weight ( kg)67.9  5.966.7  6.7paretic side ( right / left)5 / 55 / 5onset ( months)9.8  1.310.3  1.4meansd , eg : experimental group , cg : control group . the age of the experimental group was 69.1  3.2  years , height was 167.6  
 8.2  cm , weight was 67.9  5.9  kg , and time since stroke onset was 9.8  1.3 months . the age 
 of the control group was 68.0  3.1  years , height was 165.9  6.9  cm , weight was 66.7  
 6.7  kg , and time since stroke onset was 10.3  1.4 months . meansd , eg : experimental group , cg : control group the experimental group conducted pnf lower extremity patterns using the rhythmic initiation 
 ( ri ) method 110  cm below the water surface ; the water temperature was 3133  c . exercises 
 were performed in a supine posture after simple stretching ; subjects wore a body ring 
 between l5 and s1 and a neck collar . the control group conducted pnf 
 lower extremity patterns on the ground in a supine posture after simple stretching . the ri 
 method starts from passive exercise , proceeds to active resistance exercise , and helps 
 increase coordination , motor sensation , and balance . the pnf lower extremity patterns 
 consisted of patterns d1 and d2 . the d1 pattern ends at 
 either flexion - adduction - external rotation knee flexion or extension - adduction external 
 rotation knee extension . the d2 pattern ends at either flexion - adduction external 
 rotation knee flexion or extension - adduction - external rotation knee extension . pnf lower 
 extremity patterns were conducted 30 minutes / day , 5 days / week for 6 weeks . balance was measured with the berg balance scale ( bbs ) , timed up and go test ( tugt ) , 
 functional reach test ( frt ) , and one leg stand test ( olst ) . the bbs consists of 14 items and 
 can be categorized into sitting , standing , and postural changes . scores in each category 
 range from 04 , with 56 possible total points ; higher scores indicate better balance . the 
 tugt measures the time required to stand up from a chair and shuttle back and forth between 
 the chair and a spot in front of the subject three times . the frt measures the distance one 
 can reach with an arm from a standing posture . the olst measures how long one can stand on 
 one foot with the eyes open without placing the other foot on the ground . adl were measured with the functional independence measure ( fim ) , which consists of 13 
 items related to mobility and 5 related to recognition . the items were scored on a scale of 
 17 with 126 possible total points ; higher scores indicate better independence . data were analyzed using spss 12.0 ( spss , chicago , il , usa ) for windows . descriptive 
 statistics were used for the general features of the participants . a paired t - test was used 
 to determine pre- and post - experiment differences , and an independent t - test was used to 
 determine between - group differences . the changes in the result of the bbs , tug , frt , olst , and fim are listed in table 2table 2.comparison of the results of the bbs , tug , frt , olst , and fim between the 
 experimental and control groupsgroupprepostd - valuebbseg42.8  1.644.9  1.7 * 2.1  1.7*cg39.9  2.040.6  1.7 * 0.7  0.8tugteg21.9  1.320.1  1.9*1.8  1.3*cg20.4  1.019.7  1.0*0.7  0.6frteg17.7  0.919.0  1.4 * 1.3  0.9*cg16.7  0.617.2  0.4 * 0.5  0.6olsteg4.3  0.85.7  1.1 * 1.4  0.9*cg3.4  0.54.1  0.7 * 0.6  0.7fimeg82.3  2.587.5  3.7 * 5.2  5.3*cg80.1  1.281.4  1.4 * 1.3  1.3meansd , * p<0.05 , d - value : difference value , eg : experimental group , 
 cg : control group , bbs : berg balance scale , tugt : timed up and go test , frt : 
 functional reach test , olst : one leg stand test , fim : functional independence 
 measure . the experimental and control groups showed significant differences for all 
 pre- and post - experiment variables ( p < 0.05 ) . in the between - group comparison , the 
 experimental group was significantly different from the control group ( p < 0.05 ) . meansd , * p<0.05 , d - value : difference value , eg : experimental group , 
 cg : control group , bbs : berg balance scale , tugt : timed up and go test , frt : 
 functional reach test , olst : one leg stand test , fim : functional independence 
 measure the purpose of this study was to investigate the effects of aquatic pnf lower extremity 
 patterns on balance and adl of stroke patients . the experimental group showed a significant 
 improvement in balance and adl after the aquatic pnf ( p < 0.05 ) and had significantly 
 better balance and adl relative to the control group ( p < 0.05 ) . for example , performance of 10 weeks of aquatic proprioception exercise by 
 seniors enhanced their motor abilities11 . in addition , kim and lee12 pnf reported 
 that aquatic lower extremity patterns enhanced balance in healthy adults . moreover , song and 
 kim8 reported that aquatic pnf 
 effectively affected the balance of stroke patients . these results indicate that aquatic pnf 
 lower extremity patterns help enhance the balance of stroke patients . pnf , used as a gradual 
 resistance exercise that employs a helical pattern , maximizes motor unit recruitment through 
 proprioceptive stimulation5 , 13 . aquatic pnf promotes the maximum usage of muscle fibers 
 due to the intense circumstances caused by buoyancy and turbulence ; moreover , the water acts 
 as a form of resistance , stimulating proprioception and thus helping to improve postural 
 control and balance8 , 13 , 14 . the most common method for examining the adl of stroke patients is to use the fim . in the 
 present study , the experimental group showed significant enhancement of adl after the 
 aquatic pnf ( p < 0.05 ) . suomi and collier15 reported that the adl of arthritis patients were enhanced after 
 conducting aquatic exercise , and sato et al.16 reported that the adl of abnormal adults were enhanced after 
 conducting water exercise . similar to other studies , enhancement of adl was observed after 
 conducting aquatic exercise in the present study . the enhancement of adl was the result of 
 enabling movement with even a small amount of force . this was due to the assistance of the 
 water buoyancy and decreased gravity , reducing the burden on muscles and joints10 , 15 . to promote functional recovery , the paretic side was spontaneously 
 enabled , thus enhancing the adl and improving functional independence15 , 16 . the movements 
 also stimulate shortened muscles , promoting a training effect and enhancing adl17 . a limitation of this study was that it utilized a small number of participants , and it was 
 not confirmed that the positive effects persisted . future research should address these 
 things when investigating the effect of aquatic pnf lower extremity patterns in stroke 
 patients .