muscle dysfunction of the leg is very common in children with spastic diplegia cerebral 
 palsy ( cp)1 . spasticity causes muscle 
 stiffness and weakness , and decreases daily functional activities including standing and 
 walking2 . passive muscle stretching is a 
 common physical therapy for decreasing the spasticity of children and adults with cp 
 spasticity . it has been reported that prolonged passive muscle stretching improves the range 
 of movements and reduces spasticity3 . prolonged passive muscle stretching while standing on a tilt - table decreases the resistance 
 to passive ankle joint movements in children with cp4 . therefore , it has been suggested as a treatment technique for 
 children and adults with cp . whole body vibration has also been proposed as a treatment for 
 children and adults with spastic cp . some studies have shown that whole body vibration decreases the 
 spasticity of patients with stroke , spinal cord injury and multiple sclerosis5,6,7 . a whole body vibration intervention 
 decreases spasticity and improves walking speed , muscle strength and gross motor function 
 without any side effects in adults with cp7 . because both muscle stretching and vibration have underlying 
 treatment efficacy in the alleviation of spasticity , and promote muscle function in adults 
 with cp , a therapeutic program combining passive muscle stretching and whole body vibration 
 may show better treatment effects in children and adolescents with spastic cp . however , no 
 study has yet combined passive muscle stretching with whole body vibration for children and 
 adolescents with spastic cp . therefore , the aim of this study was to investigate the effect 
 of combining passive muscle stretching and whole body vibration on the spasticity , 
 functional strength and balance of children and adolescents with spastic cp . twelve children and adolescents with spastic cp aged 618 years ( age , 10.58  2.35  years ; 
 height , 127.25  9.72  cm ; body mass , 26.48  7.95  kg ; mean  sd ) were recruited from khon 
 kaen special school . subjects were classified for gross motor function at levels i , ii and 
 iii according to the gross motor function classification system ( gmfcs ) , and were included 
 in the study when their modified ashworth scale ( mas ) scores were greater than or equal to 
 1 . exclusion criteria for this study : were receiving pms more than 3 times / week ; medical 
 treatment for spasticity such as a drugs , botulinum toxin injection , or orthopedic surgery 
 during the last six months ; medical problems such as arthritis , congenital abnormality , 
 cardiovascular or pulmonary diseases , or neuromuscular diseases ; musculoskeletal disorders ; 
 or infectious disease . this study was approved by the local ethics committee for human 
 research of khon kaen university . parents of the children and the children read and signed 
 an informed consent form before the start of the study . the study was designed as a two - period cross - over trial in which all subjects received 
 both , passive muscle stretching alone as a control group ( cg ) , and a combination of passive 
 muscle stretching and whole body vibration as an experimental group ( eg ) , as shown in fig . cg : control group ; eg : experimental group ; pms : passive muscle stretching ; wbv : whole 
 body vibration . both treatment groups were evaluated for immediate effect ( one treatment ) and for 
 short - term effect ( 6 weeks treatment ) . the sample size was calculated based on a primary 
 modified ashworth scale ( mas ) outcome which was determined as the predicted value ( the 
 post - test value of mas decreased 20% ) . sampling 
 randomization was stratified according to the gmfcs from levels i to iii , and ages of 
 children ( 6 to < 10  years ) , and adolescents ( 1019 years ) . after the baseline assessment 
 of all subjects , 12 children were randomly assigned to either eg - cg or cg - eg . in eg - cg , the 
 number of subjects with gmfcs levels i , ii and iii was 1 , 1 and 4 , respectively , and 3 of 
 the 6 subjects were under the age of 10 while in cg - eg , the number of subjects with gmfcs 
 levels i , ii and iii was 1 , 2 and 3 , respectively and 2 of the 6 subjects were under the age 
 of 10 . the gmfcs levels and ages were similar in both groups and each group was crossed over 
 at the end of each phase was so that each group received the same treatment . in phase 1 , 
 subjects were evaluated for outcome variables before and immediately after a one - time 
 treatment and in phase 2 , the procedure was repeated after group crossover . all subjects 
 rested for 2 days for a washout between phases 1 and 2 . after phase 2 had finished , subjects 
 rested for the 2-day washout period , and in phase 3 , all individuals continuously received 
 treatment for 6 weeks . after phase 3 , a washout period of 2 weeks was conducted before group 
 crossover for phase 4 . pre - and post - treatment measurements were conducted in phases 3 and 
 4 . cg : control group ; eg : experimental group ; pms : passive muscle stretching ; wbv : whole 
 body vibration for cg , passive muscle stretching was performed while the subjects stood on a tilt table 
 for 40 minutes per session . the table was tilted to 7080 degrees relative to the horizontal 
 plane , and two straps around the chest and knees helped to support the body . for eg , a 
 combination of passive muscle stretching and whole body vibration was conducted . whole body 
 vibration was applied at 20  hz on the oscillation platform ( aiko vibrator , etf-001cg , 
 thailand ) . after passive muscle stretching for 30 minutes , a total of 10 minutes of 
 one - minute vibration with one minute rest was performed while the subjects stood with equal 
 weight - bearing on both feet . subjects stood in a standardized foot position on the platform 
 as recommended by the manufacturer with center of the platform located between the legs 
 placed shoulder - width apart . the amplitude of vibration becomes larger when the feet are 
 placed further from the center line . for safety reasons , some subjects held a handle - bar 
 during the vibration . both the cg and eg interventions were conducted for a total of 40 
 minutes treatment / day , 5 days / week for 6 weeks , in addition to the regular physiotherapy 
 program at school of 1 session / week . before and after the single treatments and the 6-week 
 treatments , subjects were evaluated using the modified ashworth scale ( mas ) , the five times 
 sit - to - stand test ( ftsst ) and the pediatric balance scale ( pbs ) . mas is known as an essential 
 clinical measure of muscle spasticity in people with neurological conditions8 . the topographic distribution of impairment was determined 
 as the leg with lower or higher spasticity which represented the weaker or stronger side , 
 respectively . mas scores were assigned numerical values for the evaluated mas scores ( 0 , 1 , 
 2 , 3 , 4 and 5 ) . a value of 0 indicates no increase in muscle tone ; 1 ( 1 point ) is a slight 
 increase in muscle tone , manifested by a catch and release or by minimal resistance at the 
 end of the range of motion when the affected part is moved in flexion or extension ; 1 + ( 2 
 points ) is a slight increase in muscle tone , manifested by a catch , followed by minimal 
 resistance throughout the remainder ( less than half ) of the rom ( range of movement ) ; 2 ( 3 
 points ) is a more marked increase in muscle tone through most of the rom , but the affected 
 part is easily moved ; 3 ( 4 points ) is a considerable increase in muscle tone passivity , with 
 movement difficult ; 4 ( 5 points ) is an affected part rigid in flexion or extension . mas was 
 assessed by the same evaluator throughout the experiment , and outcomes were tested for the 
 intra - tester reliability . the five times sit - to - stand test ( ftsst ) is a reliable tool for evaluating lower limb 
 muscle strength and balance ability9 . subjects sat on a chair with their arms crossed over the chest , and they were asked to stand 
 up and sit down again as quickly as possible five times without using arm support . the test 
 began with the word  go  and stopped when subjects sat after the fifth performance ; the time 
 was recorded . the pediatric balance scale ( pbs ) is a modification of the berg balance scale , which was 
 developed for the evaluation of the balance ability of school - age children with mild to 
 moderate motor impairments . pbs has been demonstrated to have good test - retest and 
 inter - rater reliabilities10 . there are 14 
 items and each item is scored on a five point ordinal scale from zero to four with a maximum 
 score of 56 points . in order to demonstrate each task and give instruction , each child was 
 allowed to practice each item once . if the child was unable to complete the task based on 
 their inability to understand the directions , a second practice trial was allowed , and the 
 best score was recorded11 . pbs took 
 approximately 15 minutes to conduct , and if some children needed more time or felt fatigued 
 during the test they were allowed to rest for a few minutes . the distribution of the data was examined using the shapiro - wilk s test to examine the 
 assumption of normality . the 
 differences of variables within and between the groups were assessed with the wilcoxon 
 signed - ranks test and the mann - whitney u - test , respectively . tables 1table 1.pre-and post - intervention evaluation items of the control and experimental 
 groupsimmediate effectshort - term effectcontrol groupexperimental groupcontrol groupexperimental groupbeforeafterbeforeafterbeforeafterbeforeaftermas scorestrongerhip adductors 2 ( 1:3.75)2 ( 1:2)2 ( 1:3)1 ( 1:2.75)2 ( 1:3)2 ( 1:2.8)2 ( 1:3)1 ( 1:1)quadriceps 2.5 ( 2:3)1 ( 1:2)2.5 ( 2:3)2 ( 1.25:2)3 ( 1.3:3)2 ( 1.3:2.8)3 ( 1.3:3)1 ( 1:2)hamstrings2 ( 1:3)1 ( 1:2)2 ( 1:3)1 ( 1:1)2.5 ( 2:3)2 ( 1.3:2.8)3 ( 2:3)1 ( 1:1.8)soleus2 ( 1.25:4.75)1.5 ( 1:3)2 ( 1.25:4.75)1 ( 1:2)3 ( 1.3:5)2 ( 1:4)3 ( 2:5)1.5 ( 1:2.8)weakerhip adductors 2 ( 1:3.75)1 ( 1:3)2 ( 1:3.75)1 ( 1:3)1.5 ( 1:2.8)1.5 ( 1:2.0)1.5 ( 1:2.8)1 ( 1:1)quadriceps 2 ( 1:2.75)2 ( 1:2)2 ( 1:2.75)1 ( 1:2)2 ( 1:2)2 ( 1:2)2 ( 1:2)1 ( 1:1.8)hamstrings 1.5 ( 1:2.75)1 ( 1:2)1.5 ( 1:2.75)1 ( 1:1)1.5 ( 1:2)2 ( 1:2.8)1.5 ( 1:2)1 ( 1:1)soleus2 ( 2:3.75)1.5 ( 1:3.75)2 ( 2:3.75)1 ( 1:2.5)2.5 ( 1:4)2 ( 1:3)2 ( 1:3.8)1 ( 1:2.8)ftsst ( s)16.59 ( 13.0:23.1)17.28 ( 10.6:22.7)16.93 ( 12.3:16.9)11.96 ( 10.9:19.9)13.34 ( 10.7:20.6)10.14 ( 9.6:12.7)13.55 ( 11.8:21.9)11.36 ( 8.1:13.4)pbs ( score)26.00 ( 7:42)25.00 ( 7.5:42.25)24.00 ( 8.5:42.25)26.50 ( 10:42.25)26.0 ( 7.3:45.8)27.5 ( 8.5:42.0)24.5 ( 8.5:42.0)31.0 ( 10.0:44.3)data are presented as median ( quartile1:quartile3 ) for all outcomes . p 
 < 0.05 , p < 0.01 and 2table 2.comparison of the median differences between the control and experimental 
 groupsimmediate effectshort - term effectcontrol groupexperimental groupcontrol groupexperimental groupmas scorestrongerhip adductors 0 ( 1.0 : 0)0 ( 1.0 : 0 ) 0 ( 1 : 0.75)0.5 ( 1 : 0)quadriceps 1.0 ( 1.75 : 0)1.0 ( 1 : 0 ) 0 ( 1 : 0)1.0 ( 1 : 1)hamstrings 0.5 ( 1.0 : 0)1.0 ( 2.0 : 0)0.5 ( 1 : 0)1.0 ( 2 : 1)soleus 0 ( 1.0 : 0)1.0 ( 2.0 : 0)0 ( 1 : 0)1.0 ( 1.75 : 0.25)weakerhip adductors 0 ( 0.75 : 0)0 ( 1.0 : 0)0 ( 0 : 0)0 ( 1 : 0)quadriceps 0 ( 0.75 : 0)0 ( 1.75 to 0)0 ( 0 : 0)0.5 ( 1 : 0)hamstrings 0 ( 1.0 : 0)0 ( 1.75 : 0)0 ( 0 : 0.75)0.5 ( 1 : 0)soleus 0 ( 1.0 : 0)1.0 ( 1.75 : 0.25)0 ( 1 : 0)1.0 ( 1 : 0)ftsst ( s)1.18 ( 3.0 : 1.6)2.61 ( 5.3 : 1.1)3.28 ( 6.70 : 0.51)4.46 ( 8.09 : 2.41)pbs ( score)0 ( 0 : 1)0 ( 0 : 1)0 ( 2 : 2.75)2.5 ( 0 : 4)data are presented as the median difference ( quartile 1 : quartile 3 ) for all 
 outcomes . p < 0.05 summarize the pre - and post - intervention measurement values of cg and eg . in 
 the immediate effect of eg , mas scores significantly decreased in all muscles of the 
 stronger side and the soleus of the weaker side . in the immediate effect of cg , mas scores 
 significantly decreased in the quadriceps , hamstrings and soleus muscles of the stronger 
 side . in the comparison of the groups , only the mas score of the soleus of the weaker side 
 was significantly improved by eg . after the 6-week treatment , all the evaluated items 
 significantly improved in eg , and the mas scores of the hamstrings and soleus of the 
 stronger side and ftsst improved in cg . in the comparison of the groups , the mas scores of 
 the quadriceps and hamstrings of both sides , and soleus of the stronger side were more 
 significantly decreased by eg than by cg . no significant differences between the groups were 
 found for ftsst , pbs and mas of the hip adductors . p 
 < 0.05 , p < 0.01 data are presented as the median difference ( quartile 1 : quartile 3 ) for all 
 outcomes . the results show the combined treatment of pms and wbv had better effects than pms alone on 
 the spasticity of children and adolescents with cp . immediately after one treatment , the 
 combined treatment showed better improvement in the scores of the mas than pms alone . after 
 the 6-week intervention , the combined treatment significantly decreased the scores of the 
 mas when compared to pms alone . both treatments significantly reduced the children s 
 performance times in the five times sit - to - stand test , while the combined treatment 
 significantly increased the scores of the pediatric balance scale . thus , the results suggest 
 that a 6-week intervention of a combination of prolonged pms and wbv may elicit beneficial 
 effects for the spasticity and balance of patients with cerebral palsy . 
 sustained passive muscle stretching for a long duration improves the range of movements , and 
 reduces the spasticity of muscles11 , 12 . passive muscle stretching activates golgi 
 tendon organs and inhibits the excitability of alpha motor neurons . current evidence supports the effectiveness of passive 
 stretching of children with spastic cp , although the reduction in spasticity may not be 
 linked with functional activities such as walking3 . a combination of exercise , massage therapy and therapeutic supports 
 is an effective treatment for the release of muscle stiffness , decrease of pain , and 
 improvement of physical functions14,15,16 . therefore , different therapeutic methods should be used to 
 normalize muscle tone , maintain or increase soft - tissue extensibility , reduce contracture 
 pain , and improve motor function18 . oscillation 
 of the ankle joints with a vibrator helps to induce release of a stiff ankle joint . during 
 vibration , standing in a neutral ankle position with body weight bearing also stimulates the 
 stretching of calf muscles . whole body vibration decreases the spasticity of muscles and 
 increases the gross motor function of subjects with cp7 , 19 . whole body vibration 
 improved muscle strength and power movement similar to conventional resistance training in 
 older women20 and in adults with cp7 . the muscle spindle senses a very small 
 change in muscle length when a skeletal muscle perceives vibration . this information is 
 transmitted to the fibers of group ia or ii , eventually reaching the spinal cord . in the 
 spinal cord , the information serves as presynaptic inhibition through an interstitial cell 
 and suppresses the alpha motor neurons21 , 22 . the activation of these sensory receptors 
 results in reflexive activation of motor units similar to the tonic vibration reflex23 . whole body vibration improved the performance of multiple 
 sclerosis patients in the timed up & go test26 . this improvement in physical balance after whole body vibration 
 may be associated with improvement of leg muscle strength27 . the activation of proprioreceptive spinal circuits can be induced 
 by upright standing on a vibration platform . because reflexes are related to the 
 time - differential activation of spindles in muscles and tendons28 , the improvement in balance might be positively related to 
 muscle strength and proprioception after vibration training . whole body vibration may allow 
 children and adolescents with cp to walk effectively with an improvement of balance . similar 
 to our results , previous research has shown that whole body vibration improves the muscle 
 tone , strength , balance and mobility of children with cp29,30,31 ; however , those studies used a vibration frequency with stepwise 
 increment up to 18  hz compared to the constant vibration frequency of 20  hz used in the 
 present study . a limitation of this study was the small number of subjects and the absence of 
 double - blinding of subjects and physiotherapists . with regard to adherence to treatment , all 
 subjects enjoyed whole body vibration therapy and engaged in regular interaction with the 
 physiotherapists . therefore , whole body vibration should be added to the physiotherapy 
 program . although improvements in outcomes were found in this study , the optimal 
 dose - response vibration was not clear . thus , further studies should focus on the training 
 protocol or whole body vibration that can provide the best results for children and 
 adolescents with cp . in conclusion , this present study showed that 6 weeks of combined passive muscle stretching 
 and whole body vibration could decrease the spasticity and increase the muscle strength and 
 balance of children and adolescents with cp . whole body vibration could be an alternative 
 additional treatment to passive muscle stretching for both clinical and home therapy 
 programs for children and adolescents with cp .
[ purpose ] this study evaluated the immediate and short - term effects of a combination of 
 prolonged passive muscle stretching ( pms ) and whole body vibration ( wbv ) on the 
 spasticity , strength and balance of children and adolescents with cerebral palsy . 
 [ subjects and methods ] a randomized two - period crossover trial was designed . 
 twelve 
 subjects with cerebral palsy aged 10.6  2.4  years received both pms alone as a control 
 group ( cg ) and a combination of pms and wbv as an experimental group ( eg ) . 
 after random 
 allocation to the trial schedules of either eg - cg or cg - eg , cg received prolonged pms 
 while standing on a tilt - table for 40 minutes / day , and eg received prolonged pms for 30 
 minutes , followed by 10 minutes wbv . 
 both cg and eg received the treatment 5 days / week for 
 6 weeks . 
 [ results ] immediately after one treatment , eg resulted in better improvement in 
 scores on the modified ashworth scale than cg . 
 after the 6-week intervention , eg also 
 showed significantly decreased scores on the modified ashworth scale compared to cg . 
 both 
 cg and eg showed significantly reduced the performance times in the five times sit to 
 stand test , and eg also showed significantly increased scores on the pediatric balance 
 scale . 
 [ conclusion ] this study showed that 6 weeks of combined prolonged pms and wbv had 
 beneficial effects on the spasticity , muscle strength and balance of children and 
 adolescents with cp .