the proper physical therapy frequency is increasingly important in the determination of 
 government financial and insurance benefits .
the physical therapist is responsible for 
 demonstrating the value and effect of services , and the therapy schedule should be planned 
 carefully1 .
although appropriate 
 treatment frequency and duration are important in pediatric physical therapy , evidence for 
 determining the optimal program is lacking2 , 3 .
the frequency of physical therapy is a 
 factor that should be considered with greater importance in children with cerebral palsy 
 ( cp ) because children with chronic disabilities should receive therapy for as long as the 
 family requests services4 . in practice
, 
 therapy is continued at various frequencies for which effectiveness has not been well 
 documented4 .
treatment frequency guidelines 
 ( tfg)4 and treatment frequency and 
 duration guidelines ( tfdg)1 have been 
 developed and published .
the tfg were developed for use by physical and occupational 
 therapists through adaptations of the existing literature .
the 4 developed modes included 
 intensive therapy ( 3 to 11 times per week ) , weekly or bimonthly therapy ( 1 to 2 times a week 
 to every other week ) , periodic therapy ( monthly or less often but at regularly scheduled 
 intervals ) , and consultative therapy ( episodic or as needed ) . the tfdg modified the tfg , and 
 consisted of 5 intensity levels : intensive , weekly , bimonthly , periodic , and consultative . 

the intensive mode was 3 to 5 times per week for a 26-week duration , while consultative 
 mode provided therapy as needed when a patient was discharged from regularly scheduled 
 therapy and consulted a therapist for only certain needs .
changes in the gross motor 
 function measure ( gmfm ) , which is used as a standard outcome measure in children with cp 
 according to intensity dosage , have been variable5 .
another drawback of previous studies on physical therapy frequency 
 is that the research was performed over a short period of time .
although physical therapy 
 services are usually short - term during recovery from illness or surgery in the outpatient 
 environment , there have been no reports on children with long - term needs6 .
in addition , current cross - sectional data are limited for revealing the long - term impact of 
 changes on outcomes in children with cp . because the effect of therapy for chronic 
 disabilities such as cp is difficult to detect in a short period of time , a longitudinal 
 follow - up study should be performed to investigate the proper therapy frequency .
this study 
 addressed the following two questions regarding the proper physical therapy frequency based 
 on neurodevelopmental therapy ( ndt ) for gross motor function in children with cp .
first , 
 what is the correlation between physical therapy frequency and gross motor function outcome 
 in children with cp ?
second , do gross motor function outcomes differ among intensive ( 3 to 
 11 times a week ) , weekly , or bimonthly frequency modes of tfg ?
the study sample comprised 161 children with cp ( mean age : 9  years , 1 month ; sd : 4  years , 6 
 months ) who attended a convalescent or rehabilitation center for disabled individuals or a 
 special school for children with physical disabilities in south korea .
this study was approved by the ethics 
 committee of jeonju university ( jeonju university irb-1 ) . written informed consent
to 
 participate in the study was obtained from the parents of all the children .
the types of cp 
 in the children were spastic ( 85.1% ) , dyskinetic / athetotic ( 7.1% ) , and ataxic ( 7.8% ) .
the 
 participants were classified using the gross motor function classification system ( gmfcs ) : 
 26 ( 16.1% ) were classified into level i , 25 ( 14.9% ) into level ii , 19 ( 11.8% ) into level 
 iii , 19 ( 11.8% ) into level iv , and 73 ( 44.8% ) into level v. the gmfm was used to assess gross motor function according to physical therapy frequency 
 for 1  year .
the gmfm is a standard criterion - referenced test that was designed to assess 
 changes in gross motor function in children with cp .
the 88-item test assesses activities in 
 the 5 dimensions of lying and rolling , sitting , crawling and kneeling , standing , and 
 walking , running , and jumping .
the one - sample kolmogorov - smirnov ( k - s ) test was employed to determine the method of 
 statistical analysis .
because the results of the k - s test were statistically significant , a 
 non - parametric test was performed to verify the physical therapy frequency .
the correlation coefficients between physical therapy frequency and gross motor function 
 are shown in table 1table 1.correlation between physical therapy frequency and gross motor function 
 changeslying androllingsittingcrawling andkneelingstandingwalking , running , and jumpinggmfm totalphysical therapy frequencyall 0.0270.0000.1910.2400.1330.162gmfcs level v0.1520.0420.1760.2860.0930.058*p<0.05 , * * p<0.01 .
the correlation between physical therapy frequency and gmfm scores , including 
 crawling and kneeling , standing , walking , running and jumping , rolling , and the gmfm total 
 score , was significant .
in gmfcs level v , only standing score showed a significant 
 correlation with physical therapy frequency .
gmfm : gross motor function measure the results of the kruskal - wallis test are presented in tables 2table 2.differences in gross motor function changes by physical therapy frequencycategorymeansdgmfm domainpt frequencylying and rollingconsultative0.6914.23bimonthly2.0817.96intensive0.7413.47sittingconsultative4.5111.04bimonthly6.8614.79intensive3.5311.59crawling and kneelingconsultative 4.215.61bimonthly0.911.32intensive 1.5610.36standingconsultative 4.2214.35bimonthly 5.0517.78intensive 4.3312.41walking , running & jumpingconsultative15.9215.42bimonthly26.322.69intensive25.1820.31gmfm totalconsultative 2.268.73bimonthly 8.2411.48intensive 6.779.13gmfm : gross motor function measure . *
the different superscript letter 
 indicates a significant difference ( p<0.05 ) . and 3table 3.differences in gross motor function changes according to physical therapy 
 frequency , gmfcs level vcategorymeansdgmfm domainpt frequencylying and rollingconsultative6.6416.14bimonthly0.8124.13intensive2.3621.94sittingconsultative3.4216.16bimonthly3.0319.04intensive5.9322.78crawling and kneelingconsultative 11.7721.29bimonthly2.3819.17intensive 4.1719.52standingconsultative2.435.23bimonthly 2.7722.45intensive5.3317.22walking , running , and jumpingconsultative20.8914.27bimonthly27.424.17intensive21.4523.25gmfm totalconsultative 1.576.89bimonthly 6.4511.04intensive 6.7418.47gmfm : gross motor function measure .
the different superscript letters 
 indicate significant differences ( p<0.05 ) .. the different superscript letters refer to significant differences 
 ( p<0.05 ) .
the differences in gross motor function according to frequency of physical 
 therapy were significant for crawling and kneeling , standing , and gmfm total score . 

intensity mode showed a significant effect for improvement in crawling and kneeling , 
 standing , and gmfm total score compared to the consultative mode .
intensity mode showed a 
 significant improvement effect for standing compared to the consultative mode in children 
 with cp , which was classified into gmfcs level v. gmfm : gross motor function measure .
gross motor function has been related to functional outcomes such as activities of daily 
 living7 .
activities and participation 
 domains based on the international classification of functioning disability and health ( icf ) 
 are considered major concepts in rehabilitation ; thus , improved gross motor function in 
 mastering tasks and activities of daily living is a major goal of therapy for children with 
 cp8 . the evidence of the correlation 
 between physical therapy frequency and gross motor function should be clarified to determine 
 the proper physical therapy frequency for improving gross motor function in children with 
 cp . in this study ,
the correlation between physical therapy frequency and gmfm data was 
 investigated during a 1  year follow - up period .
the gmfm domains that showed significant correlations with physical therapy frequency were 
 crawling and kneeling , standing , walking , running , and jumping , and gmfm total . in children 
 with cp classified into gmfcs level
there were significant differences in crawling and kneeling , 
 standing , and gmfm total .
the significant difference in standing was seen in children with 
 gmfcs level v cp .
these results indicate that intensive physical therapy might be effective 
 for improving the gross motor function in children with cp .
the cause of non - significant 
 correlations for lying and rolling as well as the differences in lying and rolling and 
 standing could be explained by the ceiling effect of the gmfm .
vos - vromans et al.9 reported the ceiling effect of the gmfm in 
 dimensions a , b , and c. they assessed gross motor function at baseline and at 3 follow - up 
 assessments at 6-month intervals to describe the responsiveness of the measures used to 
 evaluate the motor abilities of children with cp .
dimensions a ( lying and rolling ) , b 
 ( sitting ) , and c ( crawling and kneeling ) of the gmfm were not responsive in the children 
 participating in this study .
an explanation for this phenomenon is that dimensions a , b , and 
 c of the gmfm are relatively easy for children with mild cp to achieve .
the only significant 
 difference of standing in gmfcs level v might be attributed to ceiling effect .
the insignificant correlation between physical therapy frequency and walking , jumping , and 
 running might be explained by the bottom effect . walking , jumping , and running
labaf et al.10 
 reported that ndt improved gross motor function in children with cp in 4 dimensions ( lying 
 and rolling , sitting , crawling and kneeling , and standing ) but that walking , running , and 
 jumping did not improve significantly .
although there was a significant effect between gross motor function and physical therapy 
 frequency , the correlation coefficients were small .
one reason for this result might be the 
 content of the physical therapy provided for the children with cp .
activity - based 
 interventions should reduce activity limitations in children with cp8 . however , physical therapy based on ndt focused on reducing 
 abnormal tone , reflexes , and posture , which comprised an impairment - based intervention . 

another cause of the small correlation coefficients might be due to the use of the gmfm for 
 outcome measures in this study .
the effect of physical therapy frequency 
 was different at gmfcs level v. for that reason , the effect of physical therapy frequency 
 should be examined according to gmfcs level to verify the specific effect of frequency .
intensive physical therapy was more effective at improving gross motor function in children 
 with cp .
in particular , crawling and kneeling and standing ability were more increased in 
 the intensive physical therapy mode .
tsorlakis et al.12 
 compared the effect on gross motor function in group a with ndt twice a week and in group b 
 with therapy 5 times a week for 16 weeks .
the results showed that gross motor function in 
 the children of both groups improved significantly after intervention and that the children 
 in group b performed better and showed significantly greater improvement than those in group 
 a. the results of this study support the effectiveness of ndt and emphasize the need for 
 intensive treatment .
although more intensive physical therapy is thought to be more effective , evidence of this 
 assumption has been insufficient .
this study provided evidence of the effects of intensive 
 physical therapy in children with cp during a 1  year follow - up period .
however , further 
 studies should be performed to accumulate evidence of the various effects according to 
 physical therapy frequency .
first , the different effects according to physical therapy 
 content should be investigated . because the effects of therapy on gross motor function might 
 vary depending on whether therapy focused on gross motor function
second , the different effects according to the ages of the 
 children with cp should be examined . according to a previous meta - analysis10 , the effect of intensive treatment tended 
 to be stronger for children 2  years of age .
this study examined the effect of physical therapy based on ndt according to frequency 
 during a 1  year follow - up of gross motor function in children with cp . intensive therapy 
 significantly improved gross motor function for crawling and kneeling as well as 
 standing .
 [ purpose ] this study attempted to investigate the effect of physical therapy frequency 
 based on neurodevelopmental therapy on gross motor function in children with cerebral 
 palsy . [ subjects and methods ] the study sample included 161 children with cerebral palsy 
 who attended a convalescent or rehabilitation center for disabled individuals or a special 
 school for children with physical disabilities in south korea . 
 gross motor function 
 measure data were collected according to physical therapy frequency based on 
 neurodevelopmental therapy for a period of 1  year . 
 [ results ] the correlation between 
 physical therapy frequency and gross motor function measure scores for crawling and 
 kneeling , standing , walking , running and jumping , and rolling , and the gross motor 
 function measure total score was significant . 
 the differences in gross motor function 
 according to physical therapy frequency were significant for crawling , kneeling , standing , 
 and gross motor function measure total score . 
 the differences in gross motor function 
 according to frequency of physical therapy were significant for standing in gross motor 
 function classification system level v. [ conclusion ] intensive physical therapy was more 
 effective for improving gross motor function in children with cerebral palsy . 
 in 
 particular , crawling and kneeling , and standing ability showed greater increases with 
 intensive physical therapy . 
INTRODUCTION
SUBJECTS AND METHODS
RESULTS
DISCUSSION