***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: A population -based , r and omized universal classroom intervention trial for the prevention of disruptive behavior ( i.e. , attention-deficit/hyperactivity problems , oppositional defiant problems , and conduct problems ) is described . Impact on developmental trajectories in young elementary schoolchildren was studied . Three trajectories were identified in children with high , intermediate , or low levels of problems on all 3 disruptive behaviors  at baseline . The intervention had a positive impact on the development of all disruptive behavior problems in children with intermediate levels of these problems at baseline . Effect sizes of mean difference at outcome were medium or small . In children with the highest levels of disruptive behavior at baseline , a positive impact of the intervention was found for conduct problems Background Physical inactivity is recognised as a public health concern within children and interventions to increase physical activity are needed . GreatFun2Run was a school-based healthy lifestyles intervention that showed positive changes in physical activity levels and body composition immediately post-intervention . The purpose of this paper was to examine whether these changes in physical activity and body composition were maintained 18 - 20 months after the intervention ended . Method Participants ( n = 589 , aged 7 - 11 yrs ) from 4 intervention and 4 control schools took part in the 10-month intervention , of which 421 ( 71 % ) were present for follow-up . The intervention comprised a CD-rom learning and teaching re source for teachers ; an interactive website for pupils , teachers and parents ; two highlight physical activity events ( 1 mile school runs/walks ) ; a local media campaign ; and a summer activity wall planner and record . R and omisation was not possible because of local media content . Outcome measures were objective ly measured physical activity ( pedometers and accelerometers ) and body composition variables ( body mass index , waist circumference , estimated percent body fat , and sum of skinfolds ) . Teacher interviews and participant focus groups were conducted . Multi-level modelling was employed for the data analysis . Results Both control and intervention participants had increased their physical activity at follow-up but there was no group by time interaction ( control : 2726 steps per day increase ; intervention 3404 steps per day increase , p > .05 ) . There were significant increases in estimated percent body fat , sum of skinfolds , waist circumference and body mass index ( BMI ) with increasing age . In the control group , there was evidence for a plateauing in the rate of change in all body composition variables with increasing age , except BMI . In contrast , significant interaction terms suggest that the rate of change in waist circumference , BMI and BMI SDS continued to increase with age in the intervention group . Teacher interviews suggested that because of time pressures , competing re sources , curriculum dem and s and staff changes the majority of teachers had not continued to use the re sources . Conclusions While the intervention initially produced positive changes in physical activity levels and body composition , these changes were not sustained once the intervention ended . Facilitating long-term health behaviour change in children remains a challenge This study reports the effect of a  school-r and omized fruit and vegetable intervention consisting of a subscription to the Norwegian School Fruit Programme at no parental cost , and the Fruit and Vegetables Make the Marks ( FVMM ) educational programme , both delivered in the school year of 2001 - 02 . Nine r and omly chosen schools received the intervention and 10 schools served as control schools . Participating pupils completed question naires at baseline ( September 2001 ) , at Follow-up 1 ( May-June 2002 ) and at Follow-up 2 ( May 2003 ) . A total of 517 pupils ( 84 % ; mean age , 11.3 years at baseline ) participated in all three surveys . At both Follow-up 1 and Follow-up 2 , strong intervention effects were observed for all-day fruit and vegetable intake ( effect sizes were 0.6 and 0.5 portions , respectively ) . The sustained effect at Follow-up 2 , 1 year after the end of the intervention , can partly be explained by greater participation rates in the School Fruit Programme ( st and ard paid subscription ) . We conclude that the effects observed are most likely due to the no-cost subscription and not due to the FVMM educational programme , and that providing pupils with a piece of fruit or a vegetable at school at no cost for the parents is an effective strategy to increase  school children 's intake of fruit and vegetables . The effect is also sustained 1 year after the end of the no-cost subscription , providing increased health benefits To test the effectiveness of the Child and Adolescent Trial for Cardiovascular Health ( CATCH ) program , a r and omized trial was conducted in 96 elementary schools in four regions of the United States . Results from the original trial indicated a significant positive effect on the delivery of physical education ( PE ) .  All 56 former intervention schools ( FI ) , 20 r and omly selected former control schools ( FC ) , and 12 newly selected unexposed control schools ( UC ) were assessed 5 years postintervention . Results indicate a strong secular trend of increasing moderate to vigorous physical activity ( MVPA ) in PE classes among both FC and UC schools . The FI schools surpassed the Healthy People 2010 goal for MVPA during PE lesson time ( i.e. , 50 % ) , whereas the FC and UC schools came close to it . Barriers to implementing CATCH PE included insufficient training and lower importance of PE compared to other academic areas and indicate the need for in-service training 
    Output:
    
No discernible relationship was found between evidence of effectiveness and sustainability .
Key facilitators included commitment/support from senior leaders , staff observing a positive impact on students ’ engagement and wellbeing , and staff confidence in delivering health promotion and belief in its value .
Important context ual barriers emerged : the norm of prioritising educational outcomes under time and re source constraints , insufficient funding /re sources , staff turnover and a lack of ongoing training .
Adaptation of the intervention to existing routines and changing context s appeared to be part of the sustainability process .
Conclusions Existing evidence suggests that sustainability depends upon schools developing and retaining senior leaders and staff that are knowledgeable , skilled and motivated to continue delivering health promotion through ever-changing circumstances .
Evidence of effectiveness did not appear to be an influential factor .