***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: PURPOSE To determine the effect of increasing the aerobic component of the school 's physical activity program and improving the knowledge about weight control and blood pressure on the blood pressure and body fat of early adolescents . METHODS The subjects were 1140 youth aged 11 to 14 years ( 630 females , 510 males ; 64 % white , 24.4 % African-American , and 11.6 % " other " ) , who were r and omly assigned by school into four treatment groups : exercise only , education only , exercise and education combined , and control group . Heights , weights , and skinfold thicknesses were measured , and body mass index ( BMI ) was computed kg/m(2 ) . Blood pressure was obtained in duplicate using a r and om-zero mercury sphygmomanometer . Maximal oxygen uptake was predicted from a submaximal cycle ergometer test . Data were analyzed using analysis of covariance statistics , adjusting for gender , ethnicity , age , socioeconomic status , and initial baseline characteristics . RESULTS Systolic and diastolic blood pressures increased more in the control group than in the intervention groups ( p = .001 ) . The BMI did not change significantly ( p = .709 ) , but the sum of skinfolds increased less in subjects in the exercise intervention groups than the education only or control groups ( p = .0001 ) . The small increase in (p)VO(2)max of the combined exercise and education group was significantly greater than the education only group ( p = .0001 ) . CONCLUSION An exercise program for youth can have a positive effect on blood pressure independent of body weight loss Background Schools are the most frequent target for intervention programs aim ed at preventing child obesity ; however , the overall effectiveness of these programs has been limited . It has therefore been recommended that interventions target multiple ecological levels ( community , family , school and individual ) to have greater success in changing risk behaviors for obesity . This study examined the immediate and short-term , sustained effects of the Switch program , which targeted three behaviors ( decreasing children 's screen time , increasing fruit and vegetable consumption , and increasing physical activity ) at three ecological levels ( the family , school , and community ) . Methods Participants were 1,323 children and their parents from 10 schools in two states . Schools were matched and r and omly assigned to treatment and control . Measures of the key behaviors and body mass index were collected at baseline , immediately post-intervention , and 6 months post-intervention . Results The effect sizes of the differences between treatment and control groups ranged between small ( Cohen 's d = 0.15 for body mass index at 6 months post-intervention ) to large ( 1.38 ; parent report of screen time at 6 months post-intervention ) , controlling for baseline levels . There was a significant difference in parent-reported screen time at post-intervention in the experimental group , and this effect was maintained at 6 months post-intervention ( a difference of about 2 hours/week ) . The experimental group also showed a significant increase in parent-reported fruit and vegetable consumption while child-reported fruit and vegetable consumption was marginally significant . At the 6-month follow-up , parent-reported screen time was significantly lower , and parent and child-reported fruit and vegetable consumption was significantly increased . There were no significant effects on pedometer measures of physical activity or body mass index in the experimental group . The intervention effects were moderated by child sex ( for fruit and vegetable consumption , physical activity , and weight status ) , family involvement ( for fruit and vegetable consumption ) , and child body mass index ( for screen time ) . The perception of change among the experimental group was generally positive with 23 % to 62 % indicating positive changes in behaviors . Conclusion The results indicate that the Switch program yielded small-to-modest treatment effects for promoting children 's fruit and vegetable consumption and minimizing screen time . The Switch program offers promise for use in youth obesity prevention BACKGROUND Childhood obesity is a major public health problem in the United States , particularly among American Indian communities . OBJECTIVE The objective was to evaluate the effectiveness of a school-based , multicomponent intervention for reducing percentage body fat in American Indian schoolchildren . DESIGN This study was a r and omized , controlled , school-based trial involving 1704 children in 41 schools and was conducted over 3 consecutive years , from 3rd to 5th grade s , in schools serving American Indian communities in Arizona , New Mexico , and South Dakota . The intervention had 4 components : 1 ) change in dietary intake , 2 ) increase in physical activity , 3 ) a classroom curriculum focused on healthy eating and lifestyle , and 4 ) a family-involvement program . The main outcome was percentage body fat ; other outcomes included dietary intake , physical activity , and knowledge , attitudes , and behaviors . RESULTS The intervention result ed in no significant reduction in percentage body fat . However , a significant reduction in the percentage of energy from fat was observed in the intervention schools . Total energy intake ( by 24-h dietary recall ) was significantly reduced in the intervention schools but energy intake ( by direct observation ) was not . Motion sensor data showed similar activity levels in both the intervention and control schools . Several components of knowledge , attitudes , and behaviors were also positively and significantly changed by the intervention . CONCLUSIONS These results document the feasibility of implementing a multicomponent program for obesity prevention in elementary schools serving American Indian communities . The program produced significant positive changes in fat intake and in food- and health-related knowledge and behaviors . More intense or longer interventions may be needed to significantly reduce adiposity in this population Exercise during growth has a positive influence on bone mineral accrual , yet little is known about how bone geometry and strength adapt to loading during growth . Our primary objective was to compare changes in proximal femur bone geometry and strength between 31 prepubertal ( Tanner Stage 1 ) boys who participated in a school-based , high-impact circuit intervention ( 12 min , three times a week ) for 20 months and 33 maturity-matched controls . Our secondary objective was to compare changes in total body ( TB ) , proximal femur ( PF ) , and lumbar spine ( LS ) bone mineral content ( BMC ) and bone area ( BA ) in these groups . We assessed geometric variables and bone strength at the narrow neck ( NN ) , intertrochanteric ( TR ) region , and femoral shaft regions by applying the Hip Structure Analysis program to proximal femur dual energy X-ray absorptiometry scans ( DXA , Hologic QDR 4500 ) . Further , we assessed total body , lumbar spine , and proximal femur BMC and BA by DXA and derived total body lean mass and fat mass from total body scans . Intervention ( 10.2 + /- 0.5 years ) and control boys ( 10.1 + /- 0.5 years ) had similar baseline height ( 140.8 vs. 141.3 cm ) and weight ( 36.9 vs. 35.4 kg ) , and average 20-month physical activity scores ( Physical Activity Question naire for Children , PAQ-C ) and calcium intakes ( 861 vs. 852 mg/day , food frequency question naire ) . Twenty-month height and weight changes were not significantly different between groups ; lean mass changed more ( P < 0.05 ) in intervention boys ( 22.8 % ) than control boys ( 18.6 % ) . At the NN region , intervention boys had greater bone expansion on both the periosteal ( + 2.6 % , P = 0.1 ) and endosteal ( + 2.7 % , P = 0.2 ) surfaces , result ing in significantly greater changes in section modulus ( bone bending strength ) ( + 7.5 % , P = 0.02 , ANCOVA , adjusting for height change , final Tanner Stage , and baseline bone values ) . Changes at the intertrochanteric and femoral shaft regions were not significantly different between groups . Femoral neck ( FN ) BMC changes were significantly greater in intervention boys ( + 4.3 % , P < 0.01 ) ; changes in BA and BMC for other regions were not significantly different between groups . In summary , a school-based , high-impact exercise intervention implemented three times a week for 12 min is an effective strategy for site-specific gains in bone strength at the narrow neck region of the proximal femur OBJECTIVE Childhood weight-bearing physical activity is recognized as an important determinant of peak bone mass , and physical activity intervention may represent a feasible strategy for primary prevention of osteoporosis . Previous school-based exercise interventions have all been of < 10 months in duration . We implemented a high-impact , circuit-based , jumping intervention ( 10 minutes , 3 times a week ) over 2 school years and compared changes in bone mineral content ( BMC ) over 20 months ( 2 school years ) in 9.9 + /- 0.6-year-old intervention girls ( N = 32 ) and controls ( 10.3 + /- 0.4 years , N = 43 ) . METHODS We measured BMC for the total body , lumbar spine , proximal femur ( and femoral neck and trochanteric subregions ) , and lean and fat mass by dual-energy radiograph absorptiometry ( Hologic QDR 4500 ) , and height , sitting height , leg length , and weight at baseline and 20 months . We assessed Tanner stage , general physical activity , and calcium intake by question naire . RESULTS Girls were Tanner breast stage 1 to 3 at baseline . There were no significant differences in baseline or 20-month change in body size or composition , average physical activity , or calcium intake between groups . There were substantially greater gains in lumbar spine ( 41.7 % vs 38.0 % ) and femoral neck ( 24.8 % vs 20.2 % ) BMC in intervention than in control girls ( P < .05 , analysis of covariance ; covariates were baseline BMC and height , change in height , physical activity , and final Tanner stage ) . CONCLUSION Three brief sessions of high-impact exercise per week implemented over 2 consecutive years within the elementary school curriculum elicited a substantial bone mineral accrual advantage in pubertal girls OBJECTIVE --To examine the effect of physical training on physical fitness and blood pressure in children aged 9 - 11 years . DESIGN -- Prospect i ve r and omised controlled intervention study of a sample of children drawn from a population survey of coronary risk factors in children . SETTING --Odense , Denmark . SUBJECTS--69 children with mean blood pressure greater than or equal to 95th centile ( hypertensive group ) and 68 with mean blood pressure less than 95th centile ( normotensive group ) , r and omly selected from a population of 1369 children . INTERVENTION--67 children were r and omised to receive three extra lessons a week of an ordinary school physical education programme for eight months . MAIN OUTCOME MEASURES --Physical fitness assessed by calculation of maximum oxygen uptake and blood pressure recorded by one unblinded observer . RESULTS --After three months neither blood pressure nor physical fitness had changed significantly . After adjustment for values in weight , height , heart rate , and the variable in question before training physical fitness rose significantly at the end of eight months ' training , by 3.7 mlO2/kg/min ( 95 % confidence interval 2.2 to 5.3 ) in the normotensive training subgroup and by 2.1 mlO2/kg/min ( 0.1 to 4.2 ) in the hypertensive training subgroup compared with that in the controls . Systolic and diastolic blood pressures in the training subgroups fell significantly by 6.5 mm Hg ( 3.2 to 9.9 ) and 4.1 mm Hg ( 1.7 to 6.6 ) respectively in the normotensive group and by 4.9 mm Hg ( 0.7 to 9.2 ) and 3.8 mm Hg ( 0.9 to 6.6 ) respectively in the hypertensive group . CONCLUSIONS --Physical training lowers blood pressure and improves physical fitness in children and might have implication s for an important non-pharmacological approach to primary prevention of essential hypertension BACKGROUND . The prevalence and seriousness of childhood obesity has prompted calls for broad public health solutions that reach beyond clinic setting s. Schools are ideal setting s for population -based interventions to address obesity . OBJECTIVE . The purpose of this work was to examine the effects of a multicomponent , School Nutrition Policy Initiative on the prevention of overweight ( 85.0th to 94.9th percentile ) and obesity ( > 95.0th percentile ) among children in grade s 4 through 6 over a 2-year period . METHODS . Participants were 1349 students in grade s 4 through 6 from 10 schools in a US city in the Mid-Atlantic region with ≥50 % of students eligible for free or reduced-price meals .  Schools were matched on school size and type of food service and r and omly assigned to intervention or control . Students were assessed at baseline and again after 2 years . The School Nutrition Policy Initiative included the following components : school self- assessment , nutrition education , nutrition policy , social marketing , and parent outreach . RESULTS . The incidences of overweight and obesity after 2 years were primary outcomes . The prevalence and remission of overweight and obesity , BMI z score , total energy and fat intake , fruit and vegetable consumption , body dissatisfaction , and hours of activity and inactivity were secondary outcomes . The intervention result ed in a 50 % reduction in the incidence of overweight . Significantly fewer children in the intervention schools ( 7.5 % ) than in the control schools ( 14.9 % ) became overweight after 2 years . The prevalence of overweight was lower in the intervention schools . No differences were observed in the incidence or prevalence of obesity or in the remission of overweight or obesity at 2 years . CONCLUSION . A multicomponent school-based intervention can be 
    Output:
    
The interventions that combined physical activity and nutritional education had more positive effects in the reduction of body mass index among school-age students than when they were applied individually