***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: Background Obesity has become a global public health problem , which also affects children . It has been proposed that the educational interventions during childhood could be a key strategy in the prevention of obesity . Objective To evaluate the efficacy of an intervention on food habits and physical activity in school children . Methods A 2-year cluster-r and omised prospect i ve study with two parallel arms was used to evaluate an intervention programme in children in their first year of primary schooling ( 5–6 years of age ) in schools in the city of Granollers . The intervention consisted of the promotion of healthy eating habits and physical activity by means of the educational methodology Investigation , Vision , Action and Change ( IVAC ) . At the beginning and at the end of the study ( 2006 and 2008 ) the weight and height of each child was measured in situ , while the families were given a self-report physical activity question naire and the Krece Plus quick test . Results Two years after the beginning of the study , the body mass index of the children in the control group was 0.89 kg/m2 higher than that of the intervention schools . The intervention reduced by 62 % the prevalence of overweight children . Similarly , the proportion of children that ate a second piece of fruit and took part in an after-school physical activity increased in the intervention group . In the control group , the weekly consumption of fish was reduced . Conclusions The educational intervention in healthy eating habits and physical activity in the school could contribute to lessen the current increase in child obesity Abstract Objective : To assess if a school based intervention was effective in reducing risk factors for obesity . Design : Group r and omised controlled trial . Setting : 10 primary schools in Leeds . Participants : 634 children aged 7 - 11 years . Intervention : Teacher training , modification of school meals , and the development of school action plans targeting the curriculum , physical education , tuck shops , and playground activities . Main outcome measures : Body mass index , diet , physical activity , and psychological state . Results : Vegetable consumption by 24 hour recall was higher in children in the intervention group than the control group ( weighted mean difference 0.3 portions/day , 95 % confidence interval 0.2 to 0.4 ) , representing a difference equivalent to 50 % of baseline consumption . Fruit consumption was lower in obese children in the intervention group ( −1.0 , −1.8 to −0.2 ) than those in the control group . The three day diary showed higher consumption of high sugar foods ( 0.8 , 0.1 to 1.6 ) ) among overweight children in the intervention group than the control group . Sedentary behaviour was higher in overweight children in the intervention group ( 0.3 , 0.0 to 0.7 ) . Global self worth was higher in obese children in the intervention group ( 0.3 , 0.3 to 0.6 ) . There was no difference in body mass index , other psychological measures , or dieting behaviour between the groups . Focus groups indicated higher levels of self reported behaviour change , underst and ing , and knowledge among children who had received the intervention . Conclusion : Although it was successful in producing changes at school level , the programme had little effect on children 's behaviour other than a modest increase in consumption of vegetables . What is already known on this topic Obesity is increasing among school children and dem and s preventive strategies R and omised controlled trials of school based primary prevention programmes have all used a prescriptive approach What this study adds Behavioural changes were disappointing with this programme based on the health promoting schools philosophy , despite changes at school level The only positive outcome was a modest increase in vegetable consumption The discrepancy between changes achieved at the individual and school level raises issues regarding the problems inherent in such OBJECTIVE The purpose of the present study was to evaluate the effects of a school-based , 2-year , multi-component intervention on BMI , eating and physical activity behaviour in Fl and ers , Belgium , targeting children aged 3 - 6 years in communities of high and low socio-economic status ( SES ) . DESIGN Cluster-r and omized controlled trial . SETTING Thirty-one pre- primary and primary schools in three different intervention communities and three paired-matched ( on SES profile ) control communities in Fl and ers , Belgium . SUBJECTS BMI Z-scores  at baseline and follow-up were calculated for 1102 children . Question naires with sociodemographic data and FFQ were available from 694 of these 1102 children . RESULTS No significant effects were found on BMI Z-scores for the total sample . However , there was a significant decrease in BMI Z-score of 0·11 in the low-SES intervention community compared with the low-SES control community , where the BMI Z-score increased by 0·04 ( F = 6·26 , P = 0·01 ) . No significant intervention effects could be found for eating behaviour , physical activity or screen-time . There were no significant interaction effects of age and gender of the children on the outcome variables . CONCLUSIONS Although no significant effects were found for BMI Z-scores in the total sample , this intervention had a promising effect in the low-SES community of reducing excess weight gain among young children Few studies have investigated the impact of school-based physical activity interventions on anthropometric characteristics concomitantly with aerobic and anaerobic capacities in young children . The present study aim ed to assess the effect of a 6-month physical activity program on body composition and physical fitness among primary schoolchildren . Four hundred fifty-seven children aged 6 to 10 years were r and omly assigned to the intervention group ( 229 children ) or observational group ( 228 children ) . Participants ’ height and weight were assessed , and obesity was determined using French reference curves for BMI . The sum of the four skinfolds and fat-free mass were determined . Ground tests were used to assess aerobic ( 20-m shuttle run test ) and anaerobic ( cycling peak power ) fitness before and after a 6-month physical activity intervention . The anthropometric modifications obtained over the 6 months can not be attributed to the intervention as the ANOVA revealed no group effect ( intervention vs. group ) . However , anaerobic and aerobic fitness were significantly improved , thanks to the program in both lean and obese children . A 6-month school-based physical activity intervention in 6- to 10-year-old children did not yield positive anthropometric improvements , but appears effective in terms of aerobic and anaerobic physical fitness . Two physical activity sessions per week in addition to st and ard physical education classes in primary schoolchildren bring effective results for the prevention of childhood obesity INTRODUCTION AND OBJECTIVES Physical fitness level is a marker of cardiovascular health in young people . The aim of this study was to analyze the effects of a school-based intervention program , focused on increasing the volume and intensity of physical education ( PE ) sessions , on adolescents ' physical fitness . METHODS Sixty-seven adolescents ( 12 - 14 years old ) from three secondary school classes participated in a 16-week intervention . The classes were r and omly allocated to the control group , experimental group 1 ( EG1 ) or experimental group 2 ( EG2 ) . The control group received st and ard PE ( 2 sessions/week ) , the EG1 received 4 st and ard PE sessions/week and the EG2 received four high-intensity PE sessions/week . Aerobic fitness , muscle strength , speed-agility and flexibility were assessed using previously vali date d field-based tests before and after the intervention . RESULTS Doubling the number of PE sessions/week result ed in improvements in aerobic fitness and flexibility ( P=.008 and P=.04 , respectively ) . Further increases in the intensity of the sessions were related to improvements in speed-agility ( P<.001 ) . The maximal oxygen consumption increased by 3 and 5 mL/kg/min in the EG1 and EG2 , respectively . No differences were observed for muscle strength . CONCLUSIONS The results suggest that doubling the frequency of PE sessions is a sufficient stimulus to improve physical fitness , particularly aerobic fitness , which has been shown to be a powerful indicator of cardiovascular health in children and adolescents . Future studies involving larger sample sizes should confirm or refute these findings OBJECTIVE To determine whether a multicomponent health promotion intervention for Dutch adolescents ( defined as persons between 12 and 14 years of age ) would be successful in influencing body composition and dietary and physical activity behavior in both the short and long terms . DESIGN R and omized controlled trial . SETTING Ten intervention and 8 control prevocational secondary schools . PARTICIPANTS A total of 1108 adolescents ( mean age , 12.7 years ) . Intervention An interdisciplinary program with an adapted curriculum for 11 lessons in biology and physical education and environmental change options . MAIN OUTCOME MEASURES Body height and weight , waist circumference , 4 skinfold thickness measurements , and dietary and physical activity behavior data . RESULTS Multilevel analyses showed that the intervention remained effective in preventing unfavorable increases in important measures of body composition after 20-month follow-up in girls ( biceps skinfold and sum of 4 skinfolds ) and boys ( triceps , biceps , and subscapular skinfolds ) . Consumption of sugar-containing beverages was significantly lower in intervention schools both after intervention ( boys : -287 mL/d ; 95 % confidence interval [ CI ] , -527 to -47 ; girls : -249 ; -400 to -98 ) and at 12-month follow-up ( boys : -233 ; -371 to -95 ; girls : -271 ; -390 to -153 ) . For boys , screen-viewing behavior was significantly lower in the intervention group after 20 months ( -25 min/d ; 95 % CI , -50 to -0.3 ) . No significant intervention effects on consumption of snacks or active commuting to school were found . CONCLUSION The Dutch Obesity Intervention in Teenagers program result ed in beneficial effects on the sum of skinfold thickness measurements in girls and consumption of sugar-containing beverages in both boys and girls in both the short and long terms Background — The aim of this prospect i ve , r and omized study was to examine whether additional school exercise lessons would result in improved peak oxygen uptake ( primary end point ) and body mass index – st and ard deviation score , motor and coordinative abilities , circulating progenitor cells , and high-density lipoprotein cholesterol ( major secondary end points ) . Methods and Results — Seven sixth- grade classes ( 182 children , aged 11.1±0.7 years ) were r and omized to an intervention group ( 4 classes with 109 students ) with daily school exercise lessons for 1 year and a control group ( 3 classes with 73 students ) with regular school sports twice weekly . The significant effects of intervention estimated from ANCOVA adjusted for intraclass correlation were the following : increase of peak & OV0312;o2 ( 3.7 mL/kg per minute ; 95 % confidence interval , 0.3 to 7.2 ) and increase of circulating progenitor cells evaluated by flow cytometry ( 97 cells per 1 × 106 leukocytes ; 95 % confidence interval , 13 to 181 ) . No significant difference was seen for body mass index – st and ard deviation score ( −0.08 ; 95 % confidence interval , −0.28 to 0.13 ) ; however , there was a trend to reduction of the prevalence of overweight and obese children in the intervention group ( from 12.8 % to 7.3 % ) . No treatment effect was seen for motor and coordinative abilities ( 4 ; 95 % confidence interval , −1 to 8) and high-density lipoprotein cholesterol ( 0.03 mmol/L ; 95 % confidence interval , −0.08 to 0.14 ) . Conclusions — Regular physical activity by means of daily school exercise lessons has a significant positive effect on physical fitness ( & OV0312;o2max ) . Furthermore , the number of circulating progenitor cells can be increased , and there is a positive trend in body mass index – st and ard deviation score reduction and motor ability improvement . Therefore , we conclude that primary prevention by means of increasing physical activity should start in childhood . Clinical Trial Registration — URL : http://www . clinical trials.gov . Identifier : NCT00176371 BACKGROUND As an important modifiable lifestyle factor in osteoporosis prevention , physical activity has been shown to positively influence bone mass accrual during growth . We have previously shown that a nine month general school based physical activity intervention increased bone mineral content ( BMC ) and density ( aBMD )  in primary school children . From a public health perspective , a major key issue is whether these effects persist during adolescence . We therefore measured BMC and aBMD three years after cessation of the intervention to investigate whether the beneficial short-term effects persisted . METHODS All children from 28 r and omly selected first and fifth grade classes ( intervention group ( INT ) : 16 classes , n=297 ; control group ( CON ) : 12 classes , n=205 ) who had participated in KISS ( Kinder-und Jugendsportstudie ) were contacted three years after cessation of the intervention program . The intervention included daily physical education with daily impact loading activities over nine months . Measurements included  anthropometry , vigorous physical activity ( VPA ) by accelerometers  , and BMC /aBMD for total body , femoral neck , total hip , and lumbar spine by  dual-energy X-ray absorptiometry ( DXA ) . Sex- and age-adjusted Z-scores of BMC or aBMD at follow-up were regressed on intervention ( 1 vs. 0 ) , the respective Z-score at baseline , gender , follow-up height and weight , pubertal stage at follow-up , previous and current VPA , adjusting for clustering within schools . RESULTS 377 of 502 ( 75 % ) children participated in baseline DXA measurements and of 
    Output:
    
While few studies showed a decrease in BMI , positive results were achieved on other outcomes , such as metabolic parameters and physical fitness .
Conclusion : Physical activity in schools should be regarded as a simple , non-expensive and enjoyable way to reach all the children and adolescents with adequate doses of moderate to vigorous physical activity