There was some evidence that school-based physical activity interventions had a positive impact on four of the nine outcome measures .
Specifically positive effects were observed for duration of physical activity , television viewing , VO2 max , and blood cholesterol .
Generally , school-based interventions had little effect on physical activity rates , systolic and diastolic blood pressure , BMI , and pulse rate .
At a minimum , a combination of printed educational material s and changes to the school curriculum that promote physical activity result ed in positive effects .
Few changes in outcomes were observed in this up date with the exception of blood cholesterol and physical activity rates .
For example blood cholesterol was no longer positively impacted upon by school-based physical activity interventions .
The evidence suggests the ongoing implementation of school-based physical activity interventions at this time , given the positive effects on behavior and one physical health status measure .
BACKGROUND The World Health Organization ( WHO ) estimates that 1.9 million deaths worldwide are attributable to physical inactivity and at least 2.6 million deaths are a result of being overweight or obese .
In addition , WHO estimates that physical inactivity causes 10 % to 16 % of cases each of breast cancer , colon , and rectal cancers as well as type 2 diabetes , and 22 % of coronary heart disease and the burden of these and other chronic diseases has rapidly increased in recent decades .
OBJECTIVES The purpose of this systematic review was to summarize the evidence of the effectiveness of school-based interventions in promoting physical activity and fitness in children and adolescents .
An intervention to reduce television viewing by preschool children.
BACKGROUND Television viewing has been associated with increased violence in play and higher rates of obesity . Although there are interventions to reduce television viewing by school-aged children , there are none for younger children . OBJECTIVE To develop and evaluate an intervention to reduce television viewing by preschool children . DESIGN R and omized controlled trial conducted in 16 preschool and /or day care centers in rural upstate New York . PATIENTS Children aged 2.6 through 5.5 years . INTERVENTION Children attending intervention centers received a 7-session program design ed to reduce television viewing as part of a health promotion curriculum , whereas children attending the control centers received a safety and injury prevention program . OUTCOME MEASUREMENTS Change in parent-reported child television/video viewing and measured growth variables . RESULTS Before the intervention , the intervention and control groups viewed 11.9 and 14.0 h/wk of television/videos , respectively . Afterward , children in the intervention group decreased their television/video viewing 3.1 h/wk , whereas children in the control group increased their viewing by 1.6 h/wk , for an adjusted difference between the groups of -4.7 h/wk ( 95 % confidence interval , -8.4 to -1.0 h/wk ; P = .02 ) . The percentage of children watching television/videos more than 2 h/d also decreased significantly from 33 % to 18 % among the intervention group , compared with an increase of 41 % to 47 % among the control group , for a difference of -21.5 % ( 95 % confidence interval , -42.5 % to -0.5 % ; P = .046 ) . There were no statistically significant differences in children 's growth between groups . CONCLUSIONS This study is the first to show that a preschool-based intervention can lead to reductions in  young children 's television/video viewing . Further research is needed to determine the long-term effects associated with reductions in young children 's television viewing
There was some evidence that school-based physical activity interventions had a positive impact on four of the nine outcome measures .
Specifically positive effects were observed for duration of physical activity , television viewing , VO2 max , and blood cholesterol .
Generally , school-based interventions had little effect on physical activity rates , systolic and diastolic blood pressure , BMI , and pulse rate .
At a minimum , a combination of printed educational material s and changes to the school curriculum that promote physical activity result ed in positive effects .
Few changes in outcomes were observed in this up date with the exception of blood cholesterol and physical activity rates .
For example blood cholesterol was no longer positively impacted upon by school-based physical activity interventions .
The evidence suggests the ongoing implementation of school-based physical activity interventions at this time , given the positive effects on behavior and one physical health status measure .
BACKGROUND The World Health Organization ( WHO ) estimates that 1.9 million deaths worldwide are attributable to physical inactivity and at least 2.6 million deaths are a result of being overweight or obese .
In addition , WHO estimates that physical inactivity causes 10 % to 16 % of cases each of breast cancer , colon , and rectal cancers as well as type 2 diabetes , and 22 % of coronary heart disease and the burden of these and other chronic diseases has rapidly increased in recent decades .
OBJECTIVES The purpose of this systematic review was to summarize the evidence of the effectiveness of school-based interventions in promoting physical activity and fitness in children and adolescents .