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 .
Television Viewing: Moderator or Mediator of an Adolescent Physical Activity Intervention?
Purpose . To determine whether the amount of television ( TV ) watched by participants enrolled in a physical activity intervention  mediates or moderates program effectiveness . Design . Nine-month , controlled , school-based physical activity intervention . Setting . Public high school . Participants . One hundred twenty-two sedentary adolescent females ( mean + st and ard deviation age = 15.04 + 0.79 years ) . Intervention . Supervised in-class exercise , health education , and internet-based self-monitoring . Measures .  Physical activity  by  3-day physical activity recall ; TV viewing  by  self-reports ; cardiovascular fitness  by cycle ergometer . Analysis . T-tests were conducted to examine between-group differences . Linear regression equations tested the mediating or moderating role of TV watching relative to the intervention . Results . TV viewing moderated the intervention 's effect on vigorous activity ; the intervention significantly predicted change in physical activity among high ( β = −.45 ; p < .001 ) , but not among low ( p > .05 ) , TV watchers . TV viewing did not mediate the intervention effect . Conclusions . Consistent with displacement theory , adolescents who watched more TV prior to the intervention showed postintervention increases in vigorous physical activity and concomitant decreases in TV viewing , whereas those who watched less TV showed no change in physical activity or TV 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 .