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 .
Design of the Trial of Activity in Adolescent Girls (TAAG).
The primary aim of the Trial of Activity in Adolescent Girls ( TAAG ) is to test an intervention to reduce by half the age-related decline in moderate to vigorous physical activity  ( MVPA ) in middle school girls . The intervention will be evaluated using a group-r and omized trial involving 36 middle schools . The primary endpoint is the mean difference in intensity-weighted minutes ( i.e. , MET-minutes ) of MVPA between intervention and comparison schools assessed using accelerometry . The TAAG study design calls for two cross-sectional sample s , one drawn from 6th grade rs at the beginning of the study and the second drawn from 8th grade rs at the end of the study following the 2-year implementation of the intervention . An important strength of this design over a cohort design is the consistency with the goals of TAAG , which focus on environmental-level rather than individual-level interventions to produce change . The study design specifies a recruitment rate of 80 % and a smaller sample of girls at baseline ( n=48 per school ) than at follow-up ( n=96 per school ) . A two-stage model will be used to test the primary hypothesis . In the first stage , MET-weighted minutes of MVPA will be regressed on school , time ( baseline or follow-up ) , their interaction , ethnicity and week of data collection . The second stage analysis will be conducted on the 72 adjusted means from the first stage . In the main-effects model , we will regress the follow-up school mean MET-weighted minutes of MVPA on study condition , adjusting for the baseline school mean . The TAAG study addresses an important health behavior , and also advances the field of group-r and omized trials through the use of a study design and analysis plan tailored to serve the main study hypothesis
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 .