Review Findings caution on effects of school phys. activity programs

An update of a Cochrane Systematic Review of school-based physical activity programs expresses caution about the impact of such programs on the levels of activity during the school day as well as longer term effects on cholesterol and body mass. The review (at least its abstract), also illustrates the limited nature of systematic reviews that do not clearly differentiate between different types of interventions (multi-intervention approaches vs instructional programs) as well as those that do not clearly establish reasonable expectations for school programs. In this case, the review looks for increased PA during the school day (too little) or long term changes to blood pressure, body mass or cholesterol (too much), when a more realistic expectation might be that the children become more active after school. 

The abstract for the review states: "In the original review, 13,841 records were identified and screened, 302 studies were assessed for eligibility, and 26 studies were included in the review. 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, VO 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 materials and changes to the school curriculum that promote physical activity resulted in positive effects.In this update, given the addition of three new inclusion criteria (randomized design, all school-attending children invited to participate, minimum 12-week intervention) 12 of the original 26 studies were excluded. In addition, studies published between July 2007 and October 2011 evaluating the effectiveness of school-based physical interventions were identified and if relevant included. In total an additional 2378 titles were screened of which 285 unique studies were deemed potentially relevant. Of those 30 met all relevance criteria and have been included in this update. This update includes 44 studies and represents complete data for 36,593 study participants. Duration of interventions ranged from 12 weeks to six years.Generally, the majority of studies included in this update, despite being randomized controlled trials, are, at a minimum, at moderate risk of bias. The results therefore must be interpreted with caution. Few changes in outcomes were observed in this update 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. However, there was some evidence to suggest that school-based physical activity interventions led to an improvement in the proportion of children who engaged in moderate to vigorous physical activity during school hours (odds ratio (OR) 2.74, 95% confidence interval (CI), 2.01 to 3.75). Improvements in physical activity rates were not observed in the original review. Children and adolescents exposed to the intervention also spent more time engaged in moderate to vigorous physical activity (with results across studies ranging from five to 45 min more), spent less time watching television (results range from five to 60 min less per day), and had improved VOmax (results across studies ranged from 1.6 to 3.7 mL/kg per min). However, the overall conclusions of this update do not differ significantly from those reported in the original review."  

Rather than grouping various school PA programs in one general review, it might have been more useful for the reviewers to look at whether comprehensive, multi-intervention approaches to promoting PA (which have emerged in several countries recently) are more effective in influencing after school and week-end behaviours than the traditional PE class only approaches. Read more>