Long-term effects of a physical activity intervention in high school girls.

BACKGROUND Physical activity (PA) decreases during childhood and adolescence, and PA levels are significantly lower in females than males, particularly during adolescence. Schools are attractive settings in which to implement interventions designed to promote PA in girls and young women, but few studies have tested the sustained effects of such interventions. DESIGN Cross-sectional. Data were collected in 2002-2003 and analyzed in 2006-2007. SETTING/PARTICIPANTS 1594 adolescent girls in 22 high schools. INTERVENTION The intervention, Lifestyle Education for Activity Program (LEAP), was designed to increase physical activity in 9th-grade girls through two channels: changes in instructional practices and changes in the school environment. This study (LEAP 2) examined the extent to which effects of the intervention were maintained when the girls were in the 12th grade. MAIN OUTCOME MEASURES Number of 30-minute blocks per day of vigorous physical activity. RESULTS Girls in the intervention schools that most fully implemented and maintained the intervention were more likely than girls in the other schools to participate in an average of one or more blocks of vigorous physical activity per day (p=0.04, odds ratio=1.49, 95% confidence interval=1.01-2.20). CONCLUSIONS A comprehensive physical activity intervention that is fully implemented and maintained can increase participation in vigorous physical activity by high school girls.