摘要：Objectives. Many adolescent girls fail to meet national guidelines for physical activity, and the prevalence of obesity is increasing among this group. Our study examined the effects of a comprehensive school-based intervention on physical activity among high-school girls. Methods. A group-randomized controlled field trial was conducted at 24 high schools. A school-based sample of 2744 girls (48.7% African American, 46.7% White) participated in a measurement protocol when they were in eighth and then ninth grade. A comprehensive physical activity intervention was designed to change the instructional program and the school environment to increase support for physical activity among girls. Results. At follow-up, 45% of girls in the intervention schools and 36% of girls in the control schools reported vigorous physical activity during an average of 1 or more 30-minute time blocks per day over a 3-day period. Conclusions. A comprehensive school-based intervention can increase regular participation in vigorous physical activity among high-school girls. Physical activity rates decline precipitously during the high school years. These rates are consistently lower among adolescent girls than among adolescent boys, and they are particularly low among African American girls. 1 , 2 The National Heart, Lung, and Blood Institute’s Growth and Health Study reported that girls’ median activity scores decreased dramatically between the ages of 9 and 18 years: 64% among White girls and 100% among African American girls. 2 Several government agencies and public health authorities have established guidelines for physical activity among young people, but most adolescents are not active at the recommended levels. 3 – 5 Perhaps as a consequence of these low physical activity levels, rates of obesity and type 2 diabetes are increasing among all adolescent population groups and are particularly high among African American girls. 6 – 10 Young people need to become more active, and physical activity interventions in schools have the potential to reach nearly all children and adolescents. Some school-based interventions have increased physical activity at the elementary school level, 11 – 14 primarily by increasing children’s activity levels during physical education (PE) classes. Few studies have attempted to increase physical activity among older students, and none have tested a comprehensive physical activity intervention that targets high schools and high school students 11 , 15 or is designed specifically to increase physical activity among high-school girls. Decreasing rates of physical activity and increasing rates of obesity and type 2 diabetes among adolescent girls show an urgent need for a determination of how school-based programs can effectively promote physical activity among this group. Accordingly, we examined the effects of a comprehensive school-based intervention on physical activity among high-school girls in 14 South Carolina counties (1998–2000).
