High schools represent a favorable environment for the development of interventions to increase physical activity because they reach a large number of teenagers. The goal of the study was to determine the effectiveness of an intervention to promote physical activity among high school students (through the 'Saúde na Boa' project) through assessing the stages of behavior change and the practices of muscle-strengthening exercise and active commuting. The present study comprised a randomized and controlled intervention conducted in Recife and Florianopolis, Brazil, during 2006. Dependent variables included active commuting (cutoff values: ≥1 and ≥5 days per week), the practice of muscle-strengthening exercises (cutoff values: ≥1 day per week and the recommended level of physical activity), and behavioral changes regarding physical activity. Of the 2,155 students included in the baseline data, 989 were evaluated in the post-intervention period (45.9%). In comparison with the control group, the intervention group significantly increased the practice of active commuting to school on ≥ 1 day per week (80.5% vs. 86.8%, p<0.001) and ≥ 5 days per week (64.3% vs. 71.9%, p<0.001), the practice of muscle-strengthening exercises on ≥ 1 day per week (41.4% vs. 46.0%, p=0.017), and the achievement of the recommended levels of exercise (28.9% vs. 35.0%, p=0.002). The intervention group reached higher stages of change in physical activity behavior compared with controls (p = 0.004). The 'Saúde na Boa' project effectively enhanced the practices of active commuting to school and muscle-strengthening exercises and resulted in an increased physical activity status.
Adolescent; Intervention studies; Motor activity; Muscle Strength; Transport