Abstract
The Theory of Planned Behavior provides a useful framework to study attitudes toward participation in physical activity. The objective of the study was to test the effectiveness of an intervention in manipulating the variables of the Theory of Planned Behavior and exercise habits with 366 high school students (M = 14.2 yr., SD = .7; 201 boys and 165 girls). The students were divided into intervention and control groups. A questionnaire to measure components of the theory, and the Baecke Questionnaire of Habitual Activity measuring exercise habits, were administered. The intervention lasted 12 wk. and included posters and lectures promoting participation in physical activity. Analyses showed the intervention was effective in improving attitudes towards physical activity, perceived behavioral control, intention, and self-reported actual behavior, but it was ineffective for improving attitude strength, subjective norms, and role identity. The results provide useful information for physical education teachers interested in promoting students' positive attitudes towards physical activity.