PREDICTORS OF CHANGE IN ADOLESCENT PHYSICAL ACTIVITY FROM MIDDLE SCHOOL TO HIGH SCHOOL

PURPOSE: The purpose of this study was to identify predictors of change in teenagers' physical activity. METHODS: A 5-year prospective study was undertaken. Physical activity was assessed using an interviewer administered physical activity checklist. Predictor variables were borrowed from social learning theory, the theory of reasoned action, and personal investment theory. RESULTS: A group of 170 high school students remained active in the study at Year 5 from an original cohort of 421 seventh graders. The group in Year 5 included 102 girls and 68 boys. Change in moderate to vigorous physical activity (MVPA) was represented as a residualized change score. Among the 170 Year 5 participants, 59% of the boys and 61% of the girls reported declines in their physical activity during the study. A multiple regression model using baseline values of the predictor variables revealed that adequacy in physical activity and social support from peers for physical activity were positively associated with change in MVPA, accounting for 17.4% of the variance in physical activity change. CONCLUSION: These results suggest that enhancing adequacy in physical activity and promoting peer social support may be associated with positive changes in physical activity during adolescence.