Year in school and physical activity stage of change as discriminators of variation in the physical activity correlate profile of adolescent females

Background: Knowledge of the physical activity correlate profile of adolescent females will provide insight into decreasing physical activity patterns among adolescent females. Methods: Correlates of physical activity and physical activity stage of change were assessed during 2007-2008 among 871 Irish adolescent females in years 1-6 in secondary schools (15.28 ± 1.8 years). Multivariate Analysis of Variance was used to identify whether differences in correlates of physical activity could be detected across year in school and physical activity stages of change. Results: Significant differences (P < .01) were found in 11 of the 16 measured correlates across year in school and in 14 of the 16 correlates across stage of change. Effect size estimates and regression analysis revealed perceived competence, peer social support and intention to be physically active (partial eta range (n _p²) .21-.25) to be the most important predictors of physical activity stage of change. Conclusions: Females in more senior years in school and in earlier physical activity stages of change reported a significantly less positive physical activity correlate profile than females in junior years and in later physical activity stages of change. This finding supports the construct validity of the physical activity stages of change.