Stages of change in physical activity: a validation study in late adolescence.

The present study explores the validity of a recent stages of change (SoC) measure and algorithm among a sample of late adolescents. MANOVA and structural equation modeling are used to assess the relationship between five SoC groups (precontemplation, contemplation, preparation, action, and maintenance) and a set of dependent measures including physical activity level, physical activity motivation, physical self-concept, and flow. Findings are based on 705 Australian adolescents, using scale score and latent variable approaches, provided support for the construct validity of the SoC measure and algorithm. Specifically, findings reveal that participants in the upper SoC (action and maintenance) score significantly higher on positively geared dimensions (e.g., physical self-concept, flow, etc.) and significantly lower on negatively geared dimensions (e.g., maladaptive behavior). Implications for future research and practice with adolescent populations are discussed.