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.