Philip D. Parker, Andrew J. Martin, and Carissa Martinez, University of Sydney, New South Wales,
Australia. Herbert W. Marsh, Department of Education, University of Oxford, United Kingdom. Susan
A. Jackson, School of Human Movement Studies, University of Queensland, Brisbane, Australia.
Address correspondence to
Andrew J. Martin, Faculty of Education and Social Work, University of
Sydney, NSW 2006, Australia; phone: +(61) 5-9351-6273; e-mail: firstname.lastname@example.org.
Health Education & Behavior
, Vol. 37(3): 318-329 (June 2010)
© 2010 by SOPHE
Stages of Change in Physical Activity:
A Validation Study in Late Adolescence
Philip D. Parker, BA (Hons)
Andrew J. Martin, PhD
Carissa Martinez, BPsyc, BEd (Hons)
Herbert W. Marsh, PhD
Susan A. Jackson, PhD
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, pro-
vided 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 dimen-
sions (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.
physical activity; adolescents; stages of change
Sedentary lifestyles and insufficient physical activity increase the risk of physical and
mental ill health (Australian Institute of Health and Welfare [AIHW], 2003; Dubbert,
2002). Hence, health promotion programs and practitioner-based intervention aimed at
increasing physical activity are becoming increasingly important. To most effectively
intervene and promote cognitive and behavioral change directed toward more active
lifestyles, it is important to understand how individuals are oriented to such changes.