Understanding exercise behavior among New Zealand adolescents: a test of the transtheoretical.

Purpose: To test the utility of applying the Transtheoretical Model (TTM) to adolescent exercise behavior. The purpose of Study 1 was a replication study to examine whether the TTM could predict exercise stage readiness in adolescents. The purpose of Study 2 was to test the model's internal validity to predict exercise stage transition.

Methods: For Study 1, students (n = 3972) from 13 high schools completed questionnaires corresponding the variables in the TTM (i.e., stage of exercise change, processes of change, self-efficacy and decisional balance). For Study 2, 1434 of those participants completed the stage of exercise change questionnaire 6 months later. These data were used to establish an exercise stage transition profile.

Results: Results from Study 1 showed large effects for self-efficacy, decisional balance and two behavioral processes (i.e., counter-conditioning and self-liberation). Study 2 showed that all TTM construct significantly predicted exercise stage transition. Large effects were found for the same variables as in Study 1.

Conclusions: The TTM is a useful framework for understanding both exercise stage readiness and exercise stage transition in an adolescent population.