Descriptive analysis of Iranian adolescents' stages of change for physical activity behavior.

To better understand prevalence of physical inactivity among Iranian adolescents, their physical activity behavior across the hypothesized stages of change derived from the transtheoretical model was investigated in this study. This was a cross-sectional study involving 1551 adolescents, 12-14 years of age (941 boys and 610 girls). Participants were selected through a multistage sampling method. The child/adolescent activity log, physical activity calendar, and stage of change scale were used for collecting data. Data were analyzed using χ(2) and F-tests. Depending on how physical activity was assessed, the prevalence of physical inactivity ranged from 77.4% to 87.1%. Analyses revealed sex and stages of change differences between those who achieved and those who did not achieve the recommended levels of moderate-to-vigorous-intensity physical activity. Girls were less active than boys. The distribution observed across the stages of change supports the need to improve the physical activity of Iranian youth, especially among girls. For interventions to be most effective, they will need to be tailored to the sex of the participants, as well as their specific stage of readiness to change.