BACKGROUND:

This study examined predictors of adoption and maintenance of vigorous physical activity over time in a sample of 1,719 randomly selected women and men.

METHODS:

Based on reported frequency of vigorous exercise in a mail survey at baseline, subjects were classified as sedentary (zero sessions per week), intermediate (one to two sessions per week), or active (three or more sessions per week).

RESULTS:

On the same survey subjects reported on 25 potential determinants of physical activity based on a comprehensive learning model. Twenty-four months later, 85% of subjects were resurveyed, and their physical activity levels were classified. Within each baseline category and gender subgroup, predictors of follow-up physical activity were identified. In multivariate analyses, adoption of vigorous exercise by sedentary men was predicted by self-efficacy, age (inverse), and neighborhood environment (inverse). Adoption by sedentary women was predicted by education, self-efficacy, and friend and family support for exercise. Maintenance of vigorous physical activity was predicted by self-efficacy and age (inverse) for initially active men and by education for initially active women.

CONCLUSION:

These results suggest that factors influencing adoption are different for men and women, and there may be different factors influencing adoption versus maintenance of vigorous physical activity.