Comparing Psychosocial Predictors of Physical Activity Adoption and Maintenance

Most health behavior models do not distinguish between determinants of behavior adoption and maintenance. This study compared psychosocial predictors of physical activity (PA) adoption and predictors of PA maintenance among 205 initially sedentary adults enrolled in a home-based PA promotion trial. Psychosocial variables were measured at 6 months (at which point 107 participants remained inactive and 98 participants adopted regular PA) and used to predict 12-month PA status (an indicator of PA adoption among those inactive at 6 months and an indicator of PA maintenance among those active at 6 months). Six-month PA status moderated the relationships between 6-month measures of home access to PA equipment (p=.049), self-efficacy (p=.086), and perceived satisfaction (p=.062) and 12-month PA status. Simple effects analyses revealed that home access to PA equipment was predictive of PA adoption (OR=1.73; 95% CI: 1.05, 2.85), but not PA maintenance (OR=0.88; 95% CI: 0.58, 1.35), whereas self-efficacy and perceived satisfaction were predictive of PA maintenance (OR=2.65; 95% CI: 1.55, 4.52; OR=1.95; 95% CI: 0.93, 4.06), but not PA adoption (OR=1.50; 95% CI: 0.87, 2.57; OR=0.82, CI: 0.44, 1.52). Results suggest that these psychosocial variables may operate differently in predicting PA adoption versus maintenance.