Applying structural equation modeling, the fit of the HAPA model was satisfactory-χ²(191) = 569.93, p < .05, χ²/df = 2.98, comparative fit index = .91, normed-fit index = .87, and root mean square error of approximation = .06 (90% CI = .06, .07)-explaining 30% of the variance in intention and 18% of the variance in physical activity. Motivational self-efficacy, outcome expectancies, and social support were related to intention. An association between maintenance self-efficacy and coping planning was found. Recovery self-efficacy and social support were associated with physical activity. No relationships were found between risk perception and intention and between planning and physical activity. The assumptions derived from the HAPA were partly confirmed and the HAPA may, therefore, constitute a theoretical backdrop for intervention designs to promote physical activity in adults with obesity.

The results suggest that mastery experience, self-persuasion, and reduction in negative affective states are the most important predictors of self-efficacy for physical activity in community-dwelling older adults.

No abstract

What is already known on this subject? Numerous studies have shown that exercise-specific self-efficacy predicts subsequent physical activity. Prior positive experience with physical activity is suggested to be associated with exercise-specific self-efficacy. Furthermore, action control was found to be beneficial for the maintenance of physical activity. What does this study add? This study unveils the mechanisms between these social-cognitive determinants: our longitudinal results suggest that the mediation of positive experience and subsequent physical activity via self-efficacy is moderated by action control. Persons with low levels of action control did not translate positive experience into physical activity via self-efficacy.

Many individuals are motivated to improve their physical activity levels, but often fail to act upon their intention. Interventions fostering volitional strategies, such as action planning, coping planning, and self-efficacy beliefs, can help to translate intentions into behavior. This study examines the effectiveness and the mechanisms of a combined planning and self-efficacy intervention to promote physical activity among motivated individuals. Participants (N = 883) were randomly assigned to the intervention or to a waiting-list control condition. Multivariate analysis of variance revealed that the intervention resulted in significantly more physical activity, higher levels of action planning, coping planning, and volitional self-efficacy beliefs (p < 0.01). In addition, multiple mediation analysis showed that action planning, coping planning, and volitional self-efficacy mediate between the intervention and physical activity. The study shows that the intervention successfully fostered physical activity and unfolds the underlying self-regulatory mechanisms of the intervention's effectiveness.