What is the best way to change self-efficacy to promote lifestyle and recreational physical activity? A systematic review with meta-analysis

Purpose. Increasing self-efficacy is an effective method to increase physical activity. Despite this, the evidence concerning the most effective techniques to increase selfefficacy in physical activity interventions has not been systematically reviewed. The aim of the present research is to systematically gather, and meta-analyse, intervention studies which aimed to increase self-efficacy for physical activity; to estimate the association between intervention techniques used, and change in self-efficacy achieved. Methods. A systematic database search was conducted for papers reporting lifestyle or recreational physical activity interventions. Published intervention studies explicitly targeting self-efficacy in order to change physical activity behaviour in 'healthy' adults were eligible for inclusion. Results. The search strategy identified 27 unique physical activity intervention studies, with a total of 5,501 participants. A significant, yet small, relationship between the interventions and changes in self-efficacy was found (mean d = 0:16, p , :001). Owing to significant heterogeneity, moderator analyses were conducted, examining the association of changes in self-efficacy with whether or not specific intervention techniques were used. Interventions that included feedback on past or others' performance produced the highest levels of self-efficacy found in this review. Vicarious experience was also associated with higher levels of self-efficacy. Persuasion, graded mastery, and barrier identification were associated with lower levels of self-efficacy. Conclusions. This meta-analysis forms an evidence base for which psychological techniques are most effective in increasing self-efficacy for physical activity. The results are presented in terms of recommendations for those developing interventions and directions for future research.