Implementation Intentions for Exercise and Physical Activity: Who Do They Work For? A Systematic Review

Abstract

Background: As a behavior change technique, implementation intentions are a cost-effective strategy to promote physical activity and exercise. This technique helps individuals plan when and where they will do a behavior. However, previous research on implementation intentions and physical activity has shown heterogeneous outcomes. Methods: The primary aim of this review was to systematically review the literature on the social cognitive variables that moderate the mediating effects of implementation intentions on physical activity and exercise. Following Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, 22 papers yielded 24 studies. Of the 24 reviewed studies, 1 was cross-sectional, 12 were randomized control trials, 10 were longitudinal, and 1 was secondary data from a randomized control trial. Results: Habit strength, self-concordance, self-efficacy, perceived behavioral control, and intention were identified as moderating variables. Conditions for effectiveness for implementation intentions were observed. Implementation intentions are an effective behavior change technique for individuals who have preexisting intentions and strong self-efficacy. Conclusions: Implementation intentions may be a valuable behavior change technique for certain individuals. For self-efficacious individuals who desire to be physically active, implementation intentions can help translate intentions into behavior.