How big is the physical activity intention-behaviour gap? A meta-analysis using the action control framework

Objectives The physical activity (PA) intentionbehaviour gap is a topic of considerable contemporary research, given that most of our models used to understand physical activity suggest that intention is the proximal antecedent of behavioural enactment. The purpose of this study was to quantify the intentionPA gap at public health guidelines with a meta-analysis of the action control framework. Design Systematic review and meta-analysis. Methods Literature searches were conducted in July 2012 among five key search engines. This search yielded a total of 2,865 potentially relevant records; of these, 10 studies fulfilled the full eligibility criteria (N=3,899). Results Random-effects meta-analysis procedures with correction for sampling bias were employed in the analysis for estimates of non-intenders who subsequently did not engage in physical activity (21%), non-intenders who subsequently performed physical activity (2%), intenders who were not successful at following through with their PA (36%), and successful intenders (42%). The overall intentionPA gap was 46%. Conclusion These results emphasize the weakness in early intention models for understanding PA and suggest this would be a problem during intervention. Contemporary research that is validating and exploring additional constructs (e.g., self-regulation, automaticity) that augment intention or improving the measurement of motivation seems warranted.