Intentions and actual physical activity behavior change in a community‐based sample of middle‐aged women: Contributions from the theory of planned behavior and self‐determination theory

Abstract

This two‐study research assessed intentions and actual physical activity behavior change in a community‐based sample of Canadian middle‐aged women by integrating concepts from two strong and complimentary psychological theories: the Theory of Planned Behavior (TPB) and Self‐Determination Theory (SDT). Specific objectives were 1) to examine associations among TPB variables, motivation, and intention to increase physical activity and 2) to examine the relative influence of intentions and motivation on reported physical activity behavior change over time. First, in a cross‐sectional study, French‐speaking women (n = 109) recruited from community‐based facilities completed validated measures of TPB variables (attitudes, perceived behavioral control, subjective norms, and intentions) and motivation (autonomous and controlled). In a follow‐up longitudinal study, one hundred and forty‐nine English‐speaking women from similar facilities completed these measures and reported on actual physical activity at baseline and at six months. In the first study, attitudes, perceived behavioral control, and autonomous motivation were significantly associated with physical activity intentions. In the second study, attitudes, subjective norms, and autonomous motivation were significantly related to intentions to increase physical activity. In turn, intentions predicted change in physical activity behavior over time; however, the relationship was modest. Results highlight the role of intentions in physical activity behavior change among middleaged women and are discussed in light of current research and theory. Future research directions are proposed