Abstract
Although Self-Determination Theory and Self-Efficacy Theory are prominent in the physical activity (PA) literature, there has been a recent call for theory comparison and integration (Noar & Zimmerman, 2005). This study sought to test a longitudinal integrated model of these two theories in order to predict PA at the end of a 4-month cardiac rehabilitation program. Participants (N = 109) answered self-report questionnaires for self-determination and self-efficacy variables as well as for PA over the 4-month period. Data were analyzed using AMOS to assess the path analysis and model fit. Prior to integration, perceived competence and self-efficacy were combined and labelled as confidence, as one factor emerged from a factor analysis. After controlling for 2-month PA and cardiac rehabilitation site, self-determined motivation was the sole predictor of 4-month PA, however this relationship was negative (beta= -.20, p = .01). Although confidence did not predict 4-month PA, it had a strong relationship with 2-month PA (beta= .34, p < .001) and mediated the outcome expectation - PA relationship. Results diverged from theoretical predictions as self-determined motivation negatively predicted PA. In addition, self-efficacy theory variables influenced PA cross-sectionnally rather than longitudinally in this study, suggesting that these construct may have a more proximal impact on behaviour. The contrary nature of these results will be discussed.Acknowledgments: Social Sciences and Humanities Research Council of Canada funded the research project and a doctoral fellowship for Shane N. Sweet