Self-determination Theory and Self-efficacy Theory: Can They Work Together to Predict Physical Activity in Cardiac Rehabilitation?

Abstract

Cardiovascular disease is currently the leading cause of death in Canada and other developed countries. Physical activity based cardiac rehabilitation programs have been shown to reduce the likelihood of subsequent cardiac events and even reverse the disease process. However, factors influencing physical activity in cardiac patients are still not clearly understood. The overall objective of this dissertation was therefore to better understand motivation and physical activity in a cardiac rehabilitation context. Specifically, theory-based motivational variables were studied as correlates of physical activity. To accomplish this objective, a two-purpose research approach was taken. First, two articles (Article-1 and Article-2) aimed to test and integrate concepts from two strong motivational theories: Self-Efficacy Theory (SET) and Self-Determination Theory (SDT) into one comprehensive model using the novel and rigorous approach of Noar and Zimmerman (2005). The second purpose of this dissertation was to extend the findings from the first purpose by investigating physical activity and motivational patterns over a 24-month period in cardiac patients (Article 3). With regards to the first purpose, Article-1 revealed that the integration of SDT and SET was feasible as the integrated model had good model fit, explained more variance in self-determined motivation, confidence, and physical activity and supported similar number of hypothesised links in a cross-sectional cardiac sample as well two other samples: primary care adults and university students. Due to the cross-sectional nature of Article-1, Article-2 tested the integrated SDT-SET model from cardiac patients with longitudinal data of patients following a cardiac rehabilitation program. Although no motivational variables predicted residual change in physical activity at 4-months, this longitudinal model was found to have good model fit. Across both articles, the integration of SDT and SET was found to be possible. However, more research is needed to further test the integration of these theories. As for the second purpose of this dissertation, Article-3 investigated physical activity and motivational patterns of cardiac rehabilitation participants over the course of 24 months. Distinct patterns were found for physical activity, self-determined motivation, barrier self-efficacy and outcome expectations. In addition, individuals in the higher patterns of the motivational/expectancy variables had greater probability of being in the maintenance physical activity pattern compared to individuals in the other motivational/expectancy patterns. Therefore, this article extended findings from the first purpose by linking SDT and SET variables to long-term physical activity behaviour. SDT and SET should continue to be investigated together in order to increase our understanding of the mechanisms leading to greater motivation and subsequent increases in physical activity levels. Having a theoretically supported pathway to build motivation is ideal to inform future interventions and cardiac rehabilitation programs.