Background and Rationale:

In patients with coronary artery disease (CAD), physical exercise has a positive impact on physiological and psychological health. Despite the clear benefits, a major issue in cardiac rehabilitation is inadequate physical activity (PA) participation. Research has drawn on various models of health behaviour to identify determinants of PA behaviour for intervention design. Frameworks based on single theoretical constructs only explain a limited amount of variance in outcomes. There is a need for integrated models of PA regulation to provide a more comprehensive explanation for the socio-cognitive and behavioural mechanisms underlying effective and sustained regulation. By linking important intra- and inter-personal factors and identifying change agents and targets suitable for intervention, such frameworks would facilitate intervention design as well as evaluation.

Objective:

Motivation, and more specifically motivational style, is an important determinant of sustained health behaviour change. We drew on the Self-Determination Theory (SDT) to develop an integrated motivational model of PA regulation in patients with CAD. The SDT differentiates between autonomous and controlled styles of motivation. The different styles are associated with different psychosocial and behavioural consequences, autonomous forms being linked to more desirable psychological and behavioural outcomes. The purpose of the present research was to test this model in the prediction of PA behaviour at 6 months post-hospital discharge. Motivational style was considered central to this model; it was posed to be determined by general motivational orientation, social support of autonomy, and perceived competence, and to affect self-efficacy, planning, and behaviour.

Design and Methods:

827 patients with documented CAD were recruited from hospital admissions from 3 sites and followed for a period of 6 months. Data on demographic, psycho-social, clinical, and PA behaviour was collected from participants using self-report measures at baseline, 2 months and 6 months. The main outcome was PA behaviour at 6 months, assessed using the Godin Leisure Time Exercise Questionnaire. Structural equation modelling was used to model participants' PA behaviour at 6 months. The final analyses were based on 768 patients.

Results:

Model estimation yielded a satisfactory fit; 92% of sample covariance and 26% of variance in PA behaviour was explained. Autonomous regulation had a large effect on both planning (total [gamma] =.51, P < .001; 26% explained variance) and on PA behaviour (total [gamma] =.32, P < .001; 10% explained variance). While its effect on outcome exceeded the influence of all other model components, the integration of each of the constructs into the model was important in explaining the mechanisms underlying PA regulation.

Conclusion:

By specifying potential change agents and intervention targets, the motivational model provides a valuable framework for guiding the design and evaluation of interventions to promote sustained PA regulation in the cardiac population. The model also identifies variables that can be used to screen clients and group them for tailored program components.

Section Description

For more information, contact Marilyn Thomas (204) 488-5854