Prediction of leisure-time physical activity among obese individuals.

The aims of this study were to identify (i) what cognitions predict leisure-time physical activity and (ii) the moderators of cognition-behavior relationships among obese individuals. A sample of 91 adults (BMI >or=30 kg/m(2)) completed a baseline questionnaire assessing variables of the theory of planned behavior (TPB). Biological measures and socio-demographic variables were also obtained. Behavior was assessed 3 months later. Multiple hierarchical regression analyses indicated that significant variables predicting behavior were past behavior (beta = 0.39; P = 0.0001), intention (beta = 0.27; P = 0.03), and the interaction term "perceived behavioral control (PBC) x perceived built environment" (beta = 0.17; P = 0.05). The PBC-behavior relation was better when the built environment was perceived as favorable to physical activity. The model explained 41% of variance in behavior. The determinants explaining intention were PBC (beta = 0.55; P < 0.0001), anticipated regret (beta = 0.26; P = 0.0007), and past behavior (beta = 0.22; P = 0.005), accounting for 59% of variance. Participation in leisure-time physical activity is explained primarily by a person's intentions to perform this behavior. The results also suggest that people are more able to translate their perception of control into action if they perceive the built environment as favorable, although this additional gain in prediction is small relative to intention. Nonetheless, both cognitions and aspects of the built environment should be given consideration in the promotion of leisure-time physical activity among obese individuals.