Predicting physical activity promotion in health care settings

Purpose. To test the ability of the theory of planned behavior (TPB) in pre dicting the stage of change for physical activity promotion by mental healt h Professionals. Design. Six-month prospective questionnaire study. Setting. One mental health trust in the East Midlands, United Kingdom. Subjects. Three hundred ninety-four mental health professionals (men, n = 1 31; women, n = 263) of an initial sample of 477 participated in the study ( 83% response rate). Measures. Attitudes, subjective norms, intentions, perceived behavioral con trol, and stage of change were measured at the first wave of data collectio n. Stage of change was also assessed 6 months later Data were analyzed usin g structural equation modeling. Results. Intention and stage of change were successfully predicted from TPB variables. Overall, 27% of the variance in self-reported stage of promotin g physical activity was explained by the model. Sixty-one percent of the va riance in intention to promote physical activity was explained. When includ ed, past behavior was the strongest predictor of both intention and stage o f change and attenuated all other path coefficients. Past behavior improved the predicted variance in intention by 11% and stage by 6%. Conclusions. The TPB variables of attitude, subjective norms, perceived beh avioral control, and intention predict stage of change of physical activity promotion in a health care setting. However, promoting physical activity i n the past had a sizable effect on predicting subsequent promotion. Due to unequal distribution across stages, the stage model's application to unders tanding the behavior of health professionals may be limited.