Social cognitive determinants of hospital-based exercise in cancer patients following high-dose chemotherapy and bone marrow transplantation

Preliminary evidence indicates that physical exercise may bean effective st rategy for the rehabilitation of cancer patients following bone marrow tran splantation (BMT), but the determinants of such exercise are not known. In this study, we used a prospective design to evaluate the theory of planned behavior (Ajzen, 1991) as a social cognitive framework for understanding ex ercise motivation and behavior in 37 BMT patients. On admittance to the hos pital, participants completed a baseline questionnaire that assessed the th eory of planned behavior and then monitored the frequency and duration of s elf-initiated cycle ergometer exercise during their hospitalization. Hierar chical regression analyses demonstrated that intention and perceived behavi oral control explained 36% of the variance in exercise behavior when the an alyses were restricted to nonthrombocytopenic patients (n = 28). Moreover, attitude and perceived behavioral control explained 68% of the variance in exercise intentions. We concluded that the theory of planned behavior provi ded an excellent understanding of exercise intentions in this population an d context and that its ability to predict exercise behavior could be improv ed substantially by taking into account significant medical complications.