Physical activity (PA) interventions diminish some of the physical and psychosocial sequelae of breast cancer diagnosis and treatment. To increase intervention efficacy and portability, it is necessary to determine the factors mediating intervention effects on physical and psychosocial outcomes. This study presents mediator analyses from a randomized controlled trial of a home-based PA intervention (focused primarily on brisk walking) for breast cancer survivors. Eighty-six survivors were randomized to PA or contact control groups (mean age = 53.42 years, SD = 9.08 and 52.86 years, SD = 10.38 respectively; mean time since diagnosis < 2 years). The PA intervention was based on the transtheoretical model (TTM). Kraemerʼs approach was used to test hypothesized mediators. TTM variables did not mediate intervention effects on PA. Data indicate that increases in moderate-intensity PA and improved fitness may mediate intervention effects on vigor (β = .21; p = .01) and fatigue (β = .24; p = .05) and suggest the value of future research on these potential mediators.
Carolyn Rabin, Bernardine M. Pinto and Georita M. Frierson
Bernardine M. Pinto, Bess H. Marcus, Robert B. Patterson, Mary Roberts, Andrea Colucci and Christina Braun
Exercise has been shown to improve walking ability in individuals with arterial claudication. This study compared the effects of an on-site supervised exercise program and a home exercise program on quality of life and psychological outcomes in these individuals. Sixty individuals were randomly assigned to a 12-week on-site or a 12-week home-based exercise program. Quality of life, mood and pain symptoms, and walking ability were examined at baseline, posttreatment, and at 6 months follow-up. Individuals in the on-site exercise program showed significantly greater improvements in walking ability. Although sample size limited the ability to detect significant differences between groups on quality of life and psychological measures, both groups were comparable on improvements in quality of life and in mood. These data suggest that a home exercise program with weekly feedback may provide improved quality of life and mood benefits for individuals with arterial claudication but does not provide improvements in walking equivalent to those provided by an on-site exercise program.
Beth A. Lewis, LeighAnn H. Forsyth, Bernardine M. Pinto, Beth C. Bock, Mary Roberts and Bess H. Marcus
Behavioral science theories have been used to develop physical activity interventions; however, little is known as to whether these interventions are effective due to changes in constructs related to these theories. Specifically, if the intervention is successful, does it work for the reasons hypothesized by the theory underlying it? The purpose of this study was to examine the importance of particular theoretical constructs among participants (n = 150) who had been randomly assigned to a physical activity intervention based on the Transtheoretical Model and Social Cognitive Theory (i.e., tailored group) or to a standard care group. Participants in the tailored group reported greater increases in behavioral processes and self-efficacy from baseline to 3 months than participants in the standard-care group. No between-group differences were found for cognitive processes and decisional balance. This study demonstrates that theory-based physical activity interventions may be effective through changes in particular theoretical constructs.