An Adaptive Physical Activity Maintenance Intervention

Structured leisure-time physical activity (PA) (i.e., aerobic and resistance exercise) is effective for improving multiple health outcomes related to a cancer diagnosis and cancer treatment and may reduce cancer-specific mortality by as much as 40%. Thus, if cancer survivors can achieve and maintain recommended exercise levels, the public health impact would be substantial.

Supervised exercise interventions that include theory-based behavior change strategies are effective for facilitating increases in moderate to vigorous, leisure-time PA among cancer survivors. However, few studies have focused on maintaining exercise or PA levels following completion of an intervention, and evidence regarding how exercise interventions for cancer survivors can be expanded to clinic or community practice is only now emerging. To achieve the physical, psychosocial, and survival benefits of exercise, survivors must be able to maintain PA long-term, and to support PA maintenance, a socio-ecological approach is necessary. Our approach is informed by theoretical frameworks including social cognitive theory and group dynamics, which will guide intrapersonal and interpersonal level intervention strategies. Integrated research-practice partnership models will guide strategies to address organizational and community-level influences.

The goal is to develop and test an adaptive randomized trial to enhance PA maintenance among cancer survivors. Our central hypothesis is that participants who have difficulty maintaining PA following a community-based exercise program will benefit from additional support in the form of bi-weekly exercise sessions and/or PA behavior change discussion sessions. Our long-term goal is to develop an evidence-based 'stepped' PA maintenance intervention for cancer survivors that can be disseminated to existing community-based cancer-exercise programs nationwide. In the proposed study, cancer survivors will participate in an existing, cancer-specific exercise program at a community-based facility.

All programs will consist of group-based, supervised, instructor-led aerobic and resistance exercise sessions 2x per week, and three PA behavior change discussion sessions. Upon completion of the program, participants will be encouraged to maintain PA levels during a three-month free-living period, during which time there will be no active intervention. After this follow-up period, PA will be measured, and based on PA response (i.e., achieving exercise guidelines for cancer survivors), participants will be randomized to a 3-month, stepped, PA maintenance intervention. The primary outcome of PA maintenance will be assessed six-months after completion of the initial exercise program.