Feasibility of a Self-Determination Theory-based exercise intervention promoting Healthy at Every Size with sedentary overweight women: Project CHANGE

Objectives: To examine feasibility, acceptability and preliminary results of a Self-Determination Theory (SDT) -based exercise intervention with a Healthy at Every Size (HAES) orientation for sedentary overweight/obese women. Design: Project CHANGE was an 8-week randomized controlled trial with follow-up at 4-week. Method: Twenty-five sedentary, overweight women (BMI = 25-34.9) were randomized to either the SDT-based intervention with a HAES orientation (S/H) or exercise only (EX) intervention. The S/H group received exercise training and a weekly behavioral intervention while the EX group received only traditional supervised exercise training. Information about acceptability and feasibility was collected from process evaluation (i.e., participants' satisfaction and feedback) and objective data (e.g., retention, attendance, adherence to the PA goal). Assessments of PA participation and physical/psychological variables were obtained at baseline, post-intervention, and 4-week follow-up. Results: Participants reported high levels of satisfaction. Participation in the S/H group averaged 95%. Retention was high for both groups (S/H = 83.3% vs. EX = 84.6%), while adherence to the PA goal was better for the S/H group at follow-up (S/H = 60% vs. EX = 36.4%). The S/H intervention also resulted in larger effect sizes for changes in key motivational variables, including self-determination, autonomy, as well as goal-setting, planning and scheduling self-efficacy. Conclusion: The 8-week SDT-based intervention promoting Healthy at Every Size is feasible and acceptable and may result in better exercise adherence and improvements in motivational variables relative to traditional supervised exercise. These results support conducting additional research to determine the efficacy of this approach for promoting PA in sedentary, overweight women. (c) 2012 Elsevier Ltd. All rights reserved.