Changes in enjoyment, self-efficacy, and motivation during a randomized trial to promote habitual physical activity adoption in bariatric surgery patients

Abstract Background The Bari-Active trial found that a physical activity (PA) intervention (PAI), versus standard presurgical care control (SC), produced significant increases in daily bout-related moderate-to-vigorous PA (MVPA, in≥10-min bouts) preoperatively. The present study examined whether PAI also produces superior improvements in psychological and/or motivational processes that may be important for PA adoption. Objectives Compare PAI and SC on baseline to postintervention changes in PA-related enjoyment, self-efficacy, and motivations, and examine whether greater bout-related MVPA changes are associated with greater improvements in these variables. Setting University hospital, United States. Methods Participants (87% female; body mass index = 45.0±6.5 kg/m2 ) were randomly assigned to 6 weeks of PAI (n = 40) or SC (n = 35). PAI received weekly counseling sessions to increase daily walking exercise. At baseline and postintervention, both groups completed 7-day objective PA monitoring and questionnaires to evaluate changes in bout-related MVPA and PA enjoyment, self-efficacy, and motivation. Results Retention was 84% at postintervention. Intent-to-treat analyses showed that PAI on average reported more favorable changes than SC in PA enjoyment, self-efficacy, amotivation (i.e., lack of PA motivation), and identified and intrinsic regulations (i.e., more autonomous PA motivations; P