Regular participation in moderate-intensity physical activity (PA) is beneficial for patients with rheumatoid arthritis (RA); however, a large proportion of patients with RA are not physically... Show moreRegular participation in moderate-intensity physical activity (PA) is beneficial for patients with rheumatoid arthritis (RA); however, a large proportion of patients with RA are not physically active. In this dissertation, we describe the pilot-testing of an intervention to promote PA among patients with RA, as well as several preliminary studies which informed the development of the intervention. These preliminary investigations identified autonomous motivation, self-efficacy, PA goal achievement and use of self-regulation techniques as important predictors of PA behavior change. As such, and based on existing literature, motivational interviewing (MI) and self-regulation coaching (SR) were selected as intervention techniques which could impact upon these variables. In a randomized controlled trial, the combined MI+SR intervention led to increased autonomous motivation, self-efficacy and physical activity comp ared to a patient education control group over 32 weeks. Process analyses revealed that autonomous motivation and use of self-regulation skills explained the sustained increases in PA behavior, and that certain characteristics of MI sessions explained changes in autonomous motivation and PA. Despite increasing their PA, patients who received the intervention did not improve on any disease related variables. Practical implications of the findings are discussed. Show less