BackgroundPhysical activity levels in people with rheumatoid arthritis are lower than what are recommended for a healthful lifestyle. To support physical activity, health care professionals may use behavioral change techniques based on a biopsychosocial perspective. Investigating the implementation process may be relevant for understanding how these techniques translate to practice. ObjectivesThe study objective was to explore the experiences of physical therapists using behavioral change techniques to coach people with rheumatoid arthritis to health-enhancing physical activity in a 2-year trial, the Physical Activity in Rheumatoid Arthritis 2010 study. DesignThis was an exploratory study with qualitative content analysis. MethodsSemistructured interviews were conducted with all 12 physical therapists in the study. They were asked about their experiences with an educational program and with their delivery of a health-enhancing physical activity intervention. Codes, subcategories, categories, and an overarching theme were derived from the transcribed interviews by use of qualitative content analysis. ResultsThe overarching theme (from clinical expert to guide) was based on 3 main categories: challenges in the coaching role, growing into the coaching role, and coach education and support. Early in the process, the physical therapists encountered challenges that needed to be addressed for a smoother transition into their coaching role. Assisted by education and support, they gradually adopted practices that facilitated their use of behavioral change techniques and promoted growth into the role of coach. ConclusionsAdapting to a new role is a challenging process for health care professionals; it requires relevant education and support. The experiences identified in the present study may inform future educational programs targeting the skills of health care professionals in promoting various health-related behaviors.