PURPOSE: Head and neck cancer (HaNC) can be debilitating, resulting in high symptom burden. Physical activity (PA) can improve quality of life
however, less than 9% of HaNC patients are physically active. This study explored barriers to, and facilitators of, PA promotion and participation for HaNC patients. METHODS: Semi-structured interviews with patients, family members and healthcare professionals were conducted. A questionnaire was used to measure patients' self-reported self-efficacy (The General Self-Efficacy Scale) and patients' and healthcare professionals' self-reported PA (The International PA Questionnaire - Short Form). Qualitative data were analysed using reflexive thematic analysis and quantitative data were analysed descriptively. Data were synthesised drawing on the Capability-Opportunity-Motivation-Behaviour model and the Theoretical Domains Framework. RESULTS: Twenty-eight patients, 10 family members and 18 healthcare professionals participated. Most patients self-reported moderate-to-high levels of PA and self-efficacy. Professionals self-reported high levels of PA. Patients were unaware of the benefits of PA for managing side effects and improving quality of life. Family members and professionals were fearful of patients causing themselves harm by being physically active (reflective motivation and beliefs about consequences). Some professionals did not consider it within their role to promote PA to HaNC patients. Many professionals stated they required training in PA promotion, and patients and family members stated they required information and guidance (psychological capability and knowledge). CONCLUSION: The responsibility of PA promotion is multidisciplinary and educating patients on the benefits and safety of PA may mitigate treatment-related side effects and improve quality of life. Future research should explore if barriers to, and facilitators of, PA behaviour change over a patient's treatment trajectory.