A Co-design approach to develop a motivational intervention to promote physical activity engagement and maintenance among individuals in residential substance use disorder treatment settings.

Substance use disorders (SUDs) pose a significant public health concern. Preliminary research suggests benefits of physical activity (PA) for individuals receiving SUD treatment. However, current PA interventions have limitations, particularly regarding PA maintenance, due to motivational issues among people with SUDs. Our co-designed intervention is the first to target PA motivation for sustaining PA in individuals with SUDs. We employed the Behaviour Change Wheel (BCW) to co-design an intervention to increase PA motivation and support PA maintenance among people in residential SUD treatment. The BCW process involved semi-structured interviews with people with lived or living experience (n = 5) and stakeholders (n = 5) from Western Australian SUD treatment facilities and five advisory group meetings with members of the same population. Following the BCW process, we conducted a behavioural diagnosis, selected intervention functions and behaviour change techniques (BCTs) and determined modes of delivery for the intervention. Our behavioural diagnosis highlighted the need for tailored PA programs. Further, knowledge, accessibility, encouragement, role models, and routine or the lack thereof were identified as barriers and facilitators for PA motivation and PA maintenance. Barriers and facilitators were considered when selecting suitable BCTs and modes of delivery. This process resulted in a 12-session face-to-face intervention. The intervention is based on Motivational Interviewing principles and will be delivered in individual and group sessions. By integrating insights from interviews and advisory group discussions with evidence-based strategies, we co-designed a multi-dimensional PA intervention to address motivational barriers to PA maintenance for adults with SUDs.