Families: Together We Move – Protocol for a Cluster Randomised Feasibility Trial of a Family-Based Physical Activity Intervention (Preprint)

BACKGROUND The health benefits of physical activity are well recognised for both adults and children, yet participation remains insufficient in many countries globally. Socioeconomic inequalities contribute to disparities in opportunities to be active, with children in deprived communities facing barriers to physical activity such as financial constraints, lack of safe play areas, and limited access to green space. Families are an important target population for physical activity promotion, as parental behaviours can influence children’s activity levels. Although family-based physical activity interventions have shown promise, relatively few have been developed and tested specifically for families experiencing socioeconomic deprivation or delivered through local authorities. Local authorities are well placed to deliver sustainable, community-based interventions making them critical partners in developing and testing evidence-based approaches to increase physical activity and reduce health inequalities. OBJECTIVE To assess the feasibility and acceptability of the Families: Together We Move intervention for families living in areas of deprivation in Northern Ireland and to inform the design of a future definitive randomised controlled trial. METHODS This study is a feasibility cluster-randomised controlled trial of the Families: Together We Move intervention involving 50 families, each with at least one child aged 4–18 years and one adult parent/guardian from the Derry City and Strabane District Council area. Families will be randomly allocated (1:1) to intervention or control groups following baseline data collection. The 12-week intervention designed with families, includes an introductory ‘welcome session’ which will be focused on goal-setting, up to three free weekly classes delivered by local council staff, weekly activity vouchers (for use within the council facilities/leisure centres), a moderated online group chat for peer support and monthly newsletters. Control families will continue with their usual physical activity. Assessments will be conducted at baseline, 12 weeks, and six-month follow-up. Outcome measures include recruitment, retention, and adherence rates, alongside the acceptability of study procedures and intervention components. Physical activity will be assessed using accelerometers, with self-reported measures of family activity habits, enjoyment, and motivation collected. A mixed-methods process evaluation, including semi-structured interviews will explore participant and facilitator experiences and perceived barriers/facilitators to engagement. RESULTS Funding was confirmed in February 2026. Participant recruitment will commence in January 2027, with intervention delivery scheduled from May-July 2027. After data analysis, the study findings are expected to be submitted for publication in May 2028. CONCLUSIONS This study will determine the feasibility, acceptability, and implementation requirements of delivering a family-based physical activity intervention through a local authority in a community experiencing deprivation. Findings will inform the design of a future definitive randomised controlled trial and provide transferable learning for the development and delivery of community-based approaches to reducing socioeconomic inequalities in physical activity participation. CLINICALTRIAL This feasibility study has not been registered in a clinical trials registry. The study received ethical approval from Ulster University Research Ethics Committee (REC/26/0045). The study protocol is publicly available on Zenodo: https://doi.org/10.5281/zenodo.23748481