Discussion
It was feasible and safe to deliver a volunteer-led online exercise intervention in social clubs for community-dwelling older adults. The intervention was acceptable to staff, volunteers, and older adults. Volunteers were positive and relatable role models who developed a non-judgmental group atmosphere. The group environment, social connections, and sense of togetherness motivated participation. A key to success was the digital coaching and support to upskill older adults’ technological knowledge and improve access and confidence to engage with the intervention online. Volunteer retention rate was at 47.3% at the end of the study period which is in line with the usual retention rates for volunteer-based interventions [This study adds to a burgeoning evidence-base suggesting that with proper training, volunteers can take on more direct roles in supporting older adults’ PA [This feasibility study demonstrated encouraging trends in PA levels and subjective reports regarding enhanced health and fitness, but these preliminary findings need to be confirmed in a larger controlled trial. Importantly, the intervention provided opportunity for participants to exercise during the pandemic, a time when older adults experienced significant restrictions to activities of daily living with subsequent deconditioning and reductions in health-related quality of life [Most volunteers were aged over 60 years with similar ability levels to the groups they were leading, and some of them also experienced their own health problems. As such the volunteers became relatable role models in which they provided a positive vicarious experience for club members, increasing their confidence (i.e., self-efficacy to exercise) and encouraging them to join in the exercise sessions. Exercise self-efficacy refers to the participants’ beliefs in their capabilities to exercise, and can influence choice to participate, level of effort exerted, and perseverance in the face of difficulties [A key influence on the success of the intervention was participants’ digital literacy and their ability to access the online exercise. Older adults are more likely to experience barriers in the use of digital tools, such as poor prior experience with technology, and cybersecurity concerns [A motivating factor to learn how to use the online platform was to continue socialising, and the sense of belonging and trust established in the social groups. Hence, the group nature of the intervention was important. Similarly, a range of studies have pinpointed group exercise and social connection as a strong motivator to exercise in later life and a principal influence on exercise adherence [Robust collaborations with the host organisation, including valuable input from staff, volunteers and participants was a strength of this study. A mixed methods approach allowed rich in-depth qualitative exploration and understanding of implementation processes, while quantitative measures revealed the impact of the intervention on physical activity and health outcomes. A further strength was the use of NPT, which provided a set of conceptual tools to support understanding and evaluation of the adoption, implementation, and sustainment of the intervention, and considered the complexity of the beliefs, behaviours, artefacts, and practices that played out over time and between settings [