Feasibility of Online and On-Site Physical Activity Delivery Among Older Adults: Mixed Methods Pilot Randomized Controlled Trial

Physical activity (PA) is central to healthy aging, yet interventions targeting older adults often report substantial attrition and variable adherence. Although digital and internet-based exercise programs broaden accessibility and flexibility, their ability to sustain engagement compared with traditional on-site formats remains unclear. Understanding how delivery mode influences attrition and adherence-and why participants persist or withdraw-is essential for designing inclusive and sustainable PA interventions.

This pilot study evaluates the feasibility of delivering a 26-week PA intervention to older adults through 2 modes: online or on-site. Feasibility was assessed primarily by attrition, adherence, and participants' experiences of factors influencing continued participation or withdrawal. Additionally, the study explores preliminary patterns in PA levels and physical and mental health outcomes to inform the design of a future definitive trial.