This methodological reflection highlights the practical challenges encountered when designing and conducting exercise-based research with older adults. The paper draws on experiences from a mixed-methods pilot intervention in southeast Queensland, Australia. Within this paper we discuss issues related to recruitment, retention, and study design in a convenience sample (n = 20) of previously sedentary older adults (mean age 66.0, SD 9.33) and a comparison group (n = 7). While the intervention used Taekwondo adapted for older populations, this paper does not report outcome findings, but instead explores obstacles to sample representativeness, engagement, and data completion. We describe factors such as age-related health limitations, socio-economic and cultural considerations, and lifestyle-related barriers to participation, and suggest design modifications to better accommodate older adult participants. By providing reflective analysis and practical recommendations, our aim is to inform future research by sharing practice-based insights relevant to exercise interventions in this unique and growing population. We argue for the value of mixed-method approaches, context-aware sampling strategies, and ethical flexibility to better serve research in older cohorts.