OBJECTIVES: To determine the acceptability of an exercise programme and to identify barriers and facilitators to compliance with the programme from the participants' perspective. METHODS: Patients aged 75 years or older were recruited within the first 36 hours of hospital admission. Participants were randomised to complete two strengthening-based (intervention arm) or stretching-based (control arm) exercise sessions per-day. At hospital discharge, participants were asked to take part in interviews with a member of the research team exploring the barriers and facilitators to adherence to the intervention. RESULTS: 15 participants (7 intervention arm, 8 control arm) were recruited before the trial was stopped due to COVID-19. Both groups showed reductions in knee-extension strength, and improvements in functional mobility at discharge from hospital. A total of 23/60 intervention sessions were classed as 'complete', 12/60 as partially complete, and 25/60 were missed entirely. Eight participants took part in interviews. Intrinsic factors that impacted participation in the research, related to current health, health beliefs, and experience of multi-morbidity or functional decline. Staff had both a positive and negative effect on participant adherence to the intervention. CONCLUSIONS: The exercise intervention was well received, with most participants describing health benefits, though intervention fidelity was lower than expected.