Feasibility and safety of mixed reality treadmill walking in older adults: a pilot and feasibility trial

Virtual reality (VR) treadmill walking has been recognised for its potential to enhance enjoyment and motivation, although safety concerns limit its use in older adults. Mixed reality (MR), by integrating virtual elements with the real environment, may reduce these risks while maintaining motivational benefits. This pilot and feasibility trial examined the practicality of implementing MR treadmill walking in healthy older adults to determine readiness for a definitive randomised controlled trial.

Forty-two community-dwelling older adults (mean age, 73.7 years; 30 men) were randomised to treadmill walking with MR (MR+) or without MR (MR-). Each participant performed a 10-min self-paced treadmill walking task. Feasibility outcomes included recruitment, retention, adherence, safety (Simulator Sickness Questionnaire [SSQ]), enjoyment (Physical Activity Enjoyment Scale [PACES]), and exercise intensity (percentage of heart rate reserve [%HRR]).

All 42 participants consented and completed the treadmill session and follow-up assessments (recruitment, retention, and adherence, 100%). No adverse events or falls occurred. SSQ scores indicated negligible simulator sickness, confirming good tolerability, and PACES scores were significantly higher in MR+ than in MR- (110.7 ± 15.4 versus 96.7 ± 15.7; mean difference=13.95, 95% confidence interval 4.25 to 23.64; p = 0.006). %HRR values reflected moderate exercise intensity in both groups. All prespecified feasibility thresholds were achieved.

MR treadmill walking was found to be safe, tolerable, and enjoyable for older adults, meeting key feasibility criteria and providing a solid basis for progression to a definitive randomised controlled trial to establish clinical efficacy and broader applicability in geriatric rehabilitation.