Abstract Background Sit-to-stand (STS) transitions are common daily activities, and we postulate that completing them with high effort relative to one’s capacity may indicate functional difficulties in older age. Aims We examined the association between relative free-living STS thigh angular velocity and difficulties in activities of daily living (ADL) and instrumental activities of daily living (IADL), as well as walking and negotiating stairs. Methods This cross-sectional study included 230 individuals (53% women) aged 79–89 years. STS capacity was assessed with an instrumented five-times STS test. Free-living STS transitions were monitored in 2-hour intervals over four days using an accelerometer. Associations were examined using Wilcoxon rank-sum test and logistic regression analyses. Results In total, 47% had ADL/IADL difficulties, 26% reported walking difficulties, and 17% had difficulties negotiating stairs. Participants with any difficulties performed STS transitions at a higher proportion of their STS capacity compared to those without difficulties ( p < 0.05). Higher relative free-living STS thigh angular velocity was associated with walking and stair negotiation difficulties in both crude (OR 1.23–1.53; p < 0.05) and adjusted models (OR 1.20–1.40; p < 0.05), while the association with ADL/IADL difficulties weakened after adjustment. Conclusions Our findings suggest that performing STS transitions at high intensity may reflect emerging mobility difficulties.
Löppönen et al. (2026) studied this question.