Aim This study compared functional capacity in healthy and sarcopenia-prone older adults, examining the associations between smartwatch-derived accelerometry features and the Five Times Sit-to-Stand Test (5xSTS). Methods Eighty older adults were assessed; analyses included 47 with complete 5xSTS accelerometry data. Temporal and statistical features were compared between groups and correlated with 5xSTS time. Results Sarcopenia-prone older adults showed lower 5xSTS performance (p < 0.05; Delta = -50.5%) compared to healthy older adults. Accelerometry features differed between groups, and resultant acceleration variables remained significant after age adjustment. ROC analyses demonstrated acceptable discriminatory ability for minimum resultant (AUC: 0.817) and SD (AUC: 0.787) acceleration, and 5xSTS duration (AUC: 0.758). Accelerometry features correlated with 5xSTS, particularly for minimum resultant acceleration (r = 0.74) in the sarcopenia-prone group. Conclusion Smartwatch-based accelerometry during the 5xSTS provides relevant data of functional decline and supports wrist-worn devices for monitoring physical function in older adults.
