Aging, frailty, and their effects on motor performance: evidence from kinematic analysis

Aging is commonly linked to motor impairment. However, the relationship between motor performance across age groups and frailty remains unexplored through objective analysis.

To kinematically evaluate motor performance in older and younger adults and investigate its potential connection to frailty.

We included 65 healthy subjects (40 females, age range 46-83 years). We used kinematic techniques to study finger-tapping and measure several movement parameters, i.e., number of movements, movement rhythm, amplitude and velocity, as well as progressive reduction in amplitude and velocity during movement repetition (sequence effect). The frailty status was evaluated using a 40-item Frailty Index (FI). We also evaluated cognitive functions, using the Mini Mental State Examination (MMSE) and the Frontal Assessment Battery (FAB). We tested possible relationships between clinical and kinematic data using Spearman's correlation.

A key finding was a significant difference in movement velocity between younger and older adults, with the latter exhibiting lower values (P = 0.014). Accordingly, age significantly correlated with movement velocity (ρ = -0.335, P = 0.037). Among older adults, movement velocity was also found to correlate with frailty (ρr = -0.297, P = 0.033), thus indicating that greater frailty is associated with more impaired motor performance.

The relationship between the age-related slowed movement execution and frailty suggests that motor performance may serve as a sensitive indicator of physical vulnerability in aging populations.