What Physical Attributes Underlie Self- Reported vs. Observed Ability to Walk 400 m in Later Life?

Objective The aims of this study were to evaluate and contrast the physical attributes that are associated with self-reported vs. observed ability to walk 400 m among older adults. Design Analysis of baseline and 3-yr data from 1026 participants 65 yrs or older in the InCHIANTI (Invecchiare in Chianti) study was conducted. Observed and self-reported ability to walk 400 m at baseline and at 3 yrs were primary outcomes. Predictors included leg speed, leg strength, leg strength symmetry, range of motion, balance, and kyphosis. Results Balance, leg speed, leg strength, kyphosis, leg strength symmetry, and knee range of motion were associated with self-reported ability to walk 400 m at baseline (P < 0.001, c = 0.85). Balance, leg speed, and knee range of motion were associated with observed 400-m walk (P < 0.001, c = 0.85) at baseline. Prospectively, baseline leg speed and leg strength were predictive of both self-reported (P < 0.001, c = 0.79) and observed (P < 0.001, c = 0.72) ability to walk 400 m at 3 yrs. Conclusions The profiles of attributes that are associated with self-reported vs. observed walking ability differ. The factor most consistently associated with current and future walking ability is leg speed. These results draw attention to important foci for rehabilitation.