Predictors of Usual and Peak Gait Speed in Community-Dwelling Older Adults With Mild-to-Moderate Alzheimer's Dementia.

Gait speed significantly affects functional status and health outcomes in older adults. This cross-sectional study evaluated cognitive and physical fitness contributors to usual and peak gait speed in persons with Alzheimer's dementia. Multiple hierarchal linear regression was used to obtain squared semipartial correlation coefficients (sr2) and effect sizes (Cohen's ƒ2). Participants (n = 90; 56% male) averaged 77.1 ± 6.6 years of age and 21.8 ± 3.4 on Mini-Mental State Examination. Demographic/clinical, physical fitness, and cognition variables explained 45% and 39% of variance in usual and peak gait speed, respectively. Muscle strength was the only significant contributor to both usual (sr2 = .175; Cohen's ƒ2 = 0.31; p < .001) and peak gait speed (sr2 = .11; Cohen's ƒ2 = 0.18; p < .001). Women who were "slow" walkers (usual gait speed <1.0 m/s) had significantly lower cardiorespiratory fitness and executive functioning compared with "fast" walkers. In conclusion, improving muscle strength may modify gait and downstream health outcomes in Alzheimer's dementia.