Gait variability and local dynamic stability are exacerbated by age and visual cues

Gait variability increases and dynamic gait stability decreases with age, which may lead to an increased risk of falls. Additionally, the need to process visual cues can exacerbate changes in gait variability and dynamic gait stability in older adults. The purpose of this study was to compare gait variability and dynamic gait stability in young and older adults walking overground and on a treadmill with and without visual cues. We hypothesized that gait variability would increase and dynamic gait stability would decrease during the visually cued gait. We also hypothesized that older adults would have higher variability and lower stability than younger adults across all walking conditions.

Participants walked for 3 minutes overground and on a treadmill, with and without visual cues, at their self-selected overground walking speed. The visual cues were projected onto the treadmill and matched the participant's self-selected speed, step length, and width. We quantified gait variability as the coefficient of variation for stride time and stride length, and dynamic gait stability with the short-term Lyapunov exponent.

Both groups had the highest stride time variability during the visual cue condition. Older adults demonstrated higher gait variability and lower dynamic gait stability than younger adults during the treadmill conditions with and without visual cues, but not during overground gait.

Our study indicates that age increases gait variability and decreases dynamic gait stability, and this effect is exacerbated when walking becomes more challenging due to the presence of visual cues. The observed changes in gait variability and dynamic gait stability may be due to older adults requiring more cognitive capacity.