Age-related changes in the ability to side-step during gait.

OBJECTIVE: The purpose was to identify age-related changes in the ability to step sideways during gait. DESIGN: Sixteen young women (mean age 27) and 16 older women (mean age 70) were tested. BACKGROUND: The ability to safely incorporate changes of direction into our walking pattern at short notice is a requirement for full mobility. Side-stepping in particular is frequently used to avoid obstacles. METHODS: The task was to walk repeatedly down the center of a walkway divided into three parallel lanes. A suddenly-appearing visual cue instructed the subject to move to either the right or left lane or to remain in the center lane. The aim was to make the shift accurately but as quickly as possible, without halting forward progression. RESULTS: In only 26% of the trials by the older women was the shift accomplished by taking just one extra step, compared with 58% of the trials by the young women. For one of the two shift directions there was no significant difference between the groups in either speed changes or foot placement accuracy. For the other direction, however, the young women incorporated the shift with no significant change in average speed; the older women's speed decreased by 3.3%. The older women also made more errors in foot placement in the steps following the side-step (a 22% error rate compared to a 3% error rate). CONCLUSIONS: Older women were less able to quickly and accurately incorporate a sideways shift in the plane of progression into their comfortable walking pattern.