Article

Tripping is presumed to be the principal cause for falls during walking. At
minimum toe clearance, the potential for trip-related falls is considered to be
highest. Thus, controlling minimum toe clearance is essential for walking without
tripping. In theory, the central nervous system should therefore give priority to
accurate control of the variability in minimum toe clearance, as compared to
other gait parameters, since people tend to only modify variability in any given
task if it interferes with the task performance. The aim of this study was to
determine whether elderly individuals show less increase in variability of
minimum toe clearance during a dual-task condition (where an increase of gait
variability is provoked), while allowing a larger range of variability in the
other gait parameters. Forty elderly participants walked back and forth on a 25 m
long track for five minutes. They then walked a second time performing an
additional cognitive task. The variability in stride time, stride length and
minimum toe clearance as well as dual-task costs of each gait parameter were
calculated for each walk. The variability in minimum toe clearance did not change
during dual task-walking, whereas the variability of stride length and stride
time increased, showing dual-task costs of about 66% and 84%, respectively. To
avoid additional detrimental load on the central nervous system, the modification
of task-irrelevant variability may be tolerated during dual-task conditions,
whereas minimum toe clearance is controlled with high priority.
CI - Copyright (c) 2014 Elsevier B.V. All rights reserved.

Langue : ANGLAIS