Article

Older adults have varied postural responses during induced and voluntary lateral
stepping. The purpose of the research was to quantify the occurrence of different
stepping strategies during lateral step initiation in older adults and to relate
the stepping responses to retrospective history of falls. Seventy
community-ambulating older adults (mean age 76 y,
range 70-94 y) performed
voluntary lateral steps as quickly as possible to the right or left in response
to a visual cue, in a blocked design. Vertical ground reaction forces were
measured using a forceplate, and the number and latency of postural adjustments
were quantified. Subjects were assigned to groups based on their stepping
strategy. The frequency of trials with one or two postural adjustments was
compared with data from 20 younger adults (mean age 38 y, range 21-58 y).
Logistic regression was used to relate presence of a fall in the previous year
with the number and latency of postural adjustments. In comparison with younger
adults, who almost always demonstrated one postural adjustment when stepping
laterally, older adults constituted a continuous distribution in the percentage
of step trials made with one postural adjustment (from 0% to 100% of trials).
Latencies of the initial postural adjustment and foot liftoff varied depending on
the number of postural adjustments made. A history of falls was associated a
larger percentage of two postural adjustments, and a longer latency of foot
liftoff. In conclusion, the number and latency of postural adjustments made
during voluntary lateral stepping provides additional evidence that lateral
control of posture may be a critical indicator of aging.
CI - Copyright (c) 2013 Elsevier B.V. All rights reserved.

Langue : ANGLAIS