Article

OBJECTIVE: To determine whether aging diminishes one's ability to rapidly learn
to resist falls on repeated-slip exposure across different activities of daily
living. DESIGN: Quasi-experimental controlled trial. SETTING: Two
university-based research laboratories. PARTICIPANTS: Young (n=35) and older
(n=38) adults underwent slips during walking. Young (n=60) and older (n=41)
adults underwent slips during a sit-to-stand task. All (N=174) were healthy and
community dwelling. INTERVENTION: Low-friction platforms induced unannounced
blocks of 2 to 8 repeated slips interspersed with blocks of 3 to 5 nonslip trials
during the designated task. MAIN OUTCOME MEASURES: The incidence of falls and
balance loss. Dynamic stability (based on center of mass position and velocity)
and limb support (based on hip height) 300 ms after slip onset. RESULTS: Under
strictly controlled, identical low-friction conditions, all participants
experienced balance loss, but older adults were over twice as likely as young to
fall on the first, unannounced, novel slip in both tasks. Independent of age or
task, participants adapted to avoid falls and balance loss, with most adaptation
occurring in early trials. By the fifth slip, the incidence of falls and balance
loss was less than 5% and 15%, respectively, regardless of age or task.
Reductions in falls and balance loss for each task were accomplished through
improved control of stability and limb support in both age groups. A rapidly
reversible age- and task-dependent waning of motor learning occurred after a
block of nonslip trials. Adaptation to walk slips reached a steady state in the
second slip block regardless of age. CONCLUSIONS: The ability to rapidly acquire
fall-resisting skills on repeated-slip exposure remains largely intact at older
ages and across functional activities. Thus, repeated-slip exposure might be
broadly effective in inoculating older adults against falls.
CI - Copyright 2010 American Congress of Rehabilitation Medicine. Published by
Elsevier Inc. All rights reserved.

Langue : ANGLAIS