Article

Loss of postural stability, as exacerbated by chronic bed rest, aging,
neuromuscular injury or disease, results in a marked increase in the risk of
falls, potentiating severe injury and even death. To investigate the capacity of
low magnitude mechanical signals (LMMS) to retain postural stability under
conditions conducive to its decline, 29 healthy adult subjects underwent 90 days
of 6-degree head down tilt bed-rest. Treated subjects underwent a daily 10 min
regimen of 30 Hz LMMS at either a 0.3g-force (n=12) or a 0.5g-force (n=5),
introduced by Low Intensity Vibration (LIV). Control subjects (n=13) received no
LMMS treatment. Postural stability, quantified by dispersions of the
plantar-based center of pressure, deteriorated significantly from baseline in
control subjects, with displacement and velocity at 60 days increasing 98.7% and
193%, respectively, while the LMMS group increased only 26.7% and 6.4%,
reflecting a 73% and 97% relative retention in stability as compared to control.
Increasing LMMS magnitude from 0.3 to 0.5 g had no significant influence on
outcomes. LMMS failed to spare loss of muscle extension strength, but helped to
retain flexion strength (e.g., 46.2% improved retention of baseline concentric
flexion strength vs. untreated controls; p=0.01). These data suggest the
potential of extremely small mechanical signals as a non-invasive means of
preserving postural control under the challenge of chronic bed rest, and may
ultimately represent non-pharmacologic means of reducing the risk of debilitating
falls in elderly and infirm.
CI - Copyright (c) 2010 Elsevier B.V. All rights reserved.

Langue : ANGLAIS