Article

Whenever the body is moving in a curvilinear path, inertial torques resulting
from centripetal accelerations act on the body and must be counteracted to
maintain stability. We tested the hypothesis that healthy subjects orient their
center of mass in the position where gravitational torques offset the inertial
torques due to centripetal accelerations. Ten healthy subjects stood on a
platform that rotated in a circle at either a slow or fast speed, eyes open or
closed, and in narrow or wide stance. Upper body, lower body, and center of mass
(CoM) tilt with respect to vertical were measured and averaged across a 40 second
time period of constant velocity. Body tilt was compared to the gravito-inertial
acceleration (GIA) angle with respect to vertical. In all moving conditions, the
upper body, lower body, and CoM tilted inward. However, this inward tilt did not
reach the predicted GIA angle (CoM tilt was ~78% and 39% toward the predicted GIA
angle in narrow and wide stance, respectively).
Ratios of body tilt to GIA angle
were minimally influenced by visual availability and magnitude of centripetal
acceleration; but were largely influenced by stance width whereby narrow stance
inward tilt was greater than wide stance. These results further highlight the
important influence of the base of support on balance control strategies and
enhance our understanding of how the balance control system compensates for
inertial torques generated from centripetal accelerations.
CI - Copyright (c) 2012 Elsevier B.V. All rights reserved.

Langue : ANGLAIS