Article

The present study investigated the effects of somatosensory conditions at the
foot and ankle on postural responses to plantar-flexor muscle fatigue during
bipedal quiet stance. Twenty-two young healthy adults were asked to stand upright
as still as possible with their eyes closed in three somatosensory conditions
(normal, altered and improved) both prior to and after exercises inducing
plantar-flexor muscle fatigue. In the normal condition, the postural task was
executed on a firm support surface constituted by the force platform. In the
altered condition, a 2-cm thick foam support surface was placed under the
subjects' feet. In the improved condition, increased cutaneous feedback at the
foot and ankle was provided by strips of athletic tape applied across both their
ankle joints. Muscle fatigue was induced in the plantar-flexor muscles of both
legs through the execution of a repeated standing heel raise exercise. Centre of
foot pressure displacements were recorded using a force platform. Results showed
that plantar-flexor muscle fatigue yielded increased centre of foot pressure
displacements under normal foot and ankle sensory conditions. Furthermore, this
effect was exacerbated under altered foot and ankle sensory conditions and
mitigated under improved foot and ankle sensory conditions. Altogether, the
present findings suggested an increased reliance on somatosensory information
from the foot and ankle for controlling upright posture in the presence of
plantar-flexor muscle fatigue.
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Langue : ANGLAIS