Article

The purpose of this study was to investigate the changes in postural control and
in posture induced by ankle plantarflexor fatigue during a unipedal stance task.
We also studied the postural strategies in the antero-posterior and medio-lateral
planes used by participants to maintain balance. Thirteen young adults were asked
to stand barefoot on their preferred leg as still as possible for 30s with vision
or without vision. Participants performed postural trials before and after a
fatigue protocol that consisted of standing on toes until exhaustion. Centre of
pressure (COP) displacements were measured with a force platform and
electrogoniometers were placed at the ankle, knee and hip joints of the support
leg to monitor articular angles. Relationships between changes in articular
angles and displacements of the COP in the antero-posterior and medio-lateral
planes were tested using cross-correlations. Sway area and velocity increased
with fatigue, but only without vision. A posterior shift of the mean COP position
was also observed after fatigue. Ankle and hip joints were more flexed after
fatigue. Moderate to good relationships between COP displacements and ankle
angles were observed before and after fatigue in both planes whereas these
relationships were low for hip and knee joints. Ankle plantarflexors fatigue
induced impairment in postural control and changes in posture. To compensate for
the effects of fatigue, participants increased the flexion of the ankle and/or
the hip joints but conserved the ankle strategy as the dominant postural strategy
in both planes.
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Langue : ANGLAIS