Article

Coordinated control of the hip and ankle is important for maintaining postural
stability. The purpose of the study was to compare postural stability between
individuals with contrasting hip abductor strength during unipedal balance tasks
and to determine whether diminished hip abductor strength results in greater
utilization of the ankle strategy to maintain balance. Forty-five females
(276+/-35 years) participated in the study. Participants were ranked based on
their isometric hip abductor muscle strength. The top 33% of the participants
were categorized as the strong group (n=15) and the lower 33% as the weak group
(n=15). Each subject performed a static and a dynamic unipedal balance task,
during which mean COP displacement, peak ankle invertor and evertor moments, and
neuromuscular activation of the lower leg muscles were assessed. Two-way mixed
analyses of variance tests with task as a repeated factor were performed to
detect the effects of task and group on the variables of interest. When averaged
across tasks, mean medial-lateral COP displacement was significantly greater in
the weak group (136+/-117 vs. 98+/-60 mm, p=0.05). The weak group also exhibited
greater peak ankle invertor and evertor moments (0.31+/-0.10 vs. 0.25+/-0.11
Nm/kg, p=0.03; 0.04+/-0.06 vs. -0.02+/-0.07 Nm/kg, p=0.01), and increased
peroneus longus activation (46+/-12 vs. 36+/-15%, p<0.01). Our results
demonstrate that individuals with diminished hip abductor muscle strength
demonstrated decreased medial-lateral postural stability, and exhibited a shift
toward utilizing an ankle strategy to maintain balance during unipedal tasks.
CI - Published by Elsevier B.V.

Langue : ANGLAIS