Article

Individuals post stroke often rely more on hip flexors for limb advancement
during walking due to distal weakness but the effects of muscle fatigue in this
group is not known. The purpose of this study was to quantify how stroke affects
the influence of hip flexor fatigue on over ground walking kinematics and
performance and muscle activation. Ten individuals with chronic stroke and 10
without stroke (controls) participated in the study. Maximal walking speed,
walking distance, muscle electromyograms (EMG), and lower extremity joint
kinematics were compared before and after dynamic, submaximal fatiguing
contractions of the hip flexors (30% maximal load) performed until failure of the
task. Task duration and decline in hip flexion maximal voluntary contraction
(MVC) and power were used to assess fatigue. The stroke and control groups had
similar task durations and percent reductions in MVC force following fatiguing
contractions. Compared with controls, individuals with stroke had larger percent
reductions in maximal walking speed, greater decrements in hip range of motion
and peak velocity during swing, greater decrements in ankle velocity and lack of
modulation of hip flexor EMG following fatiguing dynamic hip flexion
contractions. For a given level of fatigue, the impact on walking function was
more profound in individuals with stroke than neurologically intact individuals,
and a decreased ability to up regulate hip flexor muscle activity may contribute.
These data highlight the importance of monitoring the effect of hip flexor muscle
activity during exercise or performance of activities of daily living on walking
function post stroke.
CI - Copyright (c) 2014 Elsevier B.V. All rights reserved.

Langue : ANGLAIS