Article

Postural responses are impaired after stroke, with reduced or delayed
muscle activity in the paretic leg muscles. OBJECTIVE:
The efficacy of exercises
emphasizing speed of movement in modifying postural responses to perturbations
that were not practiced was investigated. This was a dual cohort design.
METHODS: A convenience sample of 32 individuals with hemiparesis poststroke (mean
number of weeks poststroke=11.3, SD=4.1) who were recruited upon discharge from
an inpatient rehabilitation hospital and a control group of age- and sex-matched
individuals who were healthy (n=32) performed a single session of exercise
emphasizing speed of movement. To assess postural responses to internal
perturbation, unilateral arm raise and load drop tasks were performed before
exercises (pre-exercise), immediately after exercises (post-exercise), and 15
minutes after exercises (retention). The time to burst peak and area of the
biceps femoris muscle (BF) electromyographic (EMG) activity in the arm raise task
was measured with the arm acceleration and velocity of the center of pressure
(COP) excursion. For the load drop task, the anticipatory EMG deactivation area
of the BF was calculated. In both tasks, the vertical ground reaction forces were
recorded for each leg separately. RESULTS: Before exercise, EMG and force
platform measures were smaller in the stroke group than in the control group.
After exercise, the paretic BF time to burst peak decreased, the paretic BF EMG
area increased, and the COP velocity increased in the arm raise task, as did the
paretic BF anticipatory EMG deactivation area in the load drop task. The stroke
group was weight bearing more symmetrically after exercises. Most changes were
retained 15 minutes after the exercises. LIMITATIONS:
The retention period was
short, and there was no control group of individuals with stroke. CONCLUSIONS:
The results of this efficacy study demonstrated that fast movement exercises
improved postural responses to perturbations that were not practiced.

Langue : ANGLAIS