Article

OBJECTIVE: To
characterize muscle properties of paretic lower-limb (PL) and nonparetic
lower-limb (NL) knee extensors in patients with subacute stroke. DESIGN:
Case-control study. SETTING: Rehabilitation center research laboratory.
PARTICIPANTS: Patients with subacute stroke (n=14) and able-bodied age-matched
control subjects (n=12). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES:
Half relaxation times (HRTs) and maximal rates of torque development (MRTDs) were
assessed as indicators of contractile speed using both voluntary and electrically
evoked contractions. Moreover, changes in torque were measured during a fatigue
protocol (35 electrically evoked intermittent contractions; 1.5s on, 2s off) and
recovery. RESULTS: No differences among groups were found for normalized MRTDs
during electrically evoked contractions (P=.117). However, during voluntary
contractions both PLs (53% of control, P=.022) and NL (71% of control, P<.001)
had significantly lower MRTD compared with control. Both PL (134% of control,
P=.001) and NL (123% of control, P=.032) had significantly higher HRTs than
control, indicating muscle slowing in patients with subacute stroke. PLs fatigued
more and faster than control (P=.011) and both PL and NL recovered slower
(P<.001). CONCLUSIONS: The changes in HRTs and fatigue suggest adaptations in
muscle properties toward slower, more fatigable muscle shortly after stroke. The
inability to make use of contractile speed because of impaired neural activation
seems the most limiting factor during the initial phase of torque development in
PL. Thus, besides strengthening, muscle endurance and speed should also be
addressed during rehabilitation.
CI - Copyright (c) 2010 American Congress of Rehabilitation Medicine. Published by
Elsevier Inc. All rights reserved.

Langue : ANGLAIS