Article

OBJECTIVES: To determine the characteristics of motor planning surrounding
initial contact during gait through examination of thigh muscle timing,
amplitude, and co-contraction of the paretic and nonparetic limbs in people
poststroke, and to investigate whether muscle timing, amplitude, and clinical
performance measures of balance and mobility differ based on the level of
co-contraction. DESIGN: Observational study. SETTING: University-based research
laboratory. PARTICIPANTS: Individuals (n=27) in the subacute phase after stroke
and healthy controls (n=8) (N=35). INTERVENTIONS: Not applicable. MAIN OUTCOME
MEASURES: Timing (onset and offset) and normalized amplitude (percent
electromyography maximum) of the biceps femoris (BF) and rectus femoris (RF)
muscles were measured during terminal swing and early stance. A co-contraction
index (CCI) was calculated for the BF and RF muscle activity. Individuals with
CCI values equal to or below the mean of the healthy group were in the low CCI
group, whereas those with values above the mean were in the high CCI group.
Functional balance and mobility evaluation used the Community Balance and
Mobility Scale (CB&M). RESULTS: For the paretic and nonparetic limbs, measures of
timing, amplitude, and co-contraction were similar for both limbs. Compared with
the healthy group, the high CCI group had lower CB&M scores, longer durations,
and higher levels of RF and BF muscle activity, whereas the low CCI group had
electromyographic measures statistically similar to healthy controls.
CONCLUSIONS: The motor control of gait after subacute stroke is characterized by
symmetry of timing and amplitude of muscle recruitment at the knee. High
co-contraction levels surrounding the knee were associated with lower functional
balance and mobility. These findings suggest a compensatory strategy of increased
co-contraction in those with more impairment while maintaining symmetry of
lower-limb biomechanics between limbs.
CI - Copyright (c) 2016 American Congress of Rehabilitation Medicine. Published by
Elsevier Inc. All rights reserved.

Langue : ANGLAIS