Neural and muscular mechanisms of electrically induced fatigue in patients with spinal cord injury.
Spinal Cord
; 52(3): 246-50, 2014 Mar.
Article
em En
| MEDLINE
| ID: mdl-24445970
ABSTRACT
STUDY DESIGN:
Intervention study.OBJECTIVES:
The present study aimed at examining whether spinal and/or peripheral alterations are in the origin of neuromuscular fatigue development induced by intermittent neuromuscular electrical stimulation (NMES) in subjects with complete spinal cord injury (SCI).SETTING:
Neurological Rehabilitation Center CMN Propara, Montpellier, France.METHODS:
Thirteen volunteers with complete SCI participated in the study. The right triceps surae muscle was fatigued using a 30-Hz NMES protocol (2 s ON-2 s OFF) composed of three series of five trains. Spinal excitability (assessed by the H-reflex), muscle excitability (assessed by the M-wave), muscle contractile properties (assessed by mechanical response parameters) and torque evoked by NMES were tested before and after each five-train series.RESULTS:
NMES-evoked torque significantly decreased throughout the protocol (P<0.001). This decrease was accompanied by a significant increase in M-wave amplitude (P<0.001), whereas H-reflex and the Hmax/Mmax ratio were not significantly modified. The amplitude of the mechanical response was significantly decreased at the end of the protocol (P<0.05).CONCLUSION:
The results indicate significant fatigue development, which was attributed to impaired cross-bridge force-generating capacity, without modification of spinal excitability nor muscle excitability.
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Base de dados:
MEDLINE
Assunto principal:
Traumatismos da Medula Espinal
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Músculo Esquelético
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Fadiga Muscular
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Contração Muscular
Idioma:
En
Ano de publicação:
2014
Tipo de documento:
Article