Changes in corticomotor excitation and inhibition during prolonged submaximal muscle contractions. Academic Article uri icon

Overview

abstract

  • Changes in motor evoked potential (MEP) amplitude, post-MEP silent period duration, and interpolated twitch torque were measured using transcranial magnetic (TMS) and electrical (TES) stimulation during a 20% maximum voluntary contraction of the elbow flexors sustained to exhaustion. TMS- and TES-induced MEP amplitude increased progressively over the contraction period up until the point of exhaustion. The TMS-induced silent period was prolonged only during the second half of the contraction period, the time course being different from that of the MEP responses, whereas the TES-induced silent period did not change. The findings indicate that corticomotor excitability increases during a sustained submaximal voluntary contraction and that, as fatigue develops, there is a progressive buildup of intracortical inhibition. This may represent a mechanism whereby corticomotor output is maintained at an appropriate level to preserve optimal motor unit firing frequencies during a fatiguing contraction.

publication date

  • September 1, 1997

Research

keywords

  • Motor Cortex
  • Muscle Contraction
  • Neural Inhibition

Identity

Scopus Document Identifier

  • 0030753785

PubMed ID

  • 9270673

Additional Document Info

volume

  • 20

issue

  • 9