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Updated: Jun 30, 2026

Determining The Electromyographic Fatigue Threshold Following a Single Visit Exercise Test
Published on: July 27, 2015
Fatigue-induced changes in tonic vibration response (TVR) in humans: relationships between electromyographic and
Christelle Brerro-Saby1, Stéphane Delliaux1, Jean Guillaume Steinberg1
1UMR MD2, Physiologie et physiopathologie en conditions d'oxygénation extrêmes, Institut Jean Roche, Faculté de Médecine, Université de la Méditerranée, Bd. Pierre Dramard, 13916, Marseille, France.
Abstract:
Fatigue-induced changes in the proprioceptive reflex loop were explored in humans by using the tonic electromyographic (EMG) response to vibration (TVR) and relating it to lactic acidosis (LA) and oxidative stress. TVR was measured in flexor digitorum superficialis before and after sustained or intermittent handgrip at maximal voluntary contraction (MVC). TVR variations were compared with the changes in EMG power spectrum preceding contractile fatigue, the Hoffman reflex (H-reflex), and plasma concentrations of LA and thiobarbituric acid reactive substances (TBARS). After both sustained and intermittent handgrips, TVR amplitude first declined then increased, independently from the changes in EMG power spectrum and H-reflex. TVR depression and facilitation were respectively concomitant with increases in LA and TBARS. The TVR depression was proportional to the increased LA level. The origin of TVR changes after muscle fatigue is questioned because the relationship between TVR depression and LA accumulation might be temporal, not causal, and changes in muscle stiffness were not explored.
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