Related Experiment Video
Updated: May 4, 2026
Determining The Electromyographic Fatigue Threshold Following a Single Visit Exercise Test
Published on: July 27, 2015
EMG processing to interpret a neural tension-limiting mechanism with fatigue
Nicholas J La Delfa1, Chad A Sutherland, Jim R Potvin
1Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada.
Introduction:
Surface electromyography (sEMG) amplitude increases with constant muscle tension during fatiguing sub-maximum efforts. The purpose of this study was to determine if extreme highpass filtering and/or autoregressive whitening would result in a more consistent sEMG-to-moment ratio than a standard bandpass filter (20-500 Hz) during repeated, dynamic maximal efforts of the quadriceps.
Methods:
We collected sEMG and knee extensor moment from 16 participants during the concentric and eccentric phases of repeated, maximal knee extensor efforts.
Results:
The alternative processing methods provided more consistent vastus medialis and lateralis sEMG-to-moment ratios. A neural tension-limiting mechanism appeared to exist and was magnified during the eccentric phase, particularly with fatigue.
Conclusions:
There appears to be a difference in how the central nervous system controls concentric and eccentric efforts as the quadriceps fatigues, and this is more apparent with the alternative EMG processing methods we used.
