Electromyogram activity and mean power frequency in exercise-damaged human muscle
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Updated: Oct 29, 2026

Determining The Electromyographic Fatigue Threshold Following a Single Visit Exercise Test
Published on: July 27, 2015
S H Day1, A E Donnelly, S J Brown
1Muscle Research Group, School of Health Sciences, University of Wolverhampton, United Kingdom.
Abstract:
Eight volunteers performed two bouts of 50 voluntary maximal eccentric contractions of the knee extensors of one leg 3 weeks apart. During maximal voluntary isometric contractions performed at intervals after each bout, electromyogram (EMG) mean power frequency declined after bout one (P < 0.01 Duncan's test), whereas integrated EMG did not change after either bout. These results suggest that unaccustomed eccentric contractions produce a temporary reduction in mean muscle activation frequency during subsequent maximal isometric contractions.
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