Distribution of motor unit potential velocities in the biceps brachii muscle of sprinters and endurance athletes during prolonged dynamic exercises at low force levels

E.G. Klaver-Krol*, N. R. Henriquez, S J. Oosterloo, P. Klaver, H. Kuipers, M.J. Zwarts

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

In surface electromyography (sEMG), the distribution of motor unit potential (MUP) velocities has been shown to reflect the proportion of faster and slower propagating MUPs. This study investigated whether the distribution of MUP velocities could distinguish between sprinters (n=11) and endurance athletes (n=12) in not-specifically trained muscle (biceps brachii) during prolonged dynamic exercises at low forces. sEMG was acquired during 4min' exercises: unloaded, 5%, 10% and 20% of maximal voluntary contraction (MVC). The features extracted from the sEMG were: the mean muscle conduction velocity - estimated using the inter-peak latency and cross-correlation methods, the within-subject skewness (expressing the proportions of faster and slower propagating MUPs) and the within-subject standard deviation of MUP velocities (SD-mup). Sprinters showed a greater proportion of faster propagating MUPs than endurance athletes. During fatigue, the SD-mup of sprinters broadened progressively, whereas that of endurance athletes did not. The findings suggest that sprinters conveyed a greater proportion of faster motor units than endurance athletes and that motor unit behavior during fatigue differed between groups. Thus, the distribution of MUP velocities enables distinction between a muscle of sprinters and endurance athletes during prolonged dynamic exercises at low forces.
Original languageEnglish
Pages (from-to)1115-1124
Number of pages10
JournalJournal of Electromyography and Kinesiology
Volume20
Issue number6
DOIs
Publication statusPublished - Dec 2010

Keywords

  • Surface electromyography
  • Position task
  • Fatigue
  • Skewness
  • Standard deviation
  • FIBER CONDUCTION-VELOCITY
  • SURFACE EMG SIGNALS
  • LOAD TYPE
  • ISOMETRIC CONTRACTIONS
  • FATIGUING CONTRACTIONS
  • VOLUNTARY CONTRACTION
  • RECRUITMENT
  • TIME
  • ELECTROMYOGRAPHY
  • ACTIVATION

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