Mechanomyographic and electromyographic responses to eccentric muscle contractions

Jared W. Coburn, Terry J. Housh, Moh H. Malek, Joseph P. Weir, Joel T. Cramer, Travis W. Beck, Glen O. Johnson

Research output: Contribution to journalArticlepeer-review

23 Scopus citations

Abstract

Little is known regarding the modulation of torque during eccentric muscle actions. Mechanomyographic (MMG) and electromyographic (EMG) signals have been used to examine motor control strategies. The purpose of this study was to examine the MMG and EMG amplitude and frequency in relation to torque during eccentric muscle contractions. Eight women performed eccentric leg extension muscle contractions at 10-100% of peak torque (PT). A piezoelectric crystal contact sensor and bipolar surface electrodes were placed on the vastus medialis to detect the MMG and EMG signals. Polynomial regression analyses indicated that EMG amplitude (r2 = 0.994) and MMG wavelet center frequency (CF) (r2 = 0.846) increased linearly to 100% eccentric PT, whereas there were no significant relationships for EMG wavelet CF or MMG amplitude and eccentric torque. These results suggested that eccentric torque is primarily modulated through changes in motor unit firing rate.

Original languageEnglish (US)
Pages (from-to)664-671
Number of pages8
JournalMuscle and Nerve
Volume33
Issue number5
DOIs
StatePublished - May 2006
Externally publishedYes

Keywords

  • Acoustic myography
  • Eccentric contractions
  • Electromyography
  • Mechanomyography
  • Phonomyography

ASJC Scopus subject areas

  • Physiology
  • Clinical Neurology
  • Cellular and Molecular Neuroscience
  • Physiology (medical)

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