MMG-EMG cross spectrum and muscle fiber type

T. W. Beck, T. Housh, A. C. Fry, J. T. Cramer, J. Weir, B. Schilling, M. Falvo, C. Moore

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


The purpose of this study was to investigate fiber type-related differences in the patterns of responses for mechanomyographic-electromyographic (MMG-EMG) cross spectrum mean power frequency (MPF) in resistance-trained and aerobically-trained subjects during a fatiguing muscle action. Five resistance-trained and five aerobically-trained men performed a 45-s isometric muscle action of the dominant leg extensors at 50 % MVC while MMG and EMG signals were recorded simultaneously from the vastus lateralis muscle. In addition, a biopsy was taken to determine the myosin heavy chain (MHC) isoform content of the vastus lateralis. The resistance-trained and aerobically-trained subjects demonstrated similar patterns of responses for MMG-EMG cross spectrum MPF during the sustained muscle action. The vastus lateralis of the resistance-trained subjects demonstrated primarily Type II MHC isoform expression, indicative of fast-twitch muscle fibers, while that of the aerobically-trained subjects was composed mostly of Type I MHC isoform expression, indicative of slow-twitch fibers. Thus, the differences in fiber type characteristics were not manifested in the patterns of responses for MMG-EMG cross spectrum MPF.

Original languageEnglish (US)
Pages (from-to)538-544
Number of pages7
JournalInternational Journal of Sports Medicine
Issue number7
StatePublished - 2009
Externally publishedYes


  • Cross spectrum
  • Electromyography
  • Mechanomyography
  • Muscle fiber type

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation


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