Int J Sports Med 2009; 30(7): 538-544
DOI: 10.1055/s-0029-1202349
Orthopedics & Biomechanics

© Georg Thieme Verlag KG Stuttgart · New York

MMG-EMG Cross Spectrum and Muscle Fiber Type

T. W. Beck 1 , T. Housh 2 , A. C. Fry 3 , J. T. Cramer 1 , J. Weir 4 , B. Schilling 5 , M. Falvo 6 , C. Moore 5
  • 1Department of Health and Exercise Science, University of Oklahoma, Norman, United States
  • 2Department of Nutrition and Health Sciences, Lincoln, Nebraska, United States
  • 3Department of Health, Sport & Exercise Sciences, The University of Kansas, Lawrence, United States
  • 4Osteopathic Medical Center, Des Moines University, Des Moines, United States
  • 5Department of Health and Sports Sciences, University of Memphis, Memphis, United States
  • 6Program in Physical Therapy, Washington University in St. Louis, St. Louis, United States
Further Information

Publication History

accepted after revision December 31, 2008

Publication Date:
20 April 2009 (online)

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Abstract

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.

References

Correspondence

Dr. T. W.Beck 

Department of Health and Exercise Science

University of Oklahoma

Huston Huffman Center

73019-6081 Norman

United States

Phone: +405/325 13 78

Fax: +405/325 05 94

Email: tbeck@ou.edu