MMG-EMG Cross Spectrum and Muscle Fiber Type

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...

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Bibliographic Details
Published in:International journal of sports medicine 2009-07, Vol.30 (7), p.538-544
Main Authors: Beck, T. W., Housh, T., Fry, A. C., Cramer, J. T., Weir, J., Schilling, B., Falvo, M., Moore, C.
Format: Article
Language:English
Subjects:
Adult
Biological and medical sciences
Electromyography - methods
Exercise - physiology
Fundamental and applied biological sciences. Psychology
Humans
Isometric Contraction - physiology
Male
Muscle Fatigue - physiology
Muscle Fibers, Fast-Twitch - physiology
Muscle Fibers, Slow-Twitch - physiology
Myography - methods
Myosin Heavy Chains - physiology
Orthopedics & Biomechanics
Quadriceps Muscle - physiology
Vertebrates: body movement. Posture. Locomotion. Flight. Swimming. Physical exercise. Rest. Sports
Young Adult
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Summary: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.
ISSN:0172-4622
1439-3964
DOI:10.1055/s-0029-1202349