MMG-EMG cross spectrum and muscle fiber type.
- Citation data:
International journal of sports medicine, ISSN: 1439-3964, Vol: 30, Issue: 7, Page: 538-44
- Publication Year:
- Repository URL:
- https://digitalscholarship.unlv.edu/kns_fac_articles/38; http://ezproxy.library.unlv.edu/login?url=http://dx.doi.org/10.1055/s-0029-1202349
- Medicine; mechanomyography; electromyography; cross spectrum; muscle fiber type; Sports Sciences
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.