Document Detail


A noninvasive, log-transform method for fiber type discrimination using mechanomyography.
MedLine Citation:
PMID:  20172740     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
This study examined the log-transformed mechanomyographic (MMG(RMS)) and electromyographic (EMG(RMS)) amplitude vs. force relationships for aerobically-trained (AT), resistance-trained (RT), and sedentary (SED) individuals. Subjects performed isometric ramp contractions from 5% to 90% maximal voluntary contraction. Muscle biopsies were collected and thigh skinfolds, MMG and EMG were recorded from the vastus lateralis muscle. Linear regression models were fit to the log-transformed EMG(RMS) and MMG(RMS) vs. force relationships. The slope (b coefficient) and the antilog of the y-intercept (a coefficient) were calculated. The AT group had the highest percentage of type I fiber area, the RT group had the highest percentage of type IIa fiber area, and the SED group had the highest percentage of type IIx fiber area. The a coefficients were higher for the AT group than the RT and SED groups in both the MMG(RMS) and EMG(RMS) vs. force relationships, whereas the b coefficients were lower for the AT group than the RT and SED groups only in the MMG(RMS) vs. force relationship. The group differences among the a coefficients may have reflected subcutaneous fat acting as a filter thereby reducing EMG(RMS) and MMG(RMS). The lower b coefficients for the AT group in the MMG(RMS) patterns may have reflected fiber area-related differences in motor unit activation strategies.
Authors:
Trent J Herda; Terry J Housh; Andrew C Fry; Joseph P Weir; Brian K Schilling; Eric D Ryan; Joel T Cramer
Publication Detail:
Type:  Journal Article     Date:  2010-02-21
Journal Detail:
Title:  Journal of electromyography and kinesiology : official journal of the International Society of Electrophysiological Kinesiology     Volume:  20     ISSN:  1873-5711     ISO Abbreviation:  J Electromyogr Kinesiol     Publication Date:  2010 Oct 
Date Detail:
Created Date:  2010-08-02     Completed Date:  2011-01-04     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9109125     Medline TA:  J Electromyogr Kinesiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  787-94     Citation Subset:  IM    
Copyright Information:
Published by Elsevier Ltd.
Affiliation:
Department of Health and Exercise Science, Biophysics Laboratory, University of Oklahoma, Norman, Oklahoma, USA.
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MeSH Terms
Descriptor/Qualifier:
Algorithms*
Humans
Isometric Contraction / physiology*
Male
Muscle Fibers, Skeletal / classification*,  physiology*
Muscle, Skeletal / cytology*,  physiology*
Myography / methods*
Young Adult

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