title: Wavelet-based analysis of surface mechanomyographic signals from subjects with differences in myosin heavy chain isoform content.
abstract: The purpose of this study was to use a wavelet analysis designed specifically for surface mechanomyographic (MMG) signals to determine if the % myosin heavy chain (MHC) isoform content affected the shape of the MMG frequency spectrum during isometric muscle actions. Five resistance-trained (mean +/- SD age = 23.2 +/-3.7 yrs), five aerobically-trained (mean +/- SD age = 32.6 +/- 5.2 yrs), and five sedentary (mean +/- SD age = 23.4 +/- 4.1 yrs) men performed isometric muscle actions of the dominant leg extensors at 20%, 40%, 60%, 80%, and 100% of the maximum voluntary contraction (MVC). Surface MMG signals were detected from the vastus lateralis during each muscle action and processed with the MMG wavelet analysis. In addition, muscle biopsies were taken from the vastus lateralis and analyzed for % MHC isoform content. The results showed that there were distinct differences among the three groups of subjects for % MHC isoform content. These differences were not manifested, however, in the isometric force-related changes in the total intensity of the MMG signal in each wavelet band. It is possible that factors such as the thicknesses of the subcutaneous adipose tissue and/or iliotibial band reduced the potential influence of differences in % MHC isoform content on the MMG signal.
authors.affiliation: Department of Health and Exercise Science, Biophysics Laboratory, University of Oklahoma, Norman, Oklahoma 73019-6081, USA. tbeck@ou.edu
authors.forename: T W
authors.initials: TW
authors.lastname: Beck
authors.forename: T J
authors.initials: TJ
authors.lastname: Housh
authors.forename: A C
authors.initials: AC
authors.lastname: Fry
authors.forename: J T
authors.initials: JT
authors.lastname: Cramer
authors.forename: J P
authors.initials: JP
authors.lastname: Weir
authors.forename: B K
authors.initials: BK
authors.lastname: Schilling
authors.forename: M J
authors.initials: MJ
authors.lastname: Falvo
authors.forename: C A
authors.initials: CA
authors.lastname: Moore
mesh_terms: D000328:Adult; D015444:Exercise; D017079:Exercise Tolerance / Q000502:physiology; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D008297:Male; D053580:Muscle Strength; D009213:Myography / Q000379:methods*; D018995:Myosin Heavy Chains / Q000378:metabolism*; D010809:Physical Fitness; D020033:Protein Isoforms; D052097:Quadriceps Muscle / Q000502:physiology*; D015203:Reproducibility of Results; D012815:Signal Processing, Computer-Assisted; D055815:Young Adult
chemical_list: D020033:Protein Isoforms; D018995:Myosin Heavy Chains