Journal article
Muscle phenotype is related to motor unit behavior of the vastus lateralis during maximal isometric contractions
Physiological reports, Vol.6(5), pp.e13636-n/a
03/2018
DOI: 10.14814/phy2.13636
PMCID: PMC5845862
PMID: 29527830
Abstract
Previous investigations have reported a relationship between skeletal muscle phenotype and motor unit (MU) firing parameters during submaximal contractions. The purpose of the current investigation, however, was to examine the relationships between motor unit firing behavior during a maximal voluntary contraction, Myosin Heavy Chain (MHC) isoform content, and various molecular neuromuscular targets of the vastus lateralis (VL) muscle in resistance-trained men. Ten resistance-trained males completed a trapezoidal ramp contraction up to 100% of their maximal voluntary isometric strength (MVIC). Surface electromyography was recorded from the VL using a multichannel electrode array and decomposed to examine the firing characteristics of individual MUs. A skeletal muscle biopsy of the VL was also collected from each subject. Regression analyses were performed to identify relationships between type II fiber area and the slopes and/or intercepts of the mean firing rate (FR
) versus recruitment threshold (RT), max firing rate (FR
) versus RT, and RT versus MU action potential amplitude (MUAP
) relationships. There were significant inverse relationships between type II fiber area and the y-intercept of the FR versus RT relationship (P < 0.05). Additionally, strong relationships (r > 0.5) were found between type II fiber area and FR
versus RT slope and RT versus MUAP
slope and intercept. These data further support the hypothesis that skeletal muscle phenotype is related to MU behavior during isometric contraction. However, our data, in concert with previous investigations, may suggest that these relationships are influenced by the intensity of the contraction.
Details
- Title: Subtitle
- Muscle phenotype is related to motor unit behavior of the vastus lateralis during maximal isometric contractions
- Creators
- Ryan J Colquhoun - Oklahoma State UniversityMitchel A Magrini - Oklahoma State UniversityCody T Haun - Auburn UniversityTyler W D Muddle - Oklahoma State UniversityPatrick M Tomko - Oklahoma State UniversityMicheal J Luera - Oklahoma State UniversityCameron S Mackey - Oklahoma State UniversityChristopher G Vann - Auburn UniversityJeffrey S Martin - Edward Via College of Osteopathic MedicineKaelin C Young - Edward Via College of Osteopathic MedicineJason M DeFreitas - Oklahoma State UniversityMichael D Roberts - Auburn UniversityNathaniel D M Jenkins - Oklahoma State University
- Resource Type
- Journal article
- Publication Details
- Physiological reports, Vol.6(5), pp.e13636-n/a
- DOI
- 10.14814/phy2.13636
- PMID
- 29527830
- PMCID
- PMC5845862
- NLM abbreviation
- Physiol Rep
- eISSN
- 2051-817X
- Grant note
- name: FutureCeuticals Inc.
- Language
- English
- Date published
- 03/2018
- Academic Unit
- Center for Social Science Innovation; Injury Prevention Research Center; Health, Sport, and Human Physiology
- Record Identifier
- 9984259649002771
Metrics
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