Journal article
Combining regression and mean comparisons to identify the time course of changes in neuromuscular responses during the process of fatigue
Physiological measurement, Vol.37(11), pp.1993-2002
11/01/2016
DOI: 10.1088/0967-3334/37/11/1993
PMID: 27754975
Abstract
The purposes of the present study were to apply a unique method for the identification of the time course of changes in neuromuscular responses and to infer the motor unit activation strategies used to maintain force during a fatiguing, intermittent isometric workbout.
Eleven men performed 50, 6 s intermittent isometric muscle actions of the leg extensors, each separated by 2 s of rest at 60% maximal voluntary isometric contraction (MVIC). Electromyographic (EMG) and mechanomyographic (MMG) amplitude (root mean square; RMS) and frequency (mean power frequency; MPF) were obtained from the vastus lateralis (VL) every 5 of the 50 repetitions and normalized as a percent of the initial repetition. Polynomial regression analyses were used to determine the model of best fit for the normalized EMG RMS, EMG MPF, MMG RMS, and MMG MPF versus repetition relationships and one-way repeated measures ANOVAs with post-hoc Student Newman-Keuls were used to identify when these neuromuscular parameters changed from the initial repetition. The findings of the present study indicated two unique phases of neuromuscular responses (repetitions 1-20 and 20-50) during the fatiguing workbout. The time course of changes in these four neuromuscular responses suggested that the after-hyperpolarization theory could not explain the maintenance of force production, but Muscle Wisdom and the Onion Skin Scheme could. The findings of the current study suggested that the time course of changes in neuromuscular responses can provide insight in to the motor unit activation strategies used to maintain force production and allow for a greater understanding of the fatiguing process by identifying the time-points at which these neuromuscular parameters changed.
Details
- Title: Subtitle
- Combining regression and mean comparisons to identify the time course of changes in neuromuscular responses during the process of fatigue
- Creators
- Cory M. Smith - University of Nebraska–LincolnTerry J. Housh - University of Nebraska–LincolnNathaniel D. M. Jenkins - Oklahoma State UniversityEthan C. Hill - University of Nebraska–LincolnKristen C. Cochrane - California State Polytechnic UniversityAmelia A. Miramonti - University of Nebraska–LincolnRichard J. Schmidt - University of Nebraska–LincolnGlen O. Johnson - University of Nebraska–Lincoln
- Resource Type
- Journal article
- Publication Details
- Physiological measurement, Vol.37(11), pp.1993-2002
- DOI
- 10.1088/0967-3334/37/11/1993
- PMID
- 27754975
- NLM abbreviation
- Physiol Meas
- ISSN
- 0967-3334
- eISSN
- 1361-6579
- Publisher
- Iop Publishing Ltd
- Number of pages
- 10
- Language
- English
- Date published
- 11/01/2016
- Academic Unit
- Center for Social Science Innovation; Injury Prevention Research Center; Health, Sport, and Human Physiology
- Record Identifier
- 9984259643002771
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