Abstract
Objectives: This study examined the time course of changes and patterns of responses in electromyographic amplitude (EMG AMP) and EMG mean power frequency (MPF) for the superficial quadriceps muscles during exhaustive treadmill runs within the severe exercise intensity zones (SIZ1 and SIZ2). Methods: The EMG signals for the vastus lateralis (VL), rectus femoris (RF), and vastus medialis (VM) as well as times to exhaustion (Tlim) were recorded in ten runners during two exhaustive treadmill runs (SIZ1 and SIZ2). The composite and individual responses were compared among muscles and between intensities. Results: The composite patterns of responses in EMG AMP (linear, quadratic, and cubic increases; r2 /R2 =0.684–0.848) and EMG MPF (linear, quadratic, and cubic decreases; r2 /R2 =0.648 – 0.852) for the VL and RF were consistent with neuromuscular fatigue in both zones, but those for the VM were not (quadratic, cubic, and non-significant relationships with responses near baseline). The RF tended to demonstrate greater fatigue (EMG MPF decreased from 80–100% Tlim). There was large inter-individual variability (only 10–60% of responses consistent with composite) in response to fatiguing treadmill running. Conclusions: The current findings support the examination and characterization of neuromuscular fatigue on an intensity, muscle, and subject-by-subject basis.
Original language | English |
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Pages (from-to) | 77-87 |
Number of pages | 11 |
Journal | Journal of Musculoskeletal Neuronal Interactions |
Volume | 20 |
Issue number | 1 |
State | Published - Mar 2020 |
Bibliographical note
Publisher Copyright:© 2020, International Society of Musculoskeletal and Neuronal Interactions. All rights reserved.
Funding
Dr. Nathaniel Jenkins reports grants from the American Heart Association, National Strength and Conditioning Association Foundation, and from the Center for Integrative Research on Childhood Adversity under NIGMS Award Number P20GM109097, personal fees from serving as a book reviewer for Human Kinetics, and honorarium from the National Strength and Conditioning Association as a speaker at the 2019 Annual Meeting; all outside of the submitted work. The remaining authors have nothing to disclose. HCB was a substantial contributor to data acquisition, analysis, and interpretation, and drafting the manuscript, was the primary author, and takes responsibility for the integrity of the data analysis. TKD, MTB, and PJS helped carry out data analysis and interpretation. KCS and NDMJ helped with data acquisition, analysis, and interpretation of the data. TJH, RJS, and GOJ were substantial contributors to the conception and design of the work and data analysis and interpretation. All authors contributed to revising the work and approved the final submission of this manuscript. There were no sources of external funding for this work. Dr. Nathaniel Jenkins reports grants from the American Heart Association, National Strength and Conditioning Association Foundation, and from the Center for Integrative Research on Childhood Adversity under NIGMS Award Number P20GM109097, personal fees from serving as a book reviewer for Human Kinetics, and honorarium from the National Strength and Conditioning Association as a speaker at the 2019 Annual Meeting; all outside of the submitted work. The remaining authors have nothing to disclose.
Funders | Funder number |
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Center for Integrative Research on Childhood Adversity | |
National Strength and Conditioning Association | |
National Strength and Conditioning Association Foundation | |
National Institute of General Medical Sciences | P20GM109097 |
American Heart Association | |
National Strength and Conditioning Association |
Keywords
- Critical Velocity
- Individual Responses
- Neuromuscular Fatigue
- Superficial Quadriceps
- Treadmill Running
ASJC Scopus subject areas
- Endocrinology, Diabetes and Metabolism
- Physiology
- Orthopedics and Sports Medicine