| Influence of priming exercise on muscle [PCr] and pulmonary O2 uptake dynamics during 'work-to-work' knee-extension exercise. | |
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MedLine Citation:
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PMID: 20417317 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Metabolic transitions from rest to high-intensity exercise were divided into two discrete steps (i.e., rest-to-moderate-intensity (R-->M) and moderate-to-high-intensity (M-->H)) to explore the effect of prior high-intensity 'priming' exercise on intramuscular [PCr] and pulmonary VO₂ kinetics for different sections of the motor unit pool. It was hypothesized that [PCr] and VO₂ kinetics would be unaffected by priming during R-->M exercise, but that the time constants (tau) describing the fundamental [PCr] response and the phase II VO₂ response would be significantly reduced by priming for M-->H exercise. On three separate occasions, six male subjects completed two identical R-->M/M-->H 'work-to-work' prone knee-extension exercise bouts separated by 5min rest. Two trials were performed with measurement of pulmonary VO₂ and the integrated electromyogram (iEMG) of the right m. vastus lateralis. The third trial was performed within the bore of a 1.5-T superconducting magnet for (31)P-MRS assessment of muscle metabolic responses. Priming did not significantly affect the [PCr] or VO₂ tau during R-->M ([PCr] tau Unprimed: 24+/-16 vs. Primed: 22+/-14s; VO₂ tau Unprimed: 26+/-8 vs. Primed: 25+/-9s) or M-->H transitions ([PCr] tau Unprimed: 30+/-5 vs. Primed: 32+/-7s; VO₂ tau Unprimed: 37+/-5 vs. Primed: 38+/-9s). However, it did reduce the amplitudes of the [PCr] and VO₂ slow components by 50% and 46%, respectively, during M-->H (P<0.05 for both comparisons). These effects were accompanied by iEMG changes suggesting reduced muscle fiber activation during M-->H exercise after priming. It is concluded that the tau for the initial exponential change of muscle [PCr] and pulmonary VO₂ following the transition from moderate-to-high-intensity prone knee-extension exercise is not altered by priming exercise. |
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Authors:
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Fred J Dimenna; Jonathan Fulford; Stephen J Bailey; Anni Vanhatalo; Daryl P Wilkerson; Andrew M Jones |
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Publication Detail:
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Type: Journal Article Date: 2010-04-22 |
Journal Detail:
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Title: Respiratory physiology & neurobiology Volume: 172 ISSN: 1878-1519 ISO Abbreviation: Respir Physiol Neurobiol Publication Date: 2010 Jun |
Date Detail:
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Created Date: 2010-06-14 Completed Date: 2010-09-17 Revised Date: 2010-10-25 |
Medline Journal Info:
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Nlm Unique ID: 101140022 Medline TA: Respir Physiol Neurobiol Country: Netherlands |
Other Details:
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Languages: eng Pagination: 15-23 Citation Subset: IM |
Copyright Information:
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Copyright 2010 Elsevier B.V. All rights reserved. |
Affiliation:
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School of Sport and Health Sciences, St. Luke's Campus, University of Exeter, Heavitree Road, Exeter, Devon EX1 2LU, UK. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Adult Electromyography Exercise / physiology* Humans Knee Joint / physiology* Magnetic Resonance Spectroscopy / methods Male Muscle, Skeletal / metabolism* Nonlinear Dynamics Oxygen Consumption / physiology* Physical Endurance / physiology* Pulmonary Gas Exchange / physiology Quadriceps Muscle / metabolism Young Adult |
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