| Influence of dietary creatine supplementation on muscle phosphocreatine kinetics during knee-extensor exercise in humans. | |
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MedLine Citation:
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PMID: 19211722 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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We hypothesized that increasing skeletal muscle total creatine (Cr) content through dietary Cr supplementation would result in slower muscle phosphocreatine concentration ([PCr]) kinetics, as assessed using (31)P magnetic resonance spectroscopy, following the onset and offset of both moderate-intensity (Mod) and heavy-intensity (Hvy) exercise. Seven healthy males (age 29 +/- 6 yr, mean +/- SD) completed a series of square-wave transitions to Mod and Hvy knee extensor exercise inside the bore of a 1.5-T superconducting magnet both before and after a 5-day period of Cr loading (4x 5 g/day of creatine monohydrate). Cr supplementation resulted in an approximately 8% increase in the resting muscle [PCr]-to-[ATP] ratio (4.66 +/- 0.27 vs. 5.04 +/- 0.22; P < 0.05), consistent with a significant increase in muscle total Cr content consequent to the intervention. The time constant for muscle [PCr] kinetics was increased following Cr loading for Mod exercise (control: 15 +/- 8 vs. Cr: 25 +/- 9 s; P < 0.05) and subsequent recovery (control: 14 +/- 8 vs. Cr: 27 +/- 8 s; P < 0.05) and for Hvy exercise (control: 54 +/- 18 vs. Cr: 72 +/- 30 s; P < 0.05), but not for subsequent recovery (control: 41 +/- 11 vs. Cr: 44 +/- 6 s). The magnitude of the increase in [PCr] following Cr loading was correlated (P < 0.05) with the extent of the slowing of the [PCr] kinetics for the moderate off-transient (r = 0.92) and the heavy on-transient (r = 0.71). These data demonstrate, for the first time in humans, that an increase in muscle [PCr] results in a slowing of [PCr] dynamics in exercise and subsequent recovery. |
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Authors:
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Andrew M Jones; Daryl P Wilkerson; Jonathan Fulford |
Publication Detail:
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Type: Clinical Trial; Journal Article Date: 2009-02-11 |
Journal Detail:
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Title: American journal of physiology. Regulatory, integrative and comparative physiology Volume: 296 ISSN: 0363-6119 ISO Abbreviation: Am. J. Physiol. Regul. Integr. Comp. Physiol. Publication Date: 2009 Apr |
Date Detail:
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Created Date: 2009-03-27 Completed Date: 2009-06-05 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 100901230 Medline TA: Am J Physiol Regul Integr Comp Physiol Country: United States |
Other Details:
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Languages: eng Pagination: R1078-87 Citation Subset: IM |
Affiliation:
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University of Exeter, Exeter, Devon EX1 2 LU, UK. a.m.jones@exeter.ac.uk |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Adenosine Diphosphate
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metabolism Adenosine Triphosphate / metabolism Adult Creatine / administration & dosage*, metabolism Dietary Supplements* Exercise* Humans Kinetics Magnetic Resonance Spectroscopy Male Muscle Contraction* Muscle Fatigue / drug effects Muscle, Skeletal / drug effects*, metabolism Oxidative Phosphorylation / drug effects Phosphocreatine / metabolism* Phosphorus Isotopes Recovery of Function / drug effects Young Adult |
| Chemical | |
Reg. No./Substance:
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0/Phosphorus Isotopes; 56-65-5/Adenosine Triphosphate; 57-00-1/Creatine; 58-64-0/Adenosine Diphosphate; 67-07-2/Phosphocreatine |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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