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rdf:type |
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lifeskim:mentions |
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pubmed:issue |
3
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pubmed:dateCreated |
2008-2-4
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pubmed:abstractText |
The kinetics of pulmonary O(2) uptake is known to be substantially slower when exercise is initiated from a baseline of lower-intensity exercise rather than from rest. However, it is not known whether putative intracellular regulators of mitochondrial respiration (and in particular the phosphocreatine concentration, [PCr]) show similar non-linearities in their response dynamics. The purpose of this study was therefore to investigate the influence of baseline metabolic rate on muscle [PCr] kinetics (as assessed using (31)P-magnetic resonance spectroscopy) following the onset of exercise. Seven male subjects completed 'step' tests to heavy-intensity exercise (80% of peak work-rate) from a resting baseline and also from a baseline of moderate-intensity exercise (40% of peak work-rate) using a single-leg knee-extensor ergometer situated inside the bore of a 1.5 T super-conducting magnet. The time constant describing the kinetics of the initial exponential-like fall in [PCr] was significantly different between rest-to-moderate (25 +/- 14 s), rest-to-heavy (48 +/- 11 s) and moderate-to-heavy exercise (95 +/- 40 s) (P < 0.05 for all comparisons). A delayed-onset 'slow component' in the [PCr] response was observed in all subjects during rest-to-heavy exercise, but was attenuated in the moderate-to-heavy exercise condition. These data indicate that muscle [PCr] kinetics does not conform to 'linear, first-order' behaviour during dynamic exercise, and thus have implications for understanding the regulation of muscle oxidative metabolism.
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pubmed:commentsCorrections |
http://linkedlifedata.com/resource/pubmed/commentcorrection/18063663-10421675,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18063663-10647537,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18063663-11034625,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18063663-11581333,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18063663-11711581,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18063663-11822471,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18063663-12068057,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18063663-12391122,
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http://linkedlifedata.com/resource/pubmed/commentcorrection/18063663-16037398,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18063663-16337226,
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http://linkedlifedata.com/resource/pubmed/commentcorrection/18063663-3110126,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18063663-3191904,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18063663-3579007,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18063663-3866229,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18063663-3959889,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18063663-4031824,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18063663-4057091,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18063663-4083044,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18063663-4278539,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18063663-430414,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18063663-4700625,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18063663-4716162,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18063663-4716163,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18063663-5056210,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18063663-5748563,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18063663-6341268,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18063663-6679873,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18063663-6806226,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18063663-6947247,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18063663-7061985,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18063663-7741865,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18063663-7836194,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18063663-7837955,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18063663-8889771,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18063663-8904581,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18063663-8964765,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18063663-9263923
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pubmed:language |
eng
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pubmed:journal |
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pubmed:citationSubset |
IM
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pubmed:chemical |
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pubmed:status |
MEDLINE
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pubmed:month |
Feb
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pubmed:issn |
1469-7793
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pubmed:author |
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pubmed:issnType |
Electronic
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pubmed:day |
1
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pubmed:volume |
586
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
889-98
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pubmed:dateRevised |
2010-9-22
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pubmed:meshHeading |
pubmed-meshheading:18063663-Adenosine Triphosphate,
pubmed-meshheading:18063663-Adult,
pubmed-meshheading:18063663-Cell Respiration,
pubmed-meshheading:18063663-Ergometry,
pubmed-meshheading:18063663-Exercise,
pubmed-meshheading:18063663-Humans,
pubmed-meshheading:18063663-Magnetic Resonance Spectroscopy,
pubmed-meshheading:18063663-Male,
pubmed-meshheading:18063663-Models, Biological,
pubmed-meshheading:18063663-Muscle, Skeletal,
pubmed-meshheading:18063663-Oxidative Phosphorylation,
pubmed-meshheading:18063663-Phosphocreatine,
pubmed-meshheading:18063663-Physical Exertion
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pubmed:year |
2008
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pubmed:articleTitle |
Muscle [phosphocreatine] dynamics following the onset of exercise in humans: the influence of baseline work-rate.
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pubmed:affiliation |
School of Sport and Health Sciences, St Luke's Campus, University of Exeter, Heavitree Road, Exeter EX1 2LU, UK. a.m.jones@exeter.ac.uk
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pubmed:publicationType |
Journal Article
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