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dc.contributor.author Mark en_US
dc.contributor.author Jonathan en_US
dc.contributor.author Anni en_US
dc.contributor.author Andrew M. en_US
dc.date.accessioned 2010-08-13T10:20:28Z
dc.date.available 2010-08-13T10:20:28Z
dc.date.issued 2010-07 en_US
dc.identifier http://dx.doi.org/10.1113/expphysiol.2010.052688 en_US
dc.identifier.citation Burnley , M , Fulford , J , Vanhatalo , A & Jones , A M 2010 , ' Similar metabolic perturbations during all-out and constant force exhaustive exercise in humans: a 31P magnetic resonance spectroscopy study ' Experimental Physiology , pp. 798-807 . , 10.1113/expphysiol.2010.052688 en_US
dc.identifier.other PURE: 150352 en_US
dc.identifier.other dspace: 2160/5176 en_US
dc.identifier.uri http://hdl.handle.net/2160/5176
dc.description.abstract It is not possible to attain a metabolic steady state during exercise above the so-called critical force or power. We tested the hypothesis that the muscle metabolic perturbations at the end of a bout of maximal isometric contractions, which yield a stable end-test force (equal to the critical force), would be similar to that at task failure following submaximal contractions performed above the critical force. Eight healthy subjects (4 female) performed isometric single knee-extension exercise in the bore of a 1.5 T superconducting magnet on two occasions. Following familiarisation, subjects performed 1) 60 maximal contractions (3 s contraction, 2 s rest), and 2) submaximal contractions (the same contraction regime performed at 54 ± 8% MVC) to task failure. Phosphocreatine (PCr), inorganic phosphate (Pi), diprotonated phosphate ([H2PO4–]) and pH were determined using 31P-magnetic resonance spectroscopy throughout both tests. During the maximal contractions, force production fell from 213 ± 33 N to reach a plateau in the last 30 s of the test at 100 ± 20 N. The muscle metabolic responses at the end of each test were substantial, but not different between conditions: [PCr] was reduced (to 21 ± 12% and 17 ± 7% of baseline, maximal and submaximal contractions, respectively; P = 0.17), [Pi] was elevated (to 364 ± 98% and 363 ± 135% of baseline; P = 0.98), and pH reduced (to 6.64 ± 0.16 and 6.69 ± 0.17; P = 0.43). The [H2PO4–] was also elevated at the end of both tests (to 607 ± 252% and 556 ± 269% of baseline; P = 0.22). These data suggest that the exercise-induced metabolic perturbations contributing to force depression in all-out exercise are the same as those contributing to task failure during submaximal contractions. en_US
dc.format.extent 10 en_US
dc.relation.ispartof Experimental Physiology en_US
dc.title Similar metabolic perturbations during all-out and constant force exhaustive exercise in humans: a 31P magnetic resonance spectroscopy study en_US
dc.contributor.pbl Department of Sport & Exercise Science en_US


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