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Similar metabolic perturbations during all-out and constant force exhaustive exercise in humans: a 31P magnetic resonance spectroscopy study

Burnley, Mark, Vanhatalo, Anni, Fulford, Jonathan, Jones, Andrew M. (2010) Similar metabolic perturbations during all-out and constant force exhaustive exercise in humans: a 31P magnetic resonance spectroscopy study. Experimental Physiology, 95 (7). pp. 798-807. ISSN 0958-0670. (doi:10.1113/expphysiol.2010.052688) (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided)

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Official URL
http://dx.doi.org/10.1113/expphysiol.2010.052688

Abstract

It is not possible to attain a metabolic steady state during exercise above the so-called critical force or critical 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 (four female) performed isometric single knee-extension exercise in the bore of a 1.5 T superconducting magnet on two occasions. Following familiarization, subjects performed the following exercises: (1) 60 maximal contractions (3 s contraction, 2 s rest); and (2) submaximal contractions (the same contraction regime performed at 54 ± 8% maximal voluntary contraction) to task failure. Phosphocreatine (PCr), inorganic phosphate (Pi) and diprotonated phosphate (H2PO4?) concentrations 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 for maximal and submaximal contractions, respectively; P = 0.17), [Pi] was elevated (to 364 ± 98 and 363 ± 135% of baseline, respectively; P = 0.98) and pH reduced (to 6.64 ± 0.16 and 6.69 ± 0.17, respectively; P = 0.43). The [H2PO4?] was also elevated at the end of both tests (to 607 ± 252 and 556 ± 269% of baseline, respectively; 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.

Item Type: Article
DOI/Identification number: 10.1113/expphysiol.2010.052688
Additional information: The Editor of Experimental Physiology decided that this output deserved an accompanying article (Amann M. Exercise-induced metabolic perturbation: all roads lead to Rome. Exp Physiol. 2010; 95: 765-6). In this article, Markus Amann praises the group around Andy Jones and Mark Burnley for giving an answer to the important question of whether the model of similar metabolic perturbations at end-exercise holds true. Furthermore, Markus Amann notices that, by using 31P magnetic resonance spectroscopy, the group provides the first direct comparison of the development of metabolic perturbations during fatiguing muscular contractions of different intensities.; number of additional authors: 3;
Subjects: Q Science > Q Science (General)
Divisions: Faculties > Sciences > School of Sport and Exercise Sciences
Depositing User: Stewart Brownrigg
Date Deposited: 07 Mar 2014 00:05 UTC
Last Modified: 23 Jan 2020 04:08 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/40353 (The current URI for this page, for reference purposes)
Burnley, Mark: https://orcid.org/0000-0003-3407-561X
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