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dc.contributor.authorPethick, Jamie
dc.contributor.authorWinter, Samantha L
dc.contributor.authorBurnley, Mark
dc.date.accessioned2021-09-09T15:41:37Z
dc.date.available2021-09-09T15:41:37Z
dc.date.issued2019-09-25
dc.identifier.citationPethick, J., Winter, S.L. and Burnely, M. (2019) Relationship between muscle metabolic rate and muscle torque complexity during fatiguing intermittent isometric contractions in humans. Physiological reports, 7 (18), e14240, https://doi.org/10.14814/phy2.14240en
dc.identifier.issn2051-817Xen
dc.identifier.pmid31552708 (pubmed)
dc.identifier.doi10.14814/phy2.14240en
dc.identifier.urihttp://hdl.handle.net/2436/624328
dc.description© 2021 The Authors. Published by Wiley. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.14814/phy2.14240en
dc.description.abstractTo test the hypothesis that a system's metabolic rate and the complexity of fluctuations in the output of that system are related, thirteen healthy participants performed intermittent isometric knee extensor contractions at intensities where a rise in metabolic rate would (40% maximal voluntary contraction, MVC) and would not (20% MVC) be expected. The contractions had a 60% duty factor (6 sec contraction, 4 sec rest) and were performed until task failure or for 30 min, whichever occurred sooner. Torque and surface EMG signals were sampled continuously. Complexity and fractal scaling of torque were quantified using approximate entropy (ApEn) and the detrended fluctuation analysis (DFA) α scaling exponent. Muscle metabolic rate was determined using near-infrared spectroscopy. At 40% MVC, task failure occurred after (mean ± SD) 11.5 ± 5.2 min, whereas all participants completed 30 min of contractions at 20% MVC. Muscle metabolic rate increased significantly after 2 min at 40% MVC (2.70 ± 1.48 to 4.04 ± 1.23 %·s-1 , P < 0.001), but not at 20% MVC. Similarly, complexity decreased significantly at 40% MVC (ApEn, 0.53 ± 0.19 to 0.15 ± 0.09; DFA α, 1.37 ± 0.08 to 1.60 ± 0.09; both P < 0.001), but not at 20% MVC. The rates of change of torque complexity and muscle metabolic rate at 40% MVC were significantly correlated (ApEn, ρ = -0.63, P = 0.022; DFA, ρ = 0.58, P = 0.037). This study demonstrated that an inverse relationship exists between muscle torque complexity and metabolic rate during high-intensity contractions.en
dc.description.sponsorshipThis work was supported by a Research Project Grant from The Leverhulme Trust (RPG-2016-440).en
dc.formatapplication/pdfen
dc.languageeng
dc.language.isoenen
dc.publisherWileyen
dc.relation.urlhttps://physoc.onlinelibrary.wiley.com/doi/full/10.14814/phy2.14240en
dc.rightsLicence for published version: Creative Commons Attribution 4.0 International
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/
dc.subjectfatigueen
dc.subjectmuscleen
dc.subjectmetabolic rateen
dc.subjectnonlinear dynamicsen
dc.subject.meshMuscle, Skeletal
dc.subject.meshKnee Joint
dc.subject.meshHumans
dc.subject.meshSpectroscopy, Near-Infrared
dc.subject.meshElectromyography
dc.subject.meshOxygen Consumption
dc.subject.meshMuscle Fatigue
dc.subject.meshIsometric Contraction
dc.subject.meshTorque
dc.subject.meshAdult
dc.subject.meshFemale
dc.subject.meshMale
dc.subject.meshMuscle Strength Dynamometer
dc.subject.meshYoung Adult
dc.titleRelationship between muscle metabolic rate and muscle torque complexity during fatiguing intermittent isometric contractions in humansen
dc.typeJournal articleen
dc.identifier.eissn2051-817X
dc.identifier.journalPhysiological reportsen
dc.date.updated2021-09-09T10:46:33Z
dc.contributor.institutionEndurance Research Group, School of Sport and Exercise Sciences, University of Kent, Canterbury, United Kingdom.
dc.identifier.articlenumbere14240
pubs.place-of-publicationUnited States
dc.date.accepted2019-08-31
rioxxterms.funderLeverhulme Trusten
rioxxterms.identifier.projectRPG-2016-440en
rioxxterms.versionVoRen
rioxxterms.licenseref.urihttp://creativecommons.org/licenses/by/4.0/en
rioxxterms.licenseref.startdate2021-09-09en
dc.source.volume7
dc.source.issue18
dc.description.versionPublished version
refterms.dateFCD2021-09-09T15:41:23Z
refterms.versionFCDVoR
refterms.dateFOA2021-09-09T15:41:38Z


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Licence for published version: Creative Commons Attribution 4.0 International
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