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dc.contributor.authorMcKeown, Daniel J
dc.contributor.authorMcNeil, Chris J
dc.contributor.authorBrotherton, Emily J
dc.contributor.authorSimmonds, Michael J
dc.contributor.authorKavanagh, Justin J
dc.date.accessioned2021-11-17T00:10:12Z
dc.date.available2021-11-17T00:10:12Z
dc.date.issued2021
dc.identifier.issn0022-3751
dc.identifier.doi10.1113/jp281897
dc.identifier.urihttp://hdl.handle.net/10072/410156
dc.description.abstractThe purpose of this study was to determine how severe acute hypoxia alters neural mechanisms during, and following, a sustained fatiguing contraction. Fifteen participants (25 ± 3.2 years, 6 female) were exposed to a sham condition and a hypoxia condition where they performed a 10-min elbow flexor contraction at 20% of maximal torque. For hypoxia, peripheral blood oxygen saturation (SpO2) was titrated to 80% over a 15-min period and maintained for 2 hr. Maximal voluntary contraction (MVC) torque, EMG root mean square (EMGRMS), voluntary activation, rating of perceived muscle fatigue, and corticospinal excitability (motor evoked potential) and inhibition (silent period duration) were then assessed before, during, and for 6 min after the fatiguing contraction. No hypoxia-related effects were identified for neuromuscular variables during the fatigue task. However, for recovery, voluntary activation assessed by motor point stimulation of biceps brachii was lower for hypoxia than sham at 4 min (sham: 89% ± 7%; hypoxia: 80% ± 12%; P = 0.023) and 6 min (sham: 90% ± 7%; hypoxia: 78% ± 11%; P = 0.040). Similarly, voluntary activation (P = 0.01) and motor evoked potential area (P = 0.002) in response to transcranial magnetic stimulation of the motor cortex were 10% and 11% lower during recovery for hypoxia compared to sham, respectively. Although an SpO2 of 80% did not affect neural activity during the fatiguing task, motor cortical output and corticospinal excitability were reduced during recovery in the hypoxic environment. This was likely due to hypoxia-related mechanisms involving supraspinal motor circuits.
dc.description.peerreviewedYes
dc.languageen
dc.publisherWiley
dc.relation.ispartofjournalThe Journal of Physiology
dc.subject.fieldofresearchMedical physiology
dc.subject.fieldofresearchcode3208
dc.titleSevere acute hypoxia impairs recovery of voluntary muscle activation after sustained submaximal elbow flexion
dc.typeJournal article
dc.type.descriptionC1 - Articles
dcterms.bibliographicCitationMcKeown, DJ; McNeil, CJ; Brotherton, EJ; Simmonds, MJ; Kavanagh, JJ, Severe acute hypoxia impairs recovery of voluntary muscle activation after sustained submaximal elbow flexion, The Journal of Physiology
dc.date.updated2021-11-16T01:57:48Z
dc.description.versionAccepted Manuscript (AM)
gro.description.notepublicThis publication has been entered in Griffith Research Online as an advanced online version.
gro.rights.copyright© 2021 Physiological Society. This is the peer reviewed version of the following article: Severe acute hypoxia impairs recovery of voluntary muscle activation after sustained submaximal elbow flexion, The Journal of Physiology, 2021, which has been published in final form at https://doi.org/10.1113/JP281897. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving (http://olabout.wiley.com/WileyCDA/Section/id-828039.html)
gro.hasfulltextFull Text
gro.griffith.authorKavanagh, Justin J.
gro.griffith.authorMcKeown, Daniel
gro.griffith.authorBrotherton, Emily J.
gro.griffith.authorSimmonds, Michael J.


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