Changes in motor unit behavior following isometric fatigue of the first dorsal interosseous muscle

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Show simple item record McManus, Lara M. Hu, Xiaogang Rymer, William Lowery, Madeleine M. Suresh, Nina 2017-04-18T16:36:24Z 2017-04-18T16:36:24Z 2015 the American Physiological Society en 2015-05-01
dc.identifier.citation Journal of Neurophysiology en
dc.description.abstract The neuromuscular strategies employed to compensate for fatigue-induced muscle force deficits are not clearly understood. This study utilizes surface electromyography (sEMG) together with recordings of a population of individual motor unit action potentials (MUAPs) to investigate potential compensatory alterations in motor unit (MU) behavior immediately following a sustained fatiguing contraction and after a recovery period. EMG activity was recorded during abduction of the first dorsal interosseous in 12 subjects at 20% maximum voluntary contraction (MVC), before and directly after a 30% MVC fatiguing contraction to task failure, with additional 20% MVC contractions following a 10-min rest. The amplitude, duration and mean firing rate (MFR) of MUAPs extracted with a sEMG decomposition system were analyzed, together with sEMG root-mean-square (RMS) amplitude and median frequency (MPF). MUAP duration and amplitude increased immediately postfatigue and were correlated with changes to sEMG MPF and RMS, respectively. After 10 min, MUAP duration and sEMG MPF recovered to prefatigue values but MUAP amplitude and sEMG RMS remained elevated. MU MFR and recruitment thresholds decreased postfatigue and recovered following rest. The increase in MUAP and sEMG amplitude likely reflects recruitment of larger MUs, while recruitment compression is an additional compensatory strategy directly postfatigue. Recovery of MU MFR in parallel with MUAP duration suggests a possible role for metabolically sensitive afferents in MFR depression postfatigue. This study provides insight into fatigue-induced neuromuscular changes by examining the properties of a large population of concurrently recorded single MUs and outlines possible compensatory strategies involving alterations in MU recruitment and MFR. en
dc.description.sponsorship Irish Research Council en
dc.language.iso en en
dc.publisher American Psychological Society en
dc.subject Motor unit action potential en
dc.subject Surface electromyography decomposition en
dc.subject Isometric fatigue en
dc.title Changes in motor unit behavior following isometric fatigue of the first dorsal interosseous muscle en
dc.type Journal Article en
dc.status Peer reviewed en
dc.identifier.volume 113 en
dc.identifier.issue 9 en
dc.identifier.startpage 3186 en
dc.identifier.endpage 3196 en
dc.identifier.doi 10.1152/jn.00146.2015
dc.neeo.contributor McManus|Lara M.|aut|
dc.neeo.contributor Hu|Xiaogang|aut|
dc.neeo.contributor Rymer|William|aut|
dc.neeo.contributor Lowery|Madeleine M.|aut|
dc.neeo.contributor Suresh|Nina|aut|
dc.internal.rmsid 516560133 2016-12-15T16:58:49Z

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