Motor Unit Discharge Rates During Maximal Fatiguing Eccentric Contractions and Recovery in the Human Elbow Extensors.
Introduction: Eccentric (ECC) contractions are uniquely characterized by higher maximal torque output compared with concentric or isometric actions. However, this advantage is accompanied by greater and more prolonged torque loss following fatiguing ECC exercise compared with other modalities. Altho...
| Publicado en: | Medicine & Science in Sports & Exercise Vol. 58; no. 1; pp. 138 - 149 |
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| Autores principales: | , |
| Formato: | pictorial research tables/charts tracings Journal Article |
| Publicado: |
Lippincott Williams & Wilkins
Jan2026
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| Acceso en línea: | Ver este registro en EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=ccm&AN=190276746&site=ehost-live header: @attributes: shortDbName: ccm uiTerm: 190276746 longDbName: CINAHL Complete uiTag: AN controlInfo: bkinfo: dissinfo: jinfo: jid: 01959131 4DP jtl: Medicine & Science in Sports & Exercise issn: 01959131 maglogo: N pubinfo: dt: Jan2026 vid: 58 iid: 1 pid: 433 pub: Lippincott Williams & Wilkins place: Baltimore, Maryland artinfo: ui: 190276746 190276746 190276746 10.1249/MSS.0000000000003847 190276746 ppf: 138 ppct: 11 formats: tig: atl: Motor Unit Discharge Rates During Maximal Fatiguing Eccentric Contractions and Recovery in the Human Elbow Extensors. aug: au: BASILE, DANIEL C. RICE, CHARLES L. affil: School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, London, Ontario, CANADA sug: subj: Motor Unit Motor Activity Eccentric Contraction Physiology Recovery Elbow Physiology Therapeutic Exercise Task Performance and Analysis Muscle Fatigue Human Electrodes Triceps Brachii Physiology Torque Isokinetic Exercises Electromyography Exercise Physiology Young Adult Descriptive Statistics Male Female Repeated Measures Analysis of Variance Paired T-Tests Data Analysis Software Funding Source Male Female ab: Introduction: Eccentric (ECC) contractions are uniquely characterized by higher maximal torque output compared with concentric or isometric actions. However, this advantage is accompanied by greater and more prolonged torque loss following fatiguing ECC exercise compared with other modalities. Although muscle contractile responses to dynamic fatiguing contractions have been documented, the neural control of ECC contractions—particularly at the level of individual motor units—remains poorly understood. The purpose was to evaluate motor unit discharge rate (MUDR) modulation during and in recovery after a maximal effort ECC fatiguing task. Methods: Single motor unit activity was recorded with fine-wire electrodes inserted into the triceps brachii muscle. Participants completed an elbow extension protocol with subsequent recovery for 30 min, involving repetitive sets of 10 maximal repetitions until 50% torque loss relative to baseline maximal ECC torque. Results: MUDR declined substantially (>35%) from baseline to task failure (37.1 vs 23.1 Hz, P ≤ 0.001) and did not return to baseline values until 10 min of recovery (P = 0.597). However, both electrically stimulated twitch torque and maximal voluntary ECC torque remained depressed at 30 min (P = 0.001), relative to baseline. Conclusions: This study provides a novel characterization of motor unit behavior during fatigue induced by maximal ECC contractions, revealing a significant reduction consistent with prior evidence of impaired MUDR under other fatiguing tasks. In addition, results indicate that prolonged torque depression (30 min post-task failure) following the ECC fatiguing task is primarily attributable to peripheral muscle impairments, as MUDR recovered to baseline within ~10 min. pubtype: Academic Journal doctype: pictorial research tables/charts tracings Journal Article ougenre: Article language: English refInfo: holdings: @attributes: islocal: N |
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