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Neuromuscular responses to mild-muscle damaging eccentric exercise in a low glycogen state

Neuromuscular responses to mild-muscle damaging eccentric exercise in a low glycogen state
Neuromuscular responses to mild-muscle damaging eccentric exercise in a low glycogen state

The aim of this study was to examine the effect of low muscle glycogen on the neuromuscular responses to maximal eccentric contractions. Fourteen healthy men (22 ± 3 years) performed single-leg cycling (20 min at ~75% maximal oxygen uptake (V̇O2 max); eight 90 s sprints at a 1:1 work-to-rest ratio (5% decrements from 90% to 55% V̇O2 max until exhaustion) the evening before 100 eccentric (1.57 rads(-1)) with reduced (RED) and normal glycogen (NORM). Neuromuscular responses were measured during and up to 48 h after with maximal voluntary and involuntary (twitch, 20 Hz and 50 Hz) isometric contractions. During eccentric contractions, peak torque decreased (RED: -16.1 ± 2.5%; NORM: -6.2 ± 5.1%) and EMG frequency increased according to muscle length. EMG activity decreased for RED only. After eccentric contractions, maximal isometric force was reduced up to 24h for NORM (-13.5 ± 5.8%) and 48 h for RED (-7.4 ± 10.9%). Twelve hours after eccentric contractions, twitch force and the 20:50 Hz ratio were decreased for RED but not for NORM. Immediate involuntary with prolonged voluntary force loss suggests that reduced glycogen is associated with increased susceptibility to mild muscle-damaging eccentric exercise with contributions of peripheral and central mechanisms to be different during recovery.

Adult, Electromyography, Exercise, Glycogen, Humans, Isometric Contraction, Male, Muscle Fatigue, Muscle, Skeletal, Myalgia, Torque, Journal Article
1050-6411
53-60
Gavin, James P.
e0d9b404-3f63-4855-8e64-bf1692e6cc3f
Myers, Steve D.
f1f200f5-f5b1-4eab-8542-4d435b50ed33
Willems, Marc E.T.
403242a2-7f54-4f8a-887d-d501ae5db0eb
Gavin, James P.
e0d9b404-3f63-4855-8e64-bf1692e6cc3f
Myers, Steve D.
f1f200f5-f5b1-4eab-8542-4d435b50ed33
Willems, Marc E.T.
403242a2-7f54-4f8a-887d-d501ae5db0eb

Gavin, James P., Myers, Steve D. and Willems, Marc E.T. (2015) Neuromuscular responses to mild-muscle damaging eccentric exercise in a low glycogen state. Journal of Electromyography and Kinesiology, 25 (1), 53-60. (doi:10.1016/j.jelekin.2014.10.005).

Record type: Article

Abstract

The aim of this study was to examine the effect of low muscle glycogen on the neuromuscular responses to maximal eccentric contractions. Fourteen healthy men (22 ± 3 years) performed single-leg cycling (20 min at ~75% maximal oxygen uptake (V̇O2 max); eight 90 s sprints at a 1:1 work-to-rest ratio (5% decrements from 90% to 55% V̇O2 max until exhaustion) the evening before 100 eccentric (1.57 rads(-1)) with reduced (RED) and normal glycogen (NORM). Neuromuscular responses were measured during and up to 48 h after with maximal voluntary and involuntary (twitch, 20 Hz and 50 Hz) isometric contractions. During eccentric contractions, peak torque decreased (RED: -16.1 ± 2.5%; NORM: -6.2 ± 5.1%) and EMG frequency increased according to muscle length. EMG activity decreased for RED only. After eccentric contractions, maximal isometric force was reduced up to 24h for NORM (-13.5 ± 5.8%) and 48 h for RED (-7.4 ± 10.9%). Twelve hours after eccentric contractions, twitch force and the 20:50 Hz ratio were decreased for RED but not for NORM. Immediate involuntary with prolonged voluntary force loss suggests that reduced glycogen is associated with increased susceptibility to mild muscle-damaging eccentric exercise with contributions of peripheral and central mechanisms to be different during recovery.

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More information

Published date: 14 February 2015
Additional Information: Copyright © 2014 Elsevier Ltd. All rights reserved.
Keywords: Adult, Electromyography, Exercise, Glycogen, Humans, Isometric Contraction, Male, Muscle Fatigue, Muscle, Skeletal, Myalgia, Torque, Journal Article

Identifiers

Local EPrints ID: 428733
URI: https://eprints.soton.ac.uk/id/eprint/428733
ISSN: 1050-6411
PURE UUID: 5d89394b-51c8-45e5-8f6d-992b78df1c27
ORCID for James P. Gavin: ORCID iD orcid.org/0000-0003-0574-0502

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Date deposited: 07 Mar 2019 17:30
Last modified: 07 Aug 2019 00:20

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Contributors

Author: James P. Gavin ORCID iD
Author: Steve D. Myers
Author: Marc E.T. Willems

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