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Motor unit discharge characteristics and conduction velocity of the vastii muscles in long-term resistance-trained men

Purpose: Adjustments in motor unit (MU) discharge properties have been shown following short-term resistance training, however MU adaptations in long-term resistance-trained individuals are less clear. Here, we concurrently assessed MU discharge characteristics and MU conduction velocity in long-ter...

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Main Authors: Jakob Skarabot, Jonathan Folland, Jules Forsyth, Apostolos Vazoukis, Ales Holobar, Alessandro Del Vecchio
Format: Default Article
Published: 2022
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Online Access:https://hdl.handle.net/2134/21705548.v1
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author Jakob Skarabot
Jonathan Folland
Jules Forsyth
Apostolos Vazoukis
Ales Holobar
Alessandro Del Vecchio
author_facet Jakob Skarabot
Jonathan Folland
Jules Forsyth
Apostolos Vazoukis
Ales Holobar
Alessandro Del Vecchio
author_sort Jakob Skarabot (7442540)
collection Figshare
description Purpose: Adjustments in motor unit (MU) discharge properties have been shown following short-term resistance training, however MU adaptations in long-term resistance-trained individuals are less clear. Here, we concurrently assessed MU discharge characteristics and MU conduction velocity in long-term resistance-trained (RT) and untrained (UT) men. Methods: MU discharge characteristics (discharge rate, recruitment and derecruitment threshold) and MU conduction velocity were assessed after the decomposition of high-density electromyograms recorded from vastus lateralis (VL) and medialis (VM) of RT (>3 years; N=14) and UT (N=13) during submaximal and maximal isometric knee extension. Results: RT were on average 42% stronger (maximal voluntary force, MVF: 976.7±85.4 vs. 685.5±123.1 N; p
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institution Loughborough University
publishDate 2022
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spelling rr-article-217055482022-12-12T09:18:06Z Motor unit discharge characteristics and conduction velocity of the vastii muscles in long-term resistance-trained men Jakob Skarabot (7442540) Jonathan Folland (1254987) Jules Forsyth (14241788) Apostolos Vazoukis (14241791) Ales Holobar (4783839) Alessandro Del Vecchio (5932025) Medical physiology Health sciences Sports science and exercise conduction velocity surface EMG decomposition motor neuron neural drive strength training <p>Purpose: Adjustments in motor unit (MU) discharge properties have been shown following short-term resistance training, however MU adaptations in long-term resistance-trained individuals are less clear. Here, we concurrently assessed MU discharge characteristics and MU conduction velocity in long-term resistance-trained (RT) and untrained (UT) men.</p> <p>Methods: MU discharge characteristics (discharge rate, recruitment and derecruitment threshold) and MU conduction velocity were assessed after the decomposition of high-density electromyograms recorded from vastus lateralis (VL) and medialis (VM) of RT (>3 years; N=14) and UT (N=13) during submaximal and maximal isometric knee extension.</p> <p>Results: RT were on average 42% stronger (maximal voluntary force, MVF: 976.7±85.4 vs. 685.5±123.1 N; p<0.0001), but exhibited similar relative MU recruitment (VL: 21.3±4.3 vs. 21.0±2.3 %MVF; VM: 24.5±4.2 vs. 22.7±5.3 %MVF) and derecruitment thresholds (VL: 20.3±4.3 vs. 19.8±2.9 %MVF; VM: 24.2±4.8 vs. 22.9±3.7 %MVF; p≥0.4543). There were also no differences between groups in MU discharge rate at recruitment and derecruitment, or at the plateau phase of submaximal contractions (VL: 10.6±1.2 vs. 10.3±1.5 pps, VM: 10.7±1.6 vs. 10.8±1.7 pps; p≥0.3028). During maximal contractions of a subsample population (10 RT, 9 UT), MU discharge rate was also similar in RT compared to UT (VL: 21.1±4.1 vs. 14.0±4.5 pps, VM: 19.5±5.0 vs. 17.0±6.3 pps; p=0.7173). MU conduction velocity was greater in RT compared to UT individuals in both VL (4.9±0.5 vs. 4.5±0.3 m.s<sup>-1</sup>; p<0.0013) and VM (4.8±0.5 vs. 4.4±0.3 m.s<sup>-1</sup>; p<0.0073).</p> <p>Conclusions: RT and UT display similar MU discharge characteristics in the knee extensor muscles during maximal and submaximal contractions. The between-group strength difference is likely explained by superior muscle morphology of RT as suggested by greater MU conduction velocity.</p> 2022-12-12T09:18:06Z Text Journal contribution 2134/21705548.v1 https://figshare.com/articles/journal_contribution/Motor_unit_discharge_characteristics_and_conduction_velocity_of_the_vastii_muscles_in_long-term_resistance-trained_men/21705548 CC BY-NC 4.0
spellingShingle Medical physiology
Health sciences
Sports science and exercise
conduction velocity
surface EMG decomposition
motor neuron
neural drive
strength training
Jakob Skarabot
Jonathan Folland
Jules Forsyth
Apostolos Vazoukis
Ales Holobar
Alessandro Del Vecchio
Motor unit discharge characteristics and conduction velocity of the vastii muscles in long-term resistance-trained men
title Motor unit discharge characteristics and conduction velocity of the vastii muscles in long-term resistance-trained men
title_full Motor unit discharge characteristics and conduction velocity of the vastii muscles in long-term resistance-trained men
title_fullStr Motor unit discharge characteristics and conduction velocity of the vastii muscles in long-term resistance-trained men
title_full_unstemmed Motor unit discharge characteristics and conduction velocity of the vastii muscles in long-term resistance-trained men
title_short Motor unit discharge characteristics and conduction velocity of the vastii muscles in long-term resistance-trained men
title_sort motor unit discharge characteristics and conduction velocity of the vastii muscles in long-term resistance-trained men
topic Medical physiology
Health sciences
Sports science and exercise
conduction velocity
surface EMG decomposition
motor neuron
neural drive
strength training
url https://hdl.handle.net/2134/21705548.v1