Repeated exercise stress impairs volitional but not magnetically evoked electromechanical delay of the knee flexors

Minshull, C, Eston, R, Bailey, A and Gleeson, N, 2012. Repeated exercise stress impairs volitional but not magnetically evoked electromechanical delay of the knee flexors. Journal of Sports Sciences, 30 (2), pp. 217-225. ISSN 1466-447X

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Abstract

The effects of serial episodes of fatigue and recovery on volitional and magnetically evoked neuromuscular performance of the knee flexors were assessed in twenty female soccer players during: (i) an intervention comprising 4x35s maximal static exercise; (ii) a control condition. Volitional peak force (PFV) was impaired progressively (-16 % vs. baseline: 235.3±54.7 to 198.1±38.5 N) by the fatiguing exercise and recovered to within -97 % of baseline values following six-minutes of rest. Evoked peak twitch force (PTFE) was diminished subsequent to the fourth episode of exercise (23.3 %: 21.4±13.8 vs. 16.4±14.6 N) and remained impaired at this level throughout the recovery. Impairment of volitional electromechanical delay performance (EMDV) following the first episode of exercise (25.5 % :55.3±11.9 vs. 69.5±24.5 ms) contrasted with concurrent improvement (10.0 %: 24.5±4.7 vs. 22.1±5.0 ms) in evoked electromechanical delay (EMDE) (p <0.05) and this increased disparity between EMDE and EMDV remained during subsequent periods of intervention and recovery. The fatiguing exercise provoked substantial impairments to volitional strength and EMDV that showed differential patterns of recovery. However, improved EMDE performance might identify a dormant capability for optimal muscle responses during acute stressful exercise and an improved capacity to maintain dynamic joint stabilty during critical episodes of loading.

Item Type:	Journal article
Description:	This is an Author's Original Manuscript of an article whose final and definitive form, the Version of Record, has been published in the Journal of Sports Sciences, January 2012, copyright Taylor & Francis, available online at: http://www.tandfonline.com/10.1080/02640414.2011.627370.
Publication Title:	Journal of Sports Sciences
Creators:	Minshull, C., Eston, R., Bailey, A. and Gleeson, N.
Publisher:	Taylor & Francis (Routledge)
Date:	2012
Volume:	30
Number:	2
ISSN:	1466-447X
Identifiers:	Number Type 10.1080/02640414.2011.627370 DOI
Rights:	© 2012 Routledge, Taylor & Francis Group, an Informa Business.
Divisions:	Schools > School of Science and Technology
Record created by:	EPrints Services
Date Added:	09 Oct 2015 10:33
Last Modified:	23 Aug 2016 09:10
URI:	https://irep.ntu.ac.uk/id/eprint/14695

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