Effects of repetitive dynamic contractions upon electromechanical delay

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Deutscher übersetzter Titel:Auswirkungen wiederholter dynamischer Muskelkontraktionen auf die elektromechanische delay time
Autor:Gabriel, D.A.; Boucher, J.P.
Erschienen in:European journal of applied physiology
Veröffentlicht:79 (1998), 1, S. 37-40, Lit.
Format: Literatur (SPOLIT)
Publikationstyp: Zeitschriftenartikel
Medienart: Gedruckte Ressource Elektronische Ressource (online)
Sprache:Englisch
ISSN:1439-6319, 0301-5548
DOI:10.1007/s004210050470
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Erfassungsnummer:PU199901306301
Quelle:BISp

Abstract des Autors

The effect of repeated maximal effort isotonic contractions on electromechanical delay was studied. Over 4 days, 17 male subjects performed 400 rapid elbow flexion trials. The kinematics and surface electromyographic (EMG) activity of the biceps brachii of these subjects were recorded. The period from the onset of the EMG until the beginning of movement was defined as the electromechanical delay. The period from the beginning of movement until the end of the EMG was defined as the second component of the contraction. Over the 4 day period there was an increase in the speed of limb movement. The mean power frequency and the duration of the EMG during the electromechanical delay did not change, while the root-mean-square amplitude increased. The duration of the EMG during the second component of the contraction remained stable. The mean power frequency and the root-mean-square amplitude of the EMG during the second component of the contraction increased with the speed of limb movement. We conclude that the faster contractions were a result of changes in motor unit recruitment during the second component of the contraction, rather than in the electromechanical delay. Verf.-Referat