Higher muscle fiber conduction velocity and early rate of torque development in chronically strength-trained individuals
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Accepted version
Author(s)
Type
Journal Article
Abstract
Strength-trained individuals (ST) develop greater levels of force compared with untrained subjects. These differences are partly of neural origin and can be explained by training-induced changes in the neural drive to the muscles. In the present study we hypothesize a greater rate of torque development (RTD) and faster recruitment of motor units with greater muscle fiber conduction velocity (MFCV) in ST compared with a control cohort. MFCV was assessed during maximal voluntary isometric explosive contractions of the elbow flexors in eight ST and eight control individuals. MFCV was estimated from high-density surface electromyogram recordings (128 electrodes) in intervals of 50 ms starting from the onset of the electromyogram. RTD and MFCV were computed and normalized to their maximal voluntary torque (MVT) values. The explosive torque of the ST was greater than in the control group in all time intervals analyzed (P < 0.001). The absolute MFCV values were also greater for the ST than for controls at all time intervals (P < 0.001). ST also achieved greater normalized RTD in the first 50 ms of contraction [887.6 (152) vs. 568.5 (148.66)%MVT/s, mean (SD), P < 0.001] and normalized MFCV before the rise in force compared with controls. We have shown for the first time that ST can recruit motor units with greater MFCV in a shorter amount of time compared with untrained subjects during maximal voluntary isometric explosive contractions.
Date Issued
2018-10-01
Date Acceptance
2018-07-18
Citation
Journal of Applied Physiology, 2018, 125 (4), pp.1218-1226
ISSN
8750-7587
Publisher
American Physiological Society
Start Page
1218
End Page
1226
Journal / Book Title
Journal of Applied Physiology
Volume
125
Issue
4
Copyright Statement
© 2018 the American Physiological Society.
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000451443800027&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Subjects
Science & Technology
Life Sciences & Biomedicine
Physiology
Sport Sciences
explosive force contractions
motor unit conduction velocity
motor unit recruitment
neuromuscular assessment
size principle
MOTOR UNIT BEHAVIOR
SURFACE EMG SIGNALS
BALLISTIC CONTRACTIONS
FORCE DEVELOPMENT
NEURAL DRIVE
THRESHOLD
SIZE
RECRUITMENT
AMPLITUDE
POWER
Publication Status
Published
Date Publish Online
2018-10-17