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Title: Modelling suppressed muscle activation by means of an exponential sigmoid function: validation and bounds
Authors: Voukelatos, Dimitrios
Pain, Matthew T.G.
Keywords: Interpolate twitch
Issue Date: 2015
Publisher: © Elsevier Ltd.
Citation: VOUKELATOS, D. and PAIN, M.T.G., 2015. Modelling suppressed muscle activation by means of an exponential sigmoid function: Validation and bounds. Journal of Biomechanics, 48 (4), pp. 712 - 715.
Abstract: The aim of this study was to establish how well a three-parameter sigmoid exponential function, DIFACT, follows experimentally obtained voluntary neural activation-angular velocity profiles and how robust it is to perturbed levels of maximal activation. Six male volunteers (age 26.3±2.73 years) were tested before and after an 8-session, 3-week training protocol. Torque–angular velocity (T–ω) and experimental voluntary neural drive–angular velocity (%VA–ω) datasets, obtained via the interpolated twitch technique, were determined from pre- and post-training testing sessions. Non-linear regression fits of the product of DIFACT and a Hill type tetanic torque function and of the DIFACT function only were performed on the pre- and post-training T–ω and %VA–ω datasets for three different values of the DIFACT upper bound, αmax, 100%, 95% & 90%. The determination coefficients, R2, and the RMS of the fits were compared using a two way mixed ANOVA and results showed that there was no significant difference (p<0.05) due to changing αmax values indicating the DIFACT remains robust to changes in maximal activation. Mean R2 values of 0.95 and 0.96 for pre- and post-training sessions show that the maximal voluntary torque function successfully reproduces the T–ω raw dataset.
Description: This article was accepted for publication in the Journal of Biomechanics [© Elsevier Ltd.] and the definitive version is available at: http://dx.doi.org/10.1016/j.jbiomech.2015.01.009
Version: Accepted for publication
DOI: 10.1016/j.jbiomech.2015.01.009
URI: https://dspace.lboro.ac.uk/2134/17534
Publisher Link: http://dx.doi.org/10.1016/j.jbiomech.2015.01.009
ISSN: 0021-9290
Appears in Collections:Published Articles (Sport, Exercise and Health Sciences)

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