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Modelling suppressed muscle activation by means of an exponential sigmoid function: validation and bounds

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journal contribution
posted on 2015-05-19, 12:47 authored by Dimitrios VoukelatosDimitrios Voukelatos, Matthew PainMatthew Pain
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.

History

School

  • Sport, Exercise and Health Sciences

Published in

JOURNAL OF BIOMECHANICS

Volume

48

Issue

4

Pages

712 - 715 (4)

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.

Publisher

© Elsevier Ltd.

Version

  • AM (Accepted Manuscript)

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/

Publication date

2015

Notes

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

ISSN

0021-9290

Language

  • en