Estimating ankle torque and dynamics of the stabilizing mechanism

No need for horizontal ground reaction forces

Journal article (2020)

Authors

I.M. Schut Biomechatronics & Human-Machine Control - Mechanical, Maritime and Materials Engineering
J.H. Pasma Biomechatronics & Human-Machine Control - Mechanical, Maritime and Materials Engineering , Haga Hospital
J. M.B. Roelofs Radboud Universiteit Nijmegen
Vivian Weerdesteyn Radboud Universiteit Nijmegen, Sint Maartenskliniek, Nijmegen
H. Kooij University of Twente, Biomechatronics & Human-Machine Control - Mechanical, Maritime and Materials Engineering
A.C. Schouten Biomechatronics & Human-Machine Control - Mechanical, Maritime and Materials Engineering , University of Twente
Research Group
Biomechatronics & Human-Machine Control (Mechanical, Maritime and Materials Engineering) (TU Delft)
Copyright: © 2020 I.M. Schut, J.H. Pasma, J. M.B. Roelofs, V. Weerdesteyn, H. van der Kooij, A.C. Schouten
DOI: https://doi.org/10.1016/j.jbiomech.2020.109813
More Info
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Published Date

2020

Language

English

Faculty

Mechanical, Maritime and Materials Engineering

Department

Biomechanical Engineering

Research Group

Biomechatronics & Human-Machine Control

Abstract

Changes in human balance control can objectively be assessed using system identification techniques in combination with support surface translations. However, large, expensive and complex motion platforms are required, which are not suitable for the clinic. A treadmill could be a simple alternative to apply support surface translations. In this paper we first validated the estimation of the joint stiffness of an inverted pendulum using system identification methods in combination with support surface translations, by comparison with the joint stiffness calculated using a linear regression method. Second, we used the system identification method to investigate the effect of horizontal ground reaction forces on the estimation of the ankle torque and the dynamics of the stabilizing mechanism of 12 healthy participants. Ankle torque and resulting frequency response functions, which describes the dynamics of the stabilizing mechanism, were calculated by both including and excluding horizontal ground reaction forces. Results showed that the joint stiffness of an inverted pendulum estimated using system identification is comparable to the joint stiffness estimated by a regression method. Secondly, within the induced body sway angles, the ankle torque and frequency response function of the joint dynamics calculated by both including and excluding horizontal ground reaction forces are similar. Therefore, the horizontal ground reaction forces play a minor role in calculating the ankle torque and frequency response function of the dynamics of the stabilizing mechanism and can thus be omitted.