Interpretation of the Directional Properties of Voluntarily Modulated Human Ankle Mechanical Impedance
Author(s)
Ho, Patrick
Lee, Hyunglae
Rastgaar Aagaah, Mohammad
Krebs, Hermano I
Hogan, Neville
Date Issued
September 2010
Journal
ASME 2010 Dynamic Systems and Control Conference, Volume 1
Publisher
ASME International
Citation
Ho, Patrick, Hyunglae Lee, Mohammad A. Rastgaar, Hermano Igo Krebs, and Neville Hogan. “Interpretation of the Directional Properties of Voluntarily Modulated Human Ankle Mechanical Impedance.” ASME 2010 Dynamic Systems and Control Conference, Volume 1 (2010).
Version
Final published version
Abstract
This article presents the results of two in-vivo studies providing measurements of human static ankle mechanical impedance. Accurate measurements of ankle impedance when muscles were voluntarily activated were obtained using a therapeutic robot, Anklebot, and an electromyographic recording system. Important features of ankle impedance, and their variation with muscle activity, are discussed, including magnitude, symmetry and directions of minimum and maximum impedance. Voluntary muscle activation has a significant impact on ankle impedance, increasing it by up to a factor of three in our experiments. Furthermore, significant asymmetries and deviations from a linear two-spring model are present in many subjects, indicating that ankle impedance has a complex and individually idiosyncratic structure. We propose the use of Fourier series as a general representation, providing both insight and a precise quantitative characterization of human static ankle impedance.
MIT Department
Massachusetts Institute of Technology. Department of Brain and Cognitive Sciences
Massachusetts Institute of Technology. Department of Mechanical Engineering
Terms of Use
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1115/DSCC2010-4274
