Interpretation of the directional properties of voluntarily modulated human ankle mechanical impedance

Patrick Ho, Hyunglae Lee, Mohammad A. Rastgaar, Hermano Igo Krebs, Neville Hogan

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations

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.

Original languageEnglish (US)
Title of host publicationASME 2010 Dynamic Systems and Control Conference, DSCC2010
Pages467-472
Number of pages6
DOIs
StatePublished - Dec 1 2010
Externally publishedYes
EventASME 2010 Dynamic Systems and Control Conference, DSCC2010 - Cambridge, MA, United States
Duration: Sep 12 2010Sep 15 2010

Publication series

NameASME 2010 Dynamic Systems and Control Conference, DSCC2010
Volume1

Other

OtherASME 2010 Dynamic Systems and Control Conference, DSCC2010
CountryUnited States
CityCambridge, MA
Period9/12/109/15/10

ASJC Scopus subject areas

  • Control and Systems Engineering

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  • Cite this

    Ho, P., Lee, H., Rastgaar, M. A., Krebs, H. I., & Hogan, N. (2010). Interpretation of the directional properties of voluntarily modulated human ankle mechanical impedance. In ASME 2010 Dynamic Systems and Control Conference, DSCC2010 (pp. 467-472). (ASME 2010 Dynamic Systems and Control Conference, DSCC2010; Vol. 1). https://doi.org/10.1115/DSCC2010-4274