Ankle mechanical impedance under muscle fatigue

Shuo Wang, Hyunglae Lee, Neville Hogan

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


This paper reports preliminary results on the effects of ankle muscle fatigue on ankle mechanical impedance. The experiment was designed to induce fatigue in the Tibialis Anterior and Triceps Surae muscle group by asking subjects to perform isometric contractions against a constant ankle torque generated by the Anklebot, a backdriveable robot that interacts with the ankle in two degrees of freedom. Median frequencies of surface electromyographic signals collected from Tibialis Anterior and Triceps Surae muscle group were evaluated to assess muscle fatigue. Using a standard multi-input and multioutput stochastic impedance identification method, multivariable ankle mechanical impedance was measured in two degrees of freedom under muscle fatigue. Preliminary results indicate that, for both Tibialis Anterior and Triceps Surae muscle group, ankle mechanical impedance decreases in both the dorsi-plantar flexion and inversion-eversion directions under muscle fatigue. This finding suggests that decreasing ankle impedance with muscle fatigue may help to develop joint support systems to prevent ankle injuries caused by muscle fatigue.

Original languageEnglish (US)
Title of host publicationNonlinear Estimation and Control; Optimization and Optimal Control; Piezoelectric Actuation and Nanoscale Control; Robotics and Manipulators; Sensing;
PublisherAmerican Society of Mechanical Engineers (ASME)
ISBN (Print)9780791856147
StatePublished - 2013
Externally publishedYes
EventASME 2013 Dynamic Systems and Control Conference, DSCC 2013 - Palo Alto, CA, United States
Duration: Oct 21 2013Oct 23 2013

Publication series

NameASME 2013 Dynamic Systems and Control Conference, DSCC 2013


OtherASME 2013 Dynamic Systems and Control Conference, DSCC 2013
Country/TerritoryUnited States
CityPalo Alto, CA

ASJC Scopus subject areas

  • Control and Systems Engineering


Dive into the research topics of 'Ankle mechanical impedance under muscle fatigue'. Together they form a unique fingerprint.

Cite this