The dynamic effect of muscle activation on knee stiffness

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

3 Scopus citations

Abstract

Adapting limb mechanics in a task and environment dependent manner is one component of human motor control. Joint mechanics have been extensively studied under static postural conditions, but less so under time-varying movement conditions. The limited studies that have investigated joint mechanics during movement, have found a drop in joint stiffness during movement, however the source of this decrease in stiffness remains unknown. Here in this paper we investigate whether time-varying muscle activation, which occurs during volitional movement, can lead to the drop in stiffness seen during movement. We found that under time-varying isometric conditions stiffness dropped when subjects transitioned from extension to flexion and vice-versa, a phenomenon that could not be explained by simply superimposing extension and flexion contractions. These findings suggest that dynamics of muscle activation may be responsible for the complex pattern of stiffness changes seen during simple movements. Furthermore, these results imply that EMG-based estimates of stiffness, which work well for steady-state postural conditions, will need to be augmented to account for the highly non-linear relationship between muscle activation and stiffness before they can also be used to estimate stiffness during dynamic contractions.

Original languageEnglish (US)
Title of host publication2014 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBC 2014
PublisherInstitute of Electrical and Electronics Engineers Inc.
Pages1599-1602
Number of pages4
ISBN (Electronic)9781424479290
DOIs
StatePublished - Nov 2 2014
Event2014 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBC 2014 - Chicago, United States
Duration: Aug 26 2014Aug 30 2014

Publication series

Name2014 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBC 2014

Other

Other2014 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBC 2014
CountryUnited States
CityChicago
Period8/26/148/30/14

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ASJC Scopus subject areas

  • Health Informatics
  • Computer Science Applications
  • Biomedical Engineering

Cite this

Ludvig, D., & Perreault, E. J. (2014). The dynamic effect of muscle activation on knee stiffness. In 2014 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBC 2014 (pp. 1599-1602). [6943910] (2014 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBC 2014). Institute of Electrical and Electronics Engineers Inc.. https://doi.org/10.1109/EMBC.2014.6943910