Perturbation velocity affects linearly estimated neuromechanical wrist joint properties

Asbjørn Klomp, Erwin de Vlugt, Jurriaan H. de Groot, Carel G.M. Meskers, J. Hans Arendzen, Frans C.T. van der Helm

Research output: Contribution to journalArticleScientificpeer-review

Abstract

The dynamic behavior of the wrist joint is governed by nonlinear properties, yet applied mathematical models, used to describe the measured input-output (perturbation-response) relationship, are commonly linear. Consequently, the linearly estimated model parameters will depend on properties of the applied perturbation properties (such perturbation amplitude and velocity). We aimed to systematically address the effects of perturbation velocity on linearly estimated neuromechanical parameters. Using a single axis manipulator ramp and hold perturbations were applied to the wrist joint. Effects of perturbation velocity (0.5, 1 and 3 rad/s) were investigated at multiple background torque levels (0, 0.5 and 1 N·m). With increasing perturbation velocity, estimated joint stiffness remained constant, while damping and reflex gain decreased. This variation in model parameters is dependent on background torque levels, i.e. muscle contraction. These observations support the future development of nonlinear models that are capable of describing wrist joint behavior over a larger range of loading conditions, exceeding the restricted range of operation that is required for linearization.

Original languageEnglish
Pages (from-to)207-212
JournalJournal of Biomechanics
Volume74
DOIs
Publication statusPublished - 2018

Keywords

  • Neuromechanics
  • Nonlinearity
  • Reflexes
  • Velocity
  • Wrist

Fingerprint Dive into the research topics of 'Perturbation velocity affects linearly estimated neuromechanical wrist joint properties'. Together they form a unique fingerprint.

Cite this