Title
Can co-activation reduce kinematic variability? A simulation study
Abstract
Impedance modulation has been suggested as a means to suppress the effects of internal ‘noise’ on movement kinematics. We investigated this hypothesis in a neuro-musculo-skeletal model. A prerequisite is that the muscle model produces realistic force variability. We found that standard Hill-type models do not predict realistic force variability in response to variability in stimulation. In contrast, a combined motor-unit pool model and a pool of parallel Hill-type motor units did produce realistic force variability as a function of target force, largely independent of how the force was transduced to the tendon. To test the main hypothesis, two versions of the latter model were simulated as an antagonistic muscle pair, controlling the position of a frictionless hinge joint, with a distal segment having realistic inertia relative to the muscle strength. Increasing the impedance through co-activation resulted in less kinematic variability, except for the lowest levels of co-activation. Model behavior in this region was affected by the noise amplitude and the inertial properties of the model. Our simulations support the idea that muscular co-activation is in principle an effective strategy to meet accuracy demands.
Year
DOI
Venue
2005
10.1007/s00422-005-0015-y
Biological Cybernetics
Keywords
Field
DocType
Motor Unit,Interspike Interval,Force Variability,Impedance Modulation,Series Elastic Element
Inertial frame of reference,Kinematics,Control theory,Hinge joint,Modulation,Electrical impedance,Motor unit,Inertia,Amplitude,Mathematics
Journal
Volume
Issue
ISSN
93
5
0340-1200
Citations 
PageRank 
References 
17
1.50
4
Authors
3
Name
Order
Citations
PageRank
Luc P. J. Selen1172.17
Peter J. Beek27915.62
Jaap H. van Dieën3243.85