Stability and variability: indicators for passive stability and active control in a rhythmic task.

Full Abstract

Using a rhythmic task where human subjects bounced a ball with a handheld racket, fine-grained analyses of stability and variability extricated contributions from open-loop control, noise strength, and active error compensation. Based on stability analyses of a stochastic-deterministic model of the task--a surface contacting the ball by periodic movements--open-loop or dynamic stability was assessed by the acceleration of the racket at contact. Autocovariance analyses of model and data were further used to gauge the contributions of open-loop stability and noise strength. Variability and regression analyses estimated active error compensation. Empirical results demonstrated that experienced actors exploited open-loop stability more than novices, had lower noise strength, and applied more active error compensations. By manipulating the model parameter coefficient of restitution, task stability was varied and showed that actors graded these three components as a function of task stability. It is concluded that actors tune into task stability when stability is high but use more active compensation when stability is reduced. Implications for the neural underpinnings for passive stability and active control are discussed. Further, results showed that stability and variability are not simply the inverse of each other but contain more quantitative information when combined with model analyses.

Author information

Author/s: Wei, Kunlin (K); Dijkstra, Tjeerd M H (TM); Sternad, Dagmar (D);

Affiliation: Rehabilitation Institute of Chicago, Northwestern University, Chicago, Illinois, USA.

Grants: R01-HD-045639 (Agency:NICHD NIH HHS)

Journal and publication information

Publication Type: Journal Article; Research Support, N.I.H., Extramural; Research Support, U.S. Gov't, Non-P.H.S.

Journal: Journal of neurophysiology (J Neurophysiol), published in United States. (Language: eng)

Reference: 2008-Jun; vol 99 (issue 6) : pp 3027-41

Dates: Created 2008/06/11; Completed 2008/08/26; Revised 2008/11/21;

PMID: 18353911, status: MEDLINE (last retrieval date: 2/18/2009, IMS Date: )

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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