Amplitude scaling in a bimanual circle-drawing task: pattern switching and end-effector variability.

Full Abstract

The authors manipulated movement amplitude in a bimanual circle-tracing task performed by 11 participants. With pacing frequency fixed, the systematic increase and decrease of circle diameter within a trial induced phase transitions from the asymmetric (33% of trials) to the symmetric bimanual circle-tracing pattern; the transitions resulted from a loss of stability in the asymmetric pattern. Tracing frequency varied inversely with circle diameter so that end-effector variability was minimized in a set of self-paced trials in which the circle diameter in a trial was fixed. In the amplitude-scaling trials, end-effector variability varied directly with circle diameter, a consistent speed-accuracy tradeoff. The results support the conclusion that movement amplitude is a nonspecific control parameter. The findings are discussed with reference to several factors, e.g., tactile feedback, the recruitment and suppression of biomechanical degrees of freedom, and the role those factors may play in stabilizing bimanual coordination patterns

Author information

Author/s: Ryu, Young U (YU); Buchanan, John J (JJ);

Affiliation: Texas A&M University, Department of Health and Kinesiology, TX, USA.

Journal and publication information

Publication Type: Journal Article

Journal: Journal of motor behavior (J Mot Behav), published in United States. (Language: eng)

Reference: 2004-Sep; vol 36 (issue 3) : pp 265-79

Dates: Created 2004/07/20; Completed 2004/10/28; Revised 2004/11/17;

PMID: 15262623, status: MEDLINE (last retrieval date: 2/18/2009, IMS Date: )

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