TITLE: Doctor of Philosophy (Ph.D.) (1995)
INSTITUTE: McGill University, Montreal, Canada
DEPARTMENT: Physical Education and Sports Sciences,
SUBJECT: Motor Control
Thesis Ph.D. Abstract (LAC – Library and Archives Canada)
NAME(S):*Hatzitaki, Vassilia, 1967-
TITLE(S): Patterns of interlimb coordination during asymmetrical reaching movements [microform]
PUBLISHER: Ottawa : National Library of Canada = Bibliothèque nationale du Canada, 1996.
DESCRIPTION: 2 microfiches.
SERIES: Canadian theses = Thèses canadiennes
NOTES: Thesis (Ph.D.)–McGill University, 1995.
Includes bibliographical references.
The present study investigated the patterns of interlimb organization during the concurrent performance of asymmetrical reaching movements. The inherent tendency towards interlimb synchronization often constrains activities requiring the two limbs to move over different distances or at different movement speeds. The study of bimanual coordination has shown that the amount of interlimb interference during bilateral performance of asymmetrical actions, is regulated according to the magnitude characteristics of the variable used to introduce the asymmetry between the limbs. The purpose of the present study was to examine the relationship between the degree of interlimb decoupling and the magnitude of the asymmetry between the limbs. Asymmetry was systematically manipulated by scaling the magnitude of the interlimb difference in final target distance, during bimanual performance of reaching movements. The degree of interlimb decoupling was reflected in the movement time, muscle activity onset and joint torque relationship between the limbs. Decoupling of the asymmetrical limb movements was effected by an earlier onset of the antagonist muscles in the constrained limb which scaled the amount of muscle torque production and therefore the stiffness of the limb during the acceleration phase of the movement. Thus, the movement amplitude differentiation was achieved by an initial accelarative impulse attributed to the differential control of the muscle torque production at each joint. On the other hand, the interactive forces played a secondary role in the degree of decoupling process.
Overall, the degree of decoupling scaled according to the magnitude of the interlimb difference in distance; the greater the asymmetry, the greater the differentiation between the limbs. However, systematic variations of the interlimb asymmetry in distance gave rise to a wide variety of individual decoupling trends.
Bimanual practice of the asymmetrical reaching tasks did not result in the development of more independent limb movements. The results of the present study have implications to human factor design and ergonomics.
NUMBERS: Canadiana: 962098019
CLASSIFICATION: Dewey: 610 20
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