Topological relations between postural configuration and manual control performance
Lee, Dongwoo
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Permalink
https://hdl.handle.net/2142/19235
Description
Title
Topological relations between postural configuration and manual control performance
Author(s)
Lee, Dongwoo
Issue Date
1994
Doctoral Committee Chair(s)
Riccio, Gary E.
Department of Study
Kinesiology and Community Health
Discipline
Kinesiology
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Biology, Anatomy
Education, Physical
Health Sciences, Recreation
Language
eng
Abstract
The purpose of this study was to investigate the relations between postural configuration during bipedal stance and performance on manual control task. Postural control is influenced by the interaction of the constraints imposed on perceptual motor workspace. The manipulation of any constraints would bring the individual to change the body configuration to maintain stable and efficient body configuration for a given task. It was assumed that when they need to change their body configuration, organisms strive to adopt a control strategy in which minimum energy is expended to maintain a posture that is consistent with the task goal.
Five healthy subjects participated in this study and a keyboard tapping task was selected to examine the functional relations between postural configuration and task performance. Subjects were asked to tap the keyboard at a constant rate and with a constant force while its distance was manipulated discretely and continuously. Distance weighted least square smoothing was used to explore the local variations and quadratic regression was employed to see the global features and statistical implications.
The primary findings of the study were summarized as follows; First, subjects tended to adjust their body configuration as the distance of manipulanda was varied. Looking at the change of the body configuration we could infer that subjects tried to optimize performance on a given task. They attempted to keep the distance between the shoulder and keyboard constant. Fluctuation of the body segments tended to increase as the keyboard moved away from subjects. Second, the functional relations between task performance and body configuration were topologically similar although they showed slight differences in magnitude. Third, A-P force and A-P torque showed different sensitivity to the manipulation of the keyboard locations. A-P force had a significant difference between the keyboard heights. A-P torque revealed a significant difference across the keyboard distance. Fourth, there was a strong quadratic relation between performance measures and body configurations although topological distributions were somewhat dissimilar between interval variability and peak force variability as shown in DWLS smooth. Finally, it was suggested that there were some nonlinear features in the way posture was adjusted although it is speculative and needs further elaboration.
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