| Adaptive increase in force variance during fatigue in tasks with low redundancy. | |
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MedLine Citation:
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PMID: 20849913 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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We tested a hypothesis that fatigue of an element (a finger) leads to an adaptive neural strategy that involves an increase in force variability in the other finger(s) and an increase in co-variation of commands to fingers to keep total force variability relatively unchanged. We tested this hypothesis using a system with small redundancy (two fingers) and a marginally redundant system (with an additional constraint related to the total moment of force produced by the fingers, unstable condition). The subjects performed isometric accurate rhythmic force production tasks by the index (I) finger and two fingers (I and middle, M) pressing together before and after a fatiguing exercise by the I finger. Fatigue led to a large increase in force variance in the I-finger task and a smaller increase in the IM-task. We quantified two components of variance in the space of hypothetical commands to fingers, finger modes. Under both stable and unstable conditions, there was a large increase in the variance component that did not affect total force and a much smaller increase in the component that did. This resulted in an increase in an index of the force-stabilizing synergy. These results indicate that marginal redundancy is sufficient to allow the central nervous system to use adaptive increase in variability to shield important variables from effects of fatigue. We offer an interpretation of these results based on a recent development of the equilibrium-point hypothesis known as the referent configuration hypothesis. |
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Authors:
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Tarkeshwar Singh; Varadhan S K M; Vladimir M Zatsiorsky; Mark L Latash |
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Publication Detail:
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Type: Journal Article Date: 2010-09-16 |
Journal Detail:
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Title: Neuroscience letters Volume: 485 ISSN: 1872-7972 ISO Abbreviation: Neurosci. Lett. Publication Date: 2010 Nov |
Date Detail:
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Created Date: 2010-10-18 Completed Date: 2011-01-28 Revised Date: 2011-12-21 |
Medline Journal Info:
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Nlm Unique ID: 7600130 Medline TA: Neurosci Lett Country: Ireland |
Other Details:
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Languages: eng Pagination: 204-7 Citation Subset: IM |
Copyright Information:
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Copyright © 2010 Elsevier Ireland Ltd. All rights reserved. |
Affiliation:
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Department of Kinesiology, The Pennsylvania State University, University Park, PA 16802, USA. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Adaptation, Physiological
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physiology* Adult Central Nervous System / physiology Fatigue / psychology* Female Fingers / innervation, physiology Hand Strength / physiology Humans Male Muscle, Skeletal / physiology Psychomotor Performance / physiology |
| Grant Support | |
ID/Acronym/Agency:
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R01 AG018751-10/AG/NIA NIH HHS; R01 NS035032-14/NS/NINDS NIH HHS; R01 NS035032-15/NS/NINDS NIH HHS |
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