Document Detail


Mechanical properties of the human hand digits: age-related differences.
MedLine Citation:
PMID:  24355703     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: Mechanical properties of human digits may have significant implications for the hand function. We quantified several mechanical characteristics of individual digits in young and older adults.
METHODS: Digit tip friction was measured at several normal force values using a method of induced relative motion between the digit tip and the object surface. A modified quick-release paradigm was used to estimate digit apparent stiffness, damping, and inertial parameters. The subjects grasped a vertical handle instrumented with force/moment sensors using a prismatic grasp with four digits; the handle was fixed to the table. Unexpectedly, one of the sensors yielded leading to a quick displacement of the corresponding digit. A second-order, linear model was used to fit the force/displacement data.
FINDINGS: Friction of the digit pads was significantly lower in older adults. The apparent stiffness coefficient values were higher while the damping coefficients were lower in older adults leading to lower damping ratio. The damping ratio was above unity for most data in young adults and below unity for older adults. Quick release of a digit led to force changes in other digits of the hand, likely due to inertial hand properties. These phenomena of "mechanical enslaving" were smaller in older adults although no significant difference was found in the inertial parameter in the two groups.
INTERPRETATIONS: The decreased friction and damping ratio present challenges for the control of everyday prehensile tasks. They may lead to excessive digit forces and low stability of the grasped object.
Authors:
Jaebum Park; Nemanja Pažin; Jason Friedman; Vladimir M Zatsiorsky; Mark L Latash
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2013-12-04
Journal Detail:
Title:  Clinical biomechanics (Bristol, Avon)     Volume:  29     ISSN:  1879-1271     ISO Abbreviation:  Clin Biomech (Bristol, Avon)     Publication Date:  2014 Feb 
Date Detail:
Created Date:  2014-03-03     Completed Date:  2014-06-10     Revised Date:  2014-10-26    
Medline Journal Info:
Nlm Unique ID:  8611877     Medline TA:  Clin Biomech (Bristol, Avon)     Country:  England    
Other Details:
Languages:  eng     Pagination:  129-37     Citation Subset:  IM    
Copyright Information:
Copyright © 2013 Elsevier Ltd. All rights reserved.
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MeSH Terms
Descriptor/Qualifier:
Adult
Age Factors
Aged
Biomechanical Phenomena / physiology
Female
Fingers / physiology*
Friction / physiology*
Hand
Hand Strength / physiology
Humans
Male
Movement / physiology
Transducers
Grant Support
ID/Acronym/Agency:
AR-048563/AR/NIAMS NIH HHS; NS-035032/NS/NINDS NIH HHS; R01 AG018751/AG/NIA NIH HHS; R01 AR048563/AR/NIAMS NIH HHS; R01 NS035032/NS/NINDS NIH HHS

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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