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Task Dependency of Grip Stiffness—A Study of Human Grip Force and Grip Stiffness Dependency during Two Different Tasks with Same Grip Forces

Höppner, Hannes and McIntyre, Joseph and van der Smagt, Patrick (2013) Task Dependency of Grip Stiffness—A Study of Human Grip Force and Grip Stiffness Dependency during Two Different Tasks with Same Grip Forces. PLoS One, 8 (12), e80889. Public Library of Science. DOI: [10.1371/journal.pone.0080889]. ISSN 1932-6203.

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Official URL: http://dx.doi.org/10.1371%2Fjournal.pone.0080889

Abstract

It is widely known that the pinch-grip forces of the human hand are linearly related to the weight of the grasped object. Less is known about the relationship between grip force and grip <italic>stiffness</italic>. We set out to determine variations to these dependencies in different tasks with and without visual feedback. In two different settings, subjects were asked to (a) grasp and hold a stiffness-measuring manipulandum with a predefined grip force, differing from experiment to experiment, or (b) grasp and hold this manipulandum of which we varied the weight between trials in a more natural task. Both situations led to grip forces in comparable ranges. As the measured grip stiffness is the result of muscle and tendon properties, and since muscle/tendon stiffness increases more-or-less linearly as a function of muscle force, we found, as might be predicted, a linear relationship between grip force and grip stiffness. However, the measured stiffness ranges and the increase of stiffness with grip force varied significantly between the two tasks. Furthermore, we found a strong correlation between regression slope and mean stiffness for the force task which we ascribe to a force stiffness curve going through the origin. Based on a biomechanical model, we attributed the difference between both tasks to changes in wrist configuration, rather than to changes in cocontraction. In a new set of experiments where we prevent the wrist from moving by fixing it and resting it on a pedestal, we found subjects exhibiting similar stiffness/force characteristics in both tasks.</p>

Document Type:Article
Title:Task Dependency of Grip Stiffness—A Study of Human Grip Force and Grip Stiffness Dependency during Two Different Tasks with Same Grip Forces
Authors:
AuthorsInstitution or Email of Authors
Höppner, Hanneshannes.hoeppner@dlr.de
McIntyre, JosephUNSPECIFIED
van der Smagt, PatrickUNSPECIFIED
Date:December 2013
Journal or Publication Title:PLoS One
Refereed publication:Yes
In Open Access:Yes
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:8
DOI:[10.1371/journal.pone.0080889]
Page Range:e80889
Publisher:Public Library of Science
ISSN:1932-6203
Status:Published
Keywords:Grip Stiffness; Finger Stiffness; Grasp Perturbator; Force Task; Weight Task; Wrist/Finger Configuration; Cocontraction; Human Stiffness; Human Impedance
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Space Technology
DLR - Research area:Raumfahrt
DLR - Program:R SY - Technik für Raumfahrtsysteme
DLR - Research theme (Project):R - Vorhaben Weiterentwicklung Robotik - Mechatronik und Dynamik
Location: Oberpfaffenhofen
Institutes and Institutions:Institute of Robotics and Mechatronics > Mechatronic Components and Systems
Deposited By: Hannes Höppner
Deposited On:09 Jan 2014 13:55
Last Modified:20 Aug 2014 14:57

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