Force sharing and neutral line during finger extension tasks.
Human Movement Science. 2012-08-01; 31(4): 749-757
DOI: 10.1016/j.humov.2011.09.001
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1. Hum Mov Sci. 2012 Aug;31(4):749-57. doi: 10.1016/j.humov.2011.09.001. Epub 2011
Nov 26.
Force sharing and neutral line during finger extension tasks.
Quaine F(1), Paclet F, Letué F, Moutet F.
Author information:
(1)GIPSA-Lab, CNRS UMR 5216, Control System Department, SAIGA Team, Grenoble
University, France.
There is general consensus that the minimization of the secondary torque of the
hand provides a universal model for explaining the force sharing patterns among
the fingers. Since biomechanical secondary axes of the hand are unchanged in
extension, it appears relevant to validate this model for finger extension
forces. Fifteen subjects performed flexion and extension forces in a four-finger
task. Each fingertip force was expressed in percentage of the force produced by
an individual finger force over the resultant four-finger force (force sharing),
and the point of force application of the resultant force was calculated (neutral
line). The force-sharing pattern was different for flexion and extension. The
index and ring fingers were equally involved, regardless of the task. The neutral
line was located differently in flexion and extension, and for proximal and
distal force application in extension. The mode of control of the finger
redundancy was specific to the force production in flexion and extension. In
flexion, the principle of minimization of secondary torque was confirmed. This
was not observed in extension. We concluded that the minimization of the
secondary torque is not a universal mode of control of the finger redundancy.
Copyright © 2011 Elsevier B.V. All rights reserved.
DOI: 10.1016/j.humov.2011.09.001
PMID: 22119423 [Indexed for MEDLINE]