Non-linear viscoelastic models predict fingertip pulp force-displacement characteristics during voluntary tapping.

Full Abstract

We evaluated whether lumped-parameter non-linear viscoelastic models of human fingertip tissue can describe fingertip force-displacement characteristics during a range of rapid, dynamic tapping tasks. Eight human subjects tapped with their index finger on the surface of a rigid load cell while an optical system tracked fingertip position using an infra-red LED attached to the fingernail. Four different tapping conditions were tested:
normal and high-speed taps with a relaxed hand, and normal and high-speed taps with the other fingers co-contracted. A non-linear viscoelastic model comprised of an instantaneous stiffness function and viscous relaxation function was capable of predicting fingertip tissue force response due to measured pulp compression under these four different loading conditions. The model could successfully reconstruct very rapid (less than 5 ms) force transients, and forces occurring over time periods greater than 100 ms, with errors of 10%. Model parameters varied by less than 20% over the four conditions, despite almost 3-fold differences in average forces and 38% differences in fingertip velocities. Energy dissipation by the fingertip averaged 81%, and varied little (<3%) across conditions, despite a 1. 5-fold range of energy input. The ability of a lumped-parameter model to describe fingertip force-displacement characteristics during a range of conditions contributes both to understanding the transmission of force through the fingertip to the musculoskeletal system and to predicting the stimulation of mechano-receptors located within the fingertip.

Learn Faster Today Improve your study skills

Author information

Author/s: Jindrich, Devin L (DL); Zhou, Yanhong (Y); Becker, Theodore (T); Dennerlein, Jack Tigh (JT);

Affiliation: Department of Environmental Health, Harvard School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA. jax(-atsign-)hsph.harvard.edu

Journal and publication information

Publication Type: Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't; Validation Studies

Journal: Journal of biomechanics (J Biomech), published in United States. (Language: eng)

Reference: 2003-Apr; vol 36 (issue 4) : pp 497-503

Dates: Created 2003/02/25; Completed 2003/07/01; Revised 2006/11/15;

PMID: 12600340, status: MEDLINE (last retrieval date: 11/6/2008)

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

External Links for this article (including full text providers, if available):

Click Electronic Full-text Provider Links to see options for finding the electronic full text links to this article. Note there may be a subscription or fee required for access to the full text. See our FAQ for information on finding FREE full text articles.

This article may also be located in paper journal collections available in many libraries. Use the Journal and Publication Information above to find the full article.

MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Adult
Computer Simulation
Connective Tissue - physiology
Elasticity
Female
Fingers - physiology
Humans
Male
Models, Biological

Models, Biological
Movement - physiology
Nonlinear Dynamics
Pressure
Skin Physiology
Stress, Mechanical
Touch - physiology
Viscosity
Volition - physiology

This article has not been indexed for related articles as yet, however you can still use the live related article search links below.

See 100+ related articles.