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The reserve of joint torque determines movement coordination

Humans coordinate biomechanical degrees of freedom to perform tasks at minimum cost. When reaching a target from a seated position, the trunk-arm-forearm coordination moves the hand to the well-defined spatial goal, while typically minimising hand jerk and trunk motion. However, due to fatigue or st...

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Autores principales: Faity, Germain, Mottet, Denis, Pla, Simon, Froger, Jérôme
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8626510/
https://www.ncbi.nlm.nih.gov/pubmed/34836976
http://dx.doi.org/10.1038/s41598-021-02338-4
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author Faity, Germain
Mottet, Denis
Pla, Simon
Froger, Jérôme
author_facet Faity, Germain
Mottet, Denis
Pla, Simon
Froger, Jérôme
author_sort Faity, Germain
collection PubMed
description Humans coordinate biomechanical degrees of freedom to perform tasks at minimum cost. When reaching a target from a seated position, the trunk-arm-forearm coordination moves the hand to the well-defined spatial goal, while typically minimising hand jerk and trunk motion. However, due to fatigue or stroke, people visibly move the trunk more, and it is unclear what cost can account for this. Here we show that people recruit their trunk when the torque at the shoulder is too close to the maximum. We asked 26 healthy participants to reach a target while seated and we found that the trunk contribution to hand displacement increases from 11 to 27% when an additional load is handled. By flexing and rotating the trunk, participants spontaneously increase the reserve of anti-gravitational torque at the shoulder from 25 to 40% of maximal voluntary torque. Our findings provide hints on how to include the reserve of torque in the cost function of optimal control models of human coordination in healthy fatigued persons or in stroke victims.
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spelling pubmed-86265102021-11-29 The reserve of joint torque determines movement coordination Faity, Germain Mottet, Denis Pla, Simon Froger, Jérôme Sci Rep Article Humans coordinate biomechanical degrees of freedom to perform tasks at minimum cost. When reaching a target from a seated position, the trunk-arm-forearm coordination moves the hand to the well-defined spatial goal, while typically minimising hand jerk and trunk motion. However, due to fatigue or stroke, people visibly move the trunk more, and it is unclear what cost can account for this. Here we show that people recruit their trunk when the torque at the shoulder is too close to the maximum. We asked 26 healthy participants to reach a target while seated and we found that the trunk contribution to hand displacement increases from 11 to 27% when an additional load is handled. By flexing and rotating the trunk, participants spontaneously increase the reserve of anti-gravitational torque at the shoulder from 25 to 40% of maximal voluntary torque. Our findings provide hints on how to include the reserve of torque in the cost function of optimal control models of human coordination in healthy fatigued persons or in stroke victims. Nature Publishing Group UK 2021-11-26 /pmc/articles/PMC8626510/ /pubmed/34836976 http://dx.doi.org/10.1038/s41598-021-02338-4 Text en © The Author(s) 2021 https://creativecommons.org/licenses/by/4.0/Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) .
spellingShingle Article
Faity, Germain
Mottet, Denis
Pla, Simon
Froger, Jérôme
The reserve of joint torque determines movement coordination
title The reserve of joint torque determines movement coordination
title_full The reserve of joint torque determines movement coordination
title_fullStr The reserve of joint torque determines movement coordination
title_full_unstemmed The reserve of joint torque determines movement coordination
title_short The reserve of joint torque determines movement coordination
title_sort reserve of joint torque determines movement coordination
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8626510/
https://www.ncbi.nlm.nih.gov/pubmed/34836976
http://dx.doi.org/10.1038/s41598-021-02338-4
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