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Large Propulsion Demands Increase Locomotor Adaptation at the Expense of Step Length Symmetry

There is an interest to identify factors facilitating locomotor adaptation induced by split-belt walking (i.e., legs moving at different speeds) because of its clinical potential. We hypothesized that augmenting braking forces, rather than propulsion forces, experienced at the feet would increase lo...

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Autores principales: Sombric, Carly J., Calvert, Jonathan S., Torres-Oviedo, Gelsy
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6376174/
https://www.ncbi.nlm.nih.gov/pubmed/30800072
http://dx.doi.org/10.3389/fphys.2019.00060
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author Sombric, Carly J.
Calvert, Jonathan S.
Torres-Oviedo, Gelsy
author_facet Sombric, Carly J.
Calvert, Jonathan S.
Torres-Oviedo, Gelsy
author_sort Sombric, Carly J.
collection PubMed
description There is an interest to identify factors facilitating locomotor adaptation induced by split-belt walking (i.e., legs moving at different speeds) because of its clinical potential. We hypothesized that augmenting braking forces, rather than propulsion forces, experienced at the feet would increase locomotor adaptation during and after split-belt walking. To test this, forces were modulated during split-belt walking with distinct slopes: incline (larger propulsion than braking), decline (larger braking than propulsion), and flat (similar propulsion and braking). Step length asymmetry was compared between groups because it is a clinically relevant measure robustly adapted on split-belt treadmills. Unexpectedly, the group with larger propulsion demands (i.e., the incline group) changed their gait the most during adaptation, reached their final adapted state more quickly, and had larger after-effects when the split-belt perturbation was removed. We also found that subjects who experienced larger disruptions of propulsion forces in early adaptation exhibited greater after-effects, which further highlights the catalytic role of propulsion forces on locomotor adaptation. The relevance of mechanical demands on shaping our movements was also indicated by the steady state split-belt behavior, during which each group recovered their baseline leg orientation to meet leg-specific force demands at the expense of step length symmetry. Notably, the flat group was nearly symmetric, whereas the incline and decline group overshot and undershot step length symmetry, respectively. Taken together, our results indicate that forces propelling the body facilitate gait changes during and after split-belt walking. Therefore, the particular propulsion demands to walk on a split-belt treadmill might explain the gait symmetry improvements in hemiparetic gait following split-belt training.
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spelling pubmed-63761742019-02-22 Large Propulsion Demands Increase Locomotor Adaptation at the Expense of Step Length Symmetry Sombric, Carly J. Calvert, Jonathan S. Torres-Oviedo, Gelsy Front Physiol Physiology There is an interest to identify factors facilitating locomotor adaptation induced by split-belt walking (i.e., legs moving at different speeds) because of its clinical potential. We hypothesized that augmenting braking forces, rather than propulsion forces, experienced at the feet would increase locomotor adaptation during and after split-belt walking. To test this, forces were modulated during split-belt walking with distinct slopes: incline (larger propulsion than braking), decline (larger braking than propulsion), and flat (similar propulsion and braking). Step length asymmetry was compared between groups because it is a clinically relevant measure robustly adapted on split-belt treadmills. Unexpectedly, the group with larger propulsion demands (i.e., the incline group) changed their gait the most during adaptation, reached their final adapted state more quickly, and had larger after-effects when the split-belt perturbation was removed. We also found that subjects who experienced larger disruptions of propulsion forces in early adaptation exhibited greater after-effects, which further highlights the catalytic role of propulsion forces on locomotor adaptation. The relevance of mechanical demands on shaping our movements was also indicated by the steady state split-belt behavior, during which each group recovered their baseline leg orientation to meet leg-specific force demands at the expense of step length symmetry. Notably, the flat group was nearly symmetric, whereas the incline and decline group overshot and undershot step length symmetry, respectively. Taken together, our results indicate that forces propelling the body facilitate gait changes during and after split-belt walking. Therefore, the particular propulsion demands to walk on a split-belt treadmill might explain the gait symmetry improvements in hemiparetic gait following split-belt training. Frontiers Media S.A. 2019-02-08 /pmc/articles/PMC6376174/ /pubmed/30800072 http://dx.doi.org/10.3389/fphys.2019.00060 Text en Copyright © 2019 Sombric, Calvert and Torres-Oviedo. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
spellingShingle Physiology
Sombric, Carly J.
Calvert, Jonathan S.
Torres-Oviedo, Gelsy
Large Propulsion Demands Increase Locomotor Adaptation at the Expense of Step Length Symmetry
title Large Propulsion Demands Increase Locomotor Adaptation at the Expense of Step Length Symmetry
title_full Large Propulsion Demands Increase Locomotor Adaptation at the Expense of Step Length Symmetry
title_fullStr Large Propulsion Demands Increase Locomotor Adaptation at the Expense of Step Length Symmetry
title_full_unstemmed Large Propulsion Demands Increase Locomotor Adaptation at the Expense of Step Length Symmetry
title_short Large Propulsion Demands Increase Locomotor Adaptation at the Expense of Step Length Symmetry
title_sort large propulsion demands increase locomotor adaptation at the expense of step length symmetry
topic Physiology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6376174/
https://www.ncbi.nlm.nih.gov/pubmed/30800072
http://dx.doi.org/10.3389/fphys.2019.00060
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