Neuromotor Dynamics of Human Locomotion in Challenging Settings

Alessandro Santuz; Leon Brüll; Antonis Ekizos; Arno Schroll; Nils Eckardt; Armin Kibele; Michael Schwenk; Adamantios Arampatzis

doi:10.1016/j.isci.2019.100796

Neuromotor Dynamics of Human Locomotion in Challenging Settings

iScience. 2020 Jan 24;23(1):100796. doi: 10.1016/j.isci.2019.100796. Epub 2019 Dec 24.

Authors

Alessandro Santuz¹, Leon Brüll², Antonis Ekizos³, Arno Schroll³, Nils Eckardt⁴, Armin Kibele⁵, Michael Schwenk⁶, Adamantios Arampatzis³

Affiliations

¹ Department of Training and Movement Sciences, Humboldt-Universität zu Berlin, 10115 Berlin, Germany; Berlin School of Movement Science, Humboldt-Universität zu Berlin, 10115 Berlin, Germany; Atlantic Mobility Action Project, Brain Repair Centre, Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada. Electronic address: alessandro.santuz@hu-berlin.de.
² Department of Training and Movement Sciences, Humboldt-Universität zu Berlin, 10115 Berlin, Germany; Berlin School of Movement Science, Humboldt-Universität zu Berlin, 10115 Berlin, Germany; Network Aging Research, Heidelberg University, 69117 Heidelberg, Germany.
³ Department of Training and Movement Sciences, Humboldt-Universität zu Berlin, 10115 Berlin, Germany; Berlin School of Movement Science, Humboldt-Universität zu Berlin, 10115 Berlin, Germany.
⁴ Department of Training and Movement Science, Institute for Sport and Sports Science, University of Kassel, 34125 Kassel, Germany; Department of Sport and Movement Science, Institute of Sport Science, Carl von Ossietzky University of Oldenburg, 26129 Oldenburg, Germany.
⁵ Department of Training and Movement Science, Institute for Sport and Sports Science, University of Kassel, 34125 Kassel, Germany.
⁶ Network Aging Research, Heidelberg University, 69117 Heidelberg, Germany; Institute of Sports and Sports Sciences, Heidelberg University, 69117 Heidelberg, Germany.

Abstract

Is the control of movement less stable when we walk or run in challenging settings? Intuitively, one might answer that it is, given that challenging locomotion externally (e.g., rough terrain) or internally (e.g., age-related impairments) makes our movements more unstable. Here, we investigated how young and old humans synergistically activate muscles during locomotion when different perturbation levels are introduced. Of these control signals, called muscle synergies, we analyzed the local stability and the complexity (or irregularity) over time. Surprisingly, we found that perturbations force the central nervous system to produce muscle activation patterns that are less unstable and less complex. These outcomes show that robust locomotion control in challenging settings is achieved by producing less complex control signals that are more stable over time, whereas easier tasks allow for more unstable and irregular control.

Keywords: Behavioral Neuroscience; Biological Sciences; Neuroscience.