摘要：SummaryIs 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, calledmuscle 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.Graphical AbstractDisplay OmittedHighlights•We examined the dynamics of motor control of locomotion in challenging settings•We extracted muscle synergies (motor modules and primitives) from electromyography•The dynamics of the time-dependent motor primitives were modified by perturbations•Primitives were wider, less unstable, and complex in the presence of perturbationsBehavioral Neuroscience; Biological Sciences; Neuroscience
