TY - JOUR TI - Step-to-step variations in human running reveal how humans run without falling AU - Seethapathi, Nidhi AU - Srinivasan, Manoj A2 - Lentink, David A2 - King, Andrew J A2 - Biewener, Andrew A2 - Sawicki, Greg VL - 8 PY - 2019 DA - 2019/03/19 SP - e38371 C1 - eLife 2019;8:e38371 DO - 10.7554/eLife.38371 UR - https://doi.org/10.7554/eLife.38371 AB - Humans can run without falling down, usually despite uneven terrain or occasional pushes. Even without such external perturbations, intrinsic sources like sensorimotor noise perturb the running motion incessantly, making each step variable. Here, using simple and generalizable models, we show that even such small step-to-step variability contains considerable information about strategies used to run stably. Deviations in the center of mass motion predict the corrective strategies during the next stance, well in advance of foot touchdown. Horizontal motion is stabilized by total leg impulse modulations, whereas the vertical motion is stabilized by differentially modulating the impulse within stance. We implement these human-derived control strategies on a simple computational biped, showing that it runs stably for hundreds of steps despite incessant noise-like perturbations or larger discrete perturbations. This running controller derived from natural variability echoes behaviors observed in previous animal and robot studies. KW - human running KW - locomotion KW - motor control KW - stability KW - neuromechanics KW - bio-inspired control JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -