Neglected physical human-robot interaction may explain variable outcomes in gait neurorehabilitation research. - Michiel Plooij; Salil S. Apte; Urs Keller; P. Baines; Bram Sterke; L. Asboth; Grégoire Courtine; Joachim von Zitzewitz; Heike Vallery (Sci. Robotics, 2021)