Sensorimotor adaptation to altered postural dynamics implemented via closed-loop neuromuscular electrical stimulation

Studying sensorimotor adaptation in whole-body motor tasks such as locomotion and postural control remains challenging because well-controlled mechanical perturbations typically require large, specialized apparatus that constrains natural movement. Here, we introduced a novel perturbation system that alters musculoskeletal dynamics using closed-loop neuromuscular electrical stimulation (NMES) and examined how the human postural control system adapts to these altered dynamics during quiet standing. By applying NMES to the tibialis anterior as a function of anterior-posterior body sway, we imposed artificial postural dynamics. Analyses of postural sway revealed robust, systematic adaptation, with distinct patterns across perturbation types. These findings demonstrate that closed-loop NMES can impose controllable, movement-specific dynamics without mechanical constraints, while also revealing the adaptability of human postural control to externally imposed sway dynamics.