Locomotor adaptation in a randomly varying dynamic environment: evidence of whole body impedance control

Real world walking environments are constantly changing in both predictable and unpredictable ways. Our previous research suggests that people form a predictive model of their environment that is used to control whole body walking trajectories in response to novel yet consistent environment changes. It is not clear how people control their trajectory when the walking environment is unpredictable. Here we evaluate center of mass (COM) trajectory control during a discrete goal-directed walking task. A cable robot randomly applied left or right directed force fields to the COM during each walking trial. In support of our hypothesis, we found that healthy young adults utilized an impedance control strategy, increasing bilateral whole-body resistance, to control COM trajectories when walking in a randomly varying dynamic environment.