The purpose of this work is to quantify the dynamics of the human-robot system during exoskeletal-assisted locomotion (EAL). We perform controlled human subject experiments with specialized sensors and instruments to analyze the dynamics of EAL from able-bodied participants and different patient populations. In addition, we develop computational models to complement our experiments and gain additional insights on human-robot interaction during EAL. The long-term goal is to enable robotic exoskeletons to integrate seamlessly with individuals with chronic neurological disorders to restore mobility and quality of life on par with able-bodied peers.