PROJECT SUMMARY/ABSTRACT Locomotor and balance dysfunction, which have a pernicious effect on independence and quality of life, are caused by of a broad range of neural and musculoskeletal disorders as well as normal aging. While existing treatment methods can counter some dysfunctions, some pathologies are persistent, such as weight-bearing asymmetry and reduced adaptability. These pathologies are strongly defined by the dynamics of the physical interaction between the feet and the ground. Thus, there is a critical need for novel tools to study, and ultimately assist or re-train, how humans manage their physical interaction with the ground. The objective of the proposed research is to enable new research into motor learning and human adaptation and provide an accessible, effective vehicle for gait and balance rehabilitation through the development of portable robotic footwear which can modify stiffness at the foot-ground interface in real-time. The significant contributions of this work include: 1) creating the technical capability to change foot-ground interaction dynamics in both real-world and laboratory settings, 2) enabling new methods of studying, assisting, and re-training human gait and balace, 3) significantly advancing scientific knowledge by quantifying human adaptation to long-term changes in foot-ground interaction dynamics, an understudied area of research, and 4) improving clinical practice by providing a portable tool to make new treatments, preventative interventions, and early diagnoses widely accessible. The proposed research is innovative because it will employ a transdisciplinary approach, applying concepts from neuromotor control, biomechanics, and robotics, to develop a novel robotic device for research, assistance, and rehabilitation. This proposal addresses the following specific aims: Aim 1: Design, build and evaluate portable, robotic footwear that can actively modulate foot-ground stiffness and measure the ground reaction forces of each foot independently. We will design, fabricate, and validate robotic footwear with an active mechanism to modulate foot-ground interface stiffness in real-time. The stiffness control system and onboard sensors will be rigorously evaluated for validity and reliability with bench testing along with a pilot study with healthy participants performing whole-body balance and walking tasks while wearing the device. Human testing will also evaluate the perceived safety, comfort, and overall usability of the system. Aim 2: Explore the effect of asymmetrically reducing foot-ground stiffness with the robotic footwear on human motor behavior during standing and walking. An additional pilot study will be conducted with healthy participants to assess how human motor behavior changes in response to active foot-ground stiffness modulation. Results will inform the potential utility of the robotic footwear for basic and clinical research applications and the development of models to understand human neuromotor control of locomotion and balance.

Project Narrative The objective of the proposed project is to enable new research into human neuromotor control, adaptation, and learning by providing an accessible, effective vehicle for the study and rehabilitation of balance and gait through the development of portable robotic footwear, which can modify foot-ground stiffness during locomotion. This research is critically relevant to public health because it is expected to yield new technology and evidence-based research to improve the diagnosis, assistance, and retraining of gait and balance impairments in real-world contexts, addressing persistent shortcomings in current methodologies. As such, this research is relevant to the National Institutes of Health and National Institute of Biomedical Imaging and Bioengineering mission of accelerating development of new biomedical technologies to advance basic research and medical care.