Project Summary/Abstract Balance control is far more complex in walking than standing, yet has received less focus to date. As noted in a recent joint NIDCD NIA publication [1], there is a need to better understand the mechanisms of postural control in walking to develop effective rehabilitation strategies for individuals with vestibular disorders. The goal of this project is to identify how the body coordinates different strategies to maintain stability while walking and how that coordination of strategies is affected by vestibular disorders. Existing literature has identified four major stabilization strategies used in human walking: 1) regulating foot placement, 2) generating ankle inversion/eversion torque to alter the lateral trajectory of the body, 3) adjusting push-off force at the ankle, and 4) modifying trunk posture. While these strategies are actively coordinated to retain overall stability, they have not yet all been considered simultaneously. This proposal will investigate the interaction among all four major stabilization strategies through a combination of computational and experimental approaches. A computational model of human locomotion stability will be developed and a sensitivity analysis will be performed to investigate the influence of each stabilization strategy and the impact of vestibular inputs on overall stability (Aim 1). This model will provide the ability to test how individual strategies contribute to overall stability, compensate for one another, and are affected by inaccurate vestibular input. The computational model will be validated and improved through comparison with experimental data collected in healthy adults walking with and without physical constraints that remove individual stabilization strategies (Aim 2). Gait analysis with individuals with unilateral vestibular hypofunction will also be performed to understand how their reliance on specific strategies differs from healthy adults (Aim 3). This proposal will contribute to the incomplete knowledge of balance control in walking. The ultimate goal is to identify strategies to be emphasized in targeted rehabilitation plans to enhance stability in a population at high risk for falls (e.g. those with vestibular disorders). The research described above will be completed as part of the applicant’s doctoral degree in Bioengineering, with a focus on whole-body biomechanics. The applicant will develop knowledge in biomechanics, neurophysiology, controls, and statistical analysis. The applicant will further her technical and professional skills by conducting the proposed research, performing additional hands-on experiments with human motion capture technology, and receiving mentorship from a diverse team of engineers, physicians, and physical therapists.