Falls in our rapidly aging population are a significant public health challenge. Not only are they physically devastating, but they also reduce independence and quality of life and have far-reaching financial consequences. Unfortunately, the rate of injurious falls continues to accelerate. Only by understanding an individual’s risk for falls can we successfully deploy personalized prescriptions of preventative measures to mitigate that risk. There are a multitude of intrinsic and extrinsic factors that can increase an older adult's risk for falls. The purpose of this dissertation was to analyze the effects of ecologically relevant factors, such as walking speed, self-perception, and fatigue, on walking balance.

In our first study, we found that during walking, when presented with a balance challenge, an individual will instinctively reduce their walking speed in order to preserve stability better. Our results point to opportunities for leveraging self-paced treadmill controllers as a more ecologically relevant option in balance research with potential clinical applications in diagnostics and rehabilitation. In the second study, we found no “goldilocks” perturbation paradigm to endorse that would support universal interpretations about locomotor instability. Building the most accurate patient profiles of instability likely requires a series of perturbation paradigms designed to emulate the variety of environmental contexts in which falls may occur. In the third study, we found a disconnect between self-perceived falls risk and responses to walking balance perturbations in an older adult cohort. Rehabilitation techniques to prevent falls while maintaining mobility and independence likely require personalized techniques to include neuromuscular training with approaches for neuropsychological reeducation. In the fourth study, we drew a mechanistic link between gluteus medius muscle fatigue and its compromising effect when called upon to preserve stability in response to an unexpected lateral walking balance disturbance. These findings highlight the importance of targeted preventative strategies to reduce gluteus medius muscle fatigability to preserve older adults' ability to respond to unexpected environmental perturbations where falls are likely. Together, these studies provide information for the personalized deployment of perturbation paradigms to diagnose falls risk and design rehabilitation strategies to prevent falls.