https://orcid.org/0000-0002-0396-5815The overall goal of my research is to help all people to be as physically active and as mobile as they want and need to be for their whole lives. My work has identified the specific challenges that older adults and people with neurologic conditions experience with safe mobility and participation in physical activity (e.g., increased fall risk, low balance confidence and exercise self-efficacy). This work then informs the development of interventions to improve safe independent mobility and participation in daily physical activity. I evaluate these interventions, using multi-stage clinical trials (i.e., pilot studies, single-site clinical trials, and multi-site clinical trials), systematic reviews and meta-analyses, and qualitative methods to explore participant and clinician perspectives. I use implementation science theory to ensure that successful interventions are used in clinical practice.