Background: Despite the demonstrated efficacy, the frequency of physical activity (PA) promotion among outpatients United States (US) physical therapists, as well as critical factors that influence this behavior, have not been explored. The purpose of this dissertation was to identify current PA promotion practices and critical factors that influence this practice among outpatient US physical therapists. Methods: A mixed-methods explanatory sequential design was used. A cross-sectional survey was developed and sent to a nationwide physical therapist sample to determine PA promotion practices and establish factors that influence PA promotion practices. In addition, a subset of participants was invited to explore the topic further through qualitative semi-structured interviews with the researcher to understand the first-person experiences of PA promotion by clinicians phenomenologically. Data were synthesized, and implementation insights were developed. Results: 522 individuals participated, and 393 survey respondents were included in the analyses. Most participants irregularly promoted PA, and few reported always screening for patients’ PA levels. The strongest predictor of regularly promoting PA was screening for baseline PA. Twenty-six physical therapists completed semi-structured interviews. Five domains, including knowledge, skills, beliefs about capabilities, environmental context, and behavioral regulation, were identified as behavior change targets for futre interventions to improve outpatient US physical therapists’ PA promotion behaviors. Discussion: Despite guidance from national and international governing bodies, US outpatient physical therapists do not regularly promote PA to patients and perceive lack of skills, lack of confidence, and lack of time as key barriers. Future interventions should target these skills and include baseline PA screening into clinical pathways to improve outpatient US physical therapists’ PA promotion behaviors.
