PROJECT SUMMARY/ABSTRACT Built environment approaches make it safer and easier for people across the life span to walk, bicycle, or wheelchair roll, and mitigate barriers to physical activity by making the healthy choice the default choice. The National Cooperative Extension system—which serves every state and territory by bringing land-grant university resources to community members—is poised to implement built environment approaches. However, barriers exist, and relevant implementation strategies are needed to improve adoption rates. There is a dearth of research on implementation strategies (methods or techniques to improve uptake of evidence-based interventions) for community settings, and little is known about effective strategies for integration of built environment approaches. There is a critical need to develop and test evidence-based, community-driven implementation strategies to build practice-level capacity to select, adapt, and implement built environment approaches to address locally identified needs. With this support, Extension can integrate built environment approaches into their work and improve the health of the millions of Americans they serve. The long-term goal of this work is to establish an evidence base of tested implementation strategies to bridge research to practice in Extension and ultimately improve population physical activity levels, thereby reducing cancer risk. Montana has been selected for initial pilot testing due to a strong collaborative history and presence of an integrated research-practice partnership (IRPP). The overall goal of this proposed project is to establish implementation strategies to increase the uptake of built environment approaches in Montana. The rationale that underlies the proposed research is that without community-driven, tailored implementation strategies, community organizations will continue to struggle with implementing built environment approaches. The specific aims are to 1) systematically select and tailor implementation strategies to increase the uptake of built environment approaches in Extension and 2) pilot test the tailored implementation strategies through an iterative, mixed- methods approach. The first aim will employ an IRPP process to engage Extension professionals in selecting and tailoring implementation strategies through a series of collaborative decision-making sessions. The second aim will use the expanded RE-AIM (reach, effectiveness, adoption, implementation, maintenance) framework (integrating the Implementation Outcomes Framework) to assess 1) acceptability, appropriateness, and feasibility of built environment approaches (predictors of adoption), 2) Extension Agents’ adoption of built environment approaches (primary outcome), and 3) acceptability, appropriateness, feasibility, reach, and cost of implementation strategies to guide final revisions. The research proposed in this application is innovative because it incorporates key community partners to tailor and...