STepped Exercise Program for Knee Osteoarthritis: The STEP-KOA Study - Knee osteoarthritis (OA) is a leading cause of pain and disability. Exercise is a first-line component of care for knee OA. However, the majority of individuals with knee OA are inactive, and exercise-based physical therapy (PT) is underutilized across health care systems. There are no established processes or pathways for systematically integrating exercise-based therapies into clinical care for knee OA; this is a major contributor to underutilization. We recently developed and tested a STepped Exercise Program for Knee OA (STEP-KOA) as a systematic approach to delivering exercise-based therapies. STEP-KOA begins with a home-based exercise program, supported by evidence-based and behaviorally informed tools (Step 1). After 3 months, patients are evaluated for clinically meaningful improvement in pain and function; patients not meeting criteria for improvement “step up” to telephone-based coaching (Step 2). After an additional 3 months, patients still not meeting criteria for clinically relevant improvement progress to PT visits (Step 3). Patient-centeredness and efficiency are hallmarks of STEP-KOA, as the interventions are based on patient needs and improvement, and the more resource-intensive interventions (particularly PT) are reserved for later stages. In our randomized controlled trial conducted within the Department of Veterans Affairs Healthcare System, STEP-KOA resulted in significant improvements in self-reported pain and function compared with an Arthritis Education control group. We are preparing to conduct a multi-site hybrid type 1 effectiveness-implementation randomized controlled trial (RCT) that will take important steps toward enhancing and implementing STEP-KOA in different health systems. We will add physical activity monitoring, behavioral messaging and tailored exercise prescriptions (that emphasize progression to ensure a sufficient training response) to STEP-KOA. We specifically plan for a 2-site RCT in which individuals with symptomatic knee OA are randomized to STEP-KOA or a usual care / wait list control group., with outcomes collected at baseline, 9 months (end of intervention period) and 15 months (6-month maintenance period). In this planning period, we will: 1) Finalize the scientific details and intervention tools for the multi-site STEP-KOA RCT; this will include enhancing the STEP-KOA patient tools to incorporate the new components, refining tools for STEP-KOA coaches and physical therapists, finalizing training materials and fidelity assessment plans, establishing procedures for telehealth delivery of PT visits, finalizing assessment plans, and establishing the randomization scheme and statistical analysis plan. 2) Finalize the logistical and practical aspects of the multi-site STEP-KOA RCT; this will include identifying referring clinics and PT clinics, addressing regulatory and logistical details, building the study database and developing data management plans, finalizing recruitment and enrollment processes, finalizing the trial budget and preparing the protocol, manual of operating procedures and study timeline. The proposed planning period will ensure our team is prepared to conduct a rigorous and efficient multi-site RCT of STEP-KOA.