<qa>  What is the leading cause of pain and disability among Veterans?Knee osteoarthritis OA is a leading cause of pain and disability among Veterans, and Department of Veterans Affairs health care users are the most severely affected. There is ample evidence that exercise improves pain, function, and other outcomes among patients with knee OA. However, the vast majority of individuals with knee OA are physically inactive. There is clearly a need to develop and implement programs that efficiently and effectively foster regular physical activity and improve key patient-centered outcomes among Veterans with knee OA. This objective of this study is to evaluate the effectiveness a novel STepped Exercise Program for Knee OsteoArthritis STEP-KOA. 