This study will examine the effects of 3 different physical activity goals on arthritis-related outcomes in adults with arthritis. Participants will be randomized to either 45 minutes/week, 90 minutes/week, or 150 minutes/week. Additionally, this study will examine how daily activity can influence arthritis-related outcomes such as pain and fatigue.

This study aims to identify which supplemental intervention components could be added to an online physical activity program that contribute to the greatest increases in physical activity in adults with knee replacement. The 4 supplemental intervention components include phone coaching, progress reports to physicians, tailored modules, and personalized feedback. Using the most effective components, an optimized Energize! Exercise intervention will be developed for testing in a subsequent trial.