Pint-sized Olympic gold medalist Dominique Moceanu has back-flipped out of the upcoming U.S. Gymnastics Championships. Moceanu will have arthroscopic surgery on her right knee next month in Houston, preventing her from competing in the Aug. 25-28 meet in Sacramento, Calif. “I’m very disappointed to not be competing at the championships this year,” Moceanu said Monday. “This has been a goal for me, and the decision to withdraw has been difficult to make.” She’s still planning on making the 2000 Olympics in Australia.