DES MOINES — Shawn Johnson says she's going to make another run at the Olympics.

The gold medal gymnast surprised a group of elementary school students in her hometown of Des Moines on Tuesday by announcing she plans to train for the London Games in 2012. Johnson took time off from gymnastics after winning four medals in Beijing, but said repeatedly that she hadn't ruled out coming back.

While the timing of Johnson's announcement may have come as a surprise, the news itself wasn't. She's been stopping in the gym more and more often, and coach Liang Chow says she was there for three hours Monday.

Johnson is still working on a timetable for her comeback. She had surgery to repair a torn ACL in her left knee, and won't finish physical therapy for a month.