Olympic champion Naoko Takahashi has sustained a stress fracture in her left rib and could sit out the upcoming Tokyo International Women's Marathon, her management company said Wednesday.

The injury was found in tests she received at a Chiba hospital Tuesday, when she began full-fledged road workouts by running 42 km for the first time since returning from her training base in Colorado on Saturday.

Takahashi was quoted as saying that she hopes to run in the Nov. 17 race in Tokyo, which doubles as a qualifier for next year's World Championships in Paris, despite the injury that has caused her to feel pain since last month.