Sydney Olympic champion Naoko Takahashi, who is trying to make a comeback after a fractured right ankle, is unlikely to compete at the world championships in Helsinki this August after deciding to extend a scheduled one-month training camp.

Longtime coach Yoshio Koide said Wednesday that Takahashi will continue training on Tokunoshima Island in Kagoshima Prefecture until the end of March rather than concluding the camp next Friday as originally planned.

This means she will miss the Nagoya International Women's Marathon, which doubles as the final qualifier for the world championships, on March 13.

Elsewhere, in Osaka, Brazilian runner Vanderlei de Lima, who took bronze in the Athens Olympic men's marathon after being attacked by a crazed spectator while leading the race, is among nine foreign invited guests participating in the Lake Biwa Mainichi Marathon on March 6, organizers said Tuesday.