Olympic marathon gold medalist Naoko Takahashi is retiring.
"I've decided to retire from running races," the former world-record holder told a news conference. "I'm fully satisfied with my career, and I have no regrets."
Takahashi, 36, was the first Japanese woman to win a gold medal in an Olympic athletics event in Sydney in 2000, and set a world record in the Berlin Marathon in 2001.
But she has since been unable to live up to expectations due to a series of injuries. Takahashi failed to qualify for the Japan team at the Athens Olympics in 2004, and also missed the Beijing Olympics after finishing a disappointing 27th in the Nagoya International Women's Marathon in March.
Takahashi, a national idol, had been training in Colorado since May.
"I've reached the limit of my physical and mental strength," she acknowledged Monday.
"It's not like my leg hurts ... There is no specific incident that resulted in my decision," Takahashi said. "I just cannot stand in front of you as a professional runner anymore."
A tearful Takahashi said she was happy to have chosen running as a career.
"I still love running," she said. "I retire as a professional runner, but I want to keep running until I hit 50 or 60."