Athens Olympic women's 800-meter freestyle gold medalist Ai Shibata announced Thursday she will retire at the end of the season, saying she had reached her limit and would not be able to cope with the rigors of another Olympics in London in 2012.
"My shoulder and back hurt (after Athens). My body was crying out and I often thought I had reached my limit. I can't imagine (competing) at the Olympics four years from now," Shibata told a news conference.
Shibata became the first Japanese to win a women's freestyle gold medal at the Olympics when a late burst saw her come from behind to beat pace-setting Laure Manaudou of France in the Greek capital.
However, the 26-year-old has been hampered by back problems and she failed to advance to the final of either the 400 or 800 freestyle events at the Beijing Games in August.
