Athens Olympics champion Ai Shibata will retire from competition, swimming sources said Monday.

The 26-year-old Shibata, winner of the gold medal in the women's 800-meter freestyle in Athens, is scheduled to explain her decision to call it quits at a press conference on Thursday.

Shibata, who sources said will continue to work as an employee of sportswear maker Descente Ltd., grabbed the spotlight out of relative obscurity after becoming the first Japanese woman to win an Olympic freestyle event in 2004.

Shibata won the bronze medal in the women's 400-meter freestyle at the 2007 world championships but she has struggled with lower back pain since competing in Athens.