Olympic champion Ryoko Tamura has picked up a knee injury and may miss the upcoming World Championships, Japanese national judo coach Kazuo Yoshimura said Sunday.

Tamura damaged ligaments in her right knee during a training session in Fukuoka on Friday as she warmed up for the Aug. 26-29 World Championships in Munich, Germany, where she will be aiming for her fifth straight 48-kilogram title.

The 25-year-old Fukuoka native will leave Japan for Munich next Saturday as scheduled, but Yoshimura indicated she may have to sit out the championships as she currently finds it difficult to walk.