Taekwondist Chen Zhong attends award ceremony for China Taekwondo Ten-year Development in Jin Hua, east China Zhejiang Province while  National Taekwondo Championships there on Monday. [Xinhua]

"I have decided to let it be because it would need a long period to recover after surgery, which would seriously affect my training and preparations for the 2008 Games," the 24-year-old told Xinhua at the National Championships here on Monday.

Chen won women's +67kg in Sydney, where the sports was formally introduced into an Olympic Games, but has been suffering from right knee problems since 2002.

She overcame the injury to retain her title in the 2004 Athens Games before undergoing an operation to remove her seriously damaged meniscus last year.

"Doctors told me it's better also to have the ligament reconstruction surgery now. But the 2008 Olympic Games is a very precious opportunity, maybe the sole in my life, to realize my dream of snatching three successive Olympic titles." she said.

"It's worthwhile to take the risk. And in Athens, I made it with the torn ligament. I did it once, and I think I could do it for a second time."

Chen, who did not compete in the national championships, was working hard on her rehabilitation course, which was designed to strengthen lower limbs muscle.

Her coach Chen Liren, who had guided her to Sydney and Athens glory, said he had to respect her decision.

"The muscle tissue, to some degree, could substitute for the mechanical strength of the knee ligament," he said.