BEIJING - China's judo Olympic champion Tong Wen, whose doping offense was cleared by the International Judo Federation (IJF) in March, on Thursday vowed to defend her champion at next year's London Olympic Games.

Tong, 28, was banned for two years by the IJF because of Clenbuterol doping and was required to give back her gold medal from the World Championships of 2009.

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Tong subsequently contested the ban and took her case to the Court of Arbitration for Sport who ruled that a doping violation could not be proved and found in her favor ordering that she be reinstated immediately with all rights.  

Tong returned to international competition in May 2011 winning gold at the Moscow Grand Slam.

"I was shocked after being told that I had tested positive for banned drugs," Tong recalled. "I just could not accept the allegations. And after some time, I wanted to quit the sport and I just wanted to walk away from judo and have a peaceful life."

Tong, who won the world champion for four straight times from 2003 to 2009, began her judo training at the age of only 13 and she found it was very difficult to leave the sport she had devoted so many years to.

"I did not know what to do for the rest of my life if I left," she said.

Finally, with the help of her coach and family, she regained her confidence. "As an Olympic champion and four-time world titlist, I can't let everybody down. I must overcome all these difficulties. I want to come back and win honors for my country."

During the one and a half years when she tried every effort to clear her name, she had trained hard until she was told by the IJF that she was innnocent.

"I have always had my goal," she said. "That was the Olympic champion in London. The glory is the past, I am very thirsty for a second Olympic gold medal."