BEIJING -- Chinese athletics head coach Feng Shuyong said on Monday that Liu Xiang exacerbated the tendon injury in his right foot in last Saturday's training.

Defending champ Liu pulled out of the Olympic 110m hurdles first round Monday morning.

Liu Xiang kneels down as he warms up before the start of his 110m hurdles heat of the athletics competition in the National Stadium at the Beijing 2008 Olympic Games August 18, 2008. [Agencies]

"I know that kind of pain was unbearable," said Feng, also deputy chief of the Chinese track and field adminitrative center.

Feng admitted Liu has been under great pressure as a Chinese sports icon.

"But he is a great athlete and very strong mentally," he said.

Feng said Chinese would understand Liu's decision to withdraw from the race.

Liu Xiang's head coach Sun Haiping broke into tears in the press conference while hailing his student as a "fighter".

"He has been keeping fighting and fighting until the last moment," said Sun.

Defending champ Liu pulled out of the Olympic 110m hurdles first round because the five or six-year-old tendon injury in the right foot got worse.

"I know that kind of pain was unbearable," said Feng Shuyong, head coach of the Chinese team.

Great pressure as national icon

Liu Xiang's coach Sun Haiping cries during a new conference following Liu's failure to start his men's 110m hurdles heat in the National Stadium at the Beijing 2008 Olympic Games August 18, 2008. [Agencies]

Feng admitted Liu has been under great pressure as a Chinese sports icon.

"But he is great athlete and very strong mentally," he said.

Feng said, "Liu was very very upset about the result. Liu said he would never give up as long as he can run."

Feng said, "After the Athens Olympics, the only target of Liu was to defend his title. He has worked very hard for achieving this goal."

"His injury was old but controlled very well. That's the reason why Liu performed very well in competitions in the past years."

"He has strong mentality and has never given up in any case."

"In the first half year, Liu was trained systematically under the careful coaching of Sun."

"Liu has recovered 90 percent of his highest form. The injury on his Achilles's tendon deteriorated last Saturday in training. He was still confident of sprinting."

"Liu felt very hurt in the pre-race training. He went to the first round after quick medical treatment."