A contrite Liu Xiang on Monday apologized for his recent criticism of teachers.

The 110-meter hurdles star made headlines for a blog he posted during Teachers' Day on Sept 10.

Liu replied on his micro-blog at sina.com on Monday that: "Public figures should be more careful with their words and deeds. It's better to say something nice."

Liu initially wished all teachers a happy festival on his blog on Sept 10. However, after joining a discussion with fans, he wrote: "It's disgusting for some teachers to ask students to pay for after-school classes. The content has no major difference to regular school."

He also said some of his teachers made him nervous.

"When I was a young boy, I was afraid of the teachers asking me questions or to hand in test papers."

Liu's blog was forwarded by 339 people in 30 hours.

Some netizens have said, as an influential figure, Liu's words could damage his image. Others believe he was just talking with his fans on the Internet as a normal person, and it was unnecessary for the media to bring it up.

The 110m hurdles champion at the 2004 Olympic Games in Athens returned to Shanghai on Sept 9 after finishing a 24-day rehabilitation program in the United States.

After struggling with a foot injury since the 2008 Beijing Olympic Games, Liu is now preparing for the Guangzhou Asian Games.