Liu Xiang celebrates as he crosses the finish line to win the men's 110 hurdles final at the 2004 Olympic Games in this Aug 27, 2004 file photo. [Photo/IC]

China's top track and field star, Liu Xiang, officially announced his retirement on Tuesday through his Weibo account after being sidelined for more than two years in rehabilitation of an ankle surgery.

In lieu of a press conference, the 31-year-old athlete star chose a low-key way to announce his retirement.

"From today on, I will say goodbye to my professional athletics career and officially retire. It's a decision made through thorough consideration. I have no other choice despite reluctance and pain." Liu wrote on his Weibo, a Twitter-like microblogging platform.

"I'm afraid that I have to leave you (hurdles). I'm really "old" and "sick", I can't run with you any more, I can't hurdle you any more. I'm going to "retire" and kick off a new journey. Goodbye, my track, my hurdles!"

In March, Liu told China Daily that he would participate in the International Association of Athletics Federations World Championships in Beijing in August as an event ambassador rather than an athlete, implying that he would retire soon.

"Sooner or later, I have to say goodbye to everybody. I think that I am supposed to retire now as I've tried all the best to come back," Liu was quoted by Shanghai-based Xinmin Evening News as saying on Friday.

Rumors of Liu's retirement have been reported periodically since he fell down at 2012 London Olympic Games 110-meter hurdles' preliminary contest, which was the last match he ever attended.

Due to the long absence from competition to recover from his recurrent Achilles tendon injury, both fans and Chinese media have had slim hopes for Liu's comeback, highlighted by the modest reaction from the public compared with the tremendous media hype on the retirements of basketball star Yao Ming and tennis icon Li Na.

"Most of the public have accepted that Liu won't be able to come back at 31 as strong as he used to be, so his retirement is actually much anticipated. A lot of the focus has been on why he postponed for so long making a decision that should have been made earlier," Adam Zhang, sports marketing expert and founder of Key-Sports marketing agency, told China Daily on Monday.

Though chose to go back to the life of an ordinary person and start afresh, Liu, as China's first male Olympic champion in athletics, will be forever looked as the extraordinary for his milestone wins in the 2004 Olympics and world championships.

In Athens, Liu tied the 12.91 seconds world record to claim the gold medal before he set a new world mark of 12.88 in 2006 IAAF Grand Prix in Lausanne.

"His breakthrough of winning the Olympics and world championships proved that Asian people can be competitive against Western counterparts in men's sprint events at the highest level. That's a huge motivator that should be reckoned with." Zhang said.