Chinese left-hander Bao Chunlai, 28, has announced his retirement from internationals, the Badminton World Federation said yesterday.

The world badminton governing body said on its website that it had received his official retirement notice on Tuesday.

"The lanky left-hander from China has announced his retirement from the international badminton scene at 28 years of age," it said. "Known for his graceful court coverage, Bao cited recurring knee injuries as the reason for his retirement."

Bao confirmed the retirement, saying that the injuries had affected him for a long time - almost several years - and that he had no alternative but to take the decision.

The 28-year-old said that he had put in the retirement papers to the Chinese team before last week's China Badminton Masters and the Chinese team had ratified it.

"I sent my retirement application to BWF a few days ago, maybe they just received it, and then they announced it on their website today," said Bao.

Bao suffered a downturn in form in recent years as the injuries started to take their toll. He missed the 2011 world championships in August but China made a clean-sweep of all five gold medals.

China's head coach Li Yongbo said after the worlds that the Chinese line-up for the London Olympic Games will be made from shuttlers who competed at the worlds, meaning Bao could not make it to the London Olympic Games next year.

"I'm still training with the national team," said Bao, while his teammates are in Tokyo for the Japan Superseries.

Asked if he would represent his home town Hunan Province at the National Games in 2013, Bao said that depended on the negotiations with the Hunan team.

Bao has been a valuable member of China's winning Thomas Cup teams of 2004, 2006 and 2008.

He has won medals in three of the four world championships that he competed in, earning a bronze medal in the 2003 and 2007 editions, and a silver at the 2006 Championships in Madrid.

However, his performances at the Olympic Games have been somewhat disappointing. He was beaten in the round of 16 at the 2004 Athens Olympics and in the quarterfinals of the Beijing Olympics.