Liu Xiang's road back from injury to the sort of world-beating performances that earned him that status of China's top track and field athlete looks like being a long, hard slog.

The former Olympic and world 110 metres hurdles champion returned to top international competition at last week's world indoor championships, his first outing at that level since the Beijing Olympics.

The Achilles injury that caused him to limp out of his first heat at Beijing's Bird's Nest stadium in August 2008 continued to dog him in Qatar, however, and he could only finish seventh in the 60 metres final on Sunday.

"The injury is still reacting," Liu told the Oriental Sports Daily on his return from Doha.

"I dared not take off. I feel I am full of energy everywhere but in the foot."

Liu remains a sporting icon with a profile rivalled only by basketball's Yao Ming in his home country, as anyone who saw him being hounded even in the toilets by autograph-hunting reporters at the recent meeting of China's parliament will attest.

Liu now hopes to represent Asia in the new Continental Cup, formerly the World Cup, in Croatia in September.

"The World Cup is the only title I have not won in the past," Liu said.

"I really want to win it."