Chinese hurdler Liu Xiang's chances of defending his world indoor title in Doha are almost impossible, one of his country's top coaches has said .
It's Liu's first global meeting since a heartbreaking Achilles injury left him unable to start at the 2008 Beijing Olympics.
Chinese coach Feng Shuyong says Liu felt he should come because he likes the atmosphere of the championships, but he isn't aiming for a medal.
Feng says while there's still a small chance of a podium finish, it would be difficult for the athlete following his slow recovery from achilles surgery.
The U.S. doctor who performed Liu's surgery says test results have shown the tendon was good but more time would be needed for full recovery.