?Liu Xiang.

Champion Chinese hurdler Liu Xiang will head for the Indoor Grand Prix in Birmingham next Wednesday to start his Olympic Games build-up after two months of intensive training in Shanghai.

Coach Sun Haiping said Liu made obvious improvements during the winter camp, but that he now needs to be tested on the track.

"Compared with his performance at last year's World Championships in Daegu, Liu feels much better at the start of the run, and the stability of his first two strides has been especially enhanced," Sun said. "The power of his upper limbs has also been considerably strengthened."

The 28-year-old hurdler, who adopted a new technique of approaching the first hurdle with seven steps instead of eight, has also adjusted the spacing of his starting blocks, Sun said.

"Liu has increased the angle of the starting blocks, and he feels good with the change, but our experience tells us it is still not the best position for him.

"We are now in the indoor season and the human body will feel a lot different when the outdoor season comes. The strength and stretch of muscles will also get better when the weather turns warmer. Therefore, we might continue to make some minor adjustments until we find a perfect match."

Liu burst onto the world stage by winning the gold medal and equaling the world record of 12.91 seconds at the 2004 Summer Olympics in Athens in the men's 110m hurdles. However, Liu was forced to withdraw from the first round of the event at the 2008 Beijing Olympics due to a chronic Achilles tendon injury.

The London Olympics is likely to be the third and last for Liu, who finally overcame the injury last year after lengthy rehabilitation. He returned to the World Championships and claimed a silver medal after a controversial final in which Dayron Robles of Cuba was disqualified for bumping him.

After the Birmingham event and a three-day training camp in London, Liu will head to Stockholm for a meet on Feb 23, and then the IAAF World Indoor Championships in Istanbul on March 7. Liu will meet rival Robles at all three meets, but is unlikely to expose his full potential until the Olympics.

"We haven't thought about avoiding clashes with any of the top athletes it is just a coincidence that they have chosen the same meets," Sun said. "We chose the events we need, and Robles chose his.

"The target of the Europe tour is (to get good results at) the indoor worlds, a less important goal is to surpass last year's 7.55 seconds and, of course, we hope to break Liu's best result of 7.42 seconds set in 2008."

Liu's return to form saw him win the Grand Jury Prize at the 2011 CCTV Sports Personality of the Year awards in January, but he fell short in his bid to win the World Comeback of the Year at the 2012 Laureus World Sports Awards this month.

"Prizes, like Laureus, are all secondary to the athletic competitions, and the best award for athletes and coaches is the achievement they make on the track," Sun said.