Liu Xiang was the national poster boy for China at the 2008 Beijing Olympics, when China displaced the U.S. as the world’s No. 1 gold-medal harvester. The only problem for the 2004 Olympic hurdles champ: he didn’t actually compete in Beijing. Nursing an Achilles injury for months, Liu pushed through pain to no avail. As the 110-m-hurdles event began in Beijing, he blinked back tears and walked off the track, leaving a nation dazed. Now the 29-year-old veteran is back, after long spells of injury, and in blazing form. In London, without home-turf pressure, Liu may finally win a second gold medal and vanquish his Olympic demons.