Maurice Greene (2nd R), the Olympic 100m champion in 2000 and three-time world champion in 1997, 1999 and 2001, runs to pass the baton to Allyson Felix (L), the women’s 200m world champion in friendly competition against schoolchildren in a promotional campaign on February 4, 2008 in Beijing. (STR, AFP/Getty Images)
The women’s 200m world champion Allyson Felix is seen in Beijing on February 4, 2008. Felix arrived in Beijing on February 2 with a group of world and Olympic champions from the US as well as Jamaica’s Veronica Campbell-Brown, the women’s 100m world champion and 200m Olympic champion and Ethiopian distance running sensation Haile Gabrselassie. The athletes are on a pre-Olympic visit of several days to scout out the capital and to visit the 90,000-seater main Olympic stadium, where they are all hoping to snatch glory at the 2008 Games. (FREDERIC J. BROWN, AFP/Getty Images)
Allyson Felix, above, will be limited to 200 meters and won’t go against Sanya Richards in 400 at 2008 Olympics. (ERIC FEFERBERG, AFP/Getty Images)
Allyson Felix raises fist after running the world’s fastest women’s 200 meters in eight years. The 21.81-second performance left her thinking about trying for an Olympic 200-400 double. (MARK RALSTON, AFP/Getty Images)