Jamaican sprinter Asafa Powell, left, answers questions from journalists as U.S. track and field sprinter Tyson Gay, right, listens during a press conference of Shanghai Golden Grand Prix Saturday Sept. 19, 2009 in Shanghai, China. Many Olympic champions and world record holders of track and field competitions will participate in the one-day competition at Shanghai Stadium Sunday. AP Photo logo AP Photo 2 months ago

Jamaican sprinter Asafa Powell, left, answers questions from journalists as U.S. track and field sprinter Tyson Gay, right, listens during a press conference of Shanghai Golden Grand Prix Saturday Sept. 19, 2009 in Shanghai, China. Many Olympic champions and world record holders of track and field competitions will participate in the one-day competition at Shanghai Stadium Sunday.