ON THE EVENING of August 9, eight skinny, limber men will line up on the red rubber track inside London’s Olympic Stadium and await the pistol in the 800-meter final. All things being equal, this is what will happen next.

David Rudisha, a six-foot-three Kenyan Masai with dark skin and haughty cheekbones, will start hard. Rudisha, 23, is the world champion, the world-record holder (1:41.01), and the clear favorite for Olympic gold. He knows only one way to race, hitting the front early and destroying his competition with raw speed.