Bob Kempainen started feeling queasy at the 22nd mile of the 1996 Olympic marathon trials in Charlotte. The culprit, apparently, was a sports energy drink that upset his stomach. Under other circumstances, Kempainen might have slowed or stopped to let the queasiness pass. But he was leading the race and there was much at stake. The winner took home $100,000 and the top three finishers qualified for the 1996 Games in Atlanta.

So Kempainen kept going. At the 24-mile mark, with competitors Mark Coogan and Brantly just 20 yards behind, Kempainen vomited twice. He barely decelerated, however, and actually picked up speed as the race continued.

Kempainen's stomach problems weren't quite over. He threw up four more times before crossing the finish line, pale, drained, exhausted-and in first place. 

His competitors were aware of his sports-drink-induced distress -- but still couldn't catch him. Coogan and Brantly won the other two qualifying slots.

"I thought, 'This guy is the toughest human being on the face of the earth,' " Brantly told reporters then. "I would have started crying and stopped."