Track and field championships

* Friday’s (other) big event: The 400 meters, in which Jeremy Wariner led a U.S. sweep with a scintillating time of 43.45 seconds. It was a personal best for Wariner, the reigning Olympic champion and third-fastest man ever.

* Today’s big events: The men’s and women’s sprint relay finals serve as the centerpiece, with battles expected between Jamaica and the United States in both events. If Uncle Sam’s guys win, Tyson Gay will join Maurice Greene as the only men to have won world golds in the 100, 200 and 400-meter relay. Gay will probably have to hold off Jamaican world-record holder Asafa Powell to do it. Allyson Felix is to run her first championship sprint relay leg for the U.S.

* Quote of the day: “I’m pretty much an average, everyday kind of girl” - Allyson Felix, winner of two world titles and an Olympic silver medal in the 200.

-- Philip Hersh