DOHA, Qatar (AP) — The United States showed off the speed and depth of its squad to win three gold medals on the final day of the world track championships.

U.S. runners won the men's and women's 4x400-meter relays, and U.S. women finished first and second in the 100-meter hurdles. The U.S. finished with 14 gold medals — its best result at a world championships for 12 years — in the last major global competition before next year's Olympics in Tokyo.

Neither of the relays was a close contest, with the U.S. finishing more than a second clear of Jamaica in the men's event and three seconds ahead...