(Reuters) - Olympic swim king Michael Phelps and reigning Swimmer of the Year Ryan Lochte will wage a series of duels at this week's star-studded U.S. national championships in Irvine, California.
Phelps, who has competed in four meets since coming out of retirement in April, will face the toughest test of his comeback as he is entered in the 100-metre freestyle, 100m butterfly, 100m backstroke and 200m individual medley.
