Jessica Hardy makes her return to the world stage for the first time in four years. In 2008, she tested positive for traces of clenbuterol -- proved to be from a contaminated supplement -- and was given a one-year ban. Hardy is the best U.S. hope for a medal in the splash-and-dash 50 free. She also owns the world's fastest time in the 50 breast -- not an Olympic event -- each of the last three years.
400 free relay