RIO DE JANEIRO _ Sweden's Sarah Sjostrom broke her own world record in the 100-meter butterfly Sunday to win gold at the Olympic Aquatics Stadium.
Sjostrom finished in 55.48 seconds, ahead of second-place Penny Olesiak of Canada, and drew a loud cheer from the half-full building.
Dana Vollmer, the event's defending Olympic champion who returned to swimming after giving birth 16 months ago, took bronze.
