Peaty sets world mark in heats on 1st day in Olympic pool (Yahoo Sports)

Swimming got off to a fast start in preliminaries at the Olympic pool on Saturday, with a world record in the men’s 100-meter breaststroke, the second-fastest performance ever in the women’s 400 individual medley and a defending champion knocked out. Katinka Hosszu of Hungary just missed setting a world record in the 400 IM. Katie Ledecky opened her Olympic program by swimming the anchor leg of the 4×100 freestyle relay.