Gretchen Walsh sets 100m butterfly world record at US trials

INDIANAPOLIS — Gretchen Walsh set a world record in the women’s 100-meter butterfly Saturday night, posting a time of 55.18 seconds in a semifinal heat at the U.S. Olympic swimming trials. Walsh was more than a half-second under world-record pace at the turn and held on to eclipse the mark of 55.48 set by Sweden’s