NEW YORK :American Gretchen Walsh beat her own 100 metres butterfly world record by clocking 55.09 seconds in the preliminary stage at the Tyr Pro Swim Series meet in Fort Lauderdale, Florida on Saturday. She shaved nine hundredths of a second off the previous record she set in June at the U.S. Olympic trials. The achievement came a day after the 22-year-old improved on her American record in the 50m butterfly, when she clocked 24.93 and became the second-fastest woman in the event. Walsh, who helped the United States to gold in the 4x100m medley and 4x100m mixed medley at the Olympics in Paris last year, has emerged as a top contender in the 50m butterfly ahead of its debut at the 2028 Games.