Walsh won in 54.33 seconds at the Fort Lauderdale Open in Florida, where she set her previous world record of 54.60s. American swimmer Gretchen Walsh has stormed to 54.33 seconds in the women’s 100-metre butterfly to lower her own world record for the fourth time at the Fort Lauderdale Open in Florida, the United States. Walsh on Saturday sliced 27-hundredths of a second off the previous world record of 54.60 she set in the same pool at a Pro Swim event last May. She broke the record twice in one day at last year’s meeting and has now broken the record four times.…