COLUMBIA, Missouri (AFP) - Natalie Coughlin broke the women's 100m backstroke world record here Sunday, clocking 59.21sec in preliminaries at the Grand Prix of Missouri long course swimming meeting.

Coughlin sliced 23-hundredths of a second off her own world mark of 59.44, set on March 27 of last year in Melbourne, where she added the 2007 world title to the Olympic title she won in Athens.
Coughlin was the first woman to break one minute in the event, first doing so with a time of 59.58 in 2002.
The 25-year-old US veteran said she didn't go into the heats expecting to swim so fast.
“If you could see my face, I was slightly shocked,” said Coughlin, who was more than four-tenths of a second off world record pace after the first 50m. “I was thinking about barbecue and no warm down. It was a strange race. I really didn't expect it.”
Coughlin's record-breaking swim came hours after she settled for second behind Katie Hoff in the final of the 200m freestyle.
Zimbabwe's Kirsty Coventry, who set a world record in the 200m backstroke on Saturday, was second-fastest in the 100m back heats 59.61 and American Hayley McGregory was third-fastest in 1:00.31.
The 100m backstroke final was scheduled for Monday morning as the meeting matches the planned programme at the Beijing Olympics in August, where finals will be held in the morning and heats in the evening.