Rome (Reuters) - The high-tech swimsuit experiment pool is adapting to the anticipated record-breaking flow at the World Championships this Sunday, with Federica Pellegrini among those setting new marks that could last for years. Despite most versions only being approved last month, polyurethane suits are set to be banned from 2010 as the governing body FINA plans a return to an era of fabric suits and male trunks on the first day. The Rome Worlds will enter swimming folklore, but for many, it will be for all the wrong reasons. Six world records have been broken, two in semifinals, where 15-year-old Sarah Sjostrom and American Ariana Kukors were truly surprised by their successes in the 100m butterfly and 200m individual medley respectively. Dara Torres, whose U.S. women's 4x100m relay team finished fourth behind the Netherlands' gold medal-winning world-record breakers, said the sport is in turmoil. "It will be great when they go back (to the old rules) and find out who the real swimmers are. A lot of the athletes on the backend have been saying this is crazy, that this is the last time this is going to happen," www.stivaleitalia.com, 42-year-old Torres told reporters. "I don't know if they intend to keep the records or put an asterisk next to them. But even if it were me out there breaking a world record, I don't think I'd be jumping for joy." Germany's Britta Steffen also broke her own world record in the preliminary race, cutting through the water like a speedboat in a time of 52.22 seconds. The record books have been battered, and Italian Federica Pellegrini was happy to oblige, despite having a mild fever. She vertiginously won the gold in the women's 400 freestyle, breaking the four-minute barrier to shatter her own world record and leaving Olympic champion Rebecca Adlington trailing in her wake. She covered the outdoor pool in 3 minutes 59.15 seconds, with a 4:00.41 swim recorded last month. "I had a slight fever before the race so I decided I would just stick to my iPod and relax," she said. Britain's Joanne Jackson is second and compatriot Adlington third, wearing the Speedo LZR Racer, which was the first of the new suits but has now been usurped by the likes of Jaked. Michael Phelps, who won a record eight gold medals at last year's Beijing Olympics, also has a contract with Speedo and he was only third in the preliminary heats of the men's 4x100 relay won by his American team. Ian Thorpe's 2002 world best in the men's 400 freestyle final was thought to be almost sacred, but Germany's Paul Biedermann swam 40 UGG Stripes Classic Tall, 07 3 minutes to beat the mark by one hundredth of a second and take gold. South Korea's Olympic champion Park Tae-Hwan missed the final after finishing only 12th overall in the host nation's heats. Championship records fell in the morning warm-ups under the hot Roman sun, even though the temperature cooled for the evening session, shows continued to soar. Spain's Rafael Munoz qualified first for Monday's 50m butterfly final in a championship record of 22.68 seconds, but defending champion Roland Schoeman failed to make the semi-finals. Cancer survivor Eric Shanteau from the United States also set a world's best in his 100m breaststroke semi-final (additional reporting by Paul Virgo and Ian Simpson; editing by Brian Homewood). SportsItalySouth KoreaAbout: Dubai 2013 assigned aquatic championships Dolphins win thrilling jets in few seconds factbox alpine skiing.