Aug 2, 2009, 21:26 GMT
Rome - Germany's Queen of the sprints Britta Steffen on Sunday added the 50m freestyle title to her world championship 100m freestyle gold she won earlier in the week.
Other world record times were achieved by Briton Liam Tancock and Russian Yuliya Efimova in the men's 50m backstroke and the women's 50m breaststroke respectively.
Steffen, who already achieved a sprint-sweep at the Olympics in Beijing last year, won in a world record time of 23.73, beating the 23.96 Marleen Veldhuis swam in April.
Sweden's Therese Alshammar won the silver medal in a time of 23.88, while Briton's Cate Campbell and Marleen Veldhuis both took the bronze medal with a time of 23.99.
American 42-year-old Dara Torres, who finished eighth in the final, paid a tribute to Steffen after the race. 'She is an incredible athlete and that is a terrific time. It will stand for years.'
Tunisian Oussama Mellouli repeated his Beijing success in the men's 1,500m, winning in a time of 14:37.28 to beat Ryan Cochrane, who lead for much of the race.
The Canadian finished in a time of 14:41.38. China's Sun Yang won the bronze medal, 9.56 seconds behind Mellouli.
In the women's 400m individual medley Hungarian Katinka Hosszu, who went into the race with bronze medals from the 200m butterfly and 200m IM, added gold in a time of 4:30.31.
Zimbabwean Kirsty Coventry took the silver medal in a time of 4:32.12, while Stephanie Rice won bronze 1.98 seconds behind Hosszu.
Ryan Lochte won the 400m individual medley to add to his 200 IM title and the two gold medals he won in the relays to take his personal gold tally to four, equal with his US team-mate Michael Phelps, who is expected to add to that later Sunday in the 4x100m individual medley relay.
Lochte's compatriot Scott Tyler Clary took second place in a time of 4:07.31, while Hungarian Lazlo Cseh won the bronze in 4:07.37.
Earlier in the final session of the championships, Tancock and Efimova opened the swims in the Foro Italico with two world records.
Tamcock, who already broke the world record to get into the final of the men's 50m backstroke, swam a 20.04 to take the gold medal from Japan's Junya Koga, who was 0.20 seconds slower.
South African Gerhard Zandberg was a surprise bronze medal winner in 24.34 seconds.
Tamcock swam four hundredths of a second faster than the world record he established on Saturday.
In the women's 50m breaststroke, Efimova proved too strong for the field as she won in a time of 30.09 to break Amanda Reason's world record time of 30.23.
American Rebecca Soni was second in a time of 30.11, while Australian Sarah Katsoulis took the bronze medal in a time of 30.16.
The competition ends in the Foro Italico on Sunday evening with the finals of the men's 1,500m freestyle and the 4x100m medley relay, as well as the women's final in the 400m individual medley.
After the finals a short closing ceremony will be held.
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