Jul 30, 2009, 10:26 GMT
Rome - Canadian Annamay Pierse and Eric Shanteau set new championship records in Thursday's morning session at the world swimming championship at the Foro Italico in Rome.
Shanteau swam a two minute 8.55 seconds in the men's 200m breaststroke to beat Japan's Kosuke Kitajima's previous best mark of 2:09.42.
The American Shanteau led Hungarian Daniel Gyurta and local hero Loris Facci into the semi-finals, which will be held later Thursday.
Pierse topped the women's 200m breaststroke heats with 2:21.68, to beat American Rebecca Soni into second place. Pierse's time beat Australian Leisel Jones' previous best mark of 2:21.72.
In the men's 200m backstroke, Japan's Ryosuke Irie had the fastest time with 1:55.20, beating Americans Aaron Peirsol and Ryan Lochte, who were off the pace 0.68 and 0.77 seconds respectively.
Amanda Weir of the US was the fastest qualifier in the heats of the women's 100m freestyle, beating Australian Lisbeth Tickett by 0.29 seconds.
Ranomi Kromowidjojo from the Netherlands and German world record holder Britta Steffen were the next fastest.
The British women's 200m freestyle relay team of Caitlin McClatchey, Jazmin Carlin, Hannah Miley and Rebecca Adlington swam a championship record in 7:49.04, beating the time of the US by 0.47.
France had the third-fastest time.
Thursday's evening session at the July 17 - August 2 championships will see the finals of the men's 100m freestyle and the 200m individual medley, as well as the women's 50m backstroke, the 200m butterfly and the 4x200m freestyle relay.
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