The United States men's freestyle relay team broke their own world record in 4X100 in Beijing on Sunday at three minutes 12.23 seconds, while some elite swimmers banked up energy and didn't show all their cards in the heats.

The French and Australian relay quartets also swam under a previous world record of 3:12.46, but the U.S. team went out strongly to top the heats for Monday morning.

Besides the new world record, four Olympic records were shattered in women's 100-meter backstroke, 100 breaststroke and 400 freestyle, and men's 100 backstroke.

Italian world record holder Federica Pellegrini topped the women's 400 free heats with a new Olympic record of 4:02.19. "The whole event went very fast. I found that I was almost succeeded by others, so I didn't save my power," she said.

In women's 100 breaststroke, Aussie swimmer Leisel Jones comfortably set a new Games record at 1:05.64. "Yesterday I was watching men's breaststroke, and all the women's fly, and it just looked really hard in the heats, and every one was really fast. I expected that today," she said.

The record, won with ease, signalled she would go faster in the semis and the finals. "I wasn't exerting myself at all. I wasn't even puffing at the end. It felt like training," she said.

Zimbabwean golden girl Kirsty Coventry dominated the 100 backstroke heats with 59 seconds. "So many girls are swimming so fast right now. I think tomorrow you're going to see great times and even better times in the finals," she said.

In two men's races, top seeds Michael Phelps and Aaron Peirsol banked up their energy for the semifinals. Phelps placed the fourth in 200 free heats at 1:46.48, about three seconds slower than his world record.

"I'm in the top 16. That's all that matters," he said after the race." I need to bank as much rest as possible and as much sleep as I can and not get run down. This morning was pretty emotional."

Phelps won his first gold with a new world record in 400 individual medley on Sunday morning.

In the men's 100 backstroke, defending champion Peirsol placed third after the heats. "I'm just going to take it one race at a time. I don't go out there to win every heat, I just want to swim my best time," he said.

Teammate Matt Grevers ranked first with a new Olympic record of 53.41 seconds.

Four finals are scheduled on Monday: men's 100 breaststroke, 4X100 free relay, women's 400 freestyle and 100 butterfly.

(Xinhua News Agency August 10, 2008)