Olympic organizers and swimming's governing body leapt to the defense of China's world record-breaking teenage sensation Ye Shiwen yesterday.

Ye Shiwen of China speeds through heat 5 of the women's 200m Individual Medley on Day 3.

The sport's president said suspicions that she used drugs were "crazy" and motivated by jealousy and the IOC stressed its confidence in the drug-testing program.

"We need to get real here," said International Olympic Committee spokesman Mark Adams. "These are the world's best athletes competing at the very highest level. We've seen all sorts of records broken already all over the place."

Adams said the top five athletes in each event, plus two others, are tested as part of "a very, very strong drug-testing program, and we are very confident if there are cheats we will catch them."

"We can't stop speculation. It is inevitably a sad result of the fact that there are people who dope and who cheat," Adams said. "It's very sad we can't applaud a great performance. Let's give the benefit of the doubt to the athletes."

Ye won the 400-meter individual medley on the opening day of the Olympic swimming competition, and was the favorite to win the 200m event early this morning.

The 16-year-old sliced through the last lap of the 400 in 28.93 seconds - faster than the 29.10 American winner Ryan Lochte posted in the last 50 of the men's race. Ye's time was 4:28.43, more than a second faster than the previous world record set by Australia's Stephanie Rice at the 2008 Beijing Games in a now-banned bodysuit.

John Leonard, head of the American Swimming Coaches Association but not a member of the US Olympic staff, was among those openly questioning Ye's legitimacy. The Guardian newspaper quoted him as saying the last 100 of Ye's race "was reminiscent of some old East German swimmers."

Leonard was quoted as saying: "History in our sport will tell you that every time we see something, and I put quotation marks around this, 'unbelievable,' history shows us that it turns out later on there was doping involved."

Asked about Leonard's comments, FINA President Julio Maglione said people were free to say "stupid things" if they want.

"It's a big mistake," he said of Ye's doubters. "The people that said this is crazy."

Maglione said FINA, swimming's governing body, spends US$1 million to drug-test the top 30 swimmers in the world two or three times a year. "Swimming is absolutely clean," he said.

He said he had absolutely no suspicions about Ye. Her critics are jealous because China is becoming a swimming power.

"It's best for the swimming," Maglione said. "Not only two or three countries. We have now 15 countries that take medals, 20 countries. That is important that many countries in the world take medals."

The anti-doping chief for China's General Administration of Sport, Jiang Zhixue, said Chinese athletes, including swimmers, had passed nearly 100 drug tests since they arrived in London.

FINA's website shows Ye also underwent three out-of-competition drug tests between June last year and February.

Jiang told Xinhua news agency: "We never questioned Michael Phelps when he bagged eight gold medals in Beijing."