Inner strength and determination help define Olympic champions, but what they wear on the outside can be a top factor in who brings home the gold.

At the Athens 2004 games (search) this August, athletes in the pool and on the track will resemble superheroes, wearing full-body suits that have been designed by scientists who studied sharks and "Spider-Man."

Researchers at Speedo (search), sponsor of the U.S. Swimming team, and Nike, sponsor of the U.S. Track and Field team, have toiled for years to produce high-tech fabrics designed to help athletes shave milliseconds off their times.

U.S. swimmer Jenny Thompson (search), a 10-time Olympic medalist, said she'll don Speedo's newest suit this summer because timing is everything.

"When you get to the elite level and hundredths of seconds matter, that's when the technology comes in," she said.

Olympic athletes are eager to slip into anything that can quicken their pace — particularly in close races, said John Huran, publisher of Sporting Goods Intelligence (search).

"If somebody blows someone away in a race, apparently it didn't matter what they wore," he said. "But if something's incredibly close, if there's a photo finish and one had on slightly better performing fabric, it could've contributed."

Speedo expects 75 percent of Olympic swimmers to wear its new Fastskin FS II suits this summer, said spokesman Stu Isaac, who attributes the suit's popularity to the success seen in 2000.

At the last summer Olympics in Sydney, where the first Fastskin debuted, 62 out of 97 medal-winning swimmers — and 11 out of 14 record-setters — were wearing the suit.

The Fastskin (search) stirred the waters Down Under. Some claimed the suit gave wearers an unfair advantage, and the Australian Olympic Committee questioned its legality in competition. But FINA, the international swimming federation, determined that if the suits were available to all swimmers, they were fair game.

"A lot of traditionalists reacted the same way when the backstroke turn changed, which lowered times immediately," said Isaac. "The nature of sport is to constantly strive to be better, in training and in equipment."

Isaac doesn't foresee any objections arising with the new model, which will be offered to every Olympic swimmer and which Isaac said blows the debut model out of the water.

"It reduces drag better than any other suit out there," he said.

The FS II line offers male-, female- and stroke-specific suits. There are full-body suits or ones that don't cover the arms or legs. And while the original had the same fabric throughout, the new full "Bodyskin" uses different fabrics on various parts of the body to optimize the water flow around the athlete.

The idea of patching different fabrics together started when researchers studied a shark's skin and how the fish moves through water. "The shape and feel of the shark's denticles varies across its body to manage the flow of water," Speedo explains on its Web site.

The Hollywood body-scanning and special effects company CyberFX (search), which was behind "Spider-Man," also had a hand in the suit's development, creating anatomically correct models of the average swimmer and building a base upon which to test the suit.

Thompson plans to wear the full-body version, but said other swimmers' choices are a matter of personal preference.

"It's what you feel comfortable in," she said. "I'm aiming to feel comfortable in what is shown to be the fastest and that is the full-body suit."

Nike is also covering athletes from head to toe in its "Swift" line for track and field. The line, still a work in progress, focuses on sprinting, speed skating, cycling and, most recently, swimming, according to spokesman Nate Tobecksen.

The first Swift Suit made its debut in Sydney, memorably worn by track star Cathy Freeman when she won the 400-meter Olympic gold. Resembling a wet suit, the skin-tight ensemble helps keep every hair down and the body streamlined, allowing runners to zip around the track with less wind resistance.

Huran, who recently visited the Nike lab, said the sportswear has "gotten to the point where they've got so much stretch in them it's actually better than running naked."

Nike's swim accessories include the Strapless Goggle and a swim cap with a silicone outer shell and a rigid insert to reduce drag by preventing cap wrinkling.

While uber-athletes will wear the latest gear, these items won't be seen on weekend warriors. Much like the couture world of fashion, it's all about brand recognition, said Huran.

"If you look at just the commercial application of that you would think the companies were crazy. There's obviously no commercial market for these things," he said. "But from a brand point of view the Olympics are watched by the whole world.

"If you're Speedo, no one really watches your sport except once every four years. They look at it as a great opportunity to make a brand statement: 'We're synonymous with elite swimming.'"

Regardless of high-tech athletic wear, it's not the suit that will be on a box of Wheaties.

"The most important thing is to work with the basics," said Thompson. "The suit is not going to make you achieve your goals, you have to put in the hard work. The bottom line is the training and the person and their mental attitude."