Drug use may be the most prominent controversy surrounding this summer's Olympic Games in Athens. But the second burning question concerns an entirely legal approach to getting the winning edge: namely, whether or not form-fitting fast-suits made from high-tech fabrics will decide which athletes bring home a medal. These new garments will be most visible in high profile events such as swimming, but rowers and cyclists are sporting them as well. Although to the casual observer the suits might bring to mind costumes for the next Spiderman movie, they are less about good looks and more about their ability to reduce drag and thereby increase speed. In events in which the difference between gold and bronze is measured in tenths of a second, the fast suit an athlete wears may be the difference between winning a medal or not.

Manufacturers have devoted considerable energy to developing various approaches to reducing drag. Nowhere is this competition more intense than in swimming. These days, anyone who shows up at the pool in a pair of tiny trunks is a loser. Fast suits are de rigueur. Speedo, Tyr and Nike all produce them but the big battle will be between the two market leaders, Speedo and Tyr, because both companies have adopted different approaches to moving through water quickly.

In the showdown of the suits, bettors might put their money on Speedo because it has the most experience in producing fast suits and because U.S. swimmer Michael Phelps, heavily favored to bring home a sack of medals, will be wearing one. The Speedo Fastskin FSII suit Phelps is using in Athens is a substantial improvement over Speedo's first-generation suit used at the Games in Sydney, Australia, four years ago. The original Fastskin was too restrictive, says Lenny Krayzelburg, another U.S. swimmer who will be sporting the upgraded Speedo suit. I can tell the difference, Phelps agrees.

The Fastskin FSII draws on sharks for inspiration and computers for execution. Suit developers noted that although the shark is very streamlined, the shape and texture of its skin varies over its body, corresponding to varying flow conditions. Rough dermal denticles, for example, are found at the nose of a shark while smoother ones are located farther back, reflecting differences in flow at different points on the body.

To study how flow characteristics change as human swimmers move through water, Speedo adapted computational fluid dynamics (CFD) software developed for Formula One race cars. The CFD software was used to create a virtual flume. Next, virtual swimmers were added using CyberFX virtual mannequins--software also used in the making of movies such as Spiderman and The Matrix. The researchers also conducted tests using real mannequins and athletes in a real flume.

The computer modeling showed that friction drag constitutes up to 29 percent of a swimmer's total drag when underwater--much more than the 10 percent previously thought. To combat friction drag, Speedo used different fabrics arranged to mimic shark skin, altering the pattern according to the stroke used. The company also developed different suits for men and women. One fabric, the Fastskin, works like spandex to compress the body and limit muscle oscillation. Fastskin is designed to reduce friction drag by creating ridges and valleys similar to those on a shark's skin--the water skims over the ridges and skips the drag-inducing valleys in between them. At points where bodies curve, another spandexlike material called Flexskin--joined to the other fabric by low-profile seams--enables greater mobility. Speedo suits also feature titanium-silicon scales on the inner forearm that grip the water better on down strokes. Lastly, rubber bumps across the chest help reduce another type of resistance called pressure drag. The overall effect, Speedo asserts, is a 4 percent reduction in passive drag for men and a 3 percent reduction for women.

But Speedo has it all wrong, according to swimsuit maker Tyr. To go faster in water, you need to increase friction drag, not reduce it, argues David Pendergast, one of the inventors of Tyr's Aqua Shift suit and a professor at the University of Buffalo's Center for Research and Education in Special Environments (CRESE), an institution that counts the U.S. Navy SEALS and NASA among its clients. After studying swimmers in a special donut-shaped pool--a lane-wide loop that enabled continuous swimming--Pendergast found that boosting friction drag lessens two more detrimental types of drag: pressure drag, caused by the shape of the body, and wave drag, the wake created by the swimmer. Friction drag generally occurs at slower speeds, whereas pressure drag and wave drag are encountered as the swimmer moves faster.

To increase the amount of friction drag, the Aqua Shift suit uses three raised rings of equal height, called trip wires, placed where the circumference of the body is greatest--one around the calves, another around the buttocks, and the third around the chest. The overall effect is to keep water closer to the body, thereby minimizing water resistance. The idea isn't new. Prior to the 1994 Winter Olympics, downhill-ski suit maker Spyder developed a suit with raised piping that increased friction drag. The Spyder suit was banned from that Olympics because it was said to offer its wearer an unfair advantage, and the suit was available only to U.S. skiers. The new fast suits, however, are available to all swimmers. Tyr claims its Aqua Shift suit will reduce drag by 10 percent, an achievement that would blow Speedo out of the water. If Michael Phelps' multiple medal hunt is frustrated, it could be by a swimmer wearing a Tyr Aqua Shift suit. On the other hand, if all three spots on the winners' stand go to Speedo wearers, then the donut-shaped pool where Tyr's Aqua Shift suit was borne will become symbolic of its failed effort.

Meanwhile, Nike was still working on its Swift Suit design in late July, but it, too, is concentrating on reducing friction drag. Nike may feel more comfortable out of the water though, if only because of its history with a basketball star named Michael and sneakers called Air Jordans. Nike's Swift Suit is an extension of the skintight track and field suit that debuted at the Sydney Olympics. Variations have been developed for speed skating and cycling. Lance Armstrong, the king of the Tour de France cycling race, wears a Nike-made four-ounce jersey that features a lightweight mesh on the back and dimpled material on the shoulders to cut down on drag.

Canada's rowing team will make the most novel use of fast suits at this Olympics. The athletes will wear red and white hooded, sleeveless unisuits, in which all of the seams have been pushed to the front and the fabric itself draws sweat away from the skin so it can quickly evaporate. Nike says the hood alone will reduce drag by 3 percent, which translates to roughly eight feet in a 2,000-meter race. The Canadians will be the only rowers in the Olympics wearing hooded fast suits. (Nike generally prefers sleeveless suits because it believes they offer more freedom for arm movement.)

In the end, fast suits might very well turn their wearers into superheroes of sorts. By the way, if you aspire to Olympic swimmer chic, expect to pay about $400 for the garb. Of course, you can still just shave your body hair like they did in the old days. You just won't look as cool.