It's a swimsuit so revolutionary that one athlete has claimed that it makes you feel like you're "swimming downhill". And, since it was launched in February, 38 world records have been broken by swimmers wearing it. Little wonder, then, that Olympic swimming teams are now falling over themselves to ditch their sponsors in order to get Speedo's LZR Racer swimsuit in the run-up to Beijing.

So what's all the fuss about? Would those records have been broken if a different suit had been worn? The suit took nearly four years to develop and involved enlisting the help of Nasa and a technique called computational fluid dynamics, says Jason Rance, head of Speedo's Aqualab, the company's global research and development facility. He says the swimsuit can reduce drag by up to 24%.

Existing all-over bodysuits, which have been used in competition swimming for 15 years, are all designed to reduce drag. One popular and somewhat counter-intuitive way of doing this is to engineer the surface so that it is rough not smooth. This has the effect of creating a small amount of turbulence in the thin layer of water flowing close to the material's surface. The aim here is to prevent water from passing over it evenly, and so clinging to it - the same principle behind the dimples in golf balls and why the hulls of ships are rough, according to Mike Caine, director of the Sports Technology Institute at Loughborough University.

But the LZR does something different, says Rance. It is made up of two types of material, one woven and coated with water repellant, the other an extremely smooth polyurethane membrane. Both are engineered to create very little friction when water flows over it.

Another feature of the LZR is compression: it is designed to hug the body 70 times tighter than other suits. This has the effect of squashing the body together like a corset to make it more streamlined. "You're not going to want to wear it at the beach," says Rance. But for athletes the benefits appear to outweigh how uncomfortable it might be.

But if the suit really does work, doesn't this amount to an unfair advantage? "It's clearly not cheating because it doesn't break any of the rules," says Caine. It's no worse than one athlete training with a better exercise machine than another, he says. Even so, for the have-not swimmers it may amount to little more than technological doping.