Why were high-tech swimsuits banned from racing?

High-tech swimsuits were banned because they were doing part of the swimming. Suits like Speedo's LZR Racer, made from elastane-nylon and polyurethane, squeezed the body into a sleeker shape and trapped air, making swimmers more buoyant. Swimming's governing body, FINA, decided that races should be won by athletes, not fabrics, and from 1 January 2010 such suits were no longer allowed.

The numbers explain the panic. Designed with help from NASA's wind tunnels, the LZR Racer cut skin friction drag by 24% compared with Speedo's previous suit, and early studies suggested it shaved 1.9 to 2.2 percent off race times. Within a week of its launch in 2008, swimmers wearing it had set several world records. At the Beijing Olympics that summer, 94% of swimming races and 98% of medals were won in it, along with 23 of the 25 world records.

Things then got out of hand. Because extra layers meant extra compression and buoyancy, many swimmers started wearing two or more suits at once, and critics began talking about technological doping. At one European championship in December 2008, 17 world records fell.

In July 2009, FINA reversed course and voted almost unanimously to ban full-body suits. Men's suits may now only cover waist to knee, women's shoulder to knee, and the fabric must be a woven textile. As FINA put it, swimming is a sport essentially based on the physical performance of the athlete.