Whether it's swimmers or sprinters, the svelter the better. Both types of athletes are looking to greatly increase their forward propulsion so they can move as quickly as possible. And certain types of gear help them accomplish this. No ruffled bathing suits or frilly shirts in sight on the track or in the pool.
It's a concept known as hydrodynamics in the case of swimmers. Some factors of hydrodynamics can be improved by technology. There's buoyancy, which is how well an object stays above water. It's ideal for swimmers to find their center of buoyancy (usually around the sternum) in order to reduce drag and establish balance [source: Georgia State University]. And speaking of drag, it's created by friction with the water, and it can really slow swimmers down, fighting against their forward velocity.
Being both buoyant and sleek is the way to go if you want to win a gold. Although banned since 2010, for a time swimmers were allowed to wear swimsuits made of polyurethane. These waterproof swimsuits improved buoyancy by trapping in air bubbles, and their smooth surface helped streamline swimmers to reduce drag. Now swimmers are ordered to use only permeable textile swimsuits.