Men’s competitive swimsuits have evolved radically over the past 15 years.

In the nineties, swimsuit manufacturers began experimenting with new materials and “paper suits” became the standard race swimsuit for men. The suits were single-layer suits that used very little material. They were still in the “brief” style that had been popular for several decades.

In the mid-2000’s, manufacturers began focusing on using more material, in an effort to produce a suit that is more hydrodynamic than human skin. Speedo, for example, developed their Fastskin material by studying shark skin. Manufacturers also strived to compress the swimmers body to help maximize efficiency and minimize muscle fatigue.

It wasn’t long before full-body, high-tech suits appeared in competition. This created controversy and led to FINA, in 2009, placing restrictions on the material and the amount of the swimmer’s body that can be covered. FINA stated that male swimsuits must not extend below the knee or above the waist. This style of suit is called a Jammer.

While they look like compression shorts used in many other sports, swim jammers are normally made from material that repels water. Manufacturers also spend a lot of research and development to develop sitiching patterns that help swimmers hold a more hydrodynamic position.

Popular manufacturers include Speedo, Arena, TYR and BlueSeventy. They make jammers for racing and for training. The jammers used for competition are designed to be used infrequently and are significantly more expensive than jammers used for practice.

There are two major considerations when choosing a competition jammer — the material and the stitching. High-end suits will be made with very specialized materials that have been optimized to repel water. Some of these suits will be stitch-free, meaning the manufacturer has used a bonding process to cut down on the friction that raised seams can cause. Where stitching is used, the manufacturer will try to place the seam in the direction of the water flow, again to minimize drag.

Take your time choosing a Jammer. But when you do, be sure to choose a vendor with good return policy. That way, if you receive the suit and it doesn’t feel comfortable to you, you can exchange it for another.