The science behind how your wetsuit floats is rapidly changing.

Perhaps no other piece of tri equipment has evolved at a more ponderous pace than the simple wetsuit. Invented by Quintana Roo founder Dan Empfield in 1987, the triathlon wetsuit changed very little during its first two decades of existence. The prevailing wisdom throughout the 90s and early 2000s was that flotation is good—and you can’t have too much of a good thing—so manufacturers began using five millimeters of neoprene (the maximum thickness allowed in USA Triathlon’s and the International Triathlon Union’s rules) all over their suits. This helped athletes ride extremely high on the water, but wetsuit technology was brand new and they moved with the grace of the Stay Puft Marshmallow Man from “Ghostbusters.”

“Every triathlete—no matter what level of swimmer—is faster with more flotation,” says Mark Stephens, Roka’s
vice president of product development. “The trick is to do it without hindering technique, and that’s very tricky.”

Paneling, which means using different thicknesses and types of neoprene in various parts of the suit, is where manufacturers have made significant breakthroughs over the past five years. It’s all about creating that “downhill” swimming effect that your Masters coach is always talking about.

“Think of your center of gravity as the fulcrum on a see-saw. The goal is to balance the front end with the back,” says Tim Loeffler, head swim coach at the University of Illinois-Chicago. “Especially because of the air in our lungs, most of our weight in the water is in our lower half and we’re not naturally balanced in the water. In order to achieve balance on a see-saw, you’d move a lighter weight as close to the end as possible and the heavier weight closer to the fulcrum. As it relates to our body in water, we use our arms to create length and pressure on the water—like moving a little weight further from the fulcrum. The pressure creates lift in the hips and lower body, keeping the legs from dragging. This allows swimmers to use their legs for propulsion instead of just trying to stay afloat.”

Almost every manufacturer uses four or five millimeters of neoprene throughout the legs because you can’t really have too much flotation in the lower body. Wrapping your legs in half a centimeter of rubber will hinder your kick a bit, but it’s a small price to pay for improved body position and fresher legs for the rest of the race.

“A maximum of 11 percent of your propulsion is going to come from your legs if you’re an amazing kicker,” says Huub Design founder Dean Jackson, who has been working in the wetsuit world for decades. “That 11 percent might make a huge difference when you’re sprinting in a pool, but there’s so much more value in saving your legs in a triathlon.”

Beyond deciding where to put different thicknesses of rubber to keep your legs afloat, wetsuit designers have to decide what kind of rubber to use with each panel. Yamamoto is without question the world’s premier neoprene manufacturer, but more and more wetsuit designers are finding uses for rubber from the Japanese company’s rivals. The different types of rubber (Yamamoto #38, #39, and #40 are widely used) don’t float differently, but they’re vastly different when it comes to their stretch properties. You’ll see a lot of wetsuits with thin panels of the super-gummy Yamamoto #40 in the shoulders for maximum flexibility and maybe a thicker panel of the less-malleable #38 to support the lower back.

Yamamoto also produces something called Aerodome rubber, which has thousands of tiny holes in each sheet of neoprene to reduce the overall weight of the suit. Numerous tests have shown this rubber doesn’t increase buoyancy. If anything, the suit just feels lighter on dry land.

“Even Yamamoto doesn’t claim that it’s more buoyant,” Jackson says. “The triathlon public has been sold a lot of things about neoprene that just aren’t true.”

wetsuit technology
Early QR wetsuits on triathletes Spencer Smith and Julianne White. Photo: Dan Empfield

Wetsuit Technology: Men Vs. Women

The hips don’t lie—so goes a Shakira riff—but in the case of women, they do float. That doesn’t mean that women need less flotation around the hips, but it does mean that “see-saw” is different for women and needs to be accounted for. Shoulder width and torso length also matter—something finally on manufacturers’ radars.

“You can’t make a good unisex wetsuit. Men and women have very different body shapes and that’s why body mapping becomes so important in deciding how to panel a wetsuit,” Stephens says. “There’s a different center of gravity, and different shapes to the shoulders and hips that have to be accounted for.”

The bottom line is that if a wetsuit is advertised as unisex, then it’s not the right one for you.