When swimmers from around the world dive off of blocks into the pool at Paris’ Aquatics Centre beginning on July 27 and into the Seine River on August 8 and 9, they’ll be competing in suits that are a far cry from the last time the City of Lights hosted the Olympics 100 years ago. The men’s and women’s swim teams of today aren’t wearing itchy, heavy woolen briefs or singlets or see-through silk suits, but sport high-tech racing suits.
While the physical forces a swimmer is up against and the fierce competition of international sport remain the same, swimsuit technology has come incredibly far. It even went too far not too long ago, which is understandable for a sport where the difference between gold and silver is often less than the blink of an eye.
May the force be against you–as little as possible
Physics stays the same, no matter what year a swimmer is competing or what they are generally wearing. Water is over 700 times denser and 55 times more viscous than air, so it has a higher resistance to flow and is much more difficult to move through.
“Basically, there are two forces. Thrust is what propels you forward and drag which resists you,” Northwestern University engineer and fluid dynamicist Timothy Wei tells Popular Science. “That’s the battle the swimmer has to carry, and the faster the swimmer goes, the more the drag will be.”
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That drag itself is broken up into three parts. There’s a pressure drag, which is similar to sticking your arm out of a moving car’s window and feeling the force pushing it backwards. Viscous or friction drag is more like a rubbing motion when the water hits the surface of the swimmer’s body. The third form of drag isn’t always present, but is a major factor.
“Wave drag is like when you look at a boat and there’s a wave in front of it. It’s basically water piling up in front of the boat and you have to push that out of the way,” says Wei. “That only happens because there’s a free surface. There’s air on top of the water.”
While a swimmer works on their speed, technique, and endurance to work against this drag, it’s the suit’s job to help give that slight edge when victory comes down to hundredths of a second. It needs to be sleek and streamlined like an airplane fuselage. Anything dangling off too much can slow a body down and could be the difference between a medal and going home without any hardware.
Swimming like a sheep
Early swimsuits or “swimming costumes” were more like romper sweaters and made out of wool. According to the Fashion Institute of Technology, knitted swimsuits tended to become misshapen when wet, absorbing a ton of water. The material would become longer and sag, so there was often some loose material hanging off the body and slowing a swimmer down. The extra waterlogged material was even dangerous, as excess material can pull a body down into the water and increase the risk of drowning.
The first silk suits appeared in 1912, which were more sleek and did not absorb nearly as much water as their woolen counterparts. These suits were see-through and needed to be worn with underwear for modesty and privacy.
By the middle 20th century, nylon helped make suits smoother and tighter, allowing swimmers to move better through the water. Lycra continued that progress up until the turn of the 21st century.
However, sometimes there can be too much technology. Just before the 2008 Olympics in Beijing, Speedo introduced the LZR Racer competition swimsuit. Now banned from competition, the suit was made of a blend of nylon, Lycra, and non-textile polyurethane. That polyurethane is what made a huge difference to swimming speeds. It increased the buoyancy and smoothness of the suit, reducing drag by up to 8 percent.
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“They were legal at the time, so they weren’t doing anything wrong, but with those now illegal suits, they just seemed to sit about an inch higher in the water than people without them,” says Wei. “So, it was using buoyancy to help defeat that wave drag.”
Having that much buoyancy just worked too well. When 43 world records were broken at the 2009 World Championships in Rome, swimming’s body World Aquatics (formerly FINA) banned the use of non-textile materials in competitive swimsuits. The suits were compared to doping on a hanger, and the ban was put in place in an effort to level the playing field (or pool). The governing body also began to enforce stricter restrictions in the permeability, buoyancy, thickness, and design of future competition suits.
Paris 2024
Now, swimsuits must overcome all three types of drag, while adhering to standards set by World Aquatics’ regulations. That is where some materials science comes in. Swimmers sponsored by Speedo will don the LZR Intent 2.0 and LZR Valor 2.0. These suits will have a coating technology that was originally used to protect satellites. TYR athletes will compete in the TYR Venzo, which was developed by analyzing drag from a microscopic perspective.
No matter the brand, just getting into compression suits is an Olympic sport in itself. During the 2024 US Olympic Trials in June, three-time Olympian and NBC Sports commentator Elizabeth Beisel showed just how tough and time consuming it is to squeeze into these tech suits.
“One of our sponsored swimmers, Cate Campbell from Australia said, ‘if you don’t have bloody knuckles after putting on your race suit, you’re wearing a size too big,’” Mark Pinger, a two-time Olympian and general manager of Arena North America, tells Popular Science. “And that’s very extreme, but it’s true. There are women that will tell you that it takes 45 minutes and help from friends to pull it over the shoulders. That speaks to the sort of inherent trade off historically.”
Compression is a major area where the suit can really manipulate the body. It helps reduce the different types of drag, but often comes at a compromise. Compression can reduce the body’s flexibility or tire out the muscles when they are squeezed so hard.
The team at Arena believe that they have found that balance between that compression and allowing more movement. Arena-sponsored swimmers from multiple countries will be wearing the PowerSkin Primo. The men’s jammers cost $450 and both types of women’s suits (open back and close back) are $650, since they have more fabric.
“The suit going to Paris is amazing in that it can provide high compression, but it has a lot of elasticity,” head of product development for Arena Greg Steyger tells Popular Science. “It not only allows the muscles to perform at the peak without restricting them and manages to fit more bodies because of the amount of stretch.”
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Compression suits generally work like giant rubber bands that are stretched to that point right before snapping. To achieve this, they are built with a mixture of compression and taping. The taping are the X’s placed at various positions on the suit that are an aesthetic and functional choice by helping lift the suit up.
The Arena suits are also made with tensoelastic fabric that Steyger says took about four years to develop. It uses the tension within the fabric to create high compression, while stretching it as little as possible. However, every time a swimmer puts on a compression suit, there are pieces of the bands that will break. A swimmer can typically expect to get about 10 races in a suit, depending on how well the suit is maintained.
“Some of these rubber bands that are built into this are actually over stretching and ripping, so they make the suit stretch out,” says Pinger. “With this one, because you have the stretch remaining, you still get that the highest compression that we’ve ever achieved in a suit. You’re not breaking down the fabric. Does it last forever? No, but it lasts significantly longer.”
The yarns are all made with thermo polyurethane (TPU). It’s chlorine resistant, provides this high amount of compression with half the stretch, and is hydrophobic so water will slide off and move away from the swimmer.
“The TPU yarn that we use as a monofilament,” says Steyger. “It’s a single extruded yarn, it’s not many wrapped together, which means that there’s no gaps and therefore we don’t get trapped.”
By comparison, Spandex or Lycra is made up of multiple filaments that allows some of the water to be absorbed rather than pushed away from the body.
Winning the mental game–and hopefully medals
As the games begin, it’s still uncertain if any of these race suits will help bring home the most gold medals. One thing is certain–they are light years ahead of the swimsuits of the past, helping swimmers feel faster and stronger. With that, comes a mental advantage in a sport governed by the tiniest of margins.
“They’re suiting up when they put that race suit on and there’s a whole mental aspect. The suits are hard to get into and not inexpensive, so you’re not swimming every little meet in a race suit,” says Pinger. “So when you put a race suit on, you know this is an important meet and want to swim fast.”
While so much of the sport is in your head, and the forces of physics aren’t going anywhere, it’s ultimately up to the swimmer to wear what works for them and trust their training. The knowledge that years of research and testing is behind your suit can make the difference.
