You cannot help but notice these days that swimmers are putting in ever faster times. In the triathlon world, the transformation is just as big. Gone are the days when non-wetsuit racing involved wearing whatever you will have on for the rest of the race. Many competitors race in Fast-Skins, or more recently, the Blue Seventy swimsuit. These suits make you faster, and people who wear them claim that they feel like they are floating on top of the water in comparison to a regular swimsuit. But just because they think the suit is making them float better, is it?
These swimsuit manufacturers spend a lot of time and energy to test out their suits to prove that they don’t float. But their results contradict the claims people make when they race in these suits. So, which is right? Maybe these suits make you faster because they trap air which pulls you towards the surface. Or, maybe the suits are faster because their surface glides through the water better.
The chance that the suit itself pulls you up is low. The materials may be buoyant, but there isn’t enough volume to really make a difference. A blue seventy or fast-skin suit cannot have a thickness that exceeds one millimeter. A wetsuit has a little more volume, as the allowable thickness is three to four times larger.
A simple experiment was completed to determine flotation. The test subject (your author, Duane Dobko), put on a bunch of different swimsuits, sank to the bottom of the deep end of a pool, and timed how long it took to float to the surface. The suits used include: a regular nylon brief-style swimsuit, a full-sleeve Quintana Roo Superfull wetsuit, a Blue Seventy PointZero swimsuit, and a Fast-skin body-suit. The depth of the pool was eight feet. Thirty-two repetitions were completed for each suit. The time to reach the surface was timed by stopwatch to nearest 0.01 seconds.
As expected, floating to the surface was the fastest when wearing the wetsuit. But what was surprising was how little the difference was between the other suits. Use of the Blue Seventy and Fast-Skin did reduce the float time by a statistically significant amount (see summary statistics below). However, the difference was very small in magnitude. The Blue Seventy and Fast-Skin reduced the float time by just 3%. The wetsuit reduced the float time by a whopping 41%, almost 10 times higher. And no difference was found between the Blue Seventy and Fast-Skin, to an accuracy of plus/minus 3%.
The Blue Seventy and Fast-Skin may have floated to the surface faster than a regular swimsuit. But the difference was so small it could be explained by reduced friction in the water (as the test subject floated to the surface). Since nothing could be found between the Blue Seventy and Fast-Skin, it can be concluded that any difference in swimming speed between the two suits has nothing to do with flotation. The wetsuit floated to the water very fast, as expected. Because the difference between the wetsuit was so great compared to the other suits, it can be concluded that it was the only suit that caused significant flotation.
Does this mean that a Blue Seventy is just as fast as a Fast-Skin or brief-style swimsuit? No. All that is certain is that any difference in speed between Blue Seventy, Fast-Skin or nylon brief is due to something other than buoyancy. It may feel like you are walking on water wearing a Blue Seventy swimsuit, but you really aren’t. You are just cutting through the water that much faster. Hopefully, this adds to your understanding of what you get when you buy all of these expensive suits! Until next time, happy training.