Blue Seventy vs. Fast Skin

If you visit the websites of the major swimsuit manufacturers out there, you get overwhelmed with claims of reduced drag or increases in speed in the latest, greatest (and most expensive!) suits out there. You see technical arguments why their swimsuit is better than any other. But how can you know for certain if these suits are going to be faster? How much difference is it going to make for you, and is it worth the money? Triathlon is already an expensive sport, even if you don't buy the high end equipment.

The Blue Seventy swimsuit is becoming more and more popular among triathletes. It is widely known as the fastest suit you can wear if you cannot wear a wetsuit. Even top level coaches in the competitive swimming community are saying it is faster than anything else out there. Thus, we set up an experiment to determine if a Blue Seventy really does make you faster.

The experiment is simple. Wear a Blue Seventy, swim 25meters as fast as possible. After complete recovery, repeat 3 more times. Then take off the Blue Seventy and do the same thing with a single-piece Fast-Skin II triathlon suit. The setup is quick, and the result is a solid number, time improvement in seconds. Using the variable of time eliminates the need to infer more complex results like reduced drag to the effects of speed. The Blue Seventy was a PointZero3 model, and the Fast Skin was the Speedo Fast-Skin II single piece triathlon suit, also shown in the Figure.

You can argue the flaws in this experiment, so we will point them out first. The data runs weren't randomized, and the test swimmer (Duane Dobko of Dobkanize.com), knew which suit was being worn. Thus, you may get concerned that I deliberately biased results in favor of whichever suit I wanted. All you have is my word that I swam as fast as possible regardless of the suit I wore. I swam four in a row with the Blue Seventy, then later four in a row with the Fast Skin. It is possible that the Fast-Skin results would be slower because of fatigue. I was taking 12 minutes rest between each 25meter sprint. Again, all you have is my word that a 12 minute rest was enough for full recovery. Also, the sample size was low (4 runs per suit), which is barely enough to establish a standard deviation. We didn't have the time or resources to perform more test runs. This is a weekly column, after all!

The results are shown in the Figure. The Blue Seventy was faster than the Fast Skin II to a confidence of 95%. The increase in speed was 1.43%, which roughly equates to a 17 second improvement in an Olympic distance triathlon swim (1500meters) and a 43 second improvement in an Ironman swim (2.4 miles). The difference in time was small, at just 0.17 seconds over 25 meters, with a confidence interval of 0.07 seconds up to 0.26 seconds. The slowest Blue Seventy time was faster than the fastest Fast-Skin time.

Although the Blue Seventy had a faster result, it was challenging to use. It didn't fit very well and filled with water off the start and while underwater kicking. The water tended to slowly drain out of the suit while swimming, and felt tight again only at the end of 25 meters. The buoyancy of this suit made up for the extra water mass being carried. It felt like a wetsuit and not a swimsuit. Subtle differences in the way I entered the water and kicked underwater had a dramatic difference in how much water filled the suit. On the 3rd Blue Seventy repeat, hardly any water entered the suit, which was why it was the fastest repeat (11.66 versus average of 11.74). Unfortunately, the difference was so subtle that I could not find a way to consistently eliminate water filling the suit. Conversely, the Fast-Skin II fit much better and did not fill with water. It stuck to my skin regardless of pushing off the wall, kicking underwater, or swimming. Because of the consistency of fit, the Fast-Skin II data had half the standard deviation of the Blue Seventy data. But I didn't have the same feeling of buoyancy in the Fast Skin II. I could actually feel that I was lower in the water column.

It is important to note as well that both suits felt very fast. Just because I'm saying one is faster than the other doesn't mean that the slower suit is lousy. Whether I felt low or high in the water column, I swam faster in both suits than I have in a very long time. I have not sprinted 25 meters in under 12 seconds from a push start (no dive) since my Division I college swimming days. I do not have anywhere near the athletic ability I possessed 15 years ago, but I'm still putting in those times, thanks to these suits. Both of these suits are fine racing machines. It is just that one was slightly better than the other.

Overall, I recommend the Blue Seventy over the Fast-Skin II for open-water swimming where wetsuits aren't allowed so long as the swim is 1500 meters or longer. If the swim is less than 1500 meters, both suits are about equal. At short distances, the time you gain with the Blue Seventy is lost in transition taking it off, whereas the FSII can be used on the bike and run. Since water filled the Blue Seventy, it would be even faster if the fit improved. In all fairness to Blue Seventy, I borrowed the suit and didn't optimize the fit beforehand. In all fairness to Speedo, I did not compare their top-of-the-line equipment (FS Pro, or LZR) because I could not acquire a suit for the test. I would be very willing to re-do this test if I could get my hands on either of these newer suits.

Now you know what I know about the benefits of a Blue Seventy swimsuit. The Blue Seventy was faster, but the time improvement is in seconds even at the Ironman distance. Also, keep in mind that the Fast-Skin II Tri suit can be worn on the bike and run whereas the Blue Seventy is only worn during the swim. Thus you lose some of those precious seconds you gained while swimming by removing the Blue Seventy in transition. If you already own a Fast-Skin II tri suit, you don't gain a lot for the money unless every second counts. However, it may benefit inexperienced swimmers who feel much more comfortable in a wetsuit versus a regular swimsuit. If you really struggle in the water, the Blue Seventy is something you should consider. I hope this article allows you to make an informed decision for those non-wetsuit races. Until next time, happy training.

One big difference in the suits is how they work. The Blue Seventy works as an ultra low friction suit that doesn't allow water to pass through it. The Fast Skin allows water to pass through and since it is a fabric it has more flexibility.

With that said the suits perform differently with different applications.

For instance when I swam in them and "tested" them for myself I found no difference in the suits' performances. I did 100 yard repeats at about 90% effort. A pace that I could hold and repeat. I did 3-100's with jammers then I did the same with Blue Seventy and Fastskin and then finished with the jammers. I used perceived effort as my base. I wanted to compare the suits at my "race" pace. I swam my jammer repeats at 72 seconds. I swam both my blue seventy and fastskin repeats approximately 3 seconds faster. Using perceived effort I swam my final jammer sessions at 72 seconds as well. This left me with confidence that I did swim all the repeats with the same effort and I didn't have any real fatigue. I swam the repeats on 4 minutes.

What I also found with the fastskin is the diminished performance gain at faster speed. When I did the couple of swim meets two years ago I didn't see the 3 seconds per hundred in my 100 yd race that I saw during the testing. I swam my 100 in 57 seconds. I would venture that a real swimmer that is swimming a 100 under 50 seconds sees less than a half second in performance gain. However in my 500 that I swam in 5:37 I felt I did see the 15 second performance gain.

So, like your test this isn't perfect but I think the suits perform differently at 45 seconds per 100 pace than they do at 75 seconds per hundred pace. Likewise the way the suits feel after 10 minutes or 70 minutes of swimming may affect performance.

I think the Blue Seventy and fastskins are a bad additon to the swimming world. I gives the swimmers with more money a unfair advantage. It's all fine and dandy for those with a high income, but for those who don't it's comepletely unfair. For example, my brother and his friend from the team were going to be racing in finals at a meet in Tennessee. The friend went out and bought a blue seventy. My brother was just wearing a speedo jammer. He was placed to win. But the friend who bought the blue seventy dropped 5 seconds (100free) and beat him by one second. My brother said "I'm so sick and tired of him beating me because he has more money than I do." These suits are completely unfair and should be banned on every level but national or worldwide

I agree. BAN THE BLUESEVENTY!!! Please let everyone have a fair chance. Especially at the age group level. Ten yr olds wearing $300 + suits is ridiculous and discouraging to the other athletes who lose by .5 second in a "normal" suit.

I agree as well. the price for these suits are beyond what many families can pay. this also has a direct impact in college swim teams. As FINA has approved these suits the NCAA has approved them as well. Therefore the community college level athletes must follow in persuit. Many of these schools can not affoard these and thus their athletes who would have normally made the state cut now are pushed out by kids who could afford them and are inferior swimmers without such aid.

honestly swim suits are like clothes... the cheaper you buy the less you get out of them, the more expensive typically the better, depending on the brand and quality of the material. I am not rich, but I do work and I save my money to purchase good suits because it is importamt to me. But people, a suit is only a suit... its the swimmer that makes the difference, I am not terribly fast but I have worked hard to compete with those who are faster and can afford the suits and in the long run I know I win hands down because I trained without that suit and when they put on a normal suit, guess who wins? me. Its not about the suit its about the swimmer always has been and always will be. We may be getting technical nowadays but pure power beats any man made creation anyday