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Diving with a Speedo "Fast skin"suit

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Well-Known Member
Oct 17, 2003
I'm wondering if anyone here dives with a Speedo Fast skin full body suit. I know they have been used for dynamic, but how would they be for diving (of course the water would need to be very warm). For pure performance the idea seems appealing as such a suit greatly reduces drag if the user knows how to make it work corectly. Let me know what your experiences are...
I wondered this myself, but only though of it for dynamic and not Constant ballast.

Now, with people like Eric F. doing no suit dives, it may prove to be beneficial. I would think it would still allow for the exposure no suit divers are looking for as it's thin and alows water flow through the fabric.

Hopefully Eric or some others with no suit diving experience can comment.

Hi there,

Tanya di her 35m constant weight without fins in a shark skin suit. It worked very well.See attached image.



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I bought a fastskin suit in 2001 and I hated it. Far too restricting for breathing and stretching the arms. Also, the extreme tightness around my belly amplified feelings of queasiness. I did a couple of 60-65m dives with in Florida in June 2001. I'd sell mine to anyone who wants it.

Eric Fattah
BC, Canada
Hi Eric,
what you say about the tightness sounds strange. i've tried one in the past but only on dry land and yes they feel tight (as they should be) but not consticting. these suits are designed to produce world record swimming times and do acheive these results. if the arms where too tight how would world class swimmers swim in them ? i'm not saying you're wrong in your comments, but they are quite confusing. Great pic of Tanya, she seams to think it's efficient. i'm curious also to know if such a suit would offer any slight warmth. i mean would it just take the edge off from colder water ?
I don't know a lot about these suits, or competitive swimming in general for that matter, but Eric's remarks don't seem necessarily inconsistent or implausible.

I thought that I read that these suits work using two separate principles -- the "denticles" decrease drag under certain conditions and aren't the arms designed to be like cocking a spring? -- i.e., when you're moving your arms forward, they're out of the water and don't produce any propulsion and are also "unloaded", so the suit's elastic puts a load on the arms to store energy on a forward stroke and deliver it on a backward stroke. There don't seem to be any corresponding mechanics in underwater swimming, and that might defeat the benefits of the "spring action" aspect of the suit's design.

Note that Tanya's arms are back. Interestingly, this has become "pro forma" for CBNF.

When swimming underwater, your arms are never free of the water's drag, so maybe that reduces or eliminates the potential benefit of the stored energy concept.

Swimmers can breathe while they're swimming, so there is less penalty to a system that increases overall work -- as long as it increases speed, folks will use it. Anyone know if swimmers use these suits for longer distances? That might be an indicator regarding overall efficiency, though still might not apply for underwater swimming.

I suspect that any reasoning along the lines that, "if it's good for surface swiming, it's good for freediving", will give mixed results.

On the other hand, if you try it and it totally rocks, I'm interested in knowing.:cool:
I think the main benefit of the suit is not drag, but compression of the muscles, especially the thighs. Watching the videos of me diving in the fastskin, my quads do not display shockwaves with each monofin stroke. This is a sign of saved energy. If I were to dive with my arms by my side (rather than extended), I might consider using the suit under some circumstances.

It does give a bit of warmth. The sharkskin material traps micro air bubbles, and also gives a bit of buoyancy, which promptly disappears at great depth as the bubbles are collapsed and dissolve out of the suit.

Eric Fattah
BC, Canada
Thanks for that Eric. So do you think once the bubbles are gone the suit would still give any warmth ? Very true, one of the main benefits is muscle compression and vibration ellimination. The other benefit is decreased drag. If you read the report on the Speedo site "Speedoaqualab.com" about the suit (and they are about to release the new version) there is some very interesting techy info. One fact is that on a 50 meter distance, up to 15 meters are spent underwater in a streamlined position and the suit maximises your glide factor under those circomstances (among other benefits). This sounds like a valuable asset to freediving use. Also the new suit uses some stretchier panels where needed, probably for the reason you mentioned, the old full suit was maybe too constricting. It would be great to have Tanya's opinion from her experience with it.
Many competitive swimmers use models that have no arms - farmer john style - probably for the reason Eric mentions. . . full arm models feel restrictive.

The spring-loading theory of the full-arm models may be the favored propaganda, but it is not sound swimming theory. Swimmers actually achieve very little propulsion from pulling water backward with their arms/hands. Rather, the hands and forearms work as anchors - more like kayak paddles - and the swimmer twists his body forward (at least in freestyle and backstroke) against those paddles. Pulling the paddles back faster does not necessarily propel the boat faster, especially if that pull creates turbulence. The best freestylers actually glide on an extended arm for most of each stroke . . .a restrictive suit would work against them.

Anwyay, enough stroke mechanics. The main reason for the fastskins and other full-suits is to make lots of money for Speedo, Nike, Tyr, and the other companies that produce them . . .they cost about 10 times a normal racing brief. And reason #2 is that they look BAD. . .that's why my 10-year old absolutely MUST have one to swim in championship meets. . .the first time an Olympian was seen on television winning a medal in one. . .well, the marketing game was won!!
Speedo have now changed the design of the skin suit. Before the cells went in the same direction minimising drag in the water but after much testing they found that water does not travel in one direction during a race and in fact creates a lot of turbulence around the swimmer. The suit now has the cells in the direction that the water travels around the body so in theory the suit is completely hydrodynamic. Until they come up with a new theory that is. These suits will be first worn in competition in this years olympics and Tanya and I were lucky to see one of the suits at a recent NCAA swim meet. It looked like the old suit to me but I beleived the Speedo guy.

Tanya found that the suit did offer some warmth although not much, it was more protection against jellies.
Mr. Streeter,

Did Speedo tell you how much their profit margins increased with these suits?

Assuming that every swimmer's stroke is the same and matches Speedo's model for drag created as the human body swims (which is NOT like freediving), I wonder how much drag reduction per dollar the competitive swimmer is getting.

I wonder if spending an additional 5 minutes each practice perfecting one's turns might pay greater dividends, for the competitive swimmer. But why train harder when you can buy faster times, right?

I realize my post has little to do with freediving . . .the suits may be much more effective for freediving than swimming . . .but do the math, and you know why they market the suits to swimmers. Thousands of kids swim . . .few freedive.
WE of course did not discuss the financial side of there business. I for one do not think you are correct in your comments. We have worked with the Female swimming coach at the UNiversity of Texas here in Austin and I can tell you the only thing they are interested in is times and performance. Most of the girls ( and I mean 90% of them ) have bronze, silver and gold medals from the Olympics and the coaches without exception say that the suits, whether they are Speedo, Nike or another enhance the times of the swimmers. Sure Speedo make money, but they have invetsed 10s of millions of dollars in the development of there suits. I think that if they did not work then the coaches and swimmers them selves would not wear them. But of course thats just my thoughts.

On another vain, Eric mentioned that he felt restricted in the suit. This is something Tanya did not find as they are very flexible and I might say very photo genic. In fact I think they look pretty damn sexy on a good body. See attached.


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What do you find incorrect in my comments?

Do you believe that every swimmer's stroke technique is sufficiently similar that they produce an identical drag pattern? [I implied that they are not identical and would produce different drag patterns]

Do you believe that Speedo (or the UT coaches) has verified the above with research? If so, in what peer-reviewed scientific journal did they publish the results of that research? [I implied that they have not, because I have not been able to locate the publications, but perhaps you can help me out here]

Do you believe that these suits override the gains in streamlining that a swimmer can make perfecting his technique? [I implied that they do not . . .if they did, I doubt the Olympic committee or the NCAA would allow them]

Do you believe that a swimmer propels himself by pulling and pushing water behind him rather than by finding still water and pulling himself past it? [there's been alot written on this . . .I'll bet the UT coaches would agree on this one]

Do you believe that many swimmers do not use the sleeveless models of Speedo and other "skin suits"? [if so, I guess I need new glasses, because I attend many swim meets and I seem to see a lot of sleeveless skin suits . . .in fact, more than full-sleeved skin suits]

Do you believe that Speedo did not develop these suits to make a profit, and that they would market the suits even if they did not make a profit?

Those are the statements I made. Which do you find incorrect? -Or do you just object to my inference that these suits are less effective hydrodynamically (notice I did not say INeffective) than financially?
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Just for fun, I popped over to the Swimming Technique magazine website and clicked on "Tips on technique." Coincidentally, the featured article discusses "anchoring" the hands and using the full surface of the forearm to hold onto the water and create a stable fulcrum over which to propel the body. see this article The article also mentions sculling, which would not be assisted by a springloaded swim suit sleeve.

Swimming technique is not a peer-reviewed publication, but this is pretty standard stuff. The idea that a spring-loaded swim suit sleeve will help a swimmer neglects some fundamental aspects of stroke technique. And besides, is this really what ought to occur in sports . . .maybe there's a market in this for Speedo selling suits to baseball pitchers . . .increase that fastball a bit. The guy with the tightest suit wins.;)
Hey guys, this is getting a bit heated up. Well i must say i agree with you both. Yes i'm sure there is a huge financial profit from these suits but i also believe that they do offer some technical benefits, at least on an elite level where differences are made by the most minute details. What these benefits really are is up to debate and only by talking to very experienced swimmers who use them (but are not sponsored by them, to avoid bias) could one achieve some conclusions. Even then, all the information would have to be translated to potential benefits for freediving. I guess i'm gonna have to start using one and make up my own mind. My first choice is the pants only suit. Will let you know how it feels once i start using it. Till then, thanks for all the input and keep it coming.
No heat, no sweat


Please don't mistake debate with conflict. Mr. Streeter was not attacking me, nor I him.

He said I was incorrect; I challenged him to identify in what aspect. We're not fighting . . .we're disagreeing over something, but as yet, we have not identified what.

We might end up agreeing . . .and we might both learn something from the exchange.

If this had nothing to do with freediving, I would not post about it, but in some respects it does. If a suit truly reduces drag, then it could benefit a freediver by reducing the amount of energy, and thus oxygen, required to perform a dive. This might be most significant in constant ballast.

On the other hand, if some who have studied the issue are correct (see this site), then it would be difficult for a freediver to gain much advantage because the Fastskin is rather worthless after it soaks through completely . . .the advantage is seen only when the suit is donned dry, and would apply only to races (or dives) that are completed before the suit soaks through. After the suit is wet through, all advantage is lost and the suit may become a detriment, at least according to those sources.

Perhaps the "new and improved" version of the Fastskin has overcome all of that; but I have not yet found any research to demonstrate it.

There may be some good reasons the data are not published. Speedo would put themselves in a tough spot were they to prove the effectiveness of the suit with hard data. That would strenghten the move to ban the suits in swimming competition because it would lend credence to the claim that these suits are devices that aid the swimmer in buoyancy or propulsion. (-See the link on the website I gave about cheating without actually cheating.)

So my issue is the lack of data to support the claims of those who believe in the suits, and I don't see that convincing a few swim coaches constitutes "data." Maybe data is too much to ask . . .think about how one would verify that a suit actually bettered a swimmer's time, after all (or a freediver's dive). . .a swimmer would have a very difficult time being his own control because level of effort, lack of a "sham" or "placebo," etc. would confound the results.

Unless the suits make such a difference that statistical significance can be verified in some measurement of performance - increased swimming speed; reduced oxygen demand, etc. - this will remain in the realm of faith rather than fact. -And that's probably where the money is, at least in swimming. The suits don't have to work - and if they did, it could be their undoing - as long as enough swimmers and coaches believe they work.

So, I'm all for freedivers using these suits if they like them, and I don't discount psychological advantages they may confer. Theories about why they work are nice, but I'd rather see some data showing they do work before I worry about which theory explains the data.
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I was part of the team the helped test the original Fastskin suits to help prepare them for the US national team to wear them in Sidney. I was part of both the lab test group (phase I) and the field test group (phase II).

The suits were tested in phase I, both wet and dry, measuring the push off the wall, the distance that we travelled and the times. Other elite swimmers were used to test the times in actual swim events, as well as in cases where drag forces were measured. The Fastskin suit was tested against the Aquablade fabric, as well as standard nylon/lycra suits in a variety of cuts and styles.

All of this testing was done at the Olympic Training Center in Colorado Springs, CO. The tests were conducted by the OTC at their center for perfomance, the tests were administered by USA Swimming in partnership with Speedo. Data from the tests is at the OTC with USA swimming. I would not be surprised that the full test data would not be available for view, as it is probably considered proprietary info for the manufacturer.

The results of these tests were the reason behind why the suits were selected to be used at the Olympics. Quite simply, if they weren't the fastest suits available, they wouldn't be used.

The suits did prove to provide an edge in several areas:

1) overall drag reduction
2) muscle compression
3) buoyancy enhancement

In drag reduction, the suits allowed the swimmers to "slide" through the water more easily. This was tested in several different ways and under precise scientific conditions. One of the interesting things noted was that at higher velocities, swimmers had a higher relative drag reduction (i.e. the faster a swimmer was moving, the greater benefit the suit provided). This may not be of a great benefit to freedivers, who may not reach the speeds at which this effect takes place.

Muscle compression (as Eric noted above) allows for more effective energy use/power transfer. Also, the compression of muscles and the reduction of vibration has been shown to slightly decrease the onset of muscle fatigue. The vibration reduction also helps to provide a better (more solid ?) surface for the water to flow across and around the swimmer. The suits, with their unique cut and stitching of the patterns, provide much more muscle compression than previously available suits/styles. The suits that were worn at the Olympics in 2000 were individually custom cut and stitched for each swimmer. The "stock" suits available to the public provide much of the same effect, but those custom suits really maximized the benefits. This would definately be helpful for a freediver, allowing them to get the maximum out of every kick.

Also as noted above, the suits do trap micro bubbles between the fabric and the skin, providing a slight degree of added buoyancy. This happens only when the suit is donned dry, worn very tight and with longer immersion, the effects dissipate. This has been a sticky point with USA Swimming and FINA (the internation swimming governing body) on one side and Speedo on the other. Suits cannot, according to the rules, provide buoyancy. Since the effect dissipates, the buoyancy has been looked at as "incidental and non predictable", thus making it fall into the generalization as jumping into the water with trunks on, and having air trapped inside them as a result. It's right along the edge, the suits are not buoyant on their own (if dropped into the pool they will sink, albeit VERY slowly-as opposed to a wetsuit that will actually float on it's own), and that has been the standard used in this issue. This may change in the future and that change may make these suits "illegal". The fact that this effect is unpredictable and dissapates, makes this a bit of an odd issue in freediving.

I also was involved in "wear testing" the suits (Phase II). This was done to look at durability, wearablity and quality issues.

I personally used my suits to freedive, body surf, ocean swim, pool swim and in dynamic apnea/fin swimming (both pool and open water) during that phase of testing.

The things that I noticed during my use testing were:
The suits were FAR less durable than a dive skin or typical swimwear. After just a few uses, the fabric ridges started to degrade, the suits became stretched out and the seams started to come apart. Part of this is due to how tight the suits have to be worn in order to get the maximum performance, but part of it is an issue with the fabric itself. As a result of this, the Olympic swimmers were provided with one suit to wear during preliminary events and another new suit to wear in finals/medal round swims. And this was for every event that the swimmers were going to swim. Swimmers picked suit styles based on their personal prefrences. Distance swimmers preferred smaller, more conventional suits, sprinters opted for more coverage with stroke swimmers in the middle. But ultimately each swimmer had a variety of choices to try out to decide what would be "best" for them.

I felt like I rode waves "faster" wearing the full body and sleeveless Fastskin suits while body surfing. My swims in the ocean were marginally faster, and my pool times fairly consistent with previous swims. My dynamic apnea and fin swims were marginally faster as well. While freediving, I was cold. I prefer a wetsuit for freediving, but the Fastskin suits would give good jellyfish and sun protection when warm in nice warm waters.

One of the things that you have to remember when discussing these suits is that are primarly designed to benefit very well trained, highly conditioned, Olympic level swimmers. This is where every hundreth of a second counts (if you remember the 50m freestyle in 2000-the fastest swim race-where Gary Hall and Tony Earvin tied). And any minimal edge can be the difference between gold and silver.

On the marketing side, yes Speedo did well, by creating a "monkey see-monkey do" situation. As a result of the high cost of these suits, many teams have enacted rules that say they can only be worn by swimmers going to Sectional or Zone Championships, Junior & Senior National Championships and Olympic Trials. It is up to parents and more importantly coaches to impress on swimmers that NO suit will make up more crappy technical skills or lack of training.

Unfortunately Speedo also pumped sooo much money into the development of the suits and getting them on athletes in 2000, that it drove them in late 2000 into Chaper 11. Yes they are recouping their investment, but it wasn't the amazing windfall for the company (they had planned for it to be huge....and it simply wasn't....there are a bunch of reasons behind that....). The suits are much more costly to produce, look at a typical suit has 4-6 seams, where the Fastskin may have 2-3 times as many, and uses a much more expensive fabric, and more of it. But I will agree, those suits are very pricey.

(This info I know becuase I was working for Speedo from 1997-2001. I lost my job in early 2001 when Speedo's financial situation went into the crapper....they eliminated all but two jobs-out of 35- in the department that I was part of.)

Since I have not been with Speedo since 2001, I don't have the same level of insider info about the suits that are developed for 2004. But I do have some of the suits that were used at the Olympic Trials earlier this month. the side panels are more stretchy, and a different fabric, this may allow for more comfort that has been a complaint since the beginning-but the original suits were designed for short term wear and only a few wearings.

Thanks for letting me expectorate all this ;) ............
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Impressive post BlueWaveC :thankyou

About the Speedo FastSkin FSII, I read something about the low drag. Speedo says that the drag is 4% lower than the FSI's drag.

But it looks like this new swimsuit is much more specialised in swimming than before, with the orientation of the fabric bands in order to put the swimmer more horizontal for example.

You might consider many other brands making such swimsuits too, like Arena, TYR, Nike and others...
They all produce the 'muscle compression' effect, and some of them can be produced especially for you.

always impressed by the quality of this forum!
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