Sleeveless Slower: Why?
Swimming for the second time in my local lake with my 17 y/o sleeveless wetsuit, sandwiched around 2 swims in my full sleeve, I am reminded of the obvious fact that a sleeveless is slower. But why? A wet suit helps keep the hips and legs higher, so the advantage over no suit is obvious. But my arms stay the same position in either suit. I've always accepted the full sleeve advantage as a fact, but never wondered about the reason. Thoughts:
- Water enters constantly around my armpits - does this increase drag?
- My forearms are marginally wider, by 4 mm, in sleeves. Does this help?
- Micro flow around my bare skinned arms and hairs makes a difference compared to smooth neoprene, but, really?
So, I'm kinda stumped.curious. Anyone know the real answer?
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"If your arms are bigger, you'd swim faster! If you could float more, you'd swim faster! This pullover incorporates both concepts and is legal in both WTC & USAT events. The difference between the First Wave Pullover the Concept 5 Pullover is only that it has 5 mm sleeves instead of 2mm. So that addition of 3 mm to the thickness results in increasing the cross-section of your arm (from the wrist to just above the elbow) by 6 mm total along the entire length of the arm. The thicker arms also add buoyancy during the glide phase of your stroke. The difference is like adding about 3-4 additional fingers of surface area to each hand. The best way to see how significant that difference would be is to try swimming with just one or two of your fingers open and the others bent down.".
So if that is correct, then the sleeved suit would be faster than a sleeveless one.
Also, wetsuit makers go to a deal of trouble making the surface of the suits as drag free as possible. Again, if that is important (and the makers think it is) then the sleeved suit will be faster than a sleeveless one.
Yup, those are the reasons I've heard. But comparing my times, I'm 6-10% faster in a good sleeved (Xterra Vendetta) suit compared to the sleeveless, which admittedly is late 20th century technology. It just seems like a lot, and certainly an argument against ever using the sleeveless in competition. I figure, at my speeds, sleeved vs sleeveless is worth, for me, 5-6 minutes in an IM, 2 minutes in an oly.
Here are the broad strokes based on what seems to be supported by the science we have today - basically, we have physics, physiology, and the (always fun) interaction between the two:
- Stating the obvious, there are good studies showing that swimming in any kind of wetsuit (full, sleeveless, short) is significantly faster than a swimsuit (up to 10-14%), regardless of age, fitness and swimming ability;
- the effect is probably largely due to increased buoyancy reducing frontal resistance. However, since the effect of the suit on the lighter female swimmers was not different from the effect on the heavier male swimmers, a reduction in friction drag is probably also significant. Which, I suppose, begs the question - how much arm hair are we talking about?
- Surprisingly, in some tests, the sleeveless suit was faster (despite a weaker buoyancy). The increase of the swimming speed was related to a greater distance per stroke (related - studies show that wearing of any kind of wet suit contributes to significantly greater stroke length, but the effect seems to be more pronounced in sleeveless). It's worth noting that the feeling perceived by the swimmers was better in the sleeveless suit due to shoulder joint mobility.
- BUT studies have also shown our bodies' physiological responses change when wearing a wetsuit during the swim. Things like oxygen uptake and minute ventilation (at given velocities) are decreased when wearing a wet suit as compared to a conventional swimming suit. Further, these decreases were related to the amount of wet suit covering the body. We can guess, but we don't really know why this is.
- We do know, though, that swimming in a wetsuit can induce a mild heat stress, increasing skin and body temp in direct relation to water temperature, length and intensity of the swim. However, in most well trained triathletes, these heat differences are usually minor and naturally eliminated during the cycling stage.
- Interestingly, I didn't find any swim-specific studies looking at the effect of mild hypothermia on performance. That would be a good data point.
- Also important relative to the big picture, cycling efficiency was significantly higher (12%) after a wetsuit swim when compared to a regular swimsuit. The lower relative intensity observed during swimming with a wetsuit suggest the relative importance of swimming condition on the total performance. So there's that.
- It's worth noting that most of these studies were performed at shorter distances and often with elite level swimmers or triathletes. The effects may be more / less pronounced on longer distances and especially with regular mortals; either way, a difference noted during a sprint in the pool may not apply to a long course in real life. So there's that, too.
I guess then... it depends?
Maybe the question isn't why are you slower in your old sleeveless, but (physiologically) why are you faster with sleeves?
http://webcache.googleusercontent.com/search?q=cache:64vwW_kXdmAJ:www.usms.org/forums/attachment.php?attachmentid=992&d=1211480132+&cd=5&hl=en&ct=clnk&gl=ca
My opinion is that if you are on a budget, you are better off (read Faster and less downstream effect for your triathlon day) in a sleeveless wetsuit. And if you are going with a sleeveless, then may as well save some $$ and get a cheaper one. I got an Xterra Vortex for like $119 and it is great.
Really high end Full Sleeve wetsuits are pricey but super flexible up top (which is why you are paying top $$$). If you are swimming in the Huub Archimedes (my choice) or the high end Roka or the Freak, (and probably the Vendetta but I've never tried that one) then the shoulder mobility is amazing. I've heard the DeSoto is good for this also, but couldn't get the sizing to work for me. You get all of the advantages of the added speed without the physiologic cost of using a ton of extra energy "fighting" the wetsuit the whole time. My personal thought is that if you get the "low-end" full sleeve, then your shoulders/arms will be doing a lot more work to the point where this extra speed is more than offset by the extra effort.
Summary, if you want to spend $, then get the cheapest sleeveless that fits you and you'll be fine. But if you want a Full-Sleeve wetsuit, be prepared to spend $$$$$.
Yes, that's my question! Thanks for the romp through the data, such as it is. A key fact: water density increases with depth below the surface. So the higher one rides, even with a good kick, the less water needs to be moved. Key fact #2: water is 1,000 times denser than air, so a little benefit goes a long way.
I think I have seen this before....