Is your tri suit slowing you down? Results from 3 wind tunnel tests and what we can learn from them, and the rare swim condition known as SIPE. Plus, a brief review of the Women’s US Olympic Trials. It’s wind, water, and women…with a Warden, today on Tri Talk.
Welcome to Tri Talk your podcast source for triathlon tips, training, news and more. Welcome to new listeners from Sweden and the one listener from Venezuela. In Sweden I hope you are ready for the Göteborg triathlon coming up on June 15. And in Venezuela, I’m positive I know who that listener is. It’s Hugo Chávez. I’m positive. Can’t you just see the guy in a wetsuit? My goal at Tri Talk is to help you swim, bike, and run faster, to meet your personal triathlon goals. Whether you are an elite or amateur triathlete, we cover sprint distance to Ironman distance. I’m your host, David Warden, and this is Tri Talk Episode 62.
Today I am excited to go over some wind tunnel data that was provided to me by Colorado Premier Training. Some of the data will strengthen what you already now about aerodynamics, and some of it will challenge what we thought we knew, plus a very interesting wind tunnel test on a piece of triathlon apparel. Also, it’s common to panic during an open water swim, particularly your first, but when the panic moves beyond psychological to physiological, it may be a rare condition known as SIPE. We’ll talk about this at the end of the show. Also, I want to let you know that during this episode I’ll be recording the entire show in one take. That’s right, no more using the crutch of covering up my mistakes by recording a section over again. I’ll be doing live play-by-play at a few major triathlon events this year, and there won’t be any “do-overs” there. Plus, if I ever want to break into radio, it’s time to step up to the plate and be a true professional. As a result, this episode could get ugly, but it’s for my own good.
Before we get onto the good stuff, I want to briefly talk about how impressed I was with the win of Julie Swail Ertel at the US Olympic Trials in Alabama a couple of weeks ago. I recognize a lot of Tri Talk listeners are from outside the US, but there is a lesson from this event that I think we can learn from.
I know that many of you race against yourself, and are satisfied with simply using races as a method to benchmark your own progress. But if you are like me, racing is all about establishing a pecking order and beating as many other guys as possible. Plus, I hope you can appreciate the pressure on me as training “expert” to be fast and get to the podium frequently.
What I learned from watching Julie Swail Ertel was the psychological importance of taking the lead. Julie stayed with the lead pack on the bike and came out of T2 much faster than her 10k pace. She shot out of there and was going hard for the first 100-200 meters, and opened a nice gap rest of the field. There is something to be said about holding onto first rather than catching up from second. In fact, Julie Swail Ertel has very little running background. The woman who came in second, Sarah Haskins Kortuem, attended the University of Tulsa with an athletic scholarship for cross country and track. You had Julie Swail Ertel, a swimmer and former Olympic Silver medallist in water polo, open up the gap on the run against the athlete with the strong running background. That gap seemed just too much. That little surge at the beginning of the run seemed to make off of the difference.
Now, very little of us will ever have the opportunity to lead a race. But, if you are racing for your age group, and you can identify your competition, consider the advantages of taking and holding the lead.
Let’s get onto the good stuff. I’m so grateful to Colorado Premier Training for getting me this information. What I have is the complete wind tunnel results from 3 athletes of various sizes and abilities.
Let’s begin with athlete #1. This cyclist has a good threshold of 350 watts. A reminder that when training with power, your intensity threshold is no longer measured in terms of HR, but in terms of watts. This athlete can maintain about 350 watts for an hour, so his threshold is 350 watts. 350 watts may seem pretty high, but this athlete is also pretty big. Your wattage output should be compared to your weight to determine if it is a “good” output or not. This athlete is big, but he is tall and lean. I’d estimate about 175 pounds and well over 6 feet. Hunter Allen and Andrew Coggan have a chart in their book Training and Racing with a Power Meter that looks at a weight to power ratio and takes that ratio to determine your cycling level. At 175 pounds, or 79.5 kilograms, this cyclist pushing 350 watts as a threshold has a weight to power ratio of 4.4, which according to Allen and Coggan, places him as a very good cyclist, about a Category 2 cyclist if using the categorization guidelines from USA Cycling. This would place this cyclist in about the top 5-10% of the cycling leg of any given triathlon.
Now that we know a little bit more about this cyclist, let’s look at the evolution of his positioning in the wind tunnel. Athlete #1 comes into the wind tunnel with a baseline speed of 44.17 kilometers per hour. That speed is based on his current drag in the tunnel and the assumption he can maintain that 350 watts over an hour. Over a shorter or longer distance, his wattage would obviously be different, but all the speed data we’ll be looking is based on wattage threshold, or an hour of cycling, or about an Olympic-distance triathlon cycling leg.
The first notable change is that the athlete raises his cockpit by 2cm, or just adding one more ring to the stack at the base of the stem. While one would expect the outcome to be a less aerodynamic position because he is up higher, the consequence is not that bad. Those 2cm change his speed from 44.17 to 44.12 kph, or costing him just 3.4 seconds over 40K. The take-home for me initially was that if this athlete is far more comfortable in the neck and shoulders at that slightly higher position, it may well be worth the 3.4 seconds to get into a more comfortable position where you can also potentially generate more power.
However, his next position is more significant. He then drops 4cm off of his cockpit from his original position. This changes his aerodynamics dramatically and increases his speed at that given 350 watts to 44.69 kph, which is a savings of 38.15 seconds over a 40K. That is a solid increase in speed. He then drops his position another 2cm for a total of a 6cm drop, which increases his speed even more saving him 65 seconds over 40k from dropping 6cm on the stem. For this athlete, if he can maintain power in that position, and is comfortable in that position, this is a very good change to gain 65 seconds in a race.
This athlete also experimented with what is known as the “turtle” position. This is where the athlete drops his head at the neck as low as possible. I find this position uncomfortable at best. The idea is to get your head as low as possible. This athlete was actually 6 seconds slower with the head on the turtle position compared to the 6cm drop with normal or natural head positioning.
Next, the cyclist rotated his hands in so that they were touching on the aerobars, and brought in the elbow pads a centimeter. Still with a 6cm drop up front, that narrower position actual lost 12 seconds. But, as soon as the athlete went into the turtle position, it became his fastest position of the day so far, shaving ½ of a second off the regular position with a 6cm drop. Let me repeat that. A 6cm drop with elbows and arms in normal position was ½ second slower than elbows in 1cm and head in the turtle position. For ½ of a second, I would imagine that this athlete would want to stay in the far more comfortable non-turtle, wider hands and elbows position.
So now this athlete is thinking they need to go to a 6cm drop for his best aerodynamics. Regardless of the head or arm positions, that 6cm drop has provided the best aerodynamic gains so far. But they decide to do one more test with a 2 cm drop. Astonishingly, that 2cm drop is faster than the 4 or 6cm drop. The 2cm drop is 40 seconds faster than the 6cm drop, and 106 seconds faster than the baseline position he came in with. It looks like the reason this is the best position for this athlete is due to the fact that he can maintain a flatter back with 2cm of drop compared to a more arched back with the 4 or 6cm drop. I know that everyone knows about Lance Armstrong’s hump, and how much faster it made him, but for this athlete, a less aggressive, flat back is more aerodynamic than the more aggressive 6cm drop with introduces a slightly arched back. It just goes to show that more is not always better, and having a huge drop in your cockpit is not always faster.
Another eye-opener on this athlete is helmet setup. This athlete used the Rudy Project helmet. I’m a big fan of Rudy Project sunglasses, but I have been skeptical of their helmet. It is so small compared to the other helmets. You might think that is good, but it reminds me of a thick tapered downtube compared to a small round downtube. The bigger, thick downtube is more aerodynamic, and the Rudy helmet seems too small to displace the air.
What the Rudy Project helmet does have is something called the Supercomp. This is an attachment to the helmet that covers the ears. They are also called “sideburns”. It significantly increases the surface area of the helmet. For this athlete, the difference between the sideburns on and off was 109 seconds. Don’t let anyone tell you that an aero helmet’s design does not make a difference! 109 seconds from adding a little piece over your ears.
Now, what I like about the Louis Garneau helmets is that the “sideburns” are built in, and the ears are well covered with the standard Rocket helmet.
So, this athlete was able to shave off 106 seconds from learning that a 2cm drop was his best change. Let’s say that he spent $1,000 for an hour in the tunnel, and another $500 in travel. That’s $14 per second saved, which places it as a more economical investment than either aero wheels or a tri bike. Essentially, $1,500 will get you either a nice set of aero wheels, or an hour in the wind tunnel with travel. The aero wheels will shave off 60 seconds or so, while the tunnel shaved 106 seconds off this athlete’s 40K. However, the obvious difference is that the aero wheels will almost universally save you about a minute, while the wind tunnel results will widely vary. It’s a risk/reward decision.
Let’s move onto athlete #2. This athlete has a threshold of 200 watts, but is a much smaller athlete. I’d say by looking at him only about 150 pounds. Based on Allen and Coggan’s power to weight ratio, this places this athlete at about a category 4 cyclist, or top 50% of the cycling leg in any given triathlon. Compared to the 45 kph from athlete #1, this athlete’s baseline is about 39kph over a 40k ride.
The first test with athlete #1 brings his reach back by 3cm, so that his elbows are much further behind his ears. This could be accomplished by reducing the stem length by 3cm. It makes almost no difference in his aerodynamics, but in fact makes him almost 7 seconds slower from shortening his cockpit. But, when the athlete goes into a turtle position and chokes up on the aerobars, he suddenly saves 118 seconds! That is 2 minutes from chocking up on the aerobars, or bringing the arms way in towards the body where the forearms are resting on the armpads closer to the wrists than the elbows, and lowering the head into that turtle position. So, that 3cm shorter cockpit was a detriment to him if he kept his elbows on the elbow pads, but was an aerodynamic advantage to him when he choked up and lowered his head.
This athlete then moved in the bars and elbow pads as close together as they would go. Now, for this athlete, although it was in as far in as they could go, they were not that far in. I would still not consider this an aggressive elbow and hand position, with the elbows still placed at shoulder width. But, his elbow position before was actual slightly wider than the shoulders. This other subtle changed shaved off another 38 seconds on top of the 118 he already gained from chocking up with a turtle position.
So, this athlete gained 151 seconds from his wind tunnel experience. For a $1,500 investment, that is less than $10 per second saved for this athlete.
One more fascinating result with this cyclist was that he also tested 2 other helmets. On this athlete, the LG Rocket helmet was 27 seconds faster than the Rudy helmet, but that is the Rudy helmet without the sideburns. If we can assume the same savings with the sideburns that we saw with athlete #1, the Rudy with sideburns would potentially be 82 seconds faster than the LG Rocket, but this is purely speculative. All we know is that the LG was faster than the Rudy on this athlete.
On to athlete #3. This athlete can push 300 watts for an hour, also averaging about 44kph. You might be saying, “hey how come athlete #1 could push 350 watts and athlete #3 is at 300, but they both have the same 40k velocity?” The answer is that athlete #3 came into the tunnel very aerodynamic already, with an initial drag coefficient much less than athlete #1. It is an interesting example that you can have two athletes be at the same speed, but have totally different wattage numbers because one is so much more aerodynamic than the other.
This athlete started by raising his cockpit by 3cm, with an unusual result of saving 14 seconds from going up 3cm. However, when dropping 2 and 4 cm, the athlete gained 37 and 52 seconds respectively. So again, a consistent increase in speed with at least a moderate cockpit drop.
The athlete then did an interesting experiment. He slid forward riding on the nose of the saddle and gained another second. Does not seem worth the discomfort.
The turtle position for this athlete did save 4 seconds. Interesting that both for athlete #1 and #3, the turtle position did not help much, but it seemed to make a huge difference for athlete #2.
Athlete #3 then experimented with different elbow and hands width positions. The first position was the pads 12cm apart and the extensions 6cm apart. The second was slightly wider, with the elbow pads 14cm apart and the extensions for the hands 8cm apart. There was less than a 4 second difference between the two positions. A third position placed the elbows actually touching, and that ended up being 14 seconds slower than having them 12cm apart. Again, a more aggressive position in arm width does not always lead to better aerodynamics.
Possibly the most fascinating experiment of all 3 was the athlete’s decision to test different sets of racing apparel.
Using arm covers, or sleeves that cover the arms from wrist to shoulder made absolutely no difference. No change at all with those arm covers.
But, the athlete did try cycling in both a cycling suit and a tri suit. Both appeared to be one piece suits. I wish I could tell you the brands of the clothing, but I only have these small pictures to go off of, and although I can identify the helmets, I can’t identify the clothing.
Anyway, the difference between the cycling suit and the tri suit was a whopping 80 seconds. That is a scary thought to me, that what you wear can have as much effect as the wheels, or an aero helmet, or positioning.
So, this athlete, by dropping 2cm and narrowing his arm width slightly was able to drop 55 seconds from his 40k time, or $27 per second on his $1,500 investment. If you count the alarming discovery that his tri suit was another 80 seconds slower, then he saved 135 seconds for the wind tunnel analysis, or just $11 per second saved.
By the way, this is the only wind tunnel test I am aware of that ties a specific aerodynamic consequence to different types of apparel. I’m sure someone else has done it, but I have not found one.
Back to the discussion of apparel, I would imagine that any one-piece tri suit that is truly a skin suit meant for improved water hydrodynamics, could be a good investment for the bike. This would include the Xterra Velocity , 2XU Kona Fusion, Blue Seventy Pointzero, the Ultra SpeedZoot, Sailfish Furious, DeSoto LiftFoil, and the Speedo Fastskin. These are not your basic one-piece tri suits, but represent true focus on hydrodynmics, which may or may not translate into aerodynamics. But, let’s imagine that it does. A $200 investment into one of these suits that might save you 80 seconds would be $2.5 per second saved, which is the same magnitude as an aerohelmet in terms of value. The disadvantage of these suits is that they are so aerodynamic, there are no pockets and there is no mesh material for venting. They are built for speed.
By the way, I love the DeSoto LiftFoil. It is the only tri suit I have used, so I can’t really compare it to the others, but it feels wicked fast for both swimming and cycling, and I look really good in it. Plus, you can get your LiftFoil from PowerTri.com.
Again, I have to thank Colorado Premier Training for providing me with this invaluable information. For more information on what Colorado Premier Training can do for you, or to get into their wind tunnel yourself, visit http://www.coloradopremiertraining.com
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Moving on. I hesitate to even bring up this next subject. When I did a piece on hyponatremia, I got more e-mail from scared athletes than from any other subject. Should I drink? Should I not drink? What I failed to mention in that piece was that any well-trained athlete who has practiced nutrition in their training and sticks to that plan has an extremely low chance of developing hyponatrimia.
This next topic is exactly the same. Swimming Induced Pulmonary Edemia is very rare. The only reason I am even bringing it up is because one of my athletes had it happen recently, and so I did some research on it and felt it was at least worth a mention on the podcast.
I don’t know about you, but I don’t know any triathlete who did not have a bit of a panic attack the first time they swam head-down in open water. It is almost universal, even it if it lasts only a few moments, there is a big difference between swimming in the pool and swimming in the near pitch dark of open water. That sort of distress is common, and is usually easily overcome after a few minutes.
However, there is a more rare condition brought on from swimming that can have more serious results. Swimming Induced Pulmonary Edemia, or SIPE, is a pulmonary edemia, or a swelling or fluid in the lungs, brought on by swimming. It is caused when the blood gas barrier in the lungs fails under high pressure, and blood is allowed to flow back into the lungs. The bloog gas barrier in the lungs has a tough responsibility. It has to be thin so that gas can route from the lungs to the circulatory system, but it has to be strong enough so that under stress, that blood can’t get back into the lungs. This high-pressure condition is easily met when exercising in the water, as that extra pressure on the body tends to squeeze the blood into the weakest point of the circulatory system, the capillaries.
The most common symptom of SIPE includes coughing up pink, frothy spittle and mucus, which separates it from the more common panic attack of an open-water swim. Other symptoms include respiratory distress, wet-sounding popping or crackling in the lungs when breathing. These specific symptoms can help you determine the difference between normal open water distress and SIPE.
I would not have even brought this up were it not for a one piece of a study I found on SIPE that concerned me. A look at 70 cases of SIPE over 3 years was published by the Israeli army. They measured the oxygen saturation before and after the SIPE occurred. Before the attack, the swimmers oxygen saturation was 98 ± 1.7%. After the attack it was 88.4 ± 6.6%. Oxygen saturation is the measure of the amount of oxygen carried in the blood. Anything below 90% is considered clinical hypoxemia. I have a child who suffers from asthma, and from experience, I know that after a sever asthma attack, he can’t even leave the hospital until he is breathing on his own with 90% oxygen saturation. The fact that these swimmers were coming out of the water at 88% is alarming.
The whole reason I bring this up is to let you know that if you experience this problem, you should consider your day done. Being a hero and getting on the bike with the potential of a sub-90% oxygen saturation is an ugly prospect. Not only in terms of the rest of that day, but in terms of your recovery as well.
What can you do to avoid SIPE? It is really unknown but there seems to be good evidence that swimming on your back can attribute to this problem. Many athletes who start out with normal open-water distress naturally flip over to their back. The Israeli researchers hypothesize that this increases the pressure difference between the lower extremities and thethorax. Also being over-hydrated, and swimming in extra cold water.
Again, I don’t want you to worry about having a SIPE experience, I only want to let you know that if you ever do have it, remember to call it quits for the day.
I want to provide a quick shout-out to my fantastic group of athletes. To Carl, John, Paula, Rob, Steve, Kim, Damon, and Darren, I just want to tell you how lucky I am to be able to coach you all. You are a fantastic and dedicated group of athletes.
Swimming-Induced Pulmonary Edema. Clinical Presentation and Serial Lung Function Yochai Adir, MD; Avi Shupak, MD; Amnon Gil, MD; Nir Peled, MD; Yoav Keynan, MD; Liran Domachevsky, MD and Daniel Weiler-Ravell, MD, FCCP
From IDF Medical Corps (Drs. Adir, Shupak, Gil, Peled, Keynan, and Domachevsky), Israel Naval Medical Institute; and the Division of Respiratory Physiology and Chest Disease (Dr. Weiler-Ravell), Carmel Medical Center, Haifa, Israel.