Wednesday, October 28, 2009

A Day at the Wind Tunnel

A few weeks back Dean, Geoff and I traveled to the CCNS Performance Center Wind Tunnel for some equipment testing. We had a great session and we thought it was worth sharing our experience and what the wind tunnel can offer.

From past experience we know that the wind tunnel is not a place to be redefining your riding position - it is a place for subtle refinement and equipment testing. We have seen some people who have gone through wind tunnel testing at some facilities and the session focused so much on aerodynamics that the position they arrived at was not at all maintainable or comfortable for the rider outdoors. The results were a very fast looking position, but the rider actually compromising power and comfort so much that they were actually slower. To get the best results from the wind tunnel, you should have a comprehensive bike fit first to establish a solid and biomechanically functional position and then you should spend your time testing minor changes in position and testing different equipment (like helmets, hand angle…). This is what we did.

The Tunnel:

CCNS uses low air speed around 14mph which reportedly gives the same aerodynamic drag coefficient (CdA) results as at race speed. CdA is the product of a rider’s frontal area (A) and a coefficient of drag (Cd). The lower the CdA, the faster you’ll go for a given power output. CdA is generally a fixed value independent of rider speed. Our testing was done without pedaling or wheels moving. They have the capability of testing with rider pedaling, but we preferred the accuracy and precision of the rider sitting still as we were not going to redefine our position and wanted to focus on non-dynamic positioning changes and equipment differences. Knowing this ahead of time we chose to focus on testing equipment and position changes that shouldn’t be effected by pedaling mechanics. We didn’t bother to venture into wheel testing, frame water bottle placement, and anything else that’s more dependent on moving rider/frame/wheel interaction.

Dean getting ready
Dean getting ready

Testing Protocol:

Dean and Marty tested about six positions each during the course of the sessions at a 5 degree yaw angle. Based on Dean’s past testing and representative real world wind conditions he sees on most TT courses the 5 degree yaw angle best represented the conditions we were seeking. Each position test included 4 separate 30-second runs, and the CdAs from each of those 4 runs were averaged to give you the final CdA for that position. Accuracy and precision were taken seriously as the wind tunnel drag measuring equipment was checked and calibrated before each run.

Athlete’s Starting Equipment and Kit:

Dean: Cervelo P4, HED Integrated aero bars, long sleeve Champion Systems speed suit, aero booties, Louis Garneau Rocket TT helmet, Zipp ZedTech 1080 front and rear 900 disk, no hydration on the bike except the integrated P4 water bottle.

Marty: Parlee TT bike, Zipp Integrated Vuka Bar, Champion Systems Tri Top and Tri bottom, Louis Garneau Rocket TT helmet, Zipp 808 front and rear 900 disk, no hydration on the bike.

Marty's First Run
Setting Marty up for his first run

Testing and Results:

Over the years Dean has refined his position and equipment selection through hundreds of hours of field testing. As record holder of numerous local time trials and triathlon bike courses, his testing results and very aerodynamic position have propelled him to many impressive finishes. If any significant improvement was gained as a result of this testing session we would be happy.

Starting Position:

Dean: Reported CdA values tend to vary from wind tunnel to wind tunnel due to a variety of factors we won’t get into regarding air boundary layer control, air speed measurement, and drag measuring technology. CdA is also impacted by yaw angle, whether or not the rider is pedaling and wheels rotating. For the purpose of this visit it’s not the exact CdA value that matters, but the relative changes to this value that matter. Dean tested his CdA in field testing in the 0.22-0.23 range out of the wind tunnel. The first run resulted in a CdA of 0.240, so we felt we were in range.

Marty: Current CdA had not been accurately determined with field testing, but we’ve estimated his CdA at 0.250 based on race results, and training rides given his body size, equipment, and power output. Starting position resulted in a 0.261 CdA.

Position #2:

Crunching numbers
Crunching numbers


Helmet Change: Dean switched from the LG Rocket to the LG Superleggera. The Superleggera is the newest version of the Rocket helmet, but has dimples over the top and larger vents in the front. The best TT helmet for a rider tends to be very individual and this was certainly the case for Dean.The Superleggera was clearly faster than the Rocket for him so he kept this on for the rest of the tests: Result = Faster: CdA 0.236


Drop: We moved Marty 2 cm lower which resulted in the same 0.261 CdA. If anything the lower position could have proved less comfortable or resulted in some power loss from closing him off too much at the top of the pedal stroke. Since there weren’t any benefits we moved him back to the starting position and moved on to Helmets.

Position #3:


Drop: We dropped the front end 2cm lower than his current field tested position. The result was the same CdA, so there was no reason to run any more drop than he currently had. Dean had already tested this in the field and did not see a benefit, but wanted to try it under wind tunnel conditions. Result = Same: CdA 0.236


LAS Crono TT Helmet: In Marty’s case the LAS Crono proved slightly faster than the LG Rocket.Equipment can be very individual and this proved the case here. Result = Faster: CdA 0.256

Position #4:


Drop again: We raised the front end 2cm higher than the baseline (4cm higher than position #3). We only did 2 data runs because this position was clearly slower, so we didn’t waste any more time. Our conclusion was that he must have passed a critical point where his head was just getting too high in the wind and drag went up quickly. Result = Slower: CdA 0.260


Spiuk Kronos Time Trial Helmet: Big gains made with the Kronos. Marty’s starting CdA was 0.261 and the Kronos brought this down to 0.246. Significant savings on paper!

Position #5:photos-012


Horizontal Water Bottle mounted between the aerobars:We went back to the baseline drop and then added the water bottle between his forearms. Dean ran this system during Timberman and while it felt different he wanted to know the actual difference.

Cervelo tested something similar in the wind tunnel and said it reduced drag, but this definitely depends on the individual setup, and likely yaw angle as well. Result = Slightly slower than fastest run: CdA. 0.239


Reach: Marty realized during races that when he held the end of his aero extensions that his head dropped and he felt just as relaxed and powerful. We’d experimented with this in the shop and noticed not only did his head get lower, but his shoulders narrowed a bit with the longer reach. The wind tunnel confirmed our suspicions as the resulting drag reduction was notable. Marty’s CdA dropped all the way to 0.237 .and we knew that Marty had refined his riding technique enough in the past few years to the point that he could maintain this longer position comfortably.

Position #6:

A view from inside the tunnel
A view from inside the tunnel


Aerobar Angle - We tilted Dean’s Hed aerobars up just slightly - about 5 degrees. He’d tested this in the field without seeing any gains, but had made some other position changes since then. Dean noticed that a slight amount of tilt leveled off the tops of his forearms, lowered his head and shoulders slightly, and was more comfortable. As he settled into the position he figured that if he got the same CdA then he would run this position since it was more comfortable. We were all pretty excited during the first run because there was quite a reduction in drag. After 4 runs including a re-check of the calibration we confirmed a faster and more comfortable position. Result = Fastest: CdA 0.229


We tested his aero pads closer together, and it actually increased his CdA to 0.244. We went back to his original pad width and tried tilting the aerobar extensions up 5 degrees just like Dean’s. The upward extension tilt actually increased Marty’s CdA, despite helping Dean lower his, which supports our experiences that aerobar tilt/angle gains tend to be

Final Analysis:

As bike fitting experts we expected our starting positions to be fast, but looked forward to searching out any potential gains in equipment and fine tuning our positions. In Dean’s case the only two things that helped make him faster were the helmet change and the aerobar extension tilt. In Marty’s case a different helmet change and slightly longer reach made significant improvements.

Dean lowered his CdA from 0.240 to 0.229 which at his race power and speed is worth about 17 seconds in a 10-mile TT, 27 seconds in a 13-mile sprint bike leg, and about 1:40 in a typical HIM 56-mile bike leg.

Marty lowered his CdA from 0.261 to 0.237 which at his race power and speed is worth about 46 seconds in a 10-mile TT, 57 seconds in a 13-mile sprint bike leg, and about 4:16 in a HIM 56-mile bike leg.

Take Home Message:

The trip to the tunnel was a blast and the sessions are best used to refine your position and/or look into equipment options. We are excited to try out the tunnel results in 2010 and see how well they hold up in the real world.

Like previous trips to a wind tunnel, our recommendation that the athlete should go through the bike fitting process before heading to the wind tunnel was reinforced. Wind tunnel time goes by quickly and it is not cheap. It does not make any sense to use valuable tunnel time finding gains that are easily identified outside of the tunnel in the bike fitting process while also establishing the rider’s individual biomechanical range that they need to stay in if they are going to maintain power and comfort. By getting fit first, the athlete will be able to use most of his/her time refining details that can only be accomplished in the wind tunnel or carefully controlled field testing. If you have any questions or would like additional information on our fitting services please contact us directly.

Disclaimer: Our testing session at this wind tunnel was done at only one yaw angle, there wasn’t any pedaling, and the wheels weren’t turning. Actual CdA values for riders pedaling on moving bikes in a range of real world wind conditions may be slightly different but will be in the same ballpark. We are looking forward to racing in our new positions next season, and of course field testing things against them in our continuous quest to find faster positions and equipment for the athletes that work with us!

Wednesday, October 14, 2009

Swim with the fishes

Swim with the fishes usually means someone is dead, but not in this case. It's what I hope to do more efficiently as I prepare for IMLP. I've been working with Craig Lewin of the North Shore Swim Club and I'm excited share my initial evaluation with you. Lot's of work to be done, but I'm working with the right person. If the swim is an area of weakness and you want to improve Craig will get you there.

Marty Miserandino Stroke Evaluation by Craig Lewin - North Shore Swim Club -

Your stroke has come a long way since we started working together at the beginning of the summer. Your freestyle looks much better and you are starting to grasp the concepts needed for an efficient stroke. There are still some aspects of your stroke that need correcting to have an efficient stroke to help you fly through the swim using as little energy as possible. This efficiency will make your Ironman Lake Placid experience much more enjoyable because you will exit the water with a fast swim time and you will feel warmed up and ready to go for the bike. You will get on the bike feeling fresh and you will feel as though the swim was effortless. You will have the energy you need to put together solid bike and run legs to finish off the race.

The first major correction that needs to be made is in your hip rotation. As of now you still need some work rotating from one side to the next. The roll from the lower back up through the shoulders is good but the hips and legs remain flat. You need to get the hips to match the roll of the body. The body rolls as a unit, so think of the body as a log. A log cannot roll in segments, it rolls as one large unit and that is exactly how your body needs to roll as you go from one stroke to the next. This body roll is going to allow you to reduce your drag in the water so you will move faster and smoother in the water. The way we are going to go about correcting this problem is through the use of a couple of drills that focus on body position and balance in the water. We will start with fins until you get the hang of it and then from there we will drop the fins so that it will be closer to what the body position should feel like when swimming without any equipment. The use of the fins with these drills also helps to fix the dynamics of your kick and will actually make you a better kicker as well. The drills that we will be using to help correct these body roll issues are: head lead kick on stomach, head lead and hand lead sweet spot on the right and left side, Six Kicks and Roll, One Stroke Six Kicks, and the Kickboard drill. These drills are a progression that will teach where your balance point is in the water. Each drill will build on the one before it so that by the last drill you are swimming with better body rotation.

The second issue that needs correcting is in the recovery phase of your stroke. When you are entering the water, you are entering thumb first with your knuckles facing in and you are entering too shallow. The most efficient stroke is when your knuckles are aiming in the direction that you are swimming in. You also want to aim for the bottom of the T at the other end of the pool as you enter because this will ensure that your hand enters at the proper depth. This deep entry will eliminate the possibility of a shoulder press in the stroke. We want to avoid the shoulder press in the stroke when entering the water too shallow for two main reasons. The first is that having this shoulder press will lead to some major pinching in the shoulder and will result in a very serious shoulder injury. The second reason is that this motion only lifts your body up it does not move it forward. Everything in swimming is linear so any motion that is not a forward/backward motion is inefficient and a waste of energy. As your hand exits the water at your hip, you want to lift your elbow to the ceiling and drop your forearm so your hand is within a couple inches of your torso. This relaxing of the forearm and hand will naturally cause your knuckles to face the end of the pool that you are swimming toward. Once your hand is just beyond your head and inline with your shoulder you want to drive your finger tips down eight to ten inches deep. As you do this you are rolling into the stroke so that you get full arm extension and can catch more water during your catch phase. The drills that we will use to correct this problem of entering thumbs first and too shallow are: shark fin drill on your left and right side, stop-stop-switch drill, double entry drill, and catch-up drill. These drills will help get your arm in the proper position when starting the recovery. They will help keep the hand close to your side with your knuckles facing the proper direction. They will allow you to focus on entering deep and fully extending as you roll into the stroke making for a very fast and efficient stream line stroke.

The third issue that needs correction is your catch phase. Currently you drop your elbow and do not catch much water on the pull through. After your hand enters the water finger tips first and goes eight to ten inches deep, you want to fully extend your arm out as you continue to roll on your side. Once you are ready to pull you need to press down slightly with the finger tips and forearm. As you do this slight press you pop your elbow up. This will anchor in your arm and allow you to actually grab the water. Once you have popped the elbow up you want to pull through. Getting your elbow up and pressing your hand shifts the muscle group being used to pull from your shoulder to primarily your lats which is exactly what you want to do. Your shoulder muscles are not made for the constant contraction experienced when swimming. Your lats are much bigger muscles and they can handle this constant contraction and relaxation. Not only can they handle this but your lats can produce more power so that you can actually move faster with every pull, which is essentially the goal of swimming. This is why it is so important to get the elbow up when you start your pull and to keep it up throughout the pull. When you pull, you want to move your arm through the water as a unit once you have pressed your hand and forearm down and popped the elbow up. Your elbow should always be higher than your wrist during the pull phase of the stroke. Then as you pull you are rolling from one side into the next stroke on the other side. This pressing with the hand and forearm and popping the elbow up is what is missing in your stroke. To fix this problem area the drills that we will be using are: Hand lead sweet spot focusing on keeping the arm in line with the shoulder, Press-Release drill on each side, Press-Release-Press-Pull drill, One Arm Swimming, Catch-Up stroke, and Semi-Catch-Up stroke. These drills will help slow down your stroke enough so that you can focus on the slight press of the hand and forearm and the popping up of the elbow. You should be able feel the contraction in your lats as you do the slight press and continue to feel it as you pull the arm through until your hands exit at your hips.

The plan for the rest of the fall is to correct your technique while maintaining your fitness level as well as some speed. I want to really focus on making these corrections now and really reinforcing them before we hit base phase come January. This way you will have a proper stroke and you will not even have to think about what you are doing anymore. You will be able to really focus on the purpose of the sets rather than both the purpose of the sets and correcting technique. Once you get to that point we will really be able to get some big yards and fast swims in without having to worry too much about any shoulder injuries. You just have to remember that fixing these technique flaws is easy speed. Becoming more efficient makes you faster with less effort and that is why the speed comes easy. Combining this technical approach to swimming with some speed and distance workouts is going to lead to big drops in time come the 2010 triathlon season. This is not an easy process but it is essential in the sport of triathlon when the swim is only the beginning of your race. Swimming fast while saving energy in the swim through proper technique is what will lead to a successful day out on the race course. By the time the triathlon season comes around you will be swimming fast and efficiently and the 2.4 mile swim at Lake Placid will be the easiest part of your day!

Up next: The bike

Monday, October 5, 2009

It starts today

Today is what I consider to be my first day of Ironman prep. Steve Prefontaine had a great quote my brother told me about... "preparation breeds confidence" and boy is that true.

Over the last several weeks I've focused on getting my body ready for the miles that will pile up and, as I start my actual training, I will keep focused on building strength and adding in some swim technique work.

I'll be working out at B&S Fitness in Salem. I'm starting a conditioning program called Psychofitt which focuses on full-body strength, cardio, agility and core. In addition, I'll do a third day of full body work at Paradise Gym in Swampscott. Rachel at Paradise has been putting my through the paces over the last few weeks and I feel stronger already.

In addition to full body strengthening, I'm jumping back in the pool tomorrow. Craig Lewin of the North Shore Swim Club knows his stuff and we'll be focused on technique. I need this badly as my swim is an area where I can make instant gains. Craig coached me last year and I had my best swims to date, but I started late, so I didn't have the base phase of pure technique and that's what we'll be starting tomorrow.

Thank you for coming along...

Topics to follow: Nutrition and my trip to the wind tunnel



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