Ross Tucker Does Not Understand Aerodynamics/Wind-Tunnel

The Resistance wrote:

Amazing to see all these arm chair scientists saying the findings of probably the foremost sports performance scientist in the world is wrong. Lol

Lol indeed. Ross is a fraud and frequently makes in correct assumptions. To "prove" his points. Tucker often makes the same mistakes. He starts off with an answer and attempts to prove that point instead of asking a question and seeking a real answer.

closing argument wrote:

So in summary, Nike could have installed the clock, which by itself is only about 10” tall, directly on the roof of the car, or maybe on the rear deck lid. It would still be plainly visible to the runners.

If for some reason they wanted the clock to be raised overhead, they could have installed it on a wind-permeable rack made of thin metal rods. That would have pretty much eliminated the wind draft advantage suspicions.

But instead, they chose to mount the clock on a gigantic sail and then ran this ridiculous contraption suspiciously close to the runners.

If there is no slipstream advantage to running behind this type of a contrivance, can anyone explain why Nike did it that way?

Look at pace car images on google. The set up is fairly standard.

It's really not. Google it yourself.

Nikes clock is small but in a huge enclosure and the car is much closer to the runners.

I don't even think Ross Tucker has a certified degree. He just talks a big game.

rojo wrote:

I called John Kellogg today. I said, "John what did you think of the run?" He said, "My god. I've been almost exclusively cycling for the last 15 years. I think that car might have been worth 7 seconds a mile."

Then he watched some youtube clips of the Berlin marathon WR and was trying to figure out how close the car was to the runners.

Here's the bet. I'll bet anyone on here $1,000 he doesn't break 2:02:00 in Berlin. I think it's possible he does (at best 2:01:30ish) but just think people are being fooled by the final time.

One thing I want our staff to follow up with David Katz is how many extra meters does a normal marathoner run in city race due to not running the tangents. I bet it's a lot.

I think your idea is a good one to place a bet because it makes it more fun. But...it's not really a fair bet because even though it's a world marathon major, the emphasis is still on winning rather than time. If all the runners went out to simply try and break the world record, that would be a different story.

Yes, I know you might say that there might be a $$$ bonus on the line if they break the world record, incentivizing them to run a fast time, but again, the emphasis is on winning and therefore runners are less likely to chance it on a break-neck pace and then blow up when they could just run a tad easier and get 2nd or 3rd.

It's interesting to me that Katz showed a link to the youtube video of the Rio Olympic women's marathon in another thread. On that course there's a painted line suggesting the shortest tangents to runners. However, the painted line doesn't come to within 30 cm of the gutter on some of the sweeping corners I saw, I think due to the fact that line marking equipment physically can't get that close to gutters. I don't doubt that the certification would have been for tangents at 30 cm from the apex of corners. Some of the runners were following the painted line and covering more distance, others (such as Linden) were cutting their own shorter tangents. It's up to the runner to run the shortest possible distance. Easy at Monza, not so easy at Berlin or Rio.

I don't think you are looking at that in the correct way. Years ago I came across a study that found the optimal way to pace was to run the first half of a race (mile or longer) in 51% of the total time (with no pacing.) My experience would show closer to 50.5%. In a 203 marathon, that would be splits of 62:07/60:53. That is assuming no pacing. If the race was even split 61:30, I would argue the pacing benefit the first half allowed a 61:30 at an effort of a solo 62:44. That is 1:14 slower or roughly 5 seconds per mile. The 6244 came from dividing 6130 by 49.5% which gives a 2:04:14 marathon. (What a 203 would have run with no pacing) So the point is that even though the time split is nearly even, the runner would have had to run slower without a pacer the first half of the race to be able to run as fast as they did the second half.

Ayana ran 1447/1430 for 10k. Kimetto ran 33 seconds faster his second half. I have no doubt in my mind that pacing at their speed is worth at least 5-6 seconds/mile.

Lastly, I would argue that since Kipchoge had pacers the whole distance, he would have had a better chance of breaking 2 with a 60:30 first half.

The CdA could be figured out pretty easily by paying a grand or thereabouts and getting an hour at a low speed wind tunnel like the one in San Diego.

Whether the CdA is .4 like the generic hands-on-the-hoods cyclist, or closer to .6 as I might guess given a Cd of 1.1 and frontal area of about .5m^2 (Usain Bolt was estimated at .80m^2 and Cd of 1.2, quite a ways off a CdA of .4) if there is a 20% reduction in air resistance that should account for a savings of approximately 3% when running around 5.83m/s.

I suppose that 3% number is why Nike decided to go for the record when they did. They knew it was within striking distance based on the numbers. Had they REALLY wanted to break 2, they would set this up as a Nike v. Adidas race. Basically, Nike could have said, "we'll supply the track, the car, the pacers, etc. all you got to do is tell Bekele to show up." Chances are, Kipchoge AND Bekele would have done it and Nike may have created some goodwill for the first time in about 40 years.

As a side note, Bob Beamon broke the world record LJ in Mexico City by 6.6%. The predicted increase in top speed would be 6.2% at that altitude with no wind, or about 6.28% with a 2.0m/s tailwind. It is 7.2% further than what I can find as his second longest jump ever, an 8.30m indoor effort 7 months before he went 8.90m in Mexico City.

What's the highest altitude Usain Bolt has competed at?

The clock didn't hurt...... wrote:

Henrik wrote:

First were shoes, then clock, what's next?

You're delusional if you think those shoes made any difference. Nike LOVES athletes who are so easily duped.

From scientific articles I have been able to find, a runner at around the pace they were going uses 8% less energy with no wind resistance. Running behind other runners breaks 80% of the wind. That would mean Kipchoge had a 6.4% advantage. In a regular marathon, he could probably have pacers for half the race at best so he had a 3.2% benefit. Nike is using that benefit to dupe people into believing the shoes are going to give them a 4% benefit.

I consider that FRAUD!

He would have run faster in an adidas pair (and I'm not endorsing adidas).

CJW wrote:

Had they REALLY wanted to break 2, they would set this up as a Nike v. Adidas race. Basically, Nike could have said, "we'll supply the track, the car, the pacers, etc. all you got to do is tell Bekele to show up." Chances are, Kipchoge AND Bekele would have done it and Nike may have created some goodwill for the first time in about 40 years.

Bekele is a Nike athlete.

Everybody is looking for things that helped him run 2:00:25. What about this huge drafting advantage reducing the cooling effect of wind resistance? Got to be a disadvantage there and need to subtract from these 2:01:30-2:02:30 guesstimates and reduce it to 2:01-2:01:30.

Armando

I don't see the paradox. I see is a simple energy-saving strategy. The situation on successful WR attempts is generally that a highly accomplished runner is drafting behind a number of less talented, paid pacesetters. As you cite, there is huge energy advantage in drafting for as long as possible, of the order of 2sec/lap on a 400m track at 10k WR pace. Essentially the future WR holder, call him KB, is banking a free 2 seconds for every lap he stays behind a rabbit. Around halfway most of the pacesetters drop and now KB is drafting behind the strongest pacesetter, who himself may have been drafting for much of the early race. Inevitably WR pace proves too much for this last pacesetter and the pace begins to slip below WR-pace. Now KB starts calculating: how slow can he let it go before going around the pacesetter? The point at which he takes the lead balances two competing energy considerations 1) even at slower paces by drafting he saves 1 or 2 sec per lap worth of energy which can be used later in the race and 2) every second he lets slip off of WR-pace has to be made up by running at sub-WR-pace later in the race. KB knows that running faster is less energy efficient (it is easier to run two 64s laps than a 66 and a 62). so that's the trade off. I don't know what the functional forms of these competing energy considerations but qualitatively it is clear that the optimal strategy will involve continuing to save energy by drafting for a while after the pace had flagged then employing this saved energy later in the race to make up the time.

How to test this? I suppose someone could ask Geb or KB. I'm sure these guys are acutely aware of how know help they are getting from the pacesetters.

The only way to determine the drag from the car is to physically replicate the car and clock and take actual wind readings. Any explanations else are just unproven hypnosis's.

Our comprehensive CFD simulations demonstrate that the Tesla was only a minor contributor to the drag reduction on Kipchoge, compared with the significant influence on the pacing team, and worth only 10 to 30s of his time:

http://www.runnersworld.com/sweat-science/did-the-tesla-pace-car-aid-eliud-kichoges-20025-marathon

https://www.linkedin.com/pulse/uncovering-aerodynamic-trickery-behind-nikes-breaking-ferguson

I was the guy pushing for some testing, so I'm really glad they did that. The results also square right on with my estimates for the relative effects of the running pacers vs the car - that it wasn't all about the Tesla and clock. I was getting harassed by Nikolai and other must-be-the-clock guys for that assessment. From the first link:

"Moreover, the car’s effect was an order of magnitude smaller than the benefit provided by the human pacers. In terms of power consumption, Ferguson and Beves estimate that the humans saved 28 watts, while the car added another 3 watts.

In terms of time, the humans saved 4:09, while the car saved another 26 seconds. Those times are compared to running solo; compared to a “typical” big-city marathon with pacing for at most three-quarters of the race, you’d divide the result by somewhere between two and four. So you’re looking at a draft benefit of somewhere between one and two minutes, of which perhaps 10 seconds can be attributed to the car."

I was surprised that the engineers that Ross said he talked to was telling him it was the car, because that didn't seem right with my quick assessment after looking at the actual following distances figuring the speed of 13.1 mph is about half a bike race speed that many people are more familiar with in regards to drafting. Those guys must have been more off-the-cuff in their initial reaction than me:

"As aero engineers, we expected that the Tesla was creating a massive aerodynamic wake which was responsible for most or all of the time savings,” Ferguson told me. “We were relieved that the results proved us wrong, because whereas drafting behind a car seemed like a deliberately illegal stunt, running behind well-organized pacers seems like a tactic that someone might more easily be able to replicate in a legal race.”

The fact that the "red line" in Rio did not take the absolute shortest path (the line measured 30 cm from the turns and curb) was by design. I had the local organizing committee paint the line about 1m + form turns. This was important on the large 10km loops ( 3 x) for safety, not to direct the runners too close to the edge. But the line was a great asset for the long sweeping tangents. One additional note: the red line was improperly placed on the south turn of the 10k loop in Rio but I personally set up every cone to ensure it matched the measured course.

For the Monza course, I also hand placed every cone and cycled around the course several times up until the start to make sure they were in place.

In my opinion not enough is done at major marathons looking to have records in regards to making sure that the measured course is clear of barricades and obstacles. For the London Olympics, we spent several hours before the race moving back barricades off he road . Plus often elite fluid stations are too far off from the measured line forcing the runner to run extra meters.

So it looks like Ross Tucker was right all along.

zzzz wrote:

"Moreover, the car’s effect was an order of magnitude smaller than the benefit provided by the human pacers. In terms of power consumption, Ferguson and Beves estimate that the humans saved 28 watts, while the car added another 3 watts.

In terms of time, the humans saved 4:09, while the car saved another 26 seconds. Those times are compared to running solo; compared to a “typical” big-city marathon with pacing for at most three-quarters of the race, you’d divide the result by somewhere between two and four. So you’re looking at a draft benefit of somewhere between one and two minutes, of which perhaps 10 seconds can be attributed to the car."

31 watts saved is extremely unlikely if EK was around 6w/kg for this effort. I can't believe he would have saved 4:35 from the draft of the car and pacers combined. Over 10 seconds per mile seems highly unlikely otherwise Rudisha should be able to run around 1:34-1:35 for 800 in a similar setup. And Webbs AR for the mile would be well under 3:40.

That's very interesting.

I've always thought that it would be impossibly hard to run close to many barricades at big city marathons, meaning the shortest path was basically impossible. Considering people are leaning over waving flags and taking photos you don't want to end up smacked in the face, so maybe they are 1m further away than the fastest line.

Would be great if a deadly accurate shortest path line was painted on the road on he next city marathon so everyone could watch how accurately he runs the line (same as Monza). I don't mean just a guess, but a line done in coordination with the measurer.

I've seen lines painted at some marathon's before but there is usually a big question mark as to their accuracy.

D.Katz, you need to build a contraption to drip paint from your back wheel as you measure on your bike.