Detailed Drafting Analysis of Kipchoge's 2:00:25- He Gained Between 1 to 4.5 Minutes from Drafting

So the science is unsettled to the point that its somewhere between 1 minutes and 4.5 minutes?

I've definitely been in marathons where a large clock on top of a car was in front of the lead runners. At my peak I was close to the speed of the top women, so I have some very clear memories of it.

Also, I wonder how much better Eliud's pacers were than Geb's (for the time Geb had them)?

https://tonireavis.files.wordpress.com/2015/08/berlin-pacers.jpg

EK wasn't getting a drafting effect from the car or the pacers. At the speed he was running and the distance he was behind the pacers he got no measurable benefit or advantage over a runner in a typical marathon race.

adsfsdafasd wrote:

I've definitely been in marathons where a large clock on top of a car was in front of the lead runners. At my peak I was close to the speed of the top women, so I have some very clear memories of it.

Show us the photo.

Gotta bee wrote:

is this time "gained" over the course of the entire race?

pacers can usually go about 30K so you can basically take 60-75% of the "gained" time off this number

Pacing goes to 30k but it is a lot less efficient (not as many bodies, not as optimized pacing). It is hard to say if Kipchoge gains 1 min or 2 from the optimized pacing.

above_average_joe wrote:

great analysis, exactly what we needed. the contribution of the car was not obvious at all, quantitatively. the comparison to cyclists is misplaced as the speed is not comparable (and the relationship drafting - speed is not linear).

the comparison to cyclist is in fact not misplaced AT ALL. at low speeds like these runners were at AND like cyclists ride at, you can easily predict time/energy savings with a simple calculator. remember, drafting for cyclists is not only a factor on flat ground, but on climbs as well.

In 2003 Paul Tergat shattered the mens marathon record by running 2:04:55. Are we to believe that Tergat wouldnt be able to run with EK if everything is on the up and up? Give me a freaking break!

different perspective wrote:

Besides the human wall of drafting that provided such a lowering of overall wind resistance, the lack of mental stress that was required to follow the pacer had to have been a huge help too. Knowing with at least 99.9% accuracy that the pace car and pacers in front of you are going to run at the exact pace you need would have allowed Kipchoge to almost go into auto-pilot for most of that race (until the fatigue really started to kick in). No racer in normal race circumstances gets to turn their brain off in quite that way either. It must have felt pretty amazing to run in that situation, almost like having a tailwind when compared to normal conditions.

+1

And he would have gained another 30s to a minute over a real world course like Berlin by having a much easier and faster 'shortest possible line' to follow and having mobile at call feed stations.

Not that precise wrote:

So the science is unsettled to the point that its somewhere between 1 minutes and 4.5 minutes?

Our CFD simulations predict that Kipchoge would run about 4.5 mins faster using the Nike drafting setup than a solo (undrafted) runner, based on drag savings alone.

The simulations are somewhat idealised (for example assuming a perfect pacing formation for the whole race) and the conversion from "drag force" to "time saving" involves a large amount of hand waving. It might be less than 4.5 minutes, but I doubt that it's a lot less than 4.5 minutes.

nobody doubts that kipchoge is the best marathon runner in the world. i hope there is something left in the tank and he could break the record legally.

but your statement is blatantly wrong.

It amazes me you didn't already know that running right behind someone has a big drafting effect. You don't need to be a cyclist to know that already, it's common sense! Why bother having pacers at all if the car was doing all the drafting effect...

As someone else said, the lack of competition and atmosphere (most of the course was very quiet) must have had a big impact too. Kipchoge got none of the mental boost he would have from crowds lining the course. If Nike had made it an open even I think he would have gone sub 2.

different perspective wrote:

Besides the human wall of drafting that provided such a lowering of overall wind resistance, the lack of mental stress that was required to follow the pacer had to have been a huge help too. Knowing with at least 99.9% accuracy that the pace car and pacers in front of you are going to run at the exact pace you need would have allowed Kipchoge to almost go into auto-pilot for most of that race (until the fatigue really started to kick in). No racer in normal race circumstances gets to turn their brain off in quite that way either. It must have felt pretty amazing to run in that situation, almost like having a tailwind when compared to normal conditions.

Great point

an actual aero expert wrote:

As for all these people with fancy pictures doing analysis: it is neither difficult nor expensive to go to a low speed wind tunnel, such as the one in San Diego. Why don't they get actual data?

Seriously? Wind tunnels are always more expensive, and usually less accurate than numerical simulation. They also provide a lot less data.

Explain to me how you are going to fit a Tesla, and 7 runners in a wind tunnel again?

I think people need to realize he can run 2:03 at a normal race in normal shoes...with normal pacers.

So his 2:00:26 would have been a 2:03-2:06 no way! He could have run that race with normal pacers and no car. Just running on the perfect ashaplt would have helped more than the Tesla.

Have you ever tried to run a 4:30 mile on bumpy...city streets compared to a track?

For anyone they actually runs marathons and has been super fit... I think there is a velocity I can run at.... For me it's 5:25 mile pace. You can give me a head-tail wind and I do go a bit faster or slower but I can only run about 5:25 pace regardless. Aerobically I can run faster...mechanically I cannot.

If you put me out on the open road that goes from 5:25-5:35 for terrain/wind/weather. I can't run 5:20s easily for 15 miles even if it's downhill. For me it's mechanical...he was shockingly..relaxed at 4:30 pace. The other runners were struggling. He can run that pace regardless of help. He just needs a windless day/cold weather.

He looked relaxed at the sub-2 hour pace. If he gets into a race with decent pacers and with stellar weather I think he or someone can actually run that pace for a marathon.

Nervousrunner wrote:

I think people need to realize he can run 2:03 at a normal race in normal shoes...with normal pacers.

So his 2:00:26 would have been a 2:03-2:06 no way! He could have run that race with normal pacers and no car.

That's not what we are saying. We are saying that the pacing and cars combination is up to 4.5 minutes faster than an undrafted solo runner (which is 2:05).

Do you think that Kipchoge could run 2:03 on his own, without any pacers to take the wind for him in the first three quarters of the marathon? I don't.

Radcliffe was nearly 2 minutes quicker when she ran with men than when she ran alone in a female only race.

Faster yes... I'm sure the pacers don't hurt... but all marathon world records have been set with pacers lately. So now we are creating rules about to good of pacing? That is silly.

.....you still have to run...unlike drafting on the bike... the draft can be so strong you can literally not pedal. Running you still have to run.

Running behind a car/wall you still have to lift your body and impact the concrete. It isn't the same as Cycling at all. No doubt it is easier to run with a tail wind but that is different. I honestly don't think on a cold calm day you need a draft. The biggest factor in that race was running on a great road surface.

Smooth and no cracks or turns....

Their analysis is incomplete, the benefit was closer to 8-10 minutes.

With that said, think about what else happened here: Nike was able to produce/train/create a potentially absolute-peak performance on the specific day, at the specific time, with one specific athlete in a non-race environment.

That's the breakthrough.

borofergie wrote:

an actual aero expert wrote:

As for all these people with fancy pictures doing analysis: it is neither difficult nor expensive to go to a low speed wind tunnel, such as the one in San Diego. Why don't they get actual data?

Seriously? Wind tunnels are always more expensive, and usually less accurate than numerical simulation. They also provide a lot less data.

Explain to me how you are going to fit a Tesla, and 7 runners in a wind tunnel again?

Yes, seriously. It's about $1,000/hr for time at San Diego's LSWT. I've been many times. It's true you aren't going to put a Tesla in there, however you can definitely get runners in there in different configurations.

As for an actual real-world wind tunnel being less accurate and less informative than a simulation, that's laughable. You do the simulation first, sure, but then you go to the wind tunnel to see if it's accurate or more likely to find out the simulation was wrong in a way you hadn't anticipated. That's generally how it goes with aero testing. Simulations are great, truly, but if it doesn't play out that way in the real-world it's not helpful.

What do you reckon Kipchoge's CdA is anyway?

krispy kremlin_._._. wrote:

With that said, think about what else happened here: Nike was able to produce/train/create a potentially absolute-prank performance on the specific day, at the specific time, with one specific athlete in a non-race environment.

FIFY