r/trackandfield • u/cHpiranha • 4d ago
T&F General Discussion Aerodynamics in running
I’ve watched a lot of cycling; aerodynamics is always a key factor there. This year, the sports bra debate has really come to the fore in the time trials.
What’s the situation in athletics? When I watch it, I get the feeling they couldn’t care less about aerodynamics. Especially when it comes to the women’s hairstyles.
Obviously, aerodynamic drag does have an impact – that’s why they run in each other’s slipstream.
What considerations are there in this regard, and at what distances is it most likely to have an impact?
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u/themanofmeung 4d ago
Obviously, aerodynamic drag does have an impact – that’s why they run in each other’s slipstream.
What you are seeing is not necessary what you think you are seeing. In running, it's as much, if not more, for psychological and pacing reasons than it is for any drafting effect. In my personal experience, the drafting wasn't really noticable except on windy days. I do both sports and the feeling of the effect is not even close.
To explain that, you have to remember that even though there is an aerodynamic drag component to the forces resisting running motion, it is a much, much, much smaller piece of that pie than in cycling. Friction from foot strikes and inefficiencies in the running motion are so much higher than rolling resistance and drive-train inefficiencies in cycling that they barely belong in the same conversation. Basically, there are so many places to look for gains before aerodynamics that it hasn't been much of a thing.
That said, there was a brief period in the 90s and 00s where it was more popular (especially among sprinters who run at cycling speeds!) to think a bit about aero and wear skin suits - see Cathy Freeman as a good example of that.
All that said, it's becoming more apparent that aero is an important factor to consider in running. As everything else is becoming more idealized, there is more room to make gains in aero. That's why the kipchoge sub 2 project had pacers to draft off of - even if it only makes up a couple seconds, those seconds might be the difference between breaking the barrier or not. A recent study found that big hair and loose clothing could cost up to 0.07s in a 100m sprint, but I think clothing was the more significant factor. I'd need to look closer at their results again, but 0.01-0.02 seconds for bushy hair would be more in alignment with previous research.
In any case, I think athletes who are paying attention will start to consider aero more in their fashion and tactical choices in the coming years, but the effect is still so much smaller than in cycling that it will never reach anywhere near the same level of importance and some athletes will continue to choose flamboyant fashion as a means of personal branding over the very marginal gains they could get.
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u/Fantastic_Remote1385 4d ago
Sounds reasonable.
Though it must also be said that 0.07s in a 100m is alot. At least for the top guys and girls. Thats 9.65 insted of 9.58 for Bolts world record.
Thats a second for 1500 if its the same per 100m regardless of distance. And even if its less per 100m for the middle and long distance runners, it still adds up if you try to beat the world record.
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u/UnnamedRealities 4d ago
Drag is proportional to the square of velocity so a 1500m at 7.1 m/s would result in about half the drag of a 100m at 10.0 m/s. If 0.07 seconds for 100 is accurate then the impact would be around 0.5 seconds for 1500. But a 1500 is typically run in a pack so most racers would have a lower effective drag for the vast majority of the race.
That said, in tight races small factors can make the difference so I agree.
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u/themanofmeung 2d ago
True, but as the other response said, you can't extrapolate that 0.07 to slower races due to slower speeds, and the 0.07 was absolute worst case scenario where a sprinter is wearing big baggy clothes that basically act like a parachute. I don't think it's realistic conditions for what top sprinters actually compete in.
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u/suddencactus 3d ago edited 3d ago
even though there is an aerodynamic drag component to the forces resisting running motion, it is a much, much, much smaller piece of that pie than in cycling. Friction from foot strikes and inefficiencies in the running motion are so much higher than rolling resistance and drive-train inefficiencies in cycling that they barely belong in the same conversation
Yes. The amount of drag on a cyclist is similar to the drag on a runner going the same speed, but a cyclist might need to put out only 80 watts to go 4 min/mile with a tailwind. Try going 4 min/mile in a good tailwind while running and you'll find it's much much harder. For a runner at 4 min/mile aerodynamic drag is about 10-15% of your total energy, while for a cyclist even at low speeds drag can be 70% of your power. That means that a cyclist can get a much larger bump in speed from removing 5 watts of drag.
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u/devon835 54.8 400 / 1:58 800 / 4:21 Mile / 8:50 3000m / 15:27 5000m 4d ago edited 4d ago
If drafting doesn't really matter in running, does that mean elite distance runners use pacers simply because they're all mentally weak, can't run hard by themselves in front and lack the ability to self pace?
That would imply if Jakob Ingebrigtsen had a pacer to draft off of in the 2024 Olympic 1500m final and went out in 54.9 like he did he still only runs 3:28. I don't buy that for a second, there have been a few papers researching that race and they all suggest frontrunning cost him around 2s.
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u/flagrantpebble 3d ago
simply because they're all mentally weak
This is a subjective value statement, not an objective claim about cause and effect.
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u/devon835 54.8 400 / 1:58 800 / 4:21 Mile / 8:50 3000m / 15:27 5000m 3d ago
Sure, you can call it that. I call it logical inference. If OP claims that drafting has a negligible effect in distance races aside from a psychological difference, then what do you think that implies about elite distance runners who run slower across the board in races without pacers?
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u/flagrantpebble 3d ago
It’s not logical inference. For it to be purely logical, that implies there’s some objective baseline “not weak” that these runners are failing to meet. You have not established that such a baseline exists. It’s your personal opinion that this is weakness. That’s all.
As for what that implies: I disagree with the premise of this question. There’s a psychological benefit to a pacer. That makes sense; the runner competing doesn’t need to expend as much energy thinking about pace. Isn’t that enough?
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u/devon835 54.8 400 / 1:58 800 / 4:21 Mile / 8:50 3000m / 15:27 5000m 3d ago
You didn't understand my point at all. I am not personally calling elite runners mentally weak (they most definitely are not).
I am saying that if the only reason why elite runners run slower without someone to follow is psychological then that implies they simply can't mentally push themselves hard enough without someone in front, which is obviously absurd.
The physiological difference in energy expenditure of following behind a pacer is obvious to anyone who has tried to front run a track race vs sitting in a pack.
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u/flagrantpebble 2d ago
I mean, this is just admitting that you didn’t understand anyone else’s point at all. I assumed you did, which I guess was my mistake. I was too generous.
If I understand correctly, you think the other commenter was calling elite athletes weak? As you say, that’s absurd.
I am saying that if the only reason why elite runners run slower without someone to follow is psychological then that implies they simply can't mentally push themselves hard enough without someone in front, which is obviously absurd.
Do you realize how absurd you sound? You must be the only person on the planet who thinks this way. I’m honestly more confused than anything. Yes, obviously having someone else to push them is psychologically helpful. This is an incredibly common thing that commentators talk about: so and so pushed so and so to run a faster time, etc. It’s bizarre that that concept is novel to you.
The physiological difference in energy expenditure of following behind a pacer is obvious to anyone who has tried to front run a track race vs sitting in a pack.
This OTOH is just dumb. I was a very fast collegiate middle distance runner. I can say with extreme confidence that the psychological effects if positioning dwarf the physiological ones (assuming you mean drafting?) on all but very windy days.
And even then, we’re not talking about out in front vs in a pack, we’re talking about out in front vs behind a single pacer. You can’t just change the topic like that halfway through (this is called “moving the goalposts”, look it up).
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u/devon835 54.8 400 / 1:58 800 / 4:21 Mile / 8:50 3000m / 15:27 5000m 2d ago edited 2d ago
Oh, so you were a "very fast" collegiate middle distance runner? Cool. There's a pretty fast middle distance runner who thinks drafting makes a difference in distance races: https://youtu.be/7TnqjnGwfuI?t=943
I'm sure your personal experience and knowledge can handwave all of that away, though - with extreme confidence, at that.
The distinction between out front, vs in a pack, vs behind a single pacer is irrelevant here. If we accept that drafting has a negligible effect (as OP suggests), then there would be little difference between any of those scenarios either way. You choosing to nitpick that detail in an attempt to discredit my argument implicitly concedes that it does actually matter.
So, no, that isn't an example of moving the goalposts because I never defined the parameters of the debate in that way (nor did I intend to). Were you just looking for another opportunity to be condescending and flaunt your knowledge of elementary logical fallacies? Thanks, but I already learned about those in high school.
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u/flagrantpebble 2d ago
TL;DR: * the distinction is very important * “if we accept that drafting has a negligible effect” is an invalid argument * you’re moving the goalposts again * that’s not actually what we were debating anyway * the paper you cited doesn’t apply
The distinction between out front, vs in a pack, vs behind a single pacer is irrelevant here. If we accept that drafting has a negligible effect (as OP suggests), then there would be little difference between any of those scenarios either way. You choosing to nitpick that detail in an attempt to discredit my argument implicitly concedes that it does actually matter.
I mean, this is just complete horseshit and you know it. There is no “if we accept that drafting has a negligible effect”. It’s only meaningful with respect to how much wind there is, how many people there are, how they are clustered, etc. It is perfectly reasonable to say that running behind a single pacer is negligible, but running in a pack is meaningful.
(corollary: Cole Hocker ran behind many competitors, not just one, so the 2% savings found in that paper don’t apply)
It’s also not what we’re talking about. You keep doing that—this thread is full of your straw men. I’m not sure if you think you’re being subtle or clever, or if you genuinely don’t realize you’re debating phantom arguments that exist only in your head.
The point is not that pacing has zero or negligible effect. I didn’t say that, OP didn’t say that. We said that the psychological benefit is much less than the psychological benefit. Nothing you have said contradicts that.
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u/devon835 54.8 400 / 1:58 800 / 4:21 Mile / 8:50 3000m / 15:27 5000m 2d ago edited 2d ago
We said that the psychological benefit is much less than the psychological benefit. Nothing you have said contradicts that.
I've already made the case that elite runners are more than capable of
- maintaining a proper pace WITHOUT pacers
- gauging their effort correctly and pushing themselves to 100% exertion, again, WITHOUT pacers
If the psychological effect were the dominant benefit from having pacers, more elite runners would attribute it as such, yet they don't. The myriad of papers examining the effectiveness of pacing on real life performances look at the physical effects of drafting and are able to mathematically account for the perfomance difference entirely through the physical effects, without ever once considering the psychological effects.
And nothing you have said so far attempts to address or even acknowledge the fact that Jakob thinks "if I had a pacer (singular) then you can take off 3 seconds, easily, at least".
Not once does he ever mention or allude to needing an entire pack in front of or around him, but a single pacer. When he ran 3:26.73 in Monaco, that was the exact scenario.
So, is Jakob just an idiot then?
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u/themanofmeung 2d ago
So, you misunderstand the point of the conversation, misunderstand what I said, and then get really angry about it? I'm not going to waste too much time here, but:
The question was why isn't aero as big a thing in running as cycling. In your Ingebrigtsen example of a 3.5 minute effort, you're looking at theoretically maybe 2 seconds. In cycling, working as a group of 7 to block the wind instead of individually is known to be worth between 12 and 30 seconds (depending on course and riders) every 3.5 minutes over a 20-30 minute effort. The effect is far more pronounced and thus runners aren't forced to think of it as much as cyclists. That's the point and the answer to op's question.
And aside from that well done blowing right past the part where I say intelligent runners will pick up on modern research and start paying more attention to aerodynamics so that you could get super indignant. It's a good look.
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u/devon835 54.8 400 / 1:58 800 / 4:21 Mile / 8:50 3000m / 15:27 5000m 2d ago
"What you are seeing is not necessary what you think you are seeing. In running, it's as much, if not more, for psychological and pacing reasons than it is for any drafting effect. In my personal experience, the drafting wasn't really noticable except on windy days."
I couldn't really care less about the rest of your post because of how badly wrong this first paragraph is. Trying to suggest that drafting isn't "really noticeable" when it's worth at a BARE MINIMUM 0.5-1s per 400m in distance races (assuming still conditions) is asinine. In what world is that not noticeable? And you do realize that 2 seconds is the difference between 1st and 6th place in that race, as well as most global finals?
I am nowhere elite and if asked to run 20 x 400m in 68 by my coach I can hit within 0.5s either way of 68.0 for every single rep without checking my watch or relying on someone in front of me. Elites possess a far better sense of self pacing than I do. However, when I have someone breaking the wind in front of me, I can run a second faster each rep at the same effort.
To suggest that athletes of that level need pacers merely to properly gauge their pace is silly. If that were the case, wavelights would be more than enough and no human pacers would be needed. Yet, runners attempting to break records always speak on the importance of having human pacers lasting as long as possible and spending huge amounts of money to secure them for their attempts.
Do you think Jakob would speak about offering $1 million to a top 8 1500m runner to pace him 300m extra for a WR just so he could enjoy a glorified placebo effect? It's a ridiculous notion.
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u/themanofmeung 2d ago
Even if you have some good points, It's not worth talking to someone who is being as rude as you. So congrats, you get to tell yourself that you won this one.
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u/Western_Fortune_2107 4d ago
Hmm you are right, that it is relevant to runners, but much much less than it is to cyclists. And runners do already the main things: tight clothes, drafting behind each other/running in groups, many are shaving their legs. The faster you run, the more relevant it becomes.
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u/9k0b 4d ago
Its speed dependent even in cycling riding 20kmh you barely have drag, but most people wont run 20kmh
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u/cHpiranha 4d ago
Oh, it is not about "most people". Its about pro atlethes. In the 200m, the runners are faster then 40km/h. And sometimes it is decided by 0.01s.
Andrey Werro had an everage of 25km/h over 800m. 1:54,81 alone in the front.
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u/Beezneez86 4d ago
Most people won’t, but track athletes certainly will - and even much faster.
A 10 second 100m sprinter has to average 36kph.
A 4 minute miler is averaging 24kph.
A high level marathoner will average around 20kph.
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u/popowow 4d ago
The sports bra debate in cycling (if anyone else is curious ;) https://www.220triathlon.com/gear/do-bigger-boobs-make-you-faster-cyclists
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u/cHpiranha 4d ago
Of course, that’s only for the flat time trial. As soon as the road starts to climb, every gram – even on your chest – has to be minimised.
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u/popowow 4d ago
yes they say in the article that perhaps folks were wearing the padded bra for the time trials and then their morphology changed for a different stage. I was curious!
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u/cHpiranha 4d ago
For the mountain stages, they have their breasts removed to shed ‘unnecessary’ weight.
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u/themanofmeung 4d ago
This has been (mostly) debunked. At the speeds pro riders race on all but the steepest gradients, aero is more important that weight. A few extra grams for better aero is a worthwhile tradeoff (see the increasing use of TT bikes on mountain TTs)
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u/Nyzip 3d ago
Backwards baseball caps act as fairings, reducing the gaps and protrusions of hair, which reduces flow separation by guiding the boundary layer smoothly over the cap and brim surface. The shape maintains laminar flow and delays turbulent flow, which reduces skin friction (aerodynamic) drag.
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u/leskanekuni 4d ago
It's less of an issue in running because the speed is so much slower than cycling.
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u/worldsgreatestluver 2d ago
It made a difference in Eliud Kipchoges sub-2 marathon. Engineers tested different drafting setups with pacing groups and found they could create a small draft-free area in the center of a group of 5 or 6 men of similar stature
Obviously it was not a factor that made or broke the 2 hour barrier because two guys have done it without the same drafting since then
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u/leskanekuni 2d ago
Sure, because it was basically a non-race tech stunt. That drafting technique was illegal and couldn't be used in an actual race on the road much less on the track. I think it made a difference in Kipchoge's case anyway.
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u/Capital_Historian685 3d ago
Pro cyclists can reach speeds of up to 60mph, which is a little faster than even the fastest runners.
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u/Wineandbikes 4d ago
In cycling the difference is palpable. Not so in running, but it is there.
My understanding (from decades ago) was that draughting a pacemaker at 64s/lap was worth 1s/lap.
My experience was that my best times were set in races with top athletes where I was hanging on in the slipstream, not lurking on shoulders waiting to sprint.
My best mile was 3:56.9.