Do runners slipstream?

blackpoolkev

Cyclists are well drilled on the advantages of using the slipstream of the rider in front.

With the Olympic athletics season upon us,it seems to me that runners don't seem bothered with the slipstream effect.If marathon runners used the same principles as cyclists,surely they would line up behind the runner in front.

CiB

They're not going fast enough for it to make a difference. It's about splitting air; at 12mph there's virtually no advantage in following someone unlike blatting along at 32mph behind the guy making all the effort has a big advantage, as we all know.

Power is either squared or cubed for each doubling of speed. Someone who's had fewer wine units will be along soon to confirm.

team47b

you are correct, cubed.

If you double the wind speed the power is increased by 8 times.

daviesee

I always thought distance runners did it but may have been tactical, like a sprinter wanting to come from the back.
It may not save much energy at that speed but at the top level, any efficiencies can make all the difference I would have thought.

jibberjim

They are going fast enough that there's a benefit - it's part of why pacemakers are required in a marathon, but the benefit is not very large and there's an associated cost of having to make micro changes of pace to stay behind the other athlete, but they do draft. When it's windy - which you won't really see on TV then drafting can become more significant.

pb21

Do runners get in breakaways?

Monty Dog

It can make a difference on the longer distance, road events - as someone who used to race marathons weighing 8.5 stone, I found it a distinct advantage to tuck-in behind a big guy when running into a headwind at 10mph.

rick_chasey

Course they do.

It's just a lot less significant.

ilm_zero7

an an ex -runner with some international experience - on the road, yes they do slipstream, although the benefits are greater on the road than in a protected stadium. And much depends on temperature too, there is an energy saving, but it is negated by lack of cooling on hot days.

Smokin Joe

Being out of the wind isn't the only benefit of sitting behind someone. There is also the psychological edge of having the pace set for you and having the advantage of surprise when you break.

tlw1

plus the added motivation if its a female in front with a nice ar5e

dw300

Don't forget that if you're in behind you can accidentally drag your spikes down the runner in front's achilles ..

Smokin Joe

matthew h wrote:

plus the added motivation if its a female in front with a nice ar5e

And the "Concorde Effect".

When it was getting up to speed it's nose came up to give a more aerodynamic profile...

daviesee

Smokin Joe wrote:

matthew h wrote:

plus the added motivation if its a female in front with a nice ar5e

And the "Concorde Effect".

When it was getting up to speed it's nose came up to give a more aerodynamic profile...

I thought the nose went down to give the pilots visibility when climbing. :?:

pipipi

So what speed does it start becoming significant at?

rick_chasey

pipipi wrote:

So what speed does it start becoming significant at?

Depends how long you're running for as much as speed.

I notice it on the bike at 20kph in a headwind.

airbag

Being really technical, the force required to balance drag is proportional to the square of the airspeed. The power required is the force multiplied by the groundspeed for a wheel-driven vehicle. In still air, air and ground speed are equal, so power is proportional to groundspeed cubed - in head or tailwinds, a little more complicated. To demonstrate this - try holding the bike still in, say, a 30mph headwind by e.g. using the brakes - you're not developing any power but you're balancing drag. To do 30mph in still air takes more effort, but the drag force is the same.