Help with school assignment (looking for interviews about low sprinting positions)

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chris47
Posts: 98
Joined: Thu Apr 10, 2014 11:06 pm

by chris47

Ok, so i am writing about low and agressive sprinting positions in pro cycling. ala Caleb ewan & Mark Cavendish.
I am looking for some rider interviews about the sprinting positions. I have searched around and have only found comments about the sprinting positions from Cav and Caleb. Ideally i could get a comment from Kittel or someone saying that these positions are way too risky or something along those lines.
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cassard
Posts: 95
Joined: Wed Jan 24, 2018 12:31 am

by cassard

From the top of my head, this is what I could say :

In the basics of cycling aerodynamics, over 50km/h, the riders position (projected frontal aera) is responsible for around 70% of the total aerodynamic drag.

the smallest the frontal area is, the smaller your Cd (Drag coefficient), this means better. So if you talk about aerodynamics only, it would be a good idea to say that Caleb as a better aerodynamic efficiency/potentiel.

But there is some counterparts :

The studies are made on a steady, not moving bike. When you sprint all-out, the bike is moving and creating turbulence. So in my opinion, this would have to be taken in account.

Also, it as been studied that the lower the angle your trunk is (more parallel to the ground), the less power output you have. (so you watt less). By looking at Caleb position, you can think that Caleb would have a worse power output potential then Cavendish.

In last, there is the biomecanical side. being as low as Caleb, you can almost not pull on the handlebar to torque the frame and have a better power transfer. You would also have to analyse the muscle activity of the legs in this pushing position, to compare witch is the more efficient.

So to resume, a sprinting position have more components to be studied than standard sitting position such as :
- Aerodynamics with a bike that as lateral movement
- Legs biomecanics in the different positions
- upper body participation

alcatraz
Posts: 928
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

What if being really low is ok if you pull at the same time as you push each pedal stroke. Different technique. The pulling muscles are weak but for a short sprint might be enough, no?

/a

cassard
Posts: 95
Joined: Wed Jan 24, 2018 12:31 am

by cassard

The pulling motion is only here to lower the pushing resistance.

The advantage that I could see of the very low position of Caleb, is actually getting better hip extension activity from the glutes and the hamstrings (glutes are the strongest muscles on your body in terms of power and strength). But this is just by looking at his position. EMGs would be interesting to do.

chris47
Posts: 98
Joined: Thu Apr 10, 2014 11:06 pm

by chris47

Thanks for the reply Cassard. But in regards to the aerodynamic effects, i am pretty well covered. I 3d printed some models of the different positions and did a wind tunnel test on them. I can upload the results if anyone is interested.
What i was looking for was primarily just rider interviews on the subject :)


bremerradkurier
Posts: 246
Joined: Mon Jun 13, 2016 4:18 pm

by bremerradkurier

You never seem to see the low positions on track sprinters.

morganb
Posts: 535
Joined: Wed Mar 15, 2017 5:30 pm

by morganb

bremerradkurier wrote:
Thu Feb 22, 2018 11:16 pm
You never seem to see the low positions on track sprinters.
Two reasons I can think of for that: They have to make turns while sprinting, even on a banked track where you aren't cornering in the proper sense its going to be impossible in that position. The other is that they are geared lighter than a road sprinter and frequently finish their sprint in the saddle.

cassard
Posts: 95
Joined: Wed Jan 24, 2018 12:31 am

by cassard

bremerradkurier wrote:
Thu Feb 22, 2018 11:16 pm
You never seem to see the low positions on track sprinters.
a lot of factor makes a Track Sprint technique totally different than a Road cycling technique. Sprinting with a fixed gear doesn't required the same thing. The time of the sprint is also different. The energetic demand isn't the same also.

CrankAddictsRich
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Joined: Wed Jan 27, 2016 1:39 pm
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by CrankAddictsRich

I believ that GCN has does interviews with both Cav and Caleb about sprinting... perhaps Kittel as well. There might be some nuggets to pick up in each of those.
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