jpwiki wrote:
devashish_paul wrote:
RChung wrote:
Ballpark, running at x m/s requires about x watts/kg. That is, running at 3 m/s requires around 3 watts/kg, and running at 2.5 m/s requires around 2.5 watts/kg.
2.5 m/s is about 10.5 minutes per mile
3 m/s is about 9 minutes per mile.
That seems a bit "low ball". 3W per kilo has to be worth more than 3 m/s. There is no way when I ran just 3:50 it was anywhere near 3W per kilo effort....it would be a lot lower (for me). Would that not put a sub 3 IM marathon at slightly above 4W per kilo. That does not seem right. When I used to run open marathons at 3 hrs or lower, there is no way I was holding 4W per kilo effort. But I suppose the faster you go, biomechanics/flight time, come into play versus just pure engine. In any case, it is probably a good starting point to get a feel for projected IM run potential based on an FTP test, assuming reasonable run technique.
See for me I would call this pretty damn accurate when comparing my ftp (bike) with my running splits. Its certainly something I'm going to play around with now and check
I wonder if for running, body geometry comes more into play more too. For example a long leg short torso runner with a small head has less dead weight that is being carried around. Since more weight is in the legs and that is active, perhaps that runner (ex a Kenyan) can run faster at a lower percent of "FTP/kilo" because a larger percent of the body is actively being used for propulsion. So maybe a long torso runner indeed runs a bit slower for the same percent of FTP/kilo....just a hypothesis. In cycling, long leg short torso for a given watts per kilo would be an advantage on hills, but disadvantage when trying to get more aero. Just eyeballing, Mirinda Carfrae would fall into the former camp. Also the long leg short torso athlete, will have better cooling effect/heat tolerance, allowing them to run at the same speed at lower FTP/kilo percent.