Originally Posted by
wphamilton
The range between a casual runner's pace and a competitive one is similar to differences in cycling, if that's what you mean.
No that isn't what I meant.
Originally Posted by
wphamilton
If you're talking about the higher speeds of cycling causing greater aerodynamic drag - square of speed etc - I addressed that. It is meaningful at even an 8 minute pace, and would have the same "need" in running as in cycling after that point.
Aerodynamic drag is the main source of resistance when cycling (excluding hills***). When running, it is gravity. Yes, there is an aerodynamic component, but it is, proportionally, much smaller than it is with cycling. This should be obvious to anyone who has watched/participated in these sports. There's a reason why elite cyclists can't just ride someone off their wheel and have to attack hard to create an initial gap while runners don't have to do this.
Wind resistance changes far more than gravity. It changes due to wind speed and direction. It changes due to temperature. It changes due to air pressure. It changes due to your CdA. As such, the time to complete a certain distance varies far more when cycling than it does with running. As such, outside of a velodrome, time isn't a very accurate measurement of performance for cycling.
If you want to measure how much work you are doing, running speed works fairly well and is fairly consistent. For cycling, to achieve something similar wrt consistency, you need a power meter. Your day-to-day speed will vary too much to get anything meaningful other than perhaps a long-term trend.
*** cycling up a moderately steep hill is fairly close to running wrt what type/proportion of resistance is slowing you down. That's why grand tours are decided in the mountains. It's also why you see people just fall off the back, unable to maintain the pace of the leaders. It's also why lighter riders tend to be better (whereas pretty much every elite distance runner is small and light). It's also why your times going up a hill will be much more consistent (assuming consistent effort) than your times on flat terrain.