Comment by mmooss
14 hours ago
> going harder into the hard stuff and knowing when they can back off and rest.
Why is going harder in the hard stuff and easier in the easy stuff more efficient or faster than vice versa? I imagine arguments either way:
Going harder when it's easy gives you higher ROI. Or maybe going easier when it's hard is just too slow. And maybe that is too simplistic: Maybe it depends on how hard; that is, maybe there is a threshold.
Completely uninformed speculation:
Wind drag goes up with v squared, so power required goes up with v cubed.
If you run at 105% speed downhill,that requires almost 16% more power to overcome wind drag. You might be better off running at 100% speed downhill (and "saving" that 16% power), and pushing harder to run as close as you can to 100% speed on the uphill stretches that would otherwise have you running slower than 100%. The power used to increase your potential energy going uphill is "zero sum" because you get it back when you go back downhill -n there no pesky v squared or v cubed non linearity there (assuming the race starts and finishes at the same elevation).
A fun little effect is that average speed is time-averaged not distance-averaged. So when you go slower, you lose doubly - lower speed to average and over a longer time (higher weight). Hence one of the reasons why putting more energy into the harder bits is actually optimal.