Originally Posted by
rubiksoval
Figuring out the cadence at which you can sustain the highest power is pretty helpful. That's a lot more important than hr which is going to be different depending on a dozen different things.
But that's effect, not cause. How do you know when you are sustaining the highest power? That's what HR and breathing information tells one. That how one figures it out. And you don't need a power meter to do it. Just watch your speed. It's the same thing. The PM is nice once one figures it out because it helps with holding that steady effort through changes in terrain - during which cadence will of course vary since we don't have infinitely variable gearing. That's nice but one still has to find that power/cadence relationship through physiological symptoms.
And yes, those physiological symptoms are going to vary, depending a few things, mostly hydration, feeding, and training status. For those same reasons, max sustainable power will also vary according to those markers. And of course max sustainable power will also vary with the length of the effort. There's not one number. Interestingly, on my big event this past summer, I sustained a higher power on my last climb of 2500' than I did on earlier climbs and at a slightly lower average cadence. Probably I was simply giving it up. It was 20° hotter, too. I was going by breathing and holding power steady. Yes, steady power, but what steady power?
My cadence was 75-79 on the big climbs, just like it's been for the past 20 years. Lower gears now of course.