You could spin up a hill at 200W. Or cruise down the road at 200W. But you don’t. You put out more power climbing, right?
Listening to Keegan’s podcast chat last week re: Leadville, he put out more power climbing than on the flats. And I believe this was still true when he was in the front and solo. But why not just put out a constant power the entire time? Sure some steep hills require you to put out more power to hit the right cadence with your gearing maxed out, but I don’t think this was the reason behind his overall strategy.
Due to gravity it takes more power to maintain the same speed compared to the flats.
People don’t automatically generate more power just because you’re climbing. Some people are better at climbing since the power input around the pedal stroke is slightly different to riding on the flats or descents. IIRC more muscles are engaged while climbing so if you want to improve climbing do a lot of it and/or do a lot of big gear riding.
As for pacing something like lead since steeper climbs usually mean slower speeds (more time) it’s a good strategy to go up climbs at a much higher intensity than flats or descents.
You need to clarify what the needs are here. Because…
you can absolutely ride the flats and the climbs at a steady watt pace, provided you have the gearing. Your speed will fluctuate, of course.
you can absolutely ride the flats and the climbs at a steady speed, provided you have the power. Your power will fluctuate, of course.
Because…gravity
But to your second question…
My take is that this is a lot of tactics, preference, and general needs of the race. There’s a lot of variables he can’t control - ie those around him. So if the race is on and people are shoving it on the climbs, then he’s going to be digging into more power reserves in those situations. I’m sure if Leadville was a time trial, you may see more people approaching it with the intent of maintaining a consistent power output.
Increasing power on a steep hill will net you more time savings compared to increasing power on the flat, because on the flat the speed is already high and the power increase will largely be eaten up by aerodynamic drag which increases exponentially with higher speed. On the hill you get more ‘bang for the buck’ with a power increase, because it’s mostly about overcoming gravity (linear relationship).
