Photo downloaded here.
Pedaling a bike is all about getting as much power relative to weight as possible. Easy, right? But there is more. Some say you get the most power generated between 2 o'clock and 5 o'clock, and there got to be a reason they made pedals cleats at all, no? Personally I find it strange that Gilbert is able to put such extreme watts from his pedaling. The reason for this is that his position with his ankles seem to contract his calves, normally this would make the muscle less flexible and as a result less powerful. But then again, I was only watching the last 25 km so I can't say if Gilbert was focusing solely on attacks and sprints or just pedaled that way the whole race.
The old days vs the new
Well, pedaling, at least how I learned it back in the day was something like this:
When pushing down - heel down. When pulling leg upwards - heel up.
Now, I know I'm not alone on this one.
The trouble is, this is not the way Gilbert is doing it. Not the Schlecks either, although they are not as extreme as Gilbert.
I'm not all found of the method where you do all the stuff the PROs are doing, just not so much, but technique-wise learning is always important.
The way they rode was with the toe-down, bring all the leverage down, after all, that is where your power is going in the first place. Gilbert's position on the pedals is like a ballet-dancer, he is very pointy with his toes down. If you have really strong calves and ankles, that is something you could do, but most in the peloton seem to point the toe only slightly down.
Don't pull your foot up as hard as you can, that will bring fatigue to the hamstring very fast. This is what you could do on a sprint battling your mate for pints or climbing a short hill. Try focusing on assisting your foot who is pushing, pull just as hard as the "working" foot don't have to compensate.
Pedaling power and pedaling efficiency
Two aspects of pedaling that you can work on. The first one could be trained by adding a heavier gear and perform intervals up a hill, at lower cadence and PROs use both one-legged intervals as well as both legs. Pedaling efficiency is equally important, especially if you don't want to feel knackered after every ride. A good way to train this is putting on a very light gear and pedaling at very high cadence, trying not to bounce off the seat. If you can be comfortable at 120 RPMs, you're in the zone.
Photo by remepro.nl, here.