Originally Posted by koala logs

I actually move my calves differently. In fact, I only exert relatively small amount of effort with it throughout the pedal stroke. I keep it more or less relaxed throughout the forward and downstroke with the heels dropped. My calves only begin to point down ever so slightly when I pull my feet up in the upstroke. That is to keep the ball of my feet planted on the pedals when I'm pulling to unload the upstroke pedal. As I begin the forward stroke, I then use my calves as a spring as it goes back to heels dropped position. It's impossible to do it properly and smoothly if the pedal at the middle of my foot.

It's the only way I can spin easily with pedal heels down on a flat pedal. It's mostly a matter of personal preference and I do like pedaling heels down better.