Originally Posted by Carbonfiberboy

Way too many people think that "pedaling circles" means putting a constant force on the pedal all the way around the circle. It does not. Pedaling circles actually means distributing a varying force on each pedal so that, added together, a constant torque on the BB is produced. On rollers, one strives to hear a constant whiirrr. Since there is so little mass to hold inertia, the constant sound means that one is at least coming very close to the ideal of that constant BB torque. Pedaling circles does not produce more power in a steady-state application. Rather it decreases muscular fatigue. There's a good study here:
https://www.radlabor.de/fileadmin/PDF...MSS_-_2011.pdf
An interesting thing to note in this study is that the subjects decreased fatigue with almost no training. That shows how effective smooth pedaling is.

For more discussion on how to achieve a circular pedal stroke, there was a good thread here: https://www.bikeforums.net/fifty-plus...ing-about.html

The upstroke pedal is usually unweighted though not usually pulled up. The unweight decreases the downstroke force necessary. During hill sprints, I think every decent sprinter pulls up hard to produce maximum watts at cadences under ~90. At higher cadences, coordination seems to fail.

I might also mention the phenomenon of bouncing at high cadence. Bouncing happens when the downstroke force is continued for too long, thus lifting the rider off the saddle. The downstroke has to be eased off early and converted into a rearward stroke. This is part of pedaling circles. It's possible to pedal without bouncing at cadences above 200. Nowadays I can only manage 150 for a few moments though I can easily pedal at 120 or so, all without bouncing of course.