Originally Posted by
PeteHski
Countless studies have shown that this is not what actually happens, even with pro cyclists. There is no significant power produced on the upstroke. So don't go expecting an improvement in that regard.
But there are definitely other benefits to going clipless, so not trying to put you off. Just pointing out that this supposed upstroke power gain is not going to happen for you, except possibly at ultra-low cadence hauling a big gear up a steep hill (not a recommended technique).
It's not really an 'up' stroke; in practice, it's more pushing forward over the top of the stroke, and pulling back across the bottom. Pulling up with one leg while pushing down with the other is something you really have to train for, like a competitive Track cyclist.
Clipless lets you ' pedal in circles' more easily (you don't need to focus on keeping your feet in place on the pedals). Pedaling 'circles' doesn't really increase your power, since your whole system can only put out a certain amount of watts, but what it does do is take some of the peak loads off of your quads (the primary drivers) and spread it out to the other muscle groups, like hamstrings, calves and glutes, so that you're putting less maximum stress on a single muscle group.
It can make a noticable difference on a long, steep climb.