Originally Posted by TX_master

Here's how I look at it, and no I'm not drunk (just yet). But imagine a scenario where you only pedaled with one leg and the other leg contributed nothing. Doesn't actively resist or participate. This means the active leg on the downstroke must not only overcome the inherant drivetrain resistance but also the resistance of the non-participating leg, having to help propel it up on its upstroke.

The real power is in the downstroke. I would agree with others here that trying to actively propel the bike through upward pressure could lead to injuries in the hip flexors and possibly other areas. However any assistance the leg on the upstroke side can give to the leg on the downstroke side should be positive. What I mean is that when a leg gets to the bottom and begins the upstroke just remembering to pull the leg up without exerting any upward pressure on the pedal (not trying to feel like you are pulling the cleat out of the pedal), but rather just trying to unload that side should allow the leg on the downstroke to feel less resistance.

I regularly practice this on my regular morning rides and find that when I focus on it that I feel I am spinning a bit easier in whatever combination I'm in and can sometimes move to a smaller cog. But the problem for me is remembering to do it. It requires a lot of concentration and since I usually find myself thinking about work and solving the worlds problems I frequently forget and find myself back to the same leg on the upstroke not contributing as much. As long as I'm not trying to exert force on the pedal on the upstroke I am fine. Its just hard to be consistent with it.