Most pedaling power derives from the downstroke - so much so that you accomplish very little by trying to pull upwards with the opposite leg. The best technique is to try to unweight the non-drive leg by using a smooth circular rotation. Also, the gastrocnemius is a notoriously energy-hungry muscle so it is best not to try "ankling" too much in the pedal stroke. Rather relax the calf muscle and keep energy focus on the quads. This results in a flatter foot action and better energy utilization.
