That is one facet of pedalling that some espouse, but it is not universally accepted amoung biomechanical specialists as providing great benefit, ie, the backstroke. Testing has not borne it out conclusively. The biggest benefit to efficiency is unweighting the foot/leg on the upstroke (but not pulling). The backstroke proponents believe that poo wiping, as Lemond describes it, contributes to this. But you do not need clip-ins to do it anyway. The vast majority of cyclists, including myself (most definetly) and probably everyone on this board, don't have great pedalling form at any rate, clip-ins or not. Great pedalling efficiency is not easy and many top level pros struggle with it.

But this was never the question as I believe pulling up on the upstroke was the question, or issue, or questionable practice, or whatever... I never said that clip-ins did not provide any benefits.