I just can't resist. OP, you need to investigate "ankling". Google it and/or see this article:
http://cyclingtips.com.au/2009/05/ef...troke-ankling/
Maybe Sheldon Brown says something about it too.
People have been arguing about pedaling technique for decades. Ankling used to be a favorite subject before forums made it possible to argue about all this online. I haven't seen much about this lately, but that is no reason we shouldn't pick it up again here.
Robert