We do use 100% of our brains just not all at once, which, IMO, is impossible, some parts deal with mechanical things, others emtional, some memory, others basic motor functions. I guess if you wanted to try, the best way would be to try doing a bunch of things and remember a bunch of things and feel a bunch of things all at once, then its possible. As for chi control, totally exists, breaking tournaments, nuff said. Yes it takes training and practice, but part of it is sending your energy through the last brick, its a state of mind. Once saw a sixty year old man break 20 blocks of ice with his head.