Originally Posted by boliodogs
. A tighly closed fist is nessessary for best results.
Wrong, a tightly clenched fist tightens up the muscles in the forearm that inhibits speed. For the first part of the punch you want a degree of relaxation in the fist to have relaxed muscles in the forearm for maximum speed just as you would have a degree of relaxation in those muscles if throwing a ball at high speed. You can clench the fist more at impact but for max speed you don't want that before.