Try this, get a bow and arrow, pull it WAY back then put the tip up against a tree/board/mattress and let go of the nocked arrow. see how far it goes.
The arrow gets it's forward movement from the string as the flexible arms of the bow moving back to their original position. If you impede this forward movement, the arrow never gets to accelerate and is useless. That is one primary reason I don't allow missiles to be used in melee. You MAY make a maneuver roll (tumble, leap, etc) to get enough range from your opponent to get in a shot. failing this, you have a stick in your hands and are most likely dead meat.