if i grip by longbow too tight, then i feel handshock. if i do it right, there is none. im guessing all the force should be traveling through your hand down the bones in your fore arm, where it then is supported by should/arm muscle, and back/chest muscle.
the hand is really just gripping the bow enough to not drop it, or torque it in any way. so to sum it up, im not sure! haha
only been shooting a little while, but i sure know when i grip it wrong, or shoot wrong. most of the weight is resting on the base of my thumb joint, or the heel of the hand.