Originally Posted by FUNBUNCHER
All throws happen first at your base; the hips and legs. Biomechanically it's very similar to throwing the javelin.
THrowing the ball hard can be improved through becoming stronger as an athlete.
How quickly you're able to go through your throwing motion and get rid of the football at a high velocity, that's IMO more genetic.
Only Tim Tebow throws like a javelin thrower. That's the reason he can throw far, but isn't very accurate. He muscles up. He has a "different" kind of arm strength.
QBs such as Drew Brees and Robert Griffin produce whip with their arms via external rotation. They use the smaller muscles to produce velocity. It's those smaller muscles that allow them finer control on the ball to be more accurate. It's what produces what people call "flick of the wrist"-looking throwing motions.
It's not just (static) strength that enables you to throw harder/farther, it's the elastically explosive properties of muscles as well.