This question can stir up a big argument but there is only one answer. The arm does not generate the velocity. It only guides the pitch. Therefore the arm must follow the body and does not come into play until the body has done its job.

I have been in many arguments about this issue. I have listened to coaches tell their pitchers that if they want to throw harder they need to speed up their arms. My question is how will speeding up your arm increase your velocity? This doesn’t make much sense because if you arm leads your body, it must leave the body behind. If you leave the body behind then it is up to the small muscles of the arm to take the entire workload of generating 90+ mph.

I think to prove my answer to the question above we must once again look at the little pitchers in the game. This is because these guys must work a lot harder to generate 90+ mph. I go once again to my favorite little man Tim Lincecum; 5’7 165 lbs. Notice the picture here of him at front foot strike. Now, where is his arm? It is hiding behind his body. YES, all you coaches out there who are coaching your pitchers to speed up there arms, it is behind his body. This means his body is driving the pitch. This means his body is generating the velocity. This means the arm is along for the ride.

The coaches who will argue my point here are the coaches who use giant pitchers like Randy Johnson as their example of pitchers who have a lot of arm action. This is true but these pitchers have more leverage on the ball than the average man. If you are 6’8 like Randy Johnson then congratulations you are in a small percentage of baseball players but if you are 6’2 and under take it easy on your arm and learn to work your body as a single unit in your delivery. When you work on generating velocity, work on pulling it from your legs and core and not your arm.

I recommend using medicine balls as often as you can. I have many throwing drills with these balls that force the pitcher to use every muscle they have to make the throw. This is how we must pitch if we want to throw and withstand 90+ mph.

The Ace Pitcher Handbook has a full medicine ball workout.