The Great Arm Slot Myth

1/29/2007
Updated 10/27/2008

I was going through my files last night and came across an article in which the author described the three different arm slots: overhand, 3/4, and sidearm. As I read through, I found that I had a couple of problems with the assumptions that underlie this article.
   The first problem that I had with the article is a minor one. Technically, I think there are four general arm slots...

• Overhand
• 3/4
• Sidearm
• Submarine

Of course, the truth is that there are an infinite number of arm slots ranging from 45 degrees below the horizontal (submarine) to 75 or 80 degrees above the horizontal (overhand).
     The bigger problem I had with the article was how it described the 3/4 arm slot and, in particular, how it is achieved.
     In the picture that accompanied the article, the author described the 3/4 arm slot as one in which the shoulders were horizontal, the Pitching Arm Side (PAS) upper arm was also horizontal (such that the PAS elbow was at the level of the shoulders), and the PAS forearm was vertical (with the PAS elbow bent 90 degrees).

Arm Slot - Perception

The problem is that this isn't an accurate description of the 3/4 arm slot because it isn't physically possible. There is no way for someone to throw (at speed) while keeping their PAS forearm vertical.
     Instead, as the shoulders start to turn, the PAS forearm bounces or lays back so that it is horizontal (but still level with the shoulders). The PAS elbow then rapidly extends as the shoulders start to slow down. As a result, if their shoulders are level, then someone who thinks they are throwing from the 3/4 arm slot is actually throwing from what could be more accurately described as a sidearm arm slot. The only way to actually throw from what could be described as a 3/4 slot is to tilt the shoulders 45 degrees.

Arm Slot - Reality

That is what Jeff Suppan is doing in the photo below; tilting his shoulders to raise his release point.

Jeff Suppan - Shoulder Tilt

All of this reflects what I think is a bigger problem with the state of the art of pitching instruction; I don't think many pitching instructors really understand what the body does as the ball is thrown. As a result, they sometimes give advice to people that is out of touch with reality. They also make statements like "arm slot is genetic" when the truth is that changing your arm slot is as simple as tilting your shoulders more (or less).

What The Pros Actually Do

Let me illustrate what I'm talking about with some photos of major league pitchers.

Randy Johnson

Randy Johnson is the prototypical sidearm pitchers. As you can see in this photo, his shoulders -- and thus his PAS upper arm and forearm -- are level as he releases the ball.

Greg Maddux

Greg Maddux has a fairly pronounced shoulder tilt and could be described as someone who throws from a 3/4 arm slot.

Hideki Okajima

Hideki Okajima is an example of a pitcher who could be described as throwing over the top. Notice how much his shoulders are tilted in the photo above.