Reverse Pitching Forearm Bounce

What exactly is reverse pitching forearm bounce and is it bad or good?

That is Mike Marshall speak for external rotation. Is it bad? Well everyone does it, and Marshall claims it’s the cause of elbow injuries. So take that for what it’s worth.

“Bounce” doesn’t quite explain what happens with the arm action (the arm moves in a continuous loop, not a “bounce”. See the clip of Clemens below.) but it does kind of describe the stretch shortening cycle (SSC) action in the rotator cuff muscles and connective tissues (rapid stretch and reflexive rebound).

This is the prime transfer mechanism of the momentum generated in the other body parts that precede this arm action. The faster the stretch, the more forceful the subsequent contraction and elastic rebound. The rotator cuff muscles and tendons aren’t very large but they transfer large amounts of energy.

The very nature of the SSC is to stretch the muscles and tendons to well beyond their resting length and then “bounce” back. This is a very high risk action and is why I’ve always said that pitching is a nasty motion where we ask our muscles and tendons to work at or near their “breaking points” on a regular basis.

This is also why I believe that the whole discussion about why Maddux has been so durable needs to take into account the lower velocities he works at. Would he be so durable if he threw 95 mph regularly?

Great explanation, DM. And excellent point about Maddux.

I have come to believe that this is one of his weaker claims.

His guys’ forearms bounce/lay back pretty much the same and as much as everyone else.

re: “I have come to believe that this is one of his weaker claims.”

Welcome to a large club of non-believers, Chris. Better late than never I guess.

As far as the argument that his guys all more or less do the same thing with their throwing arms, well…that is certainly no impediment for a cult leader like MM. He just claims that literally no one can perform his mechanical ideas correctly. But, if they could, he would 100 % guarantee them an injury-free career at the highest levels of baseball.


It’s pretty impossible to throw 85+ mph without it.

So basically its something that you dont want to happen but must occur to increase fastball velocity, right?

I think it’s simply a natural by-product of throwing hard (due to the laws of physics).

Even Marshall’s guy experience it when they throw hard.

I often use it as a SWAG way of estimating a guy’s velocity or calling BS on him. If he says he’s throwing 85 but shows no evidence of bounce, he’s probably lying.

I think everyone is pretty right on in their explanations. While it may not be the healthiest of motions for the shoulder it is a necessary evil. It could be argued that the more external rotation one is capable of acheiving the harder he can throw. I will concede that there are many, many other factors as well, but the ability to externally rotate the arm is a large contributing factor to velocity. From a physics stand point think of the arm like a catapult. The further back you can draw back the catapult, the faster/further it will launch the projectile.