Thought Leadership
May 12, 2022

Driveline Mechanics

Driveline. No, not that evil business Kyle Boddy built. It is the phase of the pitching delivery where the arm relaxes into ER and unwinds into IR through ball release and was a term coined by the late Dr. Mike Marshall. It goes together with forward trunk rotation, as that rotational momentum needs to be transferred directly into the baseball in a line towards home plate.

If the arm acts in a curvilinear path, the driveline phase is going to be the most important piece of the arm action. The ultimate goal is to maximize the amount time the arm is in ER as it reduces the peak stress on the elbow and transfer force over a longer period of time in the direction of home plate.

In order to truly maximize the driveline phase we need to 1) improve the overall structural integrity and tissue quality of the shoulder and 2) pattern the ability for a thrower to pull the ball through release and through a narrow throwing window.

See below examples of an elite driveline phase.

How do we achieve the driveline phase?

First, we must address the structural integrity and tissue quality of the shoulder. This can be done through a combination of strength training, isometrics, and overloading external and internal rotation. Remember, if it doesn’t break, it’s getting stronger. We’ve attached a few of our exercises below.

Now what does it look like when someone isn’t achieving a driveline phase? Checkout the video below.

From a throwing perspective, there are plenty of ways we can address this.  One of our personal favorites is the rapid-fire drill.  The idea is to get the ball in and out as fast as possible, driving the ball to the target almost like a quarterback getting the ball out quick. While finding some rhythm in the throws the main goal is to not push it, actually throw it.

Second is a marshal long toss.  If you check out the video below, you’ll see we use this drill in a multitude of ways. First, we use it as a plyo drill.When we use an overload, it allows our arm path to maximize ER and transfer the force properly.  The second path we can use regarding this drill is long tossing out of this constraint.  By long tossing until we begin to bounce the baseball then blending a normal long toss routine after will allow you to transfer over the driveline phase into your throwing and delivery.

For a better understanding on how to train your driveline, contact Training@Connected-Performance.com

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