Early Trunk Rotation and Losses in Pitching Velocity

early trunk rotation

While performing hundreds of video analysis and mocaps yearly, “early trunk rotation” rears its ugly heads more than 90% of any other disconnect we see. An early trunk puts the upper body in a more compromised position to accept ground reaction force and effectively block with the lead leg while negatively affecting timing issues and transfer of force up the chain. It can also contribute to a late arm or an arm that “drags”.  All this, of course, can ultimately lead to losses in pitching velocity.  The key is finding what is causing this early rotation, training it and putting the arm in its “sweet spot”.

The problem is, everyone has slightly different strategies for getting down the mound so, trying to nail down a throwing cue that can be used universally to put guys in successful positions to time rotation can be very challenging. Having said that, today, we’ll touch briefly on two issues we see when analyzing the pitching delivery which can attribute to early rotation (as well as a few things we can do from a movement perspective to help).

    • Inadequate Rotational Core Stiffness
    • Classic “Equal and Opposite” Arm Action

Inadequate Rotational Core Stiffness

It’s common knowledge that due to the growth rates of young adolescents, core strength can be somewhat of an Achilles heel. This is also true in many older higher-level athletes as well. This not only compromises the athlete’s ability to create rotation but to resist and hold aggressive rotation later as the lower body (pelvis / hips) begins to rotate . As a matter of fact, many rotational athletes are more powerful and create better acceleration rotating eccentrically (towards their dominant / throwing side). This is possibly due to developing braking forces to help decelerate the throw over the years. This gives them the ability to better eccentrically load as well as control hip shoulder separation until it’s time to “close the gap”.

If you’re lucky enough to be able to work with a Proteus Motion machine, working on rotational core stiffness both eccentrically and concentrically can go a long way to help create a stronger more stable upper half while coming down the mound. This can in turn help enhance hip and shoulder separation, helping to create a stronger whip at ball release. If not, this exercise is great for training rotational core strength while avoiding excess rotation/extension in the lumbar spine.

(Core Stab at Stride Length)

No two pitchers are built the same way, so why would they throw a baseball the same way? Using the same universal cues to position a pitcher’s body for optimal rotation during a pitching lesson is useless, as not every athlete has the same strength, mobility or proprioception. Unfortunately, many pitching coaches often do exactly this, mostly stemming from minimal (if any) knowledge of anatomy.  This brings us to our second topic.

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Classic “Equal and Opposite” Arm Action

We see this issue often when analyzing video with pitchers who have been instructed by pitching coaches to create an “equal and opposite” arm movement in order to create momentum, balance and get the arm “inside of 90” degrees early. This may work great for some, but when it comes to pitching mechanics, much like strength training, there are no absolutes and “individualized” programming is key. Let me explain.

Opposite and equal may work great for a mature, well developed athlete such as John Smoltz who possesses great core strength to help resist early trunk rotation.

Early Trunk - Smoltz Image

But many times, in younger throwers with minimal core strength (see #1 above), if the throwing arm engages at the same time as the glove side, they sometimes begin rotating the trunk pre-maturely, leaking stored energy and taking much needed tension out of the throw.

So, for some athletes, initiating rotation with the glove side first will create the feeling as if shoulder rotation has already begun, preventing the pitcher from rotating early at the trunk. This helps prevent the throwing arm from arriving early, helping to create more hip and shoulder separation (torque) which in turn can be used to create a more rapid arm speed.

(Side View)

(Front View)

Note: Keeping a shorter (closer to the body) arm path allows for a slightly delayed arm action without compromising the anterior shoulder and medial elbow.

The net result of all this is more elastic energy and a throw mechanism with a higher velocity ceiling and less stress and force coming from the shoulder and arm.

See ya’ in the gym…

By Nunzio Signore (BA, CSCS, CPT, NASM, FMS)

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