Early Trunk Rotation and Losses in Velocity

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

Early Trunk - Top Image

While I whole-heartedly agree that a “late” arm at foot strike is definitely an issue from an injury standpoint (and should be addressed), early trunk rotation which can create an “early” arm action is an issue as well from a velocity standpoint. The key is finding what is causing this early rotation, training it and putting the arm in its “sweet spot”.

Today, we’ll touch briefly on two issues I see when analyzing video which can attribute to early rotation. They are as follows:

  1. Inadequate Rotational Core Stiffness
  2. Classic “Equal and Opposite” Arm Action

Inadequate Rotational Core Stiffness – It’s no mystery that due to the growth rates of young adolescents, core strength is the Achilles heel of all young athletes. This severely compromises the athlete’s ability to resist rotation of the trunk as the lower body begins to rotate. Working on rotational core stiffness goes a long way to create a stronger more stable upper half while coming down the mound.  In turn, this will help enhance hip and shoulder separation, creating a stronger whip at ball release and avoid excess rotation 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, due to a minimal (if any) knowledge of anatomy, do exactly this. This brings us to #2.

Classic “Equal and Opposite” Arm Action – I see this issue often when analyzing video with pitchers who have been instructed by pitching coaches to create an “equal and opposite” arm movement at first foot strike 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, 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.

Many times, 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…


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