How body presentation affects the shoulder

Baseball shoulder injuries can happen for various reasons and must be assessed to find the root causes.

Body presentation tells a story of how the athlete moves and the type of power and rotation they can express. 

More compact, compressed movers are able to express more force and rotate more efficiently. Think of a Christian Yelich-type body. He rotates and doesn’t stop rotating. 

Wider, more expanded individuals can absorb more force and have a more difficult time rotating. Think of a Mike Trout-type body. 

While these body presentations play a big role in performance, we are able to train them in the way that they need to perform. We can give the athlete what he is good at as well as what he struggles at.

Overall, we must make sure their training will benefit them on the playing field. 

Most athletes have abnormal motion; our job is to teach them how to control it. 

Structure dictates function, function dictates whether there is dysfunction. 

We must get the athlete to start in proper alignment. 

First and foremost we address posture. We must remember that we need to treat the cause of the issue and not just the site.

The body works together. Whatever one side of the body exhibits, the other side needs. For example, one side of the shoulder or hip may have excessive external rotation and flexion while the other may have extreme internal rotation and extension. 

Looking at this on a thrower, it may make more sense to why we see certain baseball shoulder injuries. 

What does the shoulder do while throwing?

The shoulder internally rotates the humerus between 7000-8000 degrees per second. 

Throwing a baseball is the most violent motion in all of sports. MRI’s reveal that more than 80% of shoulders in baseball players have tears in the labrum or fraying in the UCL. (This is why it is vital to go to a doctor that specializes in throwers). 

The difference is how many of those athletes with fraying are symptomatic. 

Studies have shown about 30% of the shoulders have symptoms. To help keep athletes to avoid baseball shoulder injuries, we like to start by looking at the rib cage and resting posture as well as breathing patterns. 

We look for an adducted posture (scaps are pulled together) that puts the elbows behind the shoulder and drives the humeral head forward. If we see this, it can mean we need to look at rhomboids being over-active because they are a scapular downward rotator. 

Most of the time this comes from a compensation of a compressed posterior thorax and a wide expanded anterior thorax. 

 Body presentations tell us a story of what the scap will do on the thorax. It is a concave, convex relationship. Think of two ½ circles stacked on top of each other. 

If the athlete is in extension (anterior pelvic tilt) will alter everything from the floor up. As for  the head of the humerus (front of the shoulder), it can be driven forward in the Joint and the lat pulls down the scap. The lats fascia connects to the pelvis, as you can see all the muscles are affected by each other. 

Extension posture is seen very often in the baseball population. A few things we look at in our screens that may cause this type of posture are:

Let’s break it down 

Breathing patterns alter change in resting posture, anterior core stability, and control which is caused from lack of diaphragmatic initiation to brace the deep core muscles, overhead flexion, showing us full expansion of the thorax and will express scapulohumeral rhythm (how well the humerus and the scap move on time together) and hip mobility will alter as well. 

Your hips /pelvis are a mirror image of the thorax, and will show how much internal/external rotation of the hip/shoulder the athlete has.

When we look at internal rotation of the shoulder, we look at both active IR and ER. 

The lat being an internal rotator to the humerus, we see an overwork of the lat when it comes to strength and conditioning programs dealing with baseball players. When the lat is overworked it can cause scapular depression, the anterior shoulder capsule to drive forward and drive someone into gross extension.

Lat tightness and glenohumeral instability all go together. Shoulder instability implies a certain symptom is present. 

Acquired external rotation drives more anterior instability of the glenohumeral joint. Working with a baseball population where we see athletes with the ability to externally rotate more than the normal population, we never want to stretch the shoulder into external rotation. This will increase the instability and irritate the biceps tendon which can pick up the stability role when instability is present. 

When you have anterior shoulder issues there more than likely is something else going on.

First, we must know what a healthy shoulder is before we can discuss an injured shoulder. 

There are three primary motions that take place at acromioclavicular joint 

  1. Internal/external rotation
  2. Anterior/posterior tilting 
  3. Upward/downward rotation

All of the motions take place on the scapular plane. 

If you train in our program, you will hear our coaches say to work in the scapular plane. This means we want the humerus 15 degrees in front of the frontal plane and 45 degrees from the inferior border of the scap.

Scapular upward rotation occurs when the arm abducts more than 30 degrees and at the acromioclavicular joint perpendicular to the scapular plane. The glenohumeral joint is surrounded by a very loose capsule that tightens when the humerus is abducted. 

There are three ligaments in the glenohumeral joint:

  1. Superior (anterior and inferior joint stability) 
  2. Middle (anterior joint stability)
  3. Inferior (anterior joint stability) 

As you can tell, these ligaments along with the rotator cuff, provide dynamic reinforcement. 

The most common dislocation of the glenohumeral joint is anteriorly. The labrum adds support to the humerus sitting in the glenoid fossa, as well as the rotator cuff. 

This is why we get the athlete into throwing positions instead of static positions to test for faulty patterns.

As soon as the glenohumeral joint begins to abduct (away from the body), the capsule tightens and increases joint stabilization. 

The deltoid is the prime mover along with the supraspinatus for abduction of the shoulder. 

The anterior deltoid is the prime mover for flexion. 

Scapular humeral rhythm is what happens when the shoulder moves over head and how the scapula upwardly rotates and how congruent with the humerus. What we are looking for is 55 degrees of upward rotation of the medial border of the scap.

The shoulder is very complex; so is addressing shoulder issues. 

Many people see shoulder issues from “overuse”. The pelvis, thorax and shoulder tells a story during the movement and performance.

I hope you learned something new from this insight and feel free to message us at with any questions. 

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