At the PT, they said that apparently there is a problem with the positioning of my shoulder blade. Said something about that...something like it makes the shoulder too high and too out in front. Just working on some back muscles to try and fix it. Still kinda confused though.
Almost all of the bones in our body are stacked one on top of the other for stability.
The scapula (shoulder blade) is an exception to this. It sort of floats in back of the upper ribs, and the two together are almost like a pair of wings.
The arm is attatched to the side of the scapula at the shoulder. So in a sense our arm/scapula comlex is free floating from the body, except by its tenuous muscluar and ligamentous attatchments. (This is much more unstable than the sturdy hip joint that attatches our legs to our torso.)
That means any weakness in the muscles of the scapula will result in a problem with the way our arm attatches to the scapula, and furthermore the way the arm is attatched to the torso.
Your exercises will include exercising the 4 rotator cuff muscles that attatch the arm to the scapula at the shoulder:
But the exercises will also strengthen the overlying muscles (trapezius, deltoid, levator scapula, rhomboids) that attatch your scapula to the posterior aspect of your upper chest. The purpose of these attatching muscles are to rotate the scapula clockwise and counterclockwise to aid in raising and lowering your arm.
Thus, you have been identified with a weakness in these overlying muscles.
A muscle imbalance exists so that the scapula has been pulled out of its usual position. You need to exercise these muscles to return your scapula to its normal position, and to provide for optimal functioning in raising and lowing your arm.
No wonder the USTA has emphasized rotator cuff and shoulder blade stabilization exercises for tennis players:
"Rotator Cuff and Shoulder Blade Stabilization
In this article we want to focus on the shoulder and muscles that stabilize that joint. When you talk about tennis and the shoulder the first thing that likely comes to mind is the rotator cuff. The rotator cuff is important in tennis, but often times strength imbalances exist within the rotator cuff that can lead to injury. Most notably, tennis players tend to be weak in the muscles that externally rotate the shoulder. External rotation is an outward rotation and is the opposite of the shoulder motion players make when they serve or hit a forehand. To improve strength of the external rotators you can perform the exercises described in this section of the web page. This exercise should be performed with the dominant arm, but should really be performed with both arms if time permits.
Not many people think of the upper back when considering how to strengthen and protect the shoulder. But try this simple drill. Place your hand on the shoulder blades of a player and ask him to raise his arms. Can you feel the shoulder blades move? Shoulder movement is very complex and involves movement of the shoulder blade as well as the actual shoulder joint itself. Weakness in the upper back muscles that stabilize the shoulder blades can cause the shoulder to function improperly and may actually contribute to shoulder pain. Exercises that train the stabilizers of the shoulder blade can help tennis players optimize performance and avoid shoulder injury.
Exercise: Standing External Rotation with Elastic Band
Exercise: Straight Arm Rowing"
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http://www.usta.com/Improve-Your-Ga...7_Strength__Conditioning_Exercise_Techniques/