Shoulder pain is a common complaint among baseball players, especially pitchers. Pain experienced during the throwing motion results in the inability to throw with velocity, causing what is commonly referred to as “dead arm” syndrome. The cause of pain is most often injury to the soft-tissue structures of the shoulder joint. More recently we are starting to realize that movement dysfunctions can also cause or be a result of shoulder pain as changed throwing mechanics puts negative stresses on shoulder tissues. Associated with this pain, altered mechanics of throwing are often observed. The athlete dysfunctionally moves, trying to accomplish the task of throwing hard. In fact, Kinetic Integrations (KI) believes that our central nervous system (movement regulating system) does not care how to accomplish a task such as pitching, it just gets the job done as best as possible even if it means that it’s methods are dysfunctional. Remember the day you sprained your ankle for the first time? You were limping for a few days weren’t you? Well, this limping gait is actually a dysfunctional form of walking. The same thing happens with our shoulder when experiencing pain, you change the way you throw if that is the task at hand.
The 4 Phases Of Throwing
To understand pain in the throwing shoulder, we need to understand and appreciate both the throwing mechanism and the anatomy of the shoulder joint. The act of throwing is often divided into 4 phases: wind up, cocking, acceleration, and deceleration, or also called follow-through. The unique anatomy of the shoulder joint allows a person to generate tremendous velocity while throwing. I remember my days in professional baseball when working for the Kansas City Royals, Texas Rangers and Baltimore Orioles. Observantly I was always sitting next to the pitching coaches as through their experiences and keen observations they would pick up even small changes of the pitching mechanics, often before the pitcher would complain of pain. Indeed, often movement dysfunctions would occur before medical care was requested. This phenomenon laid the foundations of KI as movement dysfunctions not only occur with pain but also when and injury slowly creeps up on us.
The shoulder, like the hip, is a ball-and-socket joint. However, unlike the hip where the ball fits tightly into the socket and is very stable, the shoulder ball (humeral head) fits loosely in its socket (glenoid) and is very much unrestricted, much like a golf ball sitting on a tee. Through the whip effect, the farther one is able to bring the arm back into abduction (raised away from the side of the body) and external rotation, the faster the ball will go when released. This lack of restriction though is a double-edged sword: it allows tremendous range of motion in the shoulder, making it possible to cock the arm back farther and throw with tremendous velocity. However, it also forces a reliance on relatively weak soft-tissue structures to maintain shoulder stability. These soft-tissue stabilizers feel the greatest stress during the throwing motion and are, therefore, the most frequently injured structures when this stress is applied repetitively through each throw.
The shoulder’s soft-tissue stabilizers can be divided into two categories: static and dynamic. The static stabilizers are the ligaments of the shoulder capsule and the labrum (the cartilage ring that surrounds the socket). The labrum is an important part of the thrower’s shoulder anatomy because it serves as the attachment site for the capsular ligaments at the glenoid and it also deepens the socket to provide extra stability to the ball (the humeral head). The dynamic stabilizers, which include the rotator cuff muscles as also the scapulothoracic muscles are the muscle groups that surround the shoulder. These muscles contract at different times during the various stages of throwing. The static and dynamic stabilizers work together in a delicate balance to stabilize the humeral head in the glenoid during the act of throwing. When the soft tissue stabilizers become too loose or too tight, the delicate balance of humeral head stability is thrown off, resulting in abnormal movement of the humeral head during throwing – the ball does not sit in the center of the glenoid any more. This abnormal position and movement of the humeral head puts increased stress on the whole shoulder and eventually cause injury and pain. Inevitably movement dysfunctions will occur putting stress on other surrounding tissues. It is the restoration of proper movement patterns that KI is after as proper movement = proper function and elimination of pain.
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