Athletic activities place considerable more demand on shoulders compared with typical daily activities. Throwing and racquet sports require the arm to reach above and behind the body, golf and baseball require the shoulders to rotate across the body, swimming and paddling involve pulling the arm toward the body. This increase movement demand requires the rotator cuff and scapular stabilizer muscles to generate a tremendous amount of force to move and stabilize the shoulder. To make matters worse, these sports demand that these same motions are repeated over and over again. This combination of repetitive motions and high contractile demand can cause problems to develop in the shoulder, as the muscles often cannot keep up with the workload
Over time the muscles become strained and develop small scale injury known as micro-trauma. Initially this micro-trauma is not painful, but may be perceived as a mild ache or tightness in the muscles. Although only small, the damage still needs to be repaired. The body responds to tissue injury in a very predictable way-by laying down new tissue to repair the damaged tissue. With micro-trauma the body repairs the strained tissue by laying down small amounts of scare tissue in and around the injured area. The scar tissue itself is not the problem-in fact it is a normal and necessary part of healing.
The problem occurs when the shoulder is repeatedly subjected to the same high force athletic movements. This in turn causes the same muscles to become strained and subsequently repaired over and over again. Over time scar tissue will build-up and accumulate into what we call adhesions. As these adhesions form they start to affect the normal health and function of the muscles. They will often lead to pain, tightness, stiffness, restricted joint motion, and diminished blood flow.
As these scar tissue adhesions accumulate in the shoulder region, it places more and more strain on the muscles as they must now stretch and contract against these adhesions in an attempt to move and stabilize the shoulder. This places even further strain on the shoulder muscles, which in turn leads to more micro-trauma. Essentially a repetitive injury cycle is set-up causing continued adhesion formation and progressive shoulder dysfunction.
As the cycle progresses the ability of the muscles to contract properly is affected and the stability of the shoulder becomes compromised. At this point it is not uncommon for the muscles to give way, resulting in a more severe and debilitating pain. In fact, many athletes come into my office explaining how they have hurt their shoulder during a routine task that they have done thousands of times before. When further questioned these athletes almost always describe some mild pain or tightness in their shoulders that has been building over time. As you can see from the explanation of the repetitive injury cycle, these types of injuries build-up over time and more acute injury is often just the “straw-that-broke-the-camels-back.”