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Shoulder Pain and Weight Training: Understanding the Mechanisms of a Complex Joint

Lisa Kearns, MS PT CSCSBy: Lisa Kearns, MS PT CSCS

How often have we heard the statement in the gym, "I hurt my rotator cuff benching the other day"? Shoulder pain is a frequent bane of active individuals, especially as they start to progress in age. Due to the frequency of occurrence, people tend to self diagnose, because their symptoms are just like their friend's, etc.etc. Trainers are frequently placed in the position of having to manage these problems in the early stages, and it is important to be able to identify certain signs and symptoms which will dictate the course of action.

The shoulder is a very complex joint. It does not share the same bony stability that the knee or elbow has, therefore allowing it a great degree of movement. It is critical to understand how this joint works before helping people manage any dysfunction. The easiest way to picture the dynamics of the shoulder is to picture a golf ball sitting on a tee. The tee represents the glenold component of the glenohumeral joint, and the ball represents the head of the humerus. If there is a shift in any direction of the golf ball on the tee, it will fall off. In order to function properly, the golf ball must stay centered on the tee.

Now imagine that there is a ring of cartilage around the tee, deepening it somewhat and offering more stability. This ring is called the labrum. It is a static stabilizer for the glenohumeral joint. Other static stabilizers would include the ligaments and the capsule. None of these static stabilizers are inherently rigid, all offering a great freedom of movement. Sometimes, these structures are actually looser than normal, which is a condition we call excessive joint laxity, which can lead to instability. Therefore, we rely primarily on musculature to provide stability at the shoulder. The critical factor in the shoulder is proper balance, just as with the golf ball and the tee. The muscles are what contribute to this balance. If the muscles surrounding the joint and stabilizing the scapula have a balance in both strength and flexibility, then the shoulder will be able to function properly. If not, then a wide variety of problems may result, from impingement of the rotator cuff tendon and bursa, to chronic instability, to labral tears, and so on.

A common scenario in weight training is the following: John is a 38 year old ex-athlete who now is trying to stay in shape by working out 3-4 days a week at the gym. He takes his weight training pretty seriously, and finally feels as if he is starting to lift some decent weight and to see results. He has noticed a little stiffness in his shoulders after his upper body workouts, but attributes it to normal post workout soreness. John just finished a heavy chest workout, and is going through a tricep and shoulder routine. While performing a shoulder press, he feels a significant sharp pain in his shoulder and is unable to continue lifting that day. The pain lingers for a week or so and he notices that when he gets back to his chest workout he is unable to lift nearly as much weight due to pain, and forget about shoulder press. He isn't sure what to do, so he asks a trainer at the gym for advice. So what do we tell him to do?

Let's examine the mechanics of what is going on here. After asking John some questions, we discover that he seems to pushing his chest a lot harder than his back, and he didn't build a good base with shoulder and deltoid strengthening. Thinking of our anatomy and of the golf ball sitting on the tee, where would that put his shoulder? The chest muscles attach anteriorly on the humerus, and with his training there is an imbalance of strength and flexibility compared to his opposing, or back muscles. So the head of the humerus is going to shift forward. He will develop a somewhat protracted posture, which narrows the canal beneath the acromioclavicular joint, where the rotator cuff tendon and bursa reside. So then when John performs the shoulder press, the head of the humerus doesn't glide down in the joint the way it is supposed to. It will put anterior and superior pressure at the location of the rotator cuff and bicep tendons. Over time and repetition, this will create inflammation.

We must remember that the inflammation is not the problem, only the symptom. The problem is the faulty mechanics of the joint due to muscular imbalance. John should rest, ice and use antiinflamatiories as directed for the inflammation, but he needs to alter his training to keep it from recurring. If pain persists for more than a week, he should seek the advice of a physician.

Any weight-training program should adequately address ALL of the muscles and force couples (groups of muscles working together to perform an action, such as a rotator cuff and deltoid) to "keep the golf ball centered on the tee". This would include a rotator cuff strengthening program, adequate strengthening for the back and scapular stabilizers, exercises such as press ups for the depressors, and shoulder exercises which do not compromise the mechanics of the shoulder. An example would be keeping all presses slightly in front of the head, allowing less compression at the AC joint. A good warm-up and post workout stretching will also help. With a properly balanced program, problems at the shoulder can easily be avoided.