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All About the Shoulder
The shoulder is a ball-and-socket joint that is the most flexible joint in the body. This joint attaches the upper arm (humerus) to the shoulder, and allows movement of the upper arm. This flexibility is achieved through a collection of muscles and ligaments, occasionally sacrificing stability. The stability of the shoulder joint is maintained by three sets of ligaments and four muscles. The clavicle is the only bony attachment at the shoulder. The upper arm (humerus) has an enlarged top (head) that fits into a depression (glenoid) called the scapula. The humerus is held into the scapula by a rim of cartilage, and the four rotator cuff muscles (supraspinatus, infraspinatus, subscapularis, and the teres minor.) The rotator cuff acts against the pull of gravity to keep the arm stable. The head of the humerus is also somewhat supported by the tendons in the biceps brachii in the front part of the arm. There is an overhead extension of bone (acromium) that keeps the humerus from leaving the socket. The rotator cuff is subject to repeated wear and tear simply through everyday use. This wear can compromise the stability of the shoulder joint, which can cause injury.
Chronic shoulder injuries may include inflammation of tendons, bursae, or the joint itself. This inflammation is most commonly an overuse injury. Bursitis of the subacromial bursa is fairly common, and can be aggravated when the large shoulder muscle (deltoid) compresses the bursa. This can happen most easily in any overhead motion. Impingement can occur when the rotator cuff muscles become inflamed, and the bursa is pinched when the arm moves away from the body or overhead. The muscle in the center of your back (trapezius) can also cause minor impingement. This is generally the result of a muscular imbalance, resulting from the top portion of the trapezius to have more strength than the lower portion. Impingement originating in the trapezius will lead to a rounded shoulders look, generally the result of sitting at a desk and leaning over all day. Also, cysts can form within the cavity of the joint. These cysts may rub against certain moving parts, which can cause swelling and inflammation, which can limit mobility. Also, in some cases, the cyst is in a spot that can actually “freeze” the shoulder, and make it feel like the joint locks at a certain spot.
Please note that there is a small muscle that runs from the base of your neck into the top middle of your scapula called the levator scapula. This muscle is fairly easy to pull. Simple motions such as removing your shirt can aggravate this pull.
Also, some people are susceptible to dislocations or separations of the shoulder joint (stretching or tearing of the AC joint.) Since all major ligaments cross the front of the shoulder, it is most common for the shoulder to dislocate to the back of the scapula. Improper relocating of a shoulder can result in severe tearing of the major ligaments surrounding the shoulder, and should be avoided. Please note that there is a small muscle that runs from the base of your neck into the top middle of your scapula called the levator scapula. This muscle is fairly easy to pull. Simple motions such as removing your shirt can aggravate this muscle.
During a workout, certain precautions can be taken for a sore shoulder. First of all, a doctor should be seen immediately. You want to make sure that exercise is the best
therapy. Most overhead exercises (military press, lat pulldown) should be avoided during times of inflammation. It should be noted that the inclined chest press utilizes the shoulder muscles, and should be done at a very low incline, or avoided altogether. This
movement puts the humerus at an angle that can easily inflame the surrounding bursa. Also, exercises such as a side shoulder raise should be performed in neutral rotation, and without rounded shoulders. This means that your palms should be facing directly down during the whole range of motion. Some find it easier to stick your thumb out so that it always puts forward. One who is susceptible to shoulder dislocations should be very careful with exercises such as the chest press and any overhead exercises. Since the front of the shoulder muscles and ligaments have been stretched, excessive external rotation should be avoided.
Once a doctor has decided that there is no major structural damage, shoulder and chest exercises should be performed with caution. In addition to the above precautions, any sharp pains should be noted, and that exercise should be halted immediately. It is important to keep the goal of your workout in mind. For most of us, functionality and everyday ease of activity is the goal. Aggravating the most used joint in your body is not a great way to feel better the day or days following a workout. Often, this leads to clients completely halting their workouts, and not starting up once the pain subsides. A better route is to play it safe, and accomplish what you can without pain. This keeps you active in the gym, and pain free the next day.
References
A.C.E. Personal Trainer Manual
Anatomy and Physiology- 5th edition