Because your shoulder can move in seven quadrants, it has the greatest range of motion of any joint in your body. No other joint is as flexible, and unstable as the shoulder. The shoulder (glenohumeral [GH]) joint is a shallow ball and socket variety that allows your arm to move freely in all directions. Your shoulder, therefore, depends heavily on the surrounding muscles to provide necessary stability.
The shoulder joint consists of the ball of the humerus (upper arm) and the socket (glenoid) of the scapula (shoulder blade). The surrounding capsule allows a wide range of movement. The place where the humerus articulates with the glenoid is reinforced by a fibrocartilage collar, which increases the stability of the shoulder.
Four short rotator cuff muscles and their tendons surround the joint and contribute towards its stability. The rotator cuff muscles are small, but play an important role in shoulder stabilization. These four rotator cuff muscles include your supraspinatus, infraspinatus, teres minor, and subscapularis. Together they have an essential steadying effect on the head of the humerus.
A fluid filled bursae sac acts as a shock absorber for your shoulder joint. If it is inflamed it bulges and becomes, thick, scarred, and painful. This is your body's way of letting you know that you should discontinue the activity that created inflammation in the first place. Pain also has an inhibiting effect on muscle. Your rotator cuff muscles waste away (atrophy) within a short time. Other muscles take over in an attempt to alleviate the pain. Rotator cuff problems may be attributed to the soft ligamentous structures that attach the ball to the socket. Imagine a big ball balancing on the end of a seal's nose. Compare that to the ball and socket joint of your shoulder. If the ball moves around too much in the socket, it may ride to high (subluxate). The worst case scenario is that it comes out of the socket and dislocates. It is said however, that the famous magician Harry Houdini dislocated both of his shoulders to escape from a straight jackets.
Another analogy to help you understand the importance of your rotators is to visualize a tent. Your upper arm is a tent pole, extending from the ground. Your shoulder is the place on the ground where the pole sits. Your rotator cuff muscles are the ropes that secure the tent pole. If these ropes remain strong and in place, the pole maintains its proper position, and the tent does not collapse. However if any of the ropes stretch, loosen, or snap, the remaining ropes will tug the pole out of position and the tent will fail.
Your rotator cuff muscles hold your ball in your GH socket when you cock your arm to throw, and when you follow through. Baseball players train their pectoral muscles (chest) for cosmetic value, but many do not take the time to strengthen their invisible rotator cuff muscles. When you throw a ball, your shoulder joint funnels any motion from the ground and channels the force. A pitcher uses his legs to push off and gets 60 percent of his power from his hips. Your shoulder may be the weak link in your power chain. Although it may not seem to take enormous strength to throw a baseball, conditioning and endurance are necessary.
Stand with your scapula (shoulder blades) against a wall. Attempt to raise your affected arm shoulder height, parallel to the floor. If you cannot do so without moving your scapula or trapezius (muscles on the top of your shoulder beside your neck), you may have a rotator cuff injury. There is a poor supply of blood to your rotator cuff. That is one reason it is slow to heal. If you have a rotator cuff injury, your goal is to improve blood flow to that area by performing passive range of motion (ROM) exercises.
1. The first exercise your physical therapist may provide for you is the pendulum swing. Simply bend over and support yourself from the waist with your uninjured arm. Gently rotate your injured arm in a circular motion allowing momentum to create the movement.
2. The next exercise requires you to let your fingers do the walking. Walk up and down a wall using your fingertips. Press your fingertips against the wall for balance. Walk around the wall with your fingertips. This is an exercise to strengthen your rotator muscles while maintaining stability.
3. Finally you are ready for unweighted arm circles. Move your arms in a small ROM, gently strengthening your rotator muscles. Your body is an incredible machine. Your muscles and bones become stronger the more you use them. You are correct however not to perform a mechanically incorrect pushup which could cause a breakdown. A repetitive, biomechanically, risky exercise might lead to joint degeneration over time. Or worse, an acute injury would be devastating.
4. And don’t forget your PowerBlock training to strengthen the three deltoid muscles.
