Are you plagued by shoulder pain and unsure why? Interestingly, the cause of your shoulder pain may not be coming from inside your shoulder joint itself. The shoulder joint is more complex than most of us think. The collar bone, shoulder blade, and upper arm bone all come together to form the shoulder joint. All of these parts must be operating properly in order for your arm to move freely, without pain.
Scapular dyskinesis, or impaired movement of the shoulder blade, is a common culprit of shoulder pain (1). The relationship between the shoulder and scapula is called the scapulohumeral rhythm. Meaning, the upper arm bone (humerus) and shoulder blade (scapula) have to move together for normal shoulder mobility to occur. Normal movement occurs in a two to one ratio (2). In other words, to reach over your head the humerus will cover two thirds of the movement required, while the scapula accounts for the other third. Without this rhythm, an abnormal force will be applied to the shoulder as it elevates.
Getting Out of Rhythm
What causes a disturbance in this relationship? The majority of scapular dyskinesis cases are the result of muscle overuse (imbalance) or poor posture (3). Whether you are a competitive athlete, work in an industry which requires repetitive overhead work, or are simply someone who enjoys yard work, taxing your shoulder at high workloads can lead to muscle overuse and imbalance. There are seventeen muscles that aid in the movement of the shoulder blade (3). Think of your scapula as a seventeen piece band. If one (or more) of those instruments (muscles) are too loud (over worked) it will alter the sound (movement) and throw off the (scapulohumeral) rhythm.
Poor posture leads to an abnormal resting position of the scapula, potentially leading to shoulder impingement syndrome (4). Shoulder impingement syndrome is the most common cause of shoulder pain. Think about it, if the scapula is starting out of alignment, the chances of it being in perfect rhythm with the humerus is not likely.
Many of us can admit to having a less than ideal posture, particularly slouching when sitting. A slouched posture leads to increased curve on the upper back and tightening of our chest muscles. These postural changes cause the scapula to migrate towards the front of our shoulder, leaving less room for movement. The result ends up as impingement of the shoulder blade on the rotator cuff muscles. What does mean to you? Pain with putting on your jacket, pain reaching into the top cupboard, and pain when you reach across the car seat to grab something. Sounds familiar, doesn’t it?
Getting your rhythm back
Now, what can be done to prevent (or reverse) scapular dyskinesis? Try these two exercises to help improve your posture, and increase the mobility of your shoulder blade.
Standing a foot away from the wall, place your hands evenly below your shoulder. Take a step forward, leading with your trunk drive your arms up the wall (your whole body should be moving, not just your arms.)Try one to two sets of ten repititions.
Lying on your side with the top knee resting at hip height on the table. Place your hand along the back of your neck and rotate backwards to open up your chest and rotate the upper part of your back. Complete ten repititions, to both sides.
Remember, the shoulder is complex joint, with multiple moving parts. Making sure all the parts are moving together is likely the key to returning to pain free mobility.
1. Kibler, Ben W., and John McMullen. “Scapular dyskinesis and its relation to shoulder pain.” Journal of the American Academy of Orthopaedic Surgeons11.2 (2003): 142-151.
2. McClure, Philip W., et al. “Direct 3-dimensional measurement of scapular kinematics during dynamic movements in vivo.” Journal of Shoulder and Elbow Surgery 10.3 (2001): 269-277.
3. Kibler, W. Ben. “The role of the scapula in athletic shoulder function.” The American journal of sports medicine 26.2 (1998): 325-337.
4. Struyf, F., et al. “Scapular positioning and movement in unimpaired shoulders, shoulder impingement syndrome, and glenohumeral instability.”Scandinavian journal of medicine & science in sports 21.3 (2011): 352-358.
5. Kebaetse, Maikutlo, Philip McClure, and Neal A. Pratt. “Thoracic position effect on shoulder range of motion, strength, and three-dimensional scapular kinematics.” Archives of physical medicine and rehabilitation 80.8 (1999): 945-950.