Shoulder pain is an unfortunately common condition that brings patients of all ages to physical therapy. Athletes, new moms, industrial workers, retirees — all of these patients have landed in our clinics. One of the trickiest parts of shoulder pain is that the cause of pain is often not the shoulder. While pain in the shoulder is the symptom, the cause could be elsewhere in the kinetic chain. Rest may seem like an easy way to help your shoulder pain, but during rest, underlying causes like weak muscles or joint stiffness can actually worsen, putting you right back at square one.
So what’s a big culprit in shoulder pain? Let’s talk scapular stability.
During normal arm function, the shoulder blade, or scapula, provides a solid platform on which the arm bone, or humerus, can move. Without this stability, the glenohumeral joint, which is the ball and socket shoulder joint, has increased chance of injury. Scapular instability is found in up to 68% of rotator cuff problems!
The joint where the scapula meets the ribcage is a tricky one, as its stability relies almost 100% on the coordination and strength of the surrounding musculature. This is good, because it makes your shoulder extremely mobile. But it does mean that the muscles that attach to the scapula are responsible for stabilizing that platform and putting the socket in the correct place, so that the ball of that ball and socket joint can roll smoothly when you raise your arm.
Quick anatomy lesson!
There are 17 muscles that attach to the scapula, but the main stabilizers are the rhomboids, the trapezius group, the serratus anterior, and the levator scapula.
The serratus anterior is responsible for holding the scapula tight to the body and pulling the scapula forward and around the ribs in protraction. It keeps the shoulder blade from “winging” off of the rib cage and allows for pushing or punching activities.
The rhomboids stabilize the inner border of the scapula, near the spine. They are active in scapular retraction, which is the movement toward the spine when you pinch your shoulder blades together. Full retraction is required for overhead swimming, tennis serve, or throwing motions. In pitching, the rhomboids help to brake the shoulder blade/forward arm motion released during arm acceleration.
The trapezius muscle is made up of three different sections, which are responsible for different motions. The upper traps elevate and upwardly rotate the scapula, the middle traps assist the rhomboids in retraction, and the lower traps depress and upwardly rotate the scapula. The upper traps, lower traps and serratus anterior must all three fire in a coordinated fashion in order to provide smooth rotation of the socket as the arm is elevated above the head.
The levator scapula elevates the scapula and tilts it downward.
What causes poor scapular muscle function?
Imbalances around the shoulder girdle can lead to weakness or inhibition of the scapular stabilizers. For example, many people who demonstrate poor shoulder blade position have tightness and restrictions in the pec minor, which tilts the shoulder blade forward. This can cause the lower trap and serratus anterior to become stretched and weak. Restrictions in the back of the shoulder joint itself can also cause tilting of the scapula.
Muscles can also be injured over time due to habitual strain such as repetitive motions, or from trauma such as a fall. Tissue damage or inhibition due to pain can change the muscle’s ability to activate appropriately.
Fatigue of these muscles also leads to poor scapular positioning as the more powerful prime movers of the arm like the pecs and deltoids overpower these smaller stabilizers.
What can I do to improve scapular stability?
Release restrictions. Use a lacrosse ball and focus on tightness and muscle knots in the pecs, lats, and upper traps as well as in the back of the shoulder near the rotator cuff. After that, stretching the pecs and the back of the shoulder (here’s a nice demonstration of the genie stretch help if you’re restricted in shoulder mobility. link: https://www.youtube.com/watch?v=66pybJQgBew
Improve activation of stabilizers. Begin with isometric shoulder blade pinches, A’s and W’s to get the motion down and get those muscles firing. Punches are used to activate the serratus. Progress to theraband resisted A’s, W’s, banded punches, and ‘ball over head’.
Build strength and endurance. Once you can perform high reps of the easier activities with good form, advance with cable and banded activities such as rows and lat pull downs, and be sure to incorporate the scapula when doing lower body activities. At React we love a sumo squat with a row to get the upper and lower body at the same time.
References: Paine R, Voight ML. THE ROLE OF THE SCAPULA. International Journal of Sports Physical Therapy. 2013;8(5):617-629.