The shoulder is one of the most intricate joints in the body, presenting a challenge in managing shoulder discomfort. With its involvement of multiple structures and varying pain presentations, pinpointing the precise origin of shoulder pain proves difficult. This was recently exemplified in a study performed by Barreto et al. who examined individuals with unilateral shoulder pain. The study imaged both asymptomatic (non-painful) and symptomatic (painful) shoulders of the same individual, and what they found was nearly identical results on each side. For instance, 90% of symptomatic shoulders showed signs of tendinopathy compared to 89% on the asymptomatic side (1). This underscores that structural damage or irritation does not always dictate the presence of pain, highlighting the intricacies of the shoulder. 

Looking deep into the anatomy of the shoulder, the glenohumeral joint, a ball and socket joint formed by the head of the humerus and the glenoid fossa of the scapula, is where we get most of our shoulder motion. Often likened to as a golf ball on a tee, the glenohumeral joint is the most mobile joint in our body, and it is because of this mobility that the shoulder necessitates strong passive and active stability. The rotator cuff is an active stabilizer of the glenohumeral joint, making it crucial for assisting individual’s shoulder function.

The rotator cuff is a term commonly understood by patients, but the road usually stops there. What some do not realize is that the rotator cuff consists of 4 muscles and tendons which originate on the scapula and attach at various intervals on the head of the humerus. These muscles lie deep to our deltoid muscle, which is the muscle we see on the front, side and back of the shoulder. The 4 muscles include the supraspinatus, infraspinatus, teres minor, and subscapularis.

The role of the rotator cuff is to assist with movement of the humerus and stability of the glenohumeral joint as we move our arm through space. Without our rotator cuff, or with one that is weakened or injured, the mechanics of the shoulder can become compromised, which may contribute to possible injury or pain in the shoulder. Fortunately, like other muscles and tendons in our body, we can strengthen and build resiliency of the rotator cuff through exercise. 

While no single rotator cuff muscle functions in isolation, certain shoulder movements can bias recruitment of specific muscles within the cuff. Effective exercises to strengthen the rotator cuff include (2):

Side lying ER:

Standing ER and IR:

Full Can:

Row:

These exercises are not exhaustive, but they can serve as a good place to start when attempting to address rotator cuff strength. If you have any questions about shoulder pain, the rotator cuff, or related topics discussed here, please contact us for further assistance.

Written by Andrew Traver PT, DPT, CSCS

References:

1. Barreto RPG, Braman JP, Ludewig PM, Ribeiro LP, Camargo PR. Bilateral magnetic resonance imaging findings in individuals with unilateral shoulder pain. J Shoulder Elbow Surg. 2019 Sep;28(9):1699-1706. doi: 10.1016/j.jse.2019.04.001. Epub 2019 Jul 3. PMID: 31279721.

2. Edwards PK, Ebert JR, Littlewood C, Ackland T, Wang A. A Systematic Review of Electromyography Studies in Normal Shoulders to Inform Postoperative Rehabilitation Following Rotator Cuff Repair. J Orthop Sports Phys Ther. 2017 Dec;47(12):931-944. doi: 10.2519/jospt.2017.7271. Epub 2017 Jul 13. PMID: 28704624.