Physical Therapy Corner

The Shoulder Joint: it's a Balancing Act

Swimmers, swimming coaches, and swim parents all recognize that shoulder pain is a common problem among competitive (and recreational) swimmers. To understand the problems that can occur in the swimmer's shoulder, it's important to learn a little bit about shoulder anatomy.

The shoulder complex (also known as the shoulder "girdle") is made up of a number of bones and joints. The shoulder joint itself, called the glenohumeral joint, consists of the humerus and its connection with the scapula, or shoulder blade. The head of the humerus is shaped like half a sphere and fits into a part of the scapula called the glenoid fossa, which is shaped like the top of a golf tee. This "ball and socket" relationship is what allows the shoulder to have such a large range of motion.

The head of the humerus is held in place within the glenoid fossa by muscles (the rotator cuff), ligaments and joint capsule (the tissues that surround the joint), and cartilage called the glenoid labrum. The labrum is a liner around the rim of the fossa and acts like a kind of bumper for the round head of the humerus so it won't slip over the rim of the fossa. Injury to or weakness in any of these stabilizing structures (rotator cuff, ligaments/capsule, and labrum) can cause shoulder problems because the head of the humerus will then be able to move excessively in the fossa. In extreme cases, it can even move completely out of the fossa, which is called subluxation or dislocation.

The health of a swimmer's shoulder is dependent upon maintaining adequate stability for the head of the humerus within the glenoid fossa. Swimmers need a large range of shoulder motion (good flexibility) to be able to use great technique and swim fast, but they also need stability to avoid shoulder problems that cause pain and can interrupt training! It's a delicate balancing act.

Next: The Rotator Cuff: Key to a Healthy Swimming Shoulder

J.B. Barr, PT, DPT, OCS grew up in Lincoln, Nebraska and swam competitively for Nebraska Aquatics and Lincoln Southeast High School. He competed for Stanford University, graduating in 1991. He is currently a physical therapist in Omaha, employed by Creighton University as an assistant professor in the physical therapy department. He continues to compete as a Masters swimmer. WEBMASTER UPDATE, 23 Mar 2005: J.B. Barr is the reigning Masters National Champion in the 100 Free and 100 Back, competition held 18-22 Mar 05 in Ft. Lauderdale FL, age group 35-39. See more results