April 14, 2020
Shoulder injuries are extremely common among swimmers. The incidence of shoulder pain among elite swimmers is reported as high as 91%. Swimmers at an elite level may swim up to 9 miles a day – that’s approximately 2500 shoulder revolutions day in day out. Fatigue of the trapezius, pectoral and rotator cuff muscles leaves swimmers vulnerable to microtrauma and compromises the stability of the humerus bone in the shoulder socket.
Out of swimmers that present with shoulder pain, up to 84% have varying degrees of shoulder impingement. Shoulder impingement is a painful condition whereby the tendons or soft tissue structures in the shoulder are compressed by the bones of the shoulder. Shoulder impingement tends to occur when the small muscles in the shoulder joint, call the rotator cuff, fatigue and the larger muscles stabilise the joint. WHen these larger muscles stabilise the joint they cause an increase in compression between the top of the humerous (upper arm bone) and the end of the clavical (collar bone). The space in the shoulder joint is now reduced and is about to be further compromised by the rotation that must happen within the joint in order to propel the body forward in water. This cause the muscles between these bone to get pinched and frayed with repetitive strokes.
MRI's also showed supraspinatus tendinopathy in 69% of swimmers presenting with shoulder pain. The supraspinatus muscle is one of the four rotator cuff muscles that is positioned at the top of the shoulder blade. Its tendon can become impinged and irritated as it gets pinched between the two bones, this exposes the tendon to a load that is slightly greater than it can tolerate each day and slowly over time it will cause significant damage, leading to a tendinopathy.