A "sleeper shoulder" isn't a formal medical term or diagnosis, but rather refers to a loss of internal rotation in the shoulder, often caused by tightness in the posterior capsule (back of the shoulder joint). It's commonly addressed with the "sleeper stretch." The sleeper stretch helps improve shoulder flexibility by stretching the posterior capsule, thereby increasing internal rotation range of motion.
Here's a more detailed breakdown:
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The Issue: Individuals with a "sleeper shoulder" often experience difficulty rotating their arm inward (internal rotation). This can lead to pain, stiffness, and impaired function, especially during activities involving overhead movements or throwing.
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Cause: The primary culprit is often tightness or shortening of the posterior capsule of the shoulder joint. This capsule surrounds the shoulder joint and provides stability.
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The Sleeper Stretch: This exercise is designed to address the posterior capsule tightness. It involves lying on your side with the affected shoulder on the bottom, elbow bent at 90 degrees, and gently pushing the wrist down towards the ground, holding the stretch. The linked video "Sleeper Shoulder Stretch - Physical Therapy Exercises - YouTube" demonstrates this stretch.
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Why "Sleeper"? The name likely derives from the position used to perform the stretch, which resembles a sleeping posture.
Therefore, "sleeper shoulder" is a descriptive term for restricted internal rotation in the shoulder, often caused by posterior capsule tightness, that can be improved through stretching.
