What causes rotator cuff tears?
The rotator cuff is a group of four small muscles and tendons that stabilize your shoulder through every reach, lift, and throw. When one of those tendons tears, whether suddenly or gradually over years, the shoulder loses the support it depends on for smooth, pain-free movement. Understanding whether your tear came from acute trauma or slow degeneration is what shapes whether therapy alone can restore your shoulder or whether it fits alongside other care.
Jobs and sports that involve constant reaching overhead, like painting, construction, swimming, or throwing sports, put the rotator cuff tendons through the same stressful position thousands of times. Over months and years, that repeated overhead loading can fray the tendon fibers, especially if the surrounding shoulder muscles are not strong enough to share the work.
Like any tissue, the rotator cuff tendons lose some of their blood supply and elasticity as you get older. That gradual degeneration means the tendon can tear with surprisingly little provocation, sometimes during an activity you have done a thousand times before without issue. This kind of tear often builds quietly for years before it becomes noticeable.
A fall onto an outstretched arm, a hard jolt while lifting something heavy, or a sudden jerking motion can tear a rotator cuff tendon all at once. These acute tears tend to come with sharp pain and immediate weakness, and they are different from the gradual wear-and-tear tears that build up slowly.
When the space between the shoulder blade and the upper arm bone narrows, the rotator cuff tendons can get pinched every time you lift your arm. Poor shoulder blade positioning and weak stabilizing muscles make that pinching worse over time, gradually wearing down the tendon until it frays or tears.
The rotator cuff does not work alone. It relies on the muscles around the shoulder blade to keep the joint properly positioned during movement. When those stabilizing muscles are weak or out of balance, the rotator cuff tendons absorb forces they were never meant to handle by themselves, accelerating wear and increasing tear risk.
