The areas of poor blood supply in the rotator cuff make these tendons especially vulnerable to degeneration from aging. The degeneration of aging helps explain why the rotator cuff tear is such a common injury later in life. This problem of degeneration may be accelerated by repeating the same types of shoulder motions. This can happen with overhand athletes, such as baseball pitchers. But even doing routine chores like cleaning mirrors, washing and waxing a car, or painting can cause the rotator cuff to fatigue from overuse.
Excessive force can tear weak rotator cuff tendons.
This force can come from trying to catch a heavy falling object or lifting an extremely heavy object with the arm extended. The force can also be from a fall directly onto the shoulder. Sometimes injuries that tear the rotator cuff are painful, but sometimes they aren't. The typical patient with a rotator cuff tear is in late middle age and has had problems with the shoulder for some time. This patient then lifts a load or suffers an injury that tears the tendon.