There are two main causes of rotator cuff strain: acute traumatic and degenerative. Acute traumatic strains usually occur after a specific trauma such as, falling on an outstretched hand (FOOSH), or a single violent force or blow to the shoulder. Besides, prolonged or repetitive overuse of the rotator cuff over a short period of time – especially in athletes who repeatedly make overhead or forceful pulling motions are more prone to rotator cuff strain. Acute traumatic strains can also occur when overexerting during lifting or pulling something that is too heavy, or if a pre-existing shoulder impingement syndrome is already present.
Degenerative strains are as a result of the wear and tear of the rotator cuff tendon that occurs slowly over time, and it is usually painless. This type of strain is more common in the dominant arm, but if a degenerative strain is present in one arm, there is a higher likelihood of a rotator cuff strain in the opposite arm too, even if no pain is felt. It is usually associated with minimal trauma secondary to long-standing tendonitis or chronic impingement syndrome.