A rotator cuff injury is mainly caused due to an overworked shoulder because of some heavy physical activity like swimming, tennis, cricket etc. This is mainly caused if you do these activities after a long time. There are three kinds of rotator cuff injuries:
Tendonitis: The normal and smooth gliding motion of your tendon may get weakened due to overuse of your tendon. As a result, the action of pulling the muscle becomes irritating.
Age-related changes of the tendon are diagnosed as one of the common causes of tendonitis. Individual suffering from tendonitis usually experience moderate to severe pain in the shoulder area and some limited range of motion.
Tears: Tears in the tendon occur when your tendons actually separate from your bone. These tears cause intense pain and result in immediate loss of mobility, no matter whether they are partial or complete.
Instability Impingement: It occurs when the rotator cuff tendons are weakened and worn out by repetitive activity.