Ever had or known anyone who had this injury? Protect yourself while working out. This is a serious injury, most often requires Surgery. Your Rotator Cuff is not just one muscle, as I have so often heard people refer to it as one. It actually involves 4. Your Subscapularis, Infraspinatus, Teres Minor, and Supraspinatus. Causes: Improper Body Mechanics with lifting or pulling, Tendonitis, Bursitis, Degeneration, Bone Spurs, Falling, and good ole’ Repetitive Stress. Be mindful and give your body a break once in awhile. REST! And lift with caution. Make sure your Trainer has you doing your exercises bio mechanically correct!