There are two common injury factors for rotator cuff injury, i.e. lifting heavy objects and falling. After a fall, the hand will support the ground, and the shoulder joint will be torn after the stress. Pull-ups are absolutely prohibited after rotator cuff injury, because from the observation of rotator cuff physiology, normal rotator cuff tissues grow in the bone like tree roots. The doctor’s surgery is not to weave the rotator cuff tissue into the bone like a tree root, which is not possible with the current technology. The doctor’s surgery is to fit the rotator cuff side by side and face to face with the bone. In the future, the rotator cuff will heal with the bone by the scarring of the two contact surfaces, and the healing strength will not be as strong as that of a tree root in the past. Also, rotator cuffs tear because the tendon tissue is not strong enough to heal. Therefore, the rotator cuff after surgery and then healing, but also far from a certain strength, do pull-ups and other large loads of stretching exercises are not suitable, must be prohibited, otherwise lead to rotator cuff injury pain more serious than before.