Due to the long-term, repeated and strong contraction and stretching of the forearm extensor muscles, the humeral epicondyle, where it is attached, undergoes acute or chronic cumulative injury of varying degrees, resulting in tearing, bleeding, mechanization and adhesion of the muscle fibers, causing weakness of the extensor fingers. Epicondylitis is mainly caused by the long-term, repeated and strong contraction and pulling of the forearm extensor muscle group, which causes different degrees of acute or chronic accumulative injury to the humeral epicondyle where it is attached, resulting in tearing, bleeding, mechanization and adhesion of the muscle fibers, forming a sterile inflammatory reaction and causing clinical symptoms. So how to prevent and care for extensor weakness? The following will be introduced to you. 1, the onset of extensor weakness is related to chronic injury, middle-aged and elderly people are often caused by strain so labor intensity should not be too large, do not carry heavy objects for a long time, walking once, washing clothes should not be too much, to prevent strain on the epicondylar muscle fascia of the humerus. Usually pay attention to exercise body active activities of the upper limb joints to enhance muscle strength, help prevent the occurrence of this disease before work, functional exercise to prepare for the daily initiative to make a fist flexing elbow rotating front, forceful straightening out of the fist and other exercise work, do not often punch cold water to avoid trauma. 2, let the palm face the body to extract objects. 3, trying to increase the weight-bearing exercise of the hand. Let the elbow up and then the palm of the hand. Repeatedly bend the wrist downward, if you feel pain to stop the activity. 4.When starting an activity that may be stressful, stretch the muscles involved; grasp the tops of your fingers and slowly but firmly pull your fingers backwards closer to your body, keeping your upper limbs fully extended and keeping your palms facing out.