Why is it not advisable to overdo external rotation of the forearm? In a word: to prevent tennis elbow. We usually like to play table tennis, badminton, is a small ball sports, can benefit the body, education, benefit Ren. In the mobilization of the whole body muscles, bones and joints involved in sports, physical exertion, but also test the human will, perseverance and wisdom, especially on the upper limb muscles, joints are very high requirements, how to avoid muscle strains, reduce shoulder and elbow joint injuries, prevent tennis elbow, is a subject that can not be ignored, or even a problem. Table tennis has become our national ball. As a fitness sport, playing ping pong and badminton does not require complex devices or much space, and can be practiced in pairs, but the amount of exercise is not small, especially the need for a strong swing of the upper body and fast foot movement, which is very exciting and challenging. Tennis elbow in small ball players is the most likely to happen. Whether it is table tennis or badminton, the gymnast or athlete needs the coordinated movement of the shoulder, elbow, wrist and metacarpophalangeal and interphalangeal joints of the upper limb on one side when swinging the racket, and at the same time, depends on the flexible and fast pace of both lower limbs, flexible reaction, and the tacit cooperation of the waist activities. However, if you participate in small ball sports, if you do not control the strength and posture of the elbow joint when hitting the ball, and if you rotate your forearm too much, it is very easy to damage the elbow joint and the extensor digitorum superficialis, resulting in tennis elbow, which is due to long-term, continuous, repeated and concentrated excessive or inappropriate force on the elbow joint, easily causing chronic strain and aseptic inflammation of the extensor digitorum superficialis. As in tennis, the elbow joint plays a pivotal role when swinging the racket, and the rotational movement of the move is particularly important. If the elbow joint extension and flexion and forearm internal and external rotation movement is strong, natural, soft, coordinated, then, swinging the ball on the flow of water, the magic, so that the opponent can not be defended, they will not be injured. The size of the force of hitting the ball depends on the strength of the shoulder joint and its surrounding muscles; the speed, direction, and landing point of the ball are very variable, and depend on the flexibility of the elbow and wrist joints. Once the elbow joint is injured or suffers from tennis elbow, the action is inevitably stiff, raw and awkward, and it is difficult to hit a satisfactory ball return. Many women often wash clothes, squeeze towels or knit sweaters due to household chores, which can also easily damage the extensor tendons and cause tennis elbow, causing a lot of trouble. Therefore, we should pay attention to control the frequent internal and external rotation of the elbow joint when using the upper limb; rotate the forearm when the force should be soft, not hard, excessive; avoid the cold and moisture on the elbow joint; combine work and rest, relaxed.