A tennis elbow is a sports injury and an inflammation of the tendon that joint of the forearm muscle. The first cause is practice to competition, training, and playing sports such as tennis, bowling, and throwing that this cause may find in generally young. The second cause is an overuse that occurs a strain to tendon in the forearm. The third cause of tennis elbow injury can be a tiny tear to a tendon and inflammation and scarring of the tendon. Besides, it occurs the tiny tear of Extensor Carpi Radialis Brevis (ECRB) muscle, which occurs from repeated actions or work hard. It can find in the generally people not only a tennis athlete, but everybody.