According to healthline, “tennis elbow is caused by inflammation of the muscles of the forearm that attach to the elbow.” This is most commonly due to overuse by a repetitive activity, and the inflammation can occur from repetitive activities outside of tennis. After your inflammation goes down, you can start with easy exercise to strengthen your muscles, which can prevent tennis elbow from coming back. Read the full article that shows five exercises for tennis elbow, but make sure you check in with your doctor or therapist first.