To prevent tennis elbow or return of tennis elbow, one must strengthen the tendons and muscles in the arms. One of the effective exercises is arm tensing. This works out the muscles above and below the elbow without the stressing your limb. To do this, make a fist. Your forearm muscles must be tightened to low tension. Stay for five seconds. Relax and then repeat it five times. Then focus on the upper arm muscles and repeat the process. Then re-do it with your left arm. Gradually, increase your way through medium to high.