The exercise targets the small, but important pronator teres muscle that often contributes to elbow pain and some cases of tendinosis. Sit on a chair or bench with your forearm resting on your thigh with the hand in the palms-up position. Firmly grip a sledgehammer with the heavy end extending to the side and the handle parallel to the floor. Turn your hand inward (pronation) to lift the hammer to the vertical position. Stop here. Now, slowly lower the hammer back to the starting position–slowly count to five as you perform the lowering (eccentric) phase. Stop at the horizontal position for one second before beginning the next repetition. Continue lifting the hammer in this way for fifteen to twenty repetitions. Choke up/down on the hammer to adjust the resistance/difficult. Perform two sets with each hand. Note: When used as a rehab exercise, it’s best to do only the lowering phase–use your free hand to assist in returning the hammer to the top position.
Golfers Elbow is usually caused by gripping activities; gripping either too hard or for too long can bring on the pain. Make sure the item that you are gripping, whether it's a tennis racquet, a hammer, or a canoe paddle, is the correct size for your hand. If it is too small it will cause you to grip too hard. If you play a racquet sport for the first time in a long while, or you have to decorate a room in one weekend, make sure you take regular breaks and stretch the muscles that work over the wrist by doing 'limp wrist' and 'policeman halting traffic' type stretches.
For those who have suffered from golfer's elbow in the past, it may be a good idea to wear a Compression Strap (elbow support). These work by reducing the strain on the painful area by preventing the wrist muscles from contracting fully during sporting and work activities.