The following exercises were explained to me when I first contracted shoulder tendonitis in 1992 during my college years on the Caltech Swim Team. They've proved useful time and again.

Note: Consult a personal trainer or physician if you have unbearable shoulder pain. I am neither a licensed trainer nor a physician, and cannot be held liable for any harm these may cause due to misuse, overexertion, or ignorance of pain.

Additional Note: Not all forms of shoulder pain come from the same source. Tendonitis is best described as a mildly irritating burning sensation deep within the heart of the shoulder that comes on gradually through continuous use. If you feel a stabbing pain, or pain associated with particular arm locations, motions, or exertions, it is likely that you have a more serious injury and should see a physician. Seek treatment early before you have to give up surfing altogether.

These exercises work best if performed as a warm-up to surfing or swimming. Do them regularly and you should begin to lose most forms of shoulder tendonitis.

The point of these exercises is to strengthen and warm up the muscles and tendons that work internal and external rotation of the rotator cuff. Before doing any exercise and especially before swimming, be sure to stretch!

Both forms of rotation are about the same axis, but in opposite directions. To visualize the axis of rotation, stand with your arms at your side. The line running from the tips of your fingers through the shoulder socket, parallel to the long axis of your body, is the axis of rotation. Viewing your shoulder from directly overhead, internal rotation is counter-clockwise (into the body) and external rotation is clockwise (away from the body).

The exercises are done with the upper arm kept against the side of the body, arm bent at the elbow and pointing straight away from your front side. Think of drawing a six-gun in the American Old West. Using this position as the rest position, internal rotation is done keeping the upper arm firmly against the side of your body, bringing your hand across until it just touches your abdomen. External rotation is done from the rest position outward to an angle of about 45 degrees, depending on how flexible you are.

When beginning the exercises, use a rubber resistance band or tygon tubing. Do 3 sets of 20 reps for internal rotation & the same for external rotation, for both arms.

When the resistance band becomes too easy, you can upgrade to small ankle weights or bean bags. Start around 1/4 lb of weight. Perform the exercise while lying on your side so that gravity can provide the proper resistance. You'll have to flip over when switching from external to internal rotation.

The rotator cuff muscles are not commonly exercised in everyday activity, so be very careful not to strain them. If you feel pain, back off. Pain is bad.