Hands down the most common cause is poor body rotation. In fact, I can often diagnose the problem without even seeing a person swim. I ask a few questions and bingo! Swimming flat in the water will cause the tendons (see illustration) to be pulled or stretched as the arm is reaching behind you to recover above the water. This added friction will cause inflamation (which starts to compound the issue) and pain. It’s considered an overuse injury, but poor mechanics are the true culprit.

The fix? Rotate your body more. The motion of the shoulder shouldn’t be much more than an up and down motion rather than the  circular motion that most people think of. As the arm finishes the pull and begins to recover, the body rotates to one side allowing the shoulder to simply lift. When the recovery is complete and the hand enters the water, the body rotates back allowing the shoulder to essentially lower as you pull through the water. If you find yourself moving your shoulder in large, circular motions, then chances are you are swimming too flat in the water.

Is this the only way to get swimmer’s shoulder? Heck no. There are plenty. For example, when one muscle group develops more than another in your shoulder (too much bench press, etc) the over developed muscle group will create an imbalance and pull on the joint. You can also run into problems on the back side of your shoulder if you cross the midline of your body too much during your pull. The list goes on…

Be patient as tendons and ligaments receive very little bloodflow, so it will take them longer to heal than muscle injuries. Reduce your volume or do exercises in the pool that don’t hurt the problemed shoulder such as: other strokes, stroke drills and kick sets. A little time off will do your shoulders some good. Once the pain subsides, have someone take a look at your stroke and make the necessary adjustments. The key is not to drift back into your old habits.