This is the swimmer who attempts to achieve a thumb’s first entry, but instead of rotating from their forearm they internally rotate their shoulder. This rotation wraps the rotator cuff muscles potentially rubbing the rotator cuff tendons, increasing ones risk for injury.

This will impose a large out sweep, to prevent the hand from crossing over the body, delaying the start of the catch. The difference between forearm pronation and shoulder internal rotation may look minimal, but can make a big difference. Make sure you and your swimmers know the difference between the two!