Philadelphia's
#1 Baseball Physical Therapy expert
Chris McKenzie?

After working with thousands of throwing pain sufferers across the U.S., I’ve developed some core beliefs about rehabbing injured baseball athletes and preventing injury. The first core belief is that you must measure your total arc of motion. This means that if you hold your arms up like a scarecrow, the arm you throw with will show a lot of layback, or external rotation. Due to this, you’ll naturally lose some internal rotation on the throwing arm, which is normal. However, even with this shift, your total arc (external plus internal rotation) on the throwing arm should equal the arc on the non-throwing arm. A difference of even just 5 degrees in motion between your throwing and non-throwing arms can increase the risk of a season-ending injury by nearly 250%. Five degrees might seem minor, but it’s significant. That’s why it’s crucial to measure this regularly, ideally at the start of the season and consistently throughout - maybe every two weeks. Throwing tightens the muscles, so they need regular stretching. For athletes in a return-to-throwing protocol, it’s essential to keep track of this arc throughout the season.