GIRD, The Life of a Baseball Athlete’s Shoulder
If you play or played baseball, you’ve probably got GIRD!
Glenohumeral Internal Rotation Deficit
After throwing a baseball a thousand times, the throwing arm develops this new range of motion pattern that includes increased external rotation and decreased internal rotation (loss greater than 20 degrees).
External Rotation = The Wind Up
Internal Rotation = The Follow Through
TAMD = total arc of motion (internal + external rotation) differences (greater than 5 degrees)
An awesome study called “Comparison of Glenohumeral Range of Motion Deficits in Youth, Collegiate, and Professional Baseball Players” was published in a recent issue of International Journal of Sports Physical Therapy. They measured shoulder range of motion in 223 male baseball players from 12 years old to MLB players looking for GIRD and TAMD.
· 12 and 14-year-old baseball players had the lowest internal rotation and total arc of motion!
· 30.3% of 14-year-old baseball players had GIRD
· 73.3% of 12-year-old baseball players had TAMD >5 degrees
· GIRD and TAMD >5degrees were similar among all positions (not just pitchers)
WHY DO WE LOSE INTERNAL ROTATION: If you throw a ball thousands of times, the muscles in the back of the shoulder have to control the “follow through” phase of the throw. This causes this back part of the shoulder to get really tight, thus limiting internal rotation.
POTENTIAL OVERUSE THROWING INJURIES: labral tears, biceps tears, and rotator cuff tears
As always, let’s remember that an injury can happen from a lot of different factors. Just because you have GIRD, doesn’t mean you need to quit baseball. Although the research studies have mixed results on the cause and effect relationship between range of motion differences and injury risk, let’s separate research from real life and do what we can to best help our athletes!
Proper training, prehab, and rehab through sports physical therapy and sports performance training can help combat negative consequences of high-volume throwing. Make sure we take care of our youth baseball athletes to keep them in the game!
Reference: Wilcox CL, Plummer HA, Ostrander Iii RV. Comparison of Glenohumeral Range of Motion Deficits in Youth, Collegiate, and Professional Baseball Players. Int J Sports Phys Ther. 2021 Dec 1;16(6):1485-1491.
