Does Asymmetry Equal Pathology?

baseball Jun 03, 2022

Do You Need to “Fix” An Asymmetry!?

Baseball Example: 

A baseball player has a 20 degree difference in Internal Rotation ROM, or Glenohumeral Internal Rotation Deficit (GIRD) and 20 degrees more external rotation range of motion on the throwing arm.

So now what?

Let’s see what some resources say:

Physical Therapy School:

“Treat the deficit.” More than a 20 degree difference in IR side to side is a tight posterior capsule and we need to stretch, strengthen, stabilize.

Baseball Experts: (@mikereinold, @wilk_kevin and @ericcressey):

If the total arc of motion is similar, it is more likely to be attributed to humeral retroversion. This bony adaptation to the angle of the humeral head may actually be a favorable adaptation.

Studies including Dines et al:

Indicated that “GIRD may be associated with elbow valgus instability” but if you actually read the article, the total range of motion was significantly decreased in the injured group, meaning that it was more stable than originally thought!


It seems to me that the perspective of @mikereinold that GIRD is a measurement not a pathology may give a better understanding of the big picture. Further, other alignment and positioning of structures in the body such as scapula mispositioning may make it appear that an individual has decreased IR.

This should encourage you to look deeper than “treating the deficit”!

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