Background: Anecdotal evidence suggests an association between glenohumeral internal rotation deficits (GIRD) and scapular dysfunction, an observable alteration in the normal position or motion of the scapula in relation to the thoracic cage.
Questions/purposes: We therefore hypothesized players with GIRD (15 degrees or greater) will have decreased dominant arm scapular upward rotation and increased scapular protraction compared with baseball players with GIRD (14 degrees or less).
Methods: We studied 43 baseball players with no current shoulder or elbow symptoms; 22 had GIRD 15 degrees or greater and 21 had GIRD 14 degrees or less. We measured glenohumeral internal rotation supine with the scapula stabilized. Scapular upward rotation was tested at rest; 60 degrees , 90 degrees , and 120 degrees abduction in the scapular plane; and scapular protraction at 0 degrees , hands on hips, and 90 degrees abduction in the scapular plane.
Results: The GIRD (15 degrees or greater) group had less scapular upward rotation at 60 degrees (3.58), 90 degrees (5.01), and 120 degrees (2.63) in the dominant arm. Scapular protraction at 90 degrees (0.88 cm) also was greater in the dominant arm of the GIRD (15 degrees or greater) group.
Conclusions: Baseball players with more GIRD have alterations to the position and motion of their scapula. A dual goal of minimizing GIRD and strengthening the scapular stabilizers may be warranted in this population.
Level of evidence: Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.