Myers, Am J Sports Med 2005 - Scapular Position and Orientation in Throwing Athletes - Article Summary

Scapular Position and Orientation in Throwing Athletes.

Myers, Lephart, et al.·Am J Sports Med·2005·313 citations·Shoulder & Elbow

This descriptive laboratory study used electromagnetic tracking to measure 3D scapular kinematics in 21 competitive throwing athletes versus 21 matched controls during scapular-plane humeral elevation. The goal was to establish what scapular positions and orientations are normal adaptations in healthy throwers — baseline data that did not previously exist.

Key Findings

Throwing athletes showed greater scapular upward rotation at every measured elevation angle (0°–120°), with the largest gap at 90° (throwers 26.9° vs controls 18.0°, P =.001). Upward rotation maintains subacromial clearance during the throwing motion — loss of this adaptation is a hallmark of impingement syndrome.
Scapular internal rotation was increased in throwers across all elevation angles (P =.011–.039). This is clinically visible as medial border prominence and is the same motion that defines the SICK scapula in injured throwers. Healthy adaptation and pathologic pattern differ in degree, not kind.
Scapular retraction was increased at 90° and 120° of elevation (P =.050 and P =.005, respectively). Angles that correspond to the arm-cocking phase of throwing. This positional adaptation is thought to facilitate maximum cocking for subsequent explosive acceleration.
No differences in anterior/posterior tipping or elevation/depression were found between groups at any elevation angle. Not all scapular degrees of freedom adapt to throwing. Only upward rotation, internal rotation, and retraction change chronically.
The SICK scapula (Scapula with Inferior medial border prominence, Coracoid pain and malposition, dysKinesis of movement) seen in injured throwers features the same internal rotation pattern quantified here in healthy athletes, suggesting a continuum from adaptation to pathology.

Board PearlHealthy throwing athletes chronically adapt with increased scapular upward rotation, internal rotation, and retraction — know this before calling it pathologic dyskinesis.

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Scapular Position and Orientation in Throwing Athletes.

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