Shoulder External Rotation
Definition
The rotational movement of the humerus away from the midline with the arm at 90 degrees of abduction. Normal range is approximately 80-100 degrees. Overhead athletes often develop excessive external rotation on the dominant side as an adaptation to throwing demands.
Clinical Significance
Shoulder external rotation is required for overhead pressing, throwing, and serving. Excessive external rotation without matching internal rotation (as seen in throwers) creates anterior shoulder instability. Insufficient external rotation limits overhead mechanics and forces compensatory scapular and thoracic movement. External rotation restriction is often caused by pectoralis minor tightness, subscapularis shortness, or anterior capsule contracture.
How AKMI Assesses This
AKMI measures shoulder external rotation bilaterally at 90 degrees abduction. Combined with internal rotation data to calculate total arc of rotation. Compared between sides to identify significant asymmetry. Correlated with thoracic rotation and pectoralis length data.
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A biomechanical assessment measures shoulder external rotation and its relationship to the rest of your structural chain. 18 tests, objective data, personalized programming.