Figure A shows a sleeper stretch and Figure B shows a prone internal rotation stretch with scapular stabilization which are both forms of posterior capsular stretching. Baseball pitchers often have excessive external rotation and diminished internal rotation on their throwing shoulder. A rehabilitation program that includes posterior capsular stretching is essential for the treatment of GIRD.
According to the review article by Braun et al, GIRD is a posterior shift in the total arc of motion and is thought to be a physiological adaptation of the shoulder joint to throwing. The treatment of loss of internal rotation is stretching of the posterior capsule.
The Level 3 article by Crockett et al reviewed shoulder CT scans and shoulder range of motion in 25 pitchers and 25 non-throwers. The pitcher group demonstrated a significant increase in humeral head retroversion by CT scan, external rotation at 90°, external rotation in the scapular plane, and total range of motion compared to the non-pitchers.
Braun S, Kokmeyer D, Millett PJ. Shoulder injuries in the throwing athlete. J Bone Joint Surg Am. 2009 Apr;91(4):966-78. Review.
PMID:19339585 (Link to Abstract)
Crockett HC, Gross LB, Wilk KE, Schwartz ML, Reed J, O'Mara J, Reilly MT, Dugas JR, Meister K, Lyman S, Andrews JR. Osseous adaptation and range of motion at the glenohumeral joint in professional baseball pitchers. Am J Sports Med. 2002 Jan-Feb;30(1):20-6.
PMID:11798991 (Link to Abstract)