Loss of glenohumeral internal rotation in little league pitchers: a biomechanical study

Glenohumeral internal rotation deficit (GIRD) is a significant shoulder problem for throwing athletes. GIRD, however, has not been reported in little league pitchers. The purpose of this study was to investigate GIRD in little leaguers. The range of motion of both shoulders was measured in 25 male little league pitchers. All pitchers underwent motion analyses of their pitching to evaluate shoulder kinematics. GIRD was found in 10 of the 25 pitchers. External rotation in the dominant arm in the GIRD group was not significantly different compared to the contralateral or dominant arm in the non-GIRD group. This biomechanical study showed that the GIRD group had increased external rotation while throwing compared to the non-GIRD group. These findings indicate that GIRD can occur prior to development of the increased external rotation in the dominant arm seen in adult throwers.