The Relationship Between Forward Scapular Posture and Posterior Shoulder Tightness Among Baseball Players

Background: Excessive and untimely scapular dyskinesis during the throwing motion has been associated with several shoulder injuries. The scapula provides attachment for many soft tissue structures. Therefore, many have hypothesized that posterior shoulder tightness may alter proper scapular kinematics. Hypothesis: As posterior shoulder tightness increases, so will forward scapular posture. Baseball players will have a significantly more forward scapular position of their dominant arm compared with their nondominant arm. The bilateral difference in forward scapular posture will be greater in pitchers than in position players, indicating pitchers have more forward scapular posture. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Bilateral forward scapular posture, glenohumeral horizontal adduction, and rotational range of motion were measured among 20 professional baseball pitchers and 20 position players. Results: A regression analysis showed a moderate to good negative relationship between glenohumeral horizontal adduction range of motion and forward scapular posture (r(2) = .50, P = .001). T tests demonstrated that the dominant shoulders of both groups had significantly more forward scapular posture compared with nondominant shoulders (P < .004). There were no other significant relationships or differences found (r(2) = .04, P > .15). Conclusion: There was a moderate to good relationship between posterior shoulder tightness and forward scapular posture. Furthermore, baseball players had more forward scapular posture of the dominant arm than the nondominant arm. These results suggest that posterior shoulder tightness as evidenced by decreased glenohumeral adduction range of motion may be considered a partial predictor for excessive forward scapular posture and vice versa. Because of the association between this scapular dyskinesis and shoulder dysfunction, clinicians may find it advantageous to address these characteristics when examining and treating such athletes.