The role of shoulder posture in pitching mechanics and injury risk in high school baseball pitchers
Although compromised shoulder posture impacts scapular biomechanics, the interplay between shoulder posture and scapular kinematics during the dynamic pitching motion in high school baseball pitchers remains unexplored. To characterize the shoulder postures of baseball pitchers and investigate their relationships with scapular biomechanics during pitching. Cross-sectional study. Laboratory. 38 high school baseball pitchers (age:16.9 ± 0.9). Shoulder posture was determined by acromial distance (AD), pectoralis minor index (PMI), scapular index (SI), and forward shoulder angle (FSA) in the dominant arm. The scapular kinematics and associated muscle activation (upper trapezius [UT], serratus anterior [SA], lower trapezius, biceps brachii [BB], triceps brachii [TB], anterior deltoid) during pitching were recorded. There was a moderate to strong negative correlation between AD and upward rotation (r = -0.47 to -0.55, p < 0.003) and a moderate positive correlation between AD and anterior tilt (r = 0.40 to 0.44, p = 0.005 to 0.013). PMI and FSA also showed moderate negative correlations with anterior tilt (PMI: r = -0.37, p < 0.05; FSA: r = -0.34 to -0.42, p < 0.04). AD had moderate to strong positive correlations with UT, SA, BB, TB, and anterior deltoid activation (r = 0.36 to 0.59, p < 0.03), while SI showed moderate negative correlations with UT, BB, and anterior deltoid activation (r = -0.33 to -0.40, p < 0.05). FSA displayed a moderate negativecorrelation with SA and BB activation (r = -0.32 to -0.40, p < 0.05). Shoulder posture has a significant moderate to strong correlation with scapular biomechanics during pitching in high school baseball pitchers. Forward shoulder postures with scapular biomechanics alterations during pitching may increase the risk of shoulder fatigue or injuries. Thus, the maintenance of an appropriate shoulder posture is a critical factor in reducing injuries and maximizing performance in pitchers.ABSTRACT
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Contributor Notes
Yi-Hsuan Weng PT, MS e-mail address: a0982925219@gmail.com
Tsun-Shun Huang PT, PhD e-mail address: max770625@gmail.com
Jiu-Jenq Lin PT, PhD e-mail address: jiujlin@ntu.edu.tw