Relationship between Standing Trunk Extension Angle and Medial Elbow Injuries in Young Baseball Pitchers

• Published in: International journal of environmental research and public health 2022-03, Vol.19 (7), p.3895
• Main Authors: Gonno, Megumi, Kida, Noriyuki, Nomura, Teruo, Matsui, Tomoyuki, Azuma, Yoshikazu, Hiramoto, Machiko, Hashimoto, Ruo, Miyazaki, Tetsuya, Tanaka, Maki, Watanabe, Yuya, Kai, Yoshihiro, Morihara, Toru
• Format: Article
• Language: English
• Subjects: Adolescent; Baseball; Biomechanical Phenomena; Elbow; Elbow - diagnostic imaging; Elbow Joint - diagnostic imaging; Evaluation; Holidays & special occasions; Humans; Injuries; Investigations; Male; Muscle strength; Musculoskeletal Diseases; Orthopedics; Rigid structures; Thorax; Three dimensional analysis; Three dimensional motion; Torso; Ultrasonic imaging; Ultrasound; X-rays
• ISSN: 1660-4601; 1661-7827; 1660-4601
• DOI: 10.3390/ijerph19073895

Purpose: The purpose of this study was to investigate the relationship between the standing trunk extension angle and medial elbow injuries. Subjects and methods: The study participants were 90 male baseball pitchers (10−12 years) belonging to youth baseball teams. Pitching elbow injuries were evaluated by an orthopedic surgeon using ultrasound scans and physical examination findings. A single optical three-dimensional motion analysis system was used for the trunk extension measurements, with three-dimensional coordinates captured. The overall, upper, and lower trunk angles were then analyzed. Results: Trunk extension angle during standing trunk extension was significantly smaller among participants who were positive for medial elbow injuries on ultrasound scans (positive: 71.4° ± 10.3°; negative: 75.7° ± 9.2°; t = 2.05, p < 0.05). The upper trunk extension angle was significantly smaller than the lower trunk extension angle among participants who were positive for medial elbow injuries on physical examination (upper: 33.0° ± 6.9°; lower: 41.2° ± 8.2°; t = −2.42, p < 0.05). Conclusions: Trunk extension angle during standing trunk extension is associated with medial elbow injuries. Evaluating the trunk extension angle as multiple segments rather than a single rigid body is valuable.