Cheng Shih-Chung, Lin Shu-Ming, Lin Won-Jean
Graduate Institute of Athletics and Coaching Science, National Taiwan Sport University.
Division of Physical Medicine and Rehabilitation, Taoyuan General Hospital Ministry of Health and Welfare, Taoyuan, Taiwan.
Medicine (Baltimore). 2021 Jan 22;100(3):e24066. doi: 10.1097/MD.0000000000024066.
A recent study suggested that baseball pitchers with glenohumeral internal rotation deficit (GIRD) may tend to use trunk rotation as compensation to adjust ball placement, which may lead to subsequent counter movement at the knee of the leading leg.This study aims to investigate the kinematic characteristics of the counter movements between the femur and the tibia (knee torsion), from the landing of the leading leg until the follow-through phase, during throwing between pitchers with and without GIRD at the dominant arm.This is a case-control study. Twenty-one senior high school baseball pitchers were recruited in this study. The glenohumeral internal and external rotation, hip internal and external rotation of all participants were measured. Eight pitchers without GIRD and 13 pitchers with GIRD were enrolled into the control group and experiment group, respectively. The maximal angular movement between the femur and the tibia (knee torsion) of the leading leg was measured, using The Zebris 3D (Zebris Medizintechnik GmbH, Isny, Germany) motion analysis system, in the interval from the landing until the follow-through phase during pitching a fastball to the bottom-outside corner with their dominant arm.The results showed that the maximal knee torsion of the leading leg in the experimental group (13.67 ± 0.9 degrees) was significantly greater than the control group (4.25 ± 1.369 degrees) (P < .05).Pitchers with GIRD had greater counter movement in the knee joint than pitchers without GIRD.
最近的一项研究表明，患有盂肱关节内旋不足（GIRD）的棒球投手可能倾向于利用躯干旋转作为补偿来调整球的位置，这可能会导致随后在前导腿膝盖处的反向运动。本研究旨在调查在优势手臂存在和不存在GIRD的投手投球过程中，从前导腿落地到随挥阶段，股骨和胫骨之间反向运动（膝关节扭转）的运动学特征。这是一项病例对照研究。本研究招募了21名高中棒球投手。测量了所有参与者的盂肱关节内旋和外旋、髋关节内旋和外旋。无GIRD的8名投手和有GIRD的13名投手分别纳入对照组和实验组。使用Zebris 3D（德国伊施尼的Zebris Medizintechnik GmbH公司）运动分析系统，在投手用优势手臂向中外角投出快速球的过程中，测量从前导腿落地到随挥阶段前导腿股骨和胫骨之间的最大角运动（膝关节扭转）。结果显示，实验组前导腿的最大膝关节扭转（13.67 ± 0.9度）显著大于对照组（4.25 ± 1.369度）（P < 0.05）。患有GIRD的投手膝关节的反向运动比没有GIRD的投手更大。
