Background:Individual maximum joint and segment angular velocities have shown positive associations with throwing arm kinetics and ball velocity in baseball pitchers.Purpose:To observe how cumulative maximum joint and segment angular velocities, irrespective of sequence, affect ball velocity and throwing arm kinetics in high school pitchers.Study Design:Descriptive laboratory study.Methods:High school (n = 55) pitchers threw 8 to 12 fastball pitches while being evaluated with 3-dimensional motion capture (480 Hz). Maximum joint and segment angular velocities (lead knee extension, pelvis rotation, trunk rotation, shoulder internal rotation, and forearm pronation) were calculated for each pitcher. Pitchers were classified as overall fast, overall slow, or high velocity for each joint or segment velocity subcategory, or as population, with any pitcher eligible to be included in multiple subcategories. Kinematic and kinetic parameters were compared among the various subgroups using t tests with post hoc regressions and multivariable regression models created to predict throwing arm kinetics and ball velocity, respectively.Results:The lead knee extension and pelvis rotation velocity subgroups achieved significantly higher normalized elbow varus torque ( P = .016) and elbow flexion torque ( P = .018) compared with population, with equivalent ball velocity ( P = .118). For every 1-SD increase in maximum pelvis rotation velocity (87 deg/s), the normalized elbow distractive force increased by 4.7% body weight (BW) ( B = 0.054; β = 0.290; P = .013). The overall fast group was older (mean ± standard deviation, 16.9 ± 1.4 vs 15.4 ± 0.9 years; P = .007), had 8.9-mph faster ball velocity (32.7 ± 3.1 vs 28.7 ± 2.3 m/s; P = .002), and had significantly higher shoulder internal rotation torque (63.1 ± 17.4 vs 43.6 ± 12.0 Nm; P = .005), elbow varus torque (61.8 ± 16.4 vs 41.6 ± 11.4 Nm; P = .002), and elbow flexion torque (46.4 ± 12.0 vs 29.5 ± 6.8 Nm; P < .001) compared with the overall slow group. A multiregression model for ball velocity based on maximum joint and segment angular velocities and anthropometrics predicted 53.0% of variance.Conclusion:High school pitchers with higher maximum joint and segment velocities, irrespective of sequence, demonstrated older age and faster ball velocity at the cost of increased throwing shoulder and elbow kinetics.Clinical Relevance:Pitchers and coaching staff should consider this trade-off between faster ball velocity and increasing throwing arm kinetics, an established risk factor for elbow injury.

中文翻译：

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高中投手整体快和整体慢的关节和节段累积速度的投掷臂动力学和球速度的比较


背景：单个最大关节和节段角速度与棒球投手的投掷臂动力学和球速度呈正相关。目的：观察累积最大关节和节段角速度（无论顺序如何）如何影响高投手的球速度和投掷臂动力学研究设计：描述性实验室研究。方法：高中 (n = 55) 投手投掷 8 至 12 个快球，同时使用 3 维动作捕捉 (480 Hz) 进行评估。计算每个投手的最大关节和节段角速度（主膝伸展、骨盆旋转、躯干旋转、肩部内旋和前臂旋前）。对于每个关节或节段速度子类别，投手被分为整体快、整体慢或高速，或者作为群体，任何投手都有资格包含在多个子类别中。使用事后回归和多变量回归模型对各个亚组之间的运动学和动力学参数进行比较，分别创建用于预测投掷臂动力学和球速度。结果：领先的膝关节伸展和骨盆旋转速度亚组实现了显着更高的归一化肘内翻与人口相比，具有等效球速度 (P = .118) 的扭矩 ( P = .016) 和肘部弯曲扭矩 ( P = .018)。最大骨盆旋转速度 (87 度/秒) 每增加 1-SD，标准化肘部分心力就会增加 4.7% 体重 (BW)（B = 0.054；β = 0.290；P = 0.013）。整体快速组年龄较大（平均±标准差，16.9±1.4 vs 15.4±0.9岁；P = .007），球速快8.9英里/小时（32.7±3.1 vs 28.7±2.3 m/s；P = .002），肩部内旋扭矩（63.1 ± 17.4 vs 43.6 ± 12.0 Nm；P = .005）、肘内翻扭矩（61.8 ± 16.4 vs 41.6 ± 11.4 Nm；P = .002）和肘部屈曲扭矩明显更高(46.4 ± 12.0 vs 29.5 ± 6.8 Nm; P < .001) 与整体慢速组相比。基于最大关节和节段角速度和人体测量学的球速度多元回归模型预测了 53.0% 的方差。 结论：具有较高最大关节和节段速度的高中投手，无论顺序如何，都表现出年龄较大和球速较快，但代价是增加投掷肩部和肘部动力学。临床相关性：投手和教练组应考虑更快的球速和增加投掷臂动力学之间的权衡，这是肘部受伤的既定风险因素。