Department of Orthopaedic Surgery, Lenox Hill, New York, New York, USA.
Sports Performance Center, Midwest Orthopaedics at Rush, Chicago, Illinois, USA.
Am J Sports Med. 2024 Sep;52(11):2893-2901. doi: 10.1177/03635465241271968. Epub 2024 Sep 2.
Individual maximum joint and segment angular velocities have shown positive associations with throwing arm kinetics and ball velocity in baseball pitchers.
To observe how cumulative maximum joint and segment angular velocities, irrespective of sequence, affect ball velocity and throwing arm kinetics in high school pitchers.
Descriptive laboratory study.
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 tests with post hoc regressions and multivariable regression models created to predict throwing arm kinetics and ball velocity, respectively.
The lead knee extension and pelvis rotation velocity subgroups achieved significantly higher normalized elbow varus torque ( = .016) and elbow flexion torque ( = .018) compared with population, with equivalent ball velocity ( = .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) ( = 0.054; β = 0.290; = .013). The overall fast group was older (mean ± standard deviation, 16.9 ± 1.4 vs 15.4 ± 0.9 years; = .007), had 8.9-mph faster ball velocity (32.7 ± 3.1 vs 28.7 ± 2.3 m/s; = .002), and had significantly higher shoulder internal rotation torque (63.1 ± 17.4 vs 43.6 ± 12.0 Nm; = .005), elbow varus torque (61.8 ± 16.4 vs 41.6 ± 11.4 Nm; = .002), and elbow flexion torque (46.4 ± 12.0 vs 29.5 ± 6.8 Nm; < .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.
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.
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.
个体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呈正相关。
观察不论顺序如何，累积最大关节和节段角速度如何影响高中投手的球速和投掷臂动力学。
描述性实验室研究。
55 名高中投手在进行 3 维运动捕捉（480 Hz）评估时投掷 8 到 12 次快球。为每个投手计算最大关节和节段角速度（前膝伸展、骨盆旋转、躯干旋转、肩内旋和前臂旋前）。根据每个关节或节段速度子类别，将投手分类为整体快、整体慢或高速度，或者为整体，任何投手都有资格被归入多个子类别。使用 检验比较各种亚组之间的运动学和动力学参数，并进行事后回归分析。创建多变量回归模型分别预测投掷臂动力学和球速。
前膝伸展和骨盆旋转速度子组的标准化肘内翻扭矩（ =.016）和肘屈肌扭矩（ =.018）显著高于整体（ =.118），而球速相同。最大骨盆旋转速度每增加 1-SD（87 度/秒），标准化肘部分离力增加 4.7%体重（BW）（ = 0.054；β = 0.290； =.013）。整体快组年龄较大（均值±标准差，16.9 ± 1.4 岁比 15.4 ± 0.9 岁； =.007），球速快 8.9 英里/小时（32.7 ± 3.1 英里/小时比 28.7 ± 2.3 英里/小时； =.002），肩内旋扭矩（63.1 ± 17.4 比 43.6 ± 12.0 Nm； =.005）、肘内翻扭矩（61.8 ± 16.4 比 41.6 ± 11.4 Nm； =.002）和肘屈肌扭矩（46.4 ± 12.0 比 29.5 ± 6.8 Nm； <.001）均显著高于整体慢组。基于最大关节和节段角速度和人体测量学的球速多回归模型预测了 53.0%的方差。
不论顺序如何，具有较高最大关节和节段速度的高中投手表现出更大的年龄和更快的球速，但投掷肩和肘动力学增加。
投手和教练组应该考虑到球速加快和投掷臂动力学增加之间的这种权衡，这是肘部受伤的一个既定风险因素。
