224名 NCAA 一级联盟投手分析：两种前导腿膝关节模式、球速差0.68英里每小时
一项11月14日发表于《科学报告》的研究用全轨迹数据驱动方法，分析了224名 NCAA 一级联盟棒球投手的前导腿膝关节屈伸模式，及其与球速和肘部负荷的关联。数据为比赛中无标记动作捕捉记录，每名投手取其最快的10个快速球。
研究用函数型主成分分析加竞争性聚类，识别出两个稳定的 K 均值模式：第一组131人，第二组93人。动作周期按跨步脚着地到球出手做时间标准化，肩部最大外旋对齐在周期的80%处。
球速方面，第二组的观测球速比第一组高0.68英里每小时（0.30米每秒），p 值为0.032；但在调整快速球子类型后，差异缩小为0.27英里每小时（0.12米每秒），p 值为0.454，不再显著。峰值肘内翻力矩在两组之间没有差异，p 值为0.755。
组内分析显示，在第二组中，投球周期27.6%至71.3%区间内更大的膝关节伸展与更高的峰值肘内翻力矩相关，p 值为0.012；该关联在调整球速与身高后仍存在，但在调整体重或按体型标准化力矩后不再显著，且组别与力矩的直接交互作用不显著。
作者来自 Auburn University、Louisiana State University Health Sciences Center 与 Boston Red Sox 等机构。作者表示，该结果识别出两种前导腿膝关节模式，并提示膝关节力学与绝对肘部力矩之间存在探索性关联，但该关联不能视为独立于体型。本研究未获经费资助。
Analysis of 224 NCAA Division I Pitchers Finds Two Lead-Leg Knee Patterns and a 0.68 mph Ball Velocity Difference
A study published November 14 in Scientific Reports used a data-driven full-trajectory approach to identify lead-leg knee flexion-extension patterns in 224 NCAA Division I baseball pitchers, and examined their associations with ball velocity and peak elbow varus torque. In-game markerless motion-capture data from each pitcher's 10 fastest recorded fastballs were used, time-normalized from stride foot contact to ball release, with maximum shoulder external rotation aligned at 80 percent of the cycle.
Functional principal component analysis followed by competitive clustering identified two stable K-means profiles: Cluster 1 with 131 pitchers and Cluster 2 with 93.
Cluster 2 showed a modestly higher observed ball velocity than Cluster 1, a mean difference of 0.68 mph (0.30 m/s), with a p value of 0.032. After adjustment for fastball subtype, the difference was attenuated to 0.27 mph (0.12 m/s), with a p value of 0.454. Peak elbow varus torque did not differ between clusters, with a p value of 0.755.
Within Cluster 2, greater knee extension was associated with higher peak elbow varus torque from 27.6 to 71.3 percent of the pitching cycle, with a p value of 0.012. The association persisted after adjustment for ball velocity and body height, but was no longer significant after adjustment for body mass or normalization of torque to body size, and the direct cluster-by-torque interaction was not significant.
The authors are affiliated with Auburn University, the Louisiana State University Health Sciences Center and the Boston Red Sox, among other institutions. They say the findings identify two lead-leg knee patterns and an exploratory association between knee mechanics and absolute elbow torque that cannot be considered independent of body size. No funding was received for the manuscript.
来源：Scientific Reports
发布：GSM·美国（发布链接）
图片来源：图：加利福尼亚大学圣迭戈分校棒球队投手在比赛中投球。来源：Dirk Hansen，Wikimedia Commons，CC BY 2.0。 / Photo: A UC San Diego baseball pitcher throwing in a game. Source: Dirk Hansen, Wikimedia Commons, CC BY 2.0.
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