Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan.
Sports Biomech. 2024 Jan;23(1):81-94. doi: 10.1080/14763141.2020.1822908. Epub 2020 Oct 29.
The present study was a cross-sectional comparison of probabilistic structure in the distribution of pitching location among baseball pitchers of various age groups (25 elementary school (ES), 20 junior high school (JH), 15 high school (HS), and 18 college students (CL)). In the results, despite the general age-dependent variations in pitching precision, the difference was reflected not only in error 'size' but also in the 'shape' of error as it was shown by fitting 95% confidence ellipse to the two dimensional distribution of pitch location. While the precision measure as a reflection of trial-by-trial variability of release timing (major axis length of the ellipse) was constant, minor axis length of the ellipse as a reflection of variability in the pitching form of each participant demonstrated significant differences among the groups. In the ES group particularly, the trial-by-trial variability in the trajectory angle of the throwing arm was significantly correlated with the minor axis length; this correlation was far greater than those in older groups. The present study is the first to demonstrate the detailed structure of the variability of pitching location of baseball dependent on age.
本研究是对不同年龄组（25 名小学生（ES）、20 名初中生（JH）、15 名高中生（HS）和 18 名大学生（CL））棒球投手投球位置分布的概率结构进行的横断面比较。结果表明，尽管投球精度随年龄的普遍变化，但这种差异不仅反映在误差“大小”上，而且还反映在误差的“形状”上，因为通过对投球位置的二维分布拟合 95%置信椭圆来实现。虽然作为释放时机（椭圆长轴）逐次变化的反映的精度测量值是恒定的，但作为每个参与者投球方式变化的反映的椭圆短轴长度在各组之间存在显著差异。特别是在 ES 组中，投掷臂轨迹角度的逐次变化与短轴长度显著相关；这种相关性远大于年龄较大组的相关性。本研究首次证明了棒球投球位置变化的详细结构随年龄的变化。
