Kusafuka Ayane, Yamamoto Rintaro, Okegawa Taishi, Kudo Kazutoshi
Department of Intermedia Art and Science, Faculty of Science and Engineering, Waseda University, Tokyo, Tokyo, Japan.
Japan Society for the Promotion of Science (JSPS), Japan.
Front Sports Act Living. 2023 Sep 6;5:1250938. doi: 10.3389/fspor.2023.1250938. eCollection 2023.
Repeated and accurate throwing of an object to a target position is a special human motor skill. It is particularly important to understand accuracy, which has received less attention than speed due to difficulties in measurement. Accuracy has been studied in terms of reducing errors against a single target, but also in terms of distinguishing appropriate throws for targets in different positions. In this study, this ability was investigated by evaluating the two-dimensional distributions of the pitch locations of 15 pitches to three target positions in university students with and without baseball experience. The center, major and minor axis length, major and minor axis ratio, slope, area, and percentage of overlapping area of the 95% confidence ellipse were compared between target positions and participants using a two-way repeated-measures analysis of variance (ANOVA). The center and area of the ellipse indicate the mean and variability of the error, respectively. The lengths of the major axes correspond to the variability of the release timing, and the minor axes correspond to the variability of the release point in space. Therefore, the ratio of the major and minor axes indicates how the variability of the pitching motion is controlled. The slope of the ellipse corresponds to the throwing arm's trajectory, and the percentage of overlap area means the ability to distinguish throws at different target positions. The result showed a main effect of participants on all indices except the center of the ellipse. This indicates that participants can generally distinguish throws by target positions regardless of their baseball experience, although participants with baseball experience may naturally reduce variability. Furthermore, participants with baseball experience demonstrated a decrease variability in release timing, which is a primary contributor to the pitch location variability, relative to the spatial variability of the pitching movements. This reduction in timing variability may be attributed to advanced motor control mechanisms.
将物体反复准确地投掷到目标位置是一种特殊的人类运动技能。理解准确性尤为重要，由于测量困难，准确性比速度受到的关注更少。准确性的研究既涉及减少针对单个目标的误差，也涉及区分针对不同位置目标的合适投掷。在本研究中，通过评估有和没有棒球经验的大学生向三个目标位置投出的15次投球的投球位置的二维分布来研究这种能力。使用双向重复测量方差分析（ANOVA）比较目标位置和参与者之间95%置信椭圆的中心、长轴和短轴长度、长轴和短轴比率、斜率、面积以及重叠面积百分比。椭圆的中心和面积分别表示误差的均值和变异性。长轴长度对应于释放时间的变异性，短轴对应于空间中释放点的变异性。因此，长轴和短轴的比率表明投球动作的变异性是如何被控制的。椭圆的斜率对应于投掷手臂的轨迹，重叠面积百分比意味着区分不同目标位置投球的能力。结果显示，除椭圆中心外，参与者对所有指标都有主效应。这表明参与者通常可以根据目标位置区分投球，无论他们有无棒球经验，尽管有棒球经验的参与者可能自然地减少了变异性。此外，有棒球经验的参与者相对于投球动作的空间变异性，在释放时间上表现出变异性降低，而释放时间是投球位置变异性的主要因素。这种时间变异性的降低可能归因于先进的运动控制机制。
