Department of Intermedia Art and Science, Faculty of Science and Engineering, Waseda University, Tokyo, Japan.
Department of Life Science, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan.
PLoS One. 2023 Dec 19;18(12):e0290042. doi: 10.1371/journal.pone.0290042. eCollection 2023.
Accurately throwing an object to a target position repeatedly is one of the specific human motor skills. The final arrival position of a thrown ball can be determined by its physical state at release. In baseball pitching, reducing the variability of the velocity angle of the ball at release (release angle) is important for reducing the variability of the pitch location. Although previous studies have suggested that hand and finger movements are important for accurate throwing, their relationship with the release angle has not yet been investigated in detail. This study focused on the positional relationship between the ball and fingers, which is considered to be closely related to ball movement as an action point of the force, and examined its relationship with the variability of release angle. To obtain accurate finger positions relative to the ball without impeding movement or sensation, an automatic image recognition technology based on deep learning was employed. This approach revealed a noteworthy correlation between the lower middle finger positions prior to acceleration peaks and the reduced variability in release angle, emphasizing the importance of consistent finger positioning during the pre-release phase. This finger positioning of the pitchers with low variability in the release angle is suggested to be robust against the spatial variability of ball movement.
准确地将物体重复投掷到目标位置是人类特定的运动技能之一。投掷球的最终到达位置可以通过其释放时的物理状态来确定。在棒球投球中，降低球释放时的速度角度（释放角）的可变性对于降低投球位置的可变性很重要。尽管先前的研究表明手部和手指的运动对于准确投掷很重要，但它们与释放角的关系尚未得到详细研究。本研究重点关注球和手指之间的位置关系，这被认为是与球的运动密切相关的力作用点，并研究了其与释放角可变性的关系。为了在不影响运动或感觉的情况下获得相对于球的准确手指位置，采用了基于深度学习的自动图像识别技术。这种方法揭示了在加速峰值之前中下手指位置与释放角可变性降低之间存在显著相关性，强调了在预释放阶段手指位置保持一致的重要性。具有较低释放角可变性的投手的这种手指定位方式表明，它能够抵抗球运动的空间可变性。
