Yamaguchi Takeshi, Suzuki Souta, Suzuki Shinnosuke, Nishi Toshiaki, Fukuda Takehiro, Nasu Daiki
Graduate School of Engineering, Tohoku University, 6-6-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, 980-8579, Miyagi, Japan.
Graduate School of Biomedical Engineering, Tohoku University, 6-6-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, 980-8579, Miyagi, Japan.
Sci Rep. 2025 Mar 27;15(1):9514. doi: 10.1038/s41598-025-93632-y.
This study aimed to investigate the finger-ball slip distance in baseball pitching under different finger-ball friction conditions and to demonstrate how slippage affects pitching performance. 6 experienced pitchers were instructed to throw 4-seam fastballs at approximately 36.1 m/s (130 km/h) toward a target behind the home base. The finger-ball friction conditions varied and included no application, water application, rosin powder application, and pine resin application. The finger-ball slip distance was estimated from images of the fingertips and ball during the ball release process captured by a high-speed camera (2000 frames/s). The slip distance was significantly affected by the finger-ball friction condition. The distance in the water application condition (21.6 ± 5.3 mm) was 142.3% and 163.8% greater than that in the rosin powder (8.9 ± 3.5 mm, p = 0.022) and pine resin application conditions (8.2 ± 2.2 mm, p = 0.002), respectively. In the ball release process, except for the water application condition, the ball was released by hooking the fingertips on the seam, and the ball slid against the fingers. However, in the water application condition, slip occurred throughout the ball release process. The slip distance was negatively correlated with the ball speed and ball spin rate and positively correlated with the horizontal and vertical ball arrival locations. Our findings will provide new insights into the understanding of how a ball is released in baseball pitching under different friction conditions and will lead to improvements in pitching performance.
本研究旨在调查在不同手指 - 球摩擦条件下棒球投球时手指 - 球的滑动距离，并展示滑动如何影响投球表现。6名经验丰富的投手被要求以约36.1米/秒（130公里/小时）的速度向本垒后方的目标投出四缝线快速球。手指 - 球的摩擦条件各不相同，包括不施加任何物质、喷水、涂抹松香粉和涂抹松脂。通过高速摄像机（2000帧/秒）在球释放过程中捕捉的指尖和球的图像来估计手指 - 球的滑动距离。滑动距离受到手指 - 球摩擦条件的显著影响。喷水条件下的距离（21.6±5.3毫米）分别比涂抹松香粉（8.9±3.5毫米，p = 0.022）和涂抹松脂条件（8.2±2.2毫米，p = 0.002）下的距离大142.3%和163.8%。在球释放过程中，除了喷水条件外，球是通过将指尖钩在缝线上释放的，球在手指上滑动。然而，在喷水条件下，整个球释放过程都会发生滑动。滑动距离与球速和球旋转速率呈负相关，与球的水平和垂直到达位置呈正相关。我们的研究结果将为理解在不同摩擦条件下棒球投球时球是如何释放的提供新的见解，并将有助于提高投球表现。
