A group of Professor Ken Yamaguchi of the Graduate School of Engineering, Tohoku University, Senior Researcher Daiki Nasu of NTT Communication Science Laboratories, and Senior Researcher Masayoshi of the KITE Research Institute, a Canadian rehabilitation institution, observed that baseball pitchers We found that the anti-slip agent used can reduce the difference in finger friction between people and the difference in friction coefficient due to pressing load.
According to Tohoku University, the research group investigated the coefficient of friction between the leather part of the official US Major League Baseball ball and the fingertips, compared it with the official ball of Nippon Professional Baseball, and compared the friction coefficient of rosin powder, a natural resin made from pine resin, and other sticky substances. investigated in an experiment.
As a result, it was found that the coefficient of friction when nothing was attached to the fingertip increased with the increase in the moisture content of the fingertip, and that there were significant individual differences.It was suggested that when rosin powder was used on the fingertips, individual differences in the coefficient of friction became smaller, enabling stable pitching.
Applying other sticky substances to the fingertips increased the coefficient of friction by an average of more than 50%.A comparison of the official balls of Japan and the United States confirmed that the coefficient of friction of the official ball of the American Major League Baseball is 20% lower, making it easier to slip than the official ball of Nippon Professional Baseball.
Baseball allows pitchers to apply rosin powder to their fingers, but the use of sticky substances other than rosin is prohibited.However, the illegal use of sticky substances other than rosin and the slipperiness of the official balls of the US Major League Baseball are often problematic.
There is no data to evaluate how slippery the official MLB ball is, or how much friction increases with the use of sticky substances, and it has been a pitcher's subjective debate.
Paper information:[Communications Materials] Effect of grip-enhancing agents on sliding friction between a fingertipand a baseball
