Classification of four pitching styles in Japanese baseball players

• Published in: International journal of sports science & coaching Vol. 18; no. 6; pp. 2198 - 2204
• Main Authors: Miyanishi, Tomohisa, Shimada, Kazushi, Kawamura, Takashi, Hirayama, Daisaku, Takahashi, Keizo, Nagahara, Ryu
• Format: Journal Article
• Language: English
• Published: London, England SAGE Publications 01.12.2023
• Subjects: throwing; underhand; overhand; Kinematics; sport biomechanics; motion analysis; sidearm
• ISSN: 1747-9541; 2048-397X
• DOI: 10.1177/17479541221128355

This study aimed to provide normative biomechanical data of baseball delivery styles and to verify an appropriate criterion for quantitatively classifying baseball pitches into four delivery styles. In total, 74 pitches were visually identified by seven coaches into 24 overhand (OS), 17 three-quarter (TS), 21 sidearm (SS) and 12 underhand (US) deliveries. The accuracies of the classifications of the pitches using the arm slot angle (θAS) and using the combination of trunk lateral tilt (θT) and upper arm elevation (θA) angles at release were compared. Average values for θAS were 53.9°, 31.5°, 5.8°, and −34.8° in the OS, TS, SS and US; corresponding values for θT were 31.9°, 15.4°, −0.9°, and −40.1°; and for θA were 39.8°, 16.1°, −6.3°, and−43.0°. Both variables (θAS and the average of θ'T and θ'A, which corresponded to the projection of each point on the regression line) correctly classified the delivery styles, but the accuracy of the classification using θAS (96%) was higher than that using the average of θ'T and θ'A (89%). There were fewer and smaller overlaps of the ranges of pitches classified using θAS (only 6 pitches between TS and SS (14.9° to 23.0°), which can be considered a buffer zone) compared to the average of θ'T and θ'A. Consequently, θAS seems the most appropriate for classifying baseball pitches into the four delivery styles. The separation points between the four styles were marked by θAS values of 45° (between OS and TS), 19° (between TS and SS) and −13° (between SS and US).