title: Relation Between Lift Force and Ball Spin for Different Baseball Pitches.
abstract: Although the lift force (F(L)) on a spinning baseball has been analyzed in previous studies, no study has analyzed such forces over a wide variety of spins. The purpose of this study was to describe the relationship between F(L) and spin for different types of pitches thrown by collegiate pitchers. Four high-speed video cameras were used to record flight trajectory and spin for 7 types of pitches. A total of 75 pitches were analyzed. The linear kinematics of the ball was determined at 0.008-s intervals during the flight, and the resultant fluid force acting on the ball was calculated with an inverse dynamics approach. The initial angular velocity of the ball was determined using a custom-made apparatus. Equations were derived to estimate the F(L) using the effective spin parameter (ESp), which is a spin parameter calculated using a component of angular velocity of the ball with the exception of the gyro-component. The results indicate that F(L) could be accurately explained from ESp and also that seam orientation (4-seam or 2-seam) did not produce a uniform effect on estimating F(L) from ESp.
authors.affiliation: Faculty of Sport Sciences, Waseda University, Tokorozawa, Saitama, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Nagami
authors.forename: Takatoshi
authors.initials: T
authors.lastname: Higuchi
authors.forename: Hiroki
authors.initials: H
authors.lastname: Nakata
authors.forename: Toshimasa
authors.initials: T
authors.lastname: Yanai
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Kanosue
mesh_terms: D000054:Acceleration; D000388:Air; D001484:Baseball; D003198:Computer Simulation; D017276:Friction; D008962:Models, Theoretical; D012212:Rheology / Q000379:methods*; D012399:Rotation; D019876:Sports Equipment; D013314:Stress, Mechanical