Determining Factors Of Spin On Pitched Fastballs In Baseball – A Literature Review

Baseball is a popular sport that is often referred to as “America’s game.” Of all the pitches thrown in a Major League Baseball season, more than half of them are fastballs. Three forces (gravity, drag, and Magnus force) determine the movement of a pitched baseball. Magnus force is caused by spin and is the major modifiable force in pitching. By altering spin rates and the spin axis of a pitched fastball, pitchers are able to change the movement of their pitches. Pitchers who throw fastballs the closest to true backspin have been shown to be the most effective. Modifiable factors of spin include friction between the fingers and the ball, finger placement on the ball, and arm slot variation caused by trunk and arm kinematics. The purpose of this review was to determine modifiable factors of spin that improve pitching performance through increased vertical lift on fastballs. Future research should examined altered mechanisms to increase friction as well as changes to throwing kinematics in an effort to generate increased fastball lift.