An experimental comparison of hitting mechanics in softball

Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.Page 37 blank. Cataloged from PDF version of thesis.Includes bibliographical references (page 36).To score points to win games, a softball team must be able to hit the ball with as the largest velocity as possible. In softball, there are two well-known hitting models, rotational and linear, yet little quantitative research has been done to determine which model produces the greatest ball velocity and if certain key inputs, such as weight shift and bat velocity, of the models contribute to that velocity. To determine these components, a high-speed EXLIM camera recorded the change in ball position to calculate the its exit velocity, a 70g accelerometer measured centripetal acceleration of the bat to determine bat velocity, while two force plates measured the transfer of weight as nine softball players swung a bat twenty times- ten times with a ball on the tee and ten times with a ball off of the tee. Although it was found that the two hitting models had statistically different weight shifts with 95% confidence, the average ball velocity for a linear model, 22.0 m/s ±1.9 m/s, was not different from the average ball velocity for a rotational model, 22.0 m/s ± 0.7 m/s, at 95% confidence. Since these values are not different with statistical significance, this research concludes that players that weight shift does not effect ball velocity and that players are encouraged to use whichever model feels most comfortable to them.by Tori Jensen.S.B