Research the sweet spot on a baseball bat based on optimization algorithms

Ke Zhu, Jin Zhang, Tianyi Wang, Miao Zhu

COMPUTER MODELLING & NEW TECHNOLOGIES 2014 18(12C) 96-102

Department of Information Technology, Henan Normal University, East of Construction Road, Xinxiang, China

With the popularity of baseball, numerous studies have been conducted to find methods to improve performance during a baseball match. However, it's still unclear that how the batter should hit a ball so that the batted ball speed is largest. In other words, where is the sweet spot that maximum energy is transferred to the ball when it's hit? In our paper, we take three factors into consideration to determine position of sweet spot. We build three models to confirm corresponding factors: (1) relationship between batted ball speed and distance from hit point to pivot point when the pivot point is fixed, (2) loss of energy caused by vibration of bat, (3) loss of energy caused by rotation of bat. At last, by considering the above three models to get the final energy of ball. We find that the COP (Centre of Percussion) point is just the sweet spot. What's more, by considering variation of mass, centre of mass and moment of inertia of bat after corking a bat, we get the new position of COP. Our conclusion is that when a batter does the same work to the two types of bat, corking a bat doesn't change batted ball speed dramatically. Therefore, "corking" doesn't enhance performance during baseball match even though it may lead to better control of the bat. At last, by statistical processing to results of baseball match in the last more than 30 years, we find that the aluminium bat shows a marked increase in hit-ball speeds. So different materials have different behaviours during a match. In addition to that, we also give reasons why Major League Baseball prohibits metal bats according to our model.