The Effects of Moisture Content and Workhardening on Baseball Bat Performance

In recent years, baseball bat performance has come under scrutiny. Fans of Major League Baseball have seen homerun records broken and the governing organizations of both college and high school baseball have stepped in with tighter controls of baseball bat performance. This paper discusses a few of the ways that baseball bat performance is affected by changes in the material and physical properties of the bat. The scope of the paper includes the effects of moisture content on the performance of solid wooden bats, which are used for professional baseball in the United States, and the effects of workhardening on the performance of aluminum bats, which are used by high school and college players. The results from the moisture content tests of wooden bats showed that an increase in the moisture content by soaking the bats in humidified air resulted in a small increase in the batted-ball performance. Across the positions on the bat, which were tested, the resulting increase reached a maximum of about 1%. The repeated hitting of an aluminum bat with the intent of workhardening it also showed an increase in batted-ball velocity of about 2%. Though, neither of these changes is enormous, they easily could be the difference between the warning track fly-out and a homerun.