Comparison of the performance of U.S. and Japanese aluminum baseball bats

In 1998, the National Collegiate Athletic Association (NCAA) took steps to develop a scientific test methodology to measure and to control baseball bat performance. The resulting standard uses a hitting machine that pitches a ball at a moving bat to measure the BESR (Ball Exit Speed Ratio). Concurrently, the governing body for amateur baseball in Japan developed a test protocol for controlling bat performance. In contrast to the NCAA test methodology, the Japanese protocol uses a series of static tests. This paper compares the two protocol philosophies and presents experimental data highlighting the respective criteria of each approach and discusses how successful each approach has been in controlling nonwood baseball bat performance. Comparison data and analysis showed that some Japanese bats marginally outperformed U.S. bats with respect to batted-ball speed. Despite the lack of direct restriction on batted-ball performance using a dynamic test method, the Japanese regulation is controlling the performance of aluminum bats fairly well.