For more than forty years since the advent of the aluminum bat, rules committees have been dealing with the daunting task of balancing advances in bat composition and manufacturing techniques against the integrity of the game as well as potential safety hazards. Now, to further complicate the problem, there is one more type of bat: the composite.Starting in 2011, BESR was out, BBCOR is in and ABI testing is an interesting question mark for future years. There are legal composites, illegal composites, composites that look like wood bats, composites that look like aluminum bats, half and half bats and God knows what else will appear in the coming years. Another chapter is currently being written in the evolution of the baseball bat.

Composite baseball bats are made of glass, carbon and Kevlar fibers placed together in a plastic mold. These are anisotropic, which means that these bats are designed to bring out a strength and stiffness of a different kind. The effect is that composite baseball bats are lighter than an aluminum bats. Baseball composite bats incorporated a recent technological advancement of their aluminum counterpart to be used by college and high school players. These are manufactured with an exterior similar to an aluminum baseball bat, but its inside wall is woven instead. Using these have many advantages such as higher damping, better swing effect, lower bending stiffness and an improved trampoline effect.** See BBCOR

The NFHS is currently reviewing composite bats on an on-going basis. They do not maintain their rated characteristics for the life of the bat and that their performance increases the more they are used. This has in fact been established. As the bats are consistently used, they develop interior cracks resulting in increased performance. Additional Accelerated Break In (ABI) testing is being performed on bats submitted by the manufacturers. With a few exceptions, they were banned in 2011 for high school baseball.

Bat tampering to increase performance is an additional problem that has yet to be addressed. Both "rolling" and "shaving" of a bat are illegal but virtually impossible to detect. Rolling increases interior cracks (accelerated break-in) increasing the ball's exit speed. Shaving entails removing the cap and shaving down the interior of the bat. The bat becomes lighter and more productive. Tamper-resistant bats are in the works on the manufacturing side, but no such bat is yet available.

One thing appears to be certain from 2011 college ball, BBCOR bats have had a dramatic effect on the game. This has spread to high school ball in 2012 and beyond.The change takes baseball back closer to what it once was before the dawn of the metal bat..