Story URL: http://news.medill.northwestern.edu/chicago/news.aspx?id=179053
Story Retrieval Date: 10/31/2014 2:22:14 PM CST
The familiar ping of college baseball is set to change. The start of the NCAA baseball season on Friday coincides with a new rule that ensures that metal bats perform very similar to wooden ones. And the change in the bat’s performance will alter the sound as well – with a higher frequency being produced.
All NCAA competition bats will now have to meet a new BBCOR, or “Bat-Ball Coefficient of Restitution” standard. It’s a complex formula that uses the mass and inbound and rebound speeds of the ball. But in short, what it measures is the bounciness of the ball when it hits the bat. The new enforced limit sets a coefficient of 0.50, which is typically how a wooden bat performs. This means that the new bats will not have a “trampoline effect,” which happens when the ball hits the thin metal surface of the bat causing it to depress and then return to its original position. The resulting impact to the ball is more bounce.
The older NCAA standard BESR or the “Ball Exit Speed Ratio,” which measured the ratio of the ball exit speed to the combined speeds of the pitched ball and swung bat, has been done away with.
Alan Nathan, a physics professor at the University of Illinois at Urbana-Champaign, has been on the NCAA Baseball Research Panel since 2001 and also does independent research on the physics of baseball. Nathan answers questions on and why the NCAA took the decision and what this new regulation means.
Q: Why did the NCAA find the need to move to the BBCOR standard? What does it measure differently from BESR?
A: There has been a considerable amount of research into bat performance over the last decade, since the adoption of the BESR standard. The research concludes that the primary factor that determines field performance is the BBCOR. The BESR is a more indirect method of regulating performance, so switching from BESR to BBCOR is actually a simplification.
Q: Is BBCOR a stricter standard?
A: The BBCOR is not necessarily a stricter standard. As with any standard, the degree of strictness depends on where the line is drawn. The recent change by the NCAA was really two different changes. One was to use BBCOR as the metric of performance, as recommended by the Baseball Research Panel. The other was to set a maximum BBCOR so that the best performing non-wood bats are no better than the best wood bats. That line was set by the NCAA Rules Committee.
Q: Do you see any basic similarity in principle between the the NCAA’s new standards and the recent moratorium on composite bats by the Little League?
A: The moratorium on composite bats by the Little League really has nothing to do with the new NCAA standards. Composite bats are a problem for the governing organization regardless of the standard used to regulate their performance. Little Leagues uses the so-called BPF standard.
NCAA uses the BBCOR standard. The Amateur Softball Association uses a batted-ball speed (BBS) standard. And for all these organizations, the “moving target” associated with the changing performance of composite bats is a problem.
Q: Are these moves a step back for school and college baseball into the wooden age of bat technology?
A: Certainly bat manufacturers are capable of producing bats that perform far better than the rules allow. That was true even with the BESR standard, under which non-wood bats could outperform wood bats by about 5 percent. With the new BBCOR standard, the gap in performance between wood and non-wood will be reduced to very close to zero. I suppose in that sense this is a step back.
Q: Will that mean better preparation for younger players for professional leagues?
A: I can only offer an informed opinion. Since professional baseball uses only wood bats, it must be considered better preparation for high school and college players to use wood bats, or at least bats that perform like wood.
Q: Would the change translate into fewer home runs, or smaller run production?
A: Of course, we shall have to wait and see what the statistics show. However, the expectation is that the number of home runs will be reduced in 2011 relative to previous years. Quite possibly total run production will also be reduced.
Q: So if these bats perform very close to the level of wood bats, why can’t metal bats be completely done away with?
A: By requiring that the BBCOR of metal bats be no greater than for wood, we are essentially saying that the maximum batted ball speed of metal will be no more than for wood. However, metal and wood bats are still different from each other in a very important way.
The [moment of inertia] of a metal bat is less than [that] of a wood bat. While that does not have a big effect on the maximum batted ball speed, it does mean that a metal bat will be easier to swing. That allows a batter more bat control, perhaps allowing him to ‘get around’ quicker on a fastball, make adjustments on the curveball and other off-speed pitchers, etc. So, while a batter might not hit the ball harder with a metal bat, he might make good contact more often.
But the original reason for aluminum was that they don’t break, and ultimately that might be the main reason not to abandon them.