The BBCOR Bat Standard

Batted Ball Coefficient of Restitution
by Steve Orinick

Steve O's Baseball Umpire Resources 

Illegal Bat Penalties

This new standard measures bat performance and replaces the previous BESR standard. The NCAA (college) began requiring BBCOR baseball bats starting with the 2011 season. For NFHS (high school) play, all bats must be BBCOR certified for the 2012 season and beyond. BESR (Ball Exit Speed Ratio) is no longer considered accurate enough to determine the actual performance of differing bat models.

Instead of measuring the speed of the ball after it is batted, BBCOR measures the "bounciness" of the ball and bat, or the "trampoline" effect. When a bat hits a ball, the ball actually compresses / deforms by nearly a third at high pitch velocities.

Bat performance is specified by using the BBCOR, which for mathematicians is calculated using the inbound and rebound speeds of the ball:

BBCOR Calculation

where vI and vR  are the ball inbound and rebound speeds respectively, r is calculated using the equation below, and Cball is the measured correction factor for each baseball.1

R Calculation

A pitched ball holds a lot of energy that you can see in the spin and speed of the ball. With solid wood bats, much of that energy is lost as the ball compresses on impact. The batted ball speed gets much of its energy from the bat. With hollow-core aluminum or composite bats, the thin walls "flex" slightly, the ball distorts less, retains its pitched energy and adds to it the power of the bat speed. Hence, non-wood bats hit balls faster.

The loss of energy at impact is what BBCOR measures. The less energy lost, the faster the ball speed after it gets launched off the bat.

A simple way to think of BBCOR is to jump up and down on a hard floor. It takes a lot of energy in your legs to get off the ground. The floor doesn't help at all. Contrast that feeling by jumping on a trampoline. Even with very little energy from your body, you will still get a bounce because that energy isn't being absorbed by the trampoline. Instead, the trampoline is flexing with the impact and then "bouncing" back to its original shape, thus launching you higher into the air.

It's that faster flight that has changed the game of baseball over the last several years. Home runs are far more common today than they were years ago. According to NCAA Divisions I baseball statistics, in 2007 the per-game average of home runs hit was 0.68. That number increased to .84 in 2008 and .96 in 2009. The per-game average of home runs hit was .94 during spring, 2010. The runs scored per game have also increased steadily since 2007 when it was 6.10 runs per game. In 2008, there were an average of 6.57 runs per contest and that rose to 6.88 in 2009 and 6.98 in 2010.2

With at least a 5-6% decrease in bat performance, the game will be much more "balanced" among all players. More importantly, slower speed batted balls will address some of the safety concerns that have become prevalent in recent years. Both the NCAA and NFHS want all bats to have the same performance factors as the best wood bats. While it may still be cost effective to purchase aluminum or composite bats that will last longer than wood bats, it won't necessarily make you a better hitter. You'll have to swing faster and more accurately to get the same results as before.

According to the NFHS, “the new standard ensures that performances by non-wood bats are more comparable to those of wood bats. It’s also expected to minimize risk, improve play and increase teaching opportunities”. They also state “After working with the NCAA and having access to its research, we’ve concluded it’s in our best interest to make this change. BBCOR includes the BESR standard, so we’re actually expanding upon our current standard, which will be more appropriate for our age and skill level."

If your team plays under NCAA or NFHS rules, you will need new bats. Bat manufacturers have been able to adjust their designs with very little notice. The first BBCOR-certified bats began appearing in warehouses in August 2010 and I saw a few in high school games during the 2011 season. Look for the BBCOR compliance mark which will be on all bats that meet the new standard (see below). The BBCOR must be less than or equal to .500.

Manufacturers are modifying aluminum and composite bats to make the walls stiffer. In some cases they are actually inserting a block behind the sweet spot so it won't flex as much. In other instances they are simply adding thickness to the wall.

The NFHS is currently reviewing composite bats, which is a separate issue. It is felt that they do not maintain their rated characteristics for the life of the bat and that their performance increases the more they are used. Additional Accelerated Break In (ABI) testing is being performed on bats submitted by the manufacturer. With a few exceptions, they were banned in 2011. Since the advent of composite bats, it was found that the more they were used the better they performed. This led to tampering with the bats to artificially accelerate the break-in process and improve bat performance. To account for this, bats are now tested after various stages of simulated use in the lab, so that a bat never performs beyond the BBCOR standard at any point during its useful life.

The NCAA began requiring BBCOR bats for the 2011 season. Reports are that it has made a dramatic change in the offensive side of the game, similar to wood bat leagues. This has resulted in bats that will have less pop and trampoline effect with the performance level being significantly less than 2010 bats. Moment of Inertia Tests will prevent the bulk of the weight being near the handle which makes the bat swing faster than barrel weighted bats (see detail article in Collegiate Baseball, Sept. 3, 2010 issue for additional details). The advent of the new NCAA timing and BBCOR bat rules resulted in a significant reduction in all levels of post-season game times in 2011, with an average reduction in time of 19 minutes per game.

The change should take baseball back closer to what it once was before the dawn of the metal bat

All bats must be BBCOR certified and stamped.


NFHS Bat Rules / NCAA BBCOR Testing Protocol (Word Doc)

Illegal Bat Penalties

Before the batter steps into the box: Under all codes, if detected, the umpire can direct the player to switch to a legal bat. There is no penalty.

The batter is in the box but has not seen a pitch: Under NFHS and pro rules, the batter is considered to have used the illegal bat as soon as he steps into the box.

The batter is in the box and a pitch has been thrown: Under NCAA rules, a pitch has to be thrown for the illegal bat to be considered as used. It is irrelevant if the batter has swung at the pitch or not.

Penalty: The batter is out and all runners return to the base occupied at the start of the at-bat. Any runner advance that did not come as a result of the plate appearance (balk, stolen base, etc.) is permitted. The illegal bat must be discovered before the first pitch to the next batter.

Beginning with the 2012 season, under NFHS rules coaches are responsible for their team equipment. First offense for an illegal bat results in a bench ejection (restricted to bench) for the head coach. A second infraction for the same team results in ejection of the head coach.

Bat / Ball


1 see NCAA BBCOR testing protocol
2 stats from NCAA web site


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