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DOES BAT ROLLING WORK?
Composite Bats, Break-in, and the Amateur Softball Association
Anyone who has played with an all-composite bat knows that composite bats are often not as hot "out of the wrapper" as they are after a few hundred hits
have been put on the bat. In fact, this is the principle reason that "artificial break-in" techniques are applied to a bat - players want to reduce the time required
to get their new bat to its highest playing performance. The amount of improvement in performance varies from bat to bat, but most composite bats tend to
improve noticeably the more they are used. This is true despite marketing claims that a particular composite bat is "hot right out of the wrapper." This fact
poses a problem for governing associations who are trying to reduce the problem of illegally altered bats because it can sometimes be difficult to determine
whether the increase in performance is due to the bat having been doctored or just to its natural break-in. Some of the associations are putting considerable
pressure on manufacturers to design bats that do not increase in performance over time. And while some of the techniques being developed for detecting bats
which perform higher than the set performance standard may not be able to distinguish between an altered bat and a naturally broken-in bat, the associations'
viewpoint is that if a bat bears a certification stamp then it must perform at or below the performance limit represented by that stamp throughout the bat's
entire life. It doesn't matter how the bat increased in performance; any increase in performance after production is not allowed.
As an example of how seriously associations are taking this issue, the ASA recently changed their bat certification policy. When the ASA certifies a bat as
passing its 98-mph Batted-Ball Speed standard, that bat is expected to pass the standard forever, even after being broken-in. As of October, 2007 all
composite bats are now being artificially broken-in using a barrel rolling technique before they are sent to the Sports Science Laboratory at Washington State
University to be performance tested for certification. I'm not sure what it means for the future of ASA softball, or for the future of composite bats, but at the end
of January, 2008, only one composite bat (including all 2007-2008 composite bat models that had previously been certified "out of the wrapper") has passed
the 98-mph ASA cerfication test after being broken in by rolling. I would expect to see some changes in the design of composite bats in 2009 in accordance
with the ASA policy change.
How Much Does a Composite Bat's Performance Improve as it is Broken-in?
By how much might a typical bat improve with use? A recent Master's Thesis from the Washington State University[1] studied the performance of composite
slow-pitch softball bats and the performance improvements gained through various ways a bat might be modidified. The bar chart at right shows test
results[1,2] for three bats that were broken-in naturally by hitting balls. Bats JN05 and JE04 are multi-walled composite bats and JA05 is a multi-walled
aluminum bat. First, the bats were performance tested brand new, right out of the wrapper, in accordance with the high-speed cannon test (ASTM F2219) used
by the ASA to certify bats. Then each bat was used to hit ASA certified 0.44 COR 375lb softballs 500 times in an indoor batting cage. Balls were pitched
slow-pitch style, and batters were experience amateurs. After 500 hits the bats were performance tested again. Then another 500 hits and another
performance check, and so on until 2000 hits were accumlated.
The results in the bar graph show that all three of the bats showed noticeable improvement of 2.5-3.5 mph in batted-ball speed after the first 500 hits, followed
by a slight decrease in performance after 1000 hits. The experimental evidence seems clear - the performance of a bat can improve significantly after the bat
has been broken in naturally by using it to hit balls. What does a 3.5mph increase in batted-ball speed mean in terms of performance? The difference between a
softball leaving a bat at 98-mph and a softball leaving a bat at 101.5-mph is about 27feet in distance travelled. That could very easily be the difference
between a pop fly to the outfield and a homerun.
This improvement after break-in poses a problem for associations with bat performance standards and certification. All three bats started out meeting the
98-mph criteria (although the JN05 bat was pushing the limit) when tested brand new. However, after 500 hits, all three bats are now above the 98-mph
threshold. The ASA requires that a bat pass the certification test at any time during its useful life. So, from the ASA viewpoint, these bats three bats are no
longer legal bats after they have been broken in. This is largely why the ASA has moved to begin breaking in bats prior to sending them out for certification
testing - and why very few composite bats are able to pass the 98-mph certification performance standard after being broken-in.
Accelerated Break-In Processes
So, there is data showing that the performance of composite bats improves as they are broken. Unfortunately, it takes 300-500 hits before a bat is fully
broken-in, and many players are not willing to wait that long before bringing their composite bat to its full potential. Accelerated Break-In (ABI) Processes are
methods used to break-in a bat quickly and bring it to its maximum performance without having to actually put 500 hits on a bat. I will mention here that the
ASA considers ABI processes to be a form of bat doctoring[4] and holds that bats must meet the 98-mph performance standard at any time. I don't know if the
USSSA and other associations apply their standards the same way - though USSSA does have a pretty strong stance against bat doctoring.
After perusing several websites and discussion boards, it is apparent that there are several popular methods of acclerating the break-in process. Below I'll
describe some of the more popular techniques, discuss some data showing how effective they are, and then I'll offer some comments on the issue of whether
advanced break-in techniques should be considered bat doctoring techniques. Rolling
One of the most popular ABI techniques is bat rolling. The technique of rolling the bat involves inserting the bat between two rollers, using a press to squeeze
the rollers together, and pushing the bat back and forth between the rollers. This squeezes the barrel of the bat enough that the composite fibers and the bonds
between the multiple layers making up barrel walls are physically broken. This decreases the stiffness of the bat walls and increases the trampoline effect.
Most rollers put the bat long-ways between rollers. The photo below right shows a screen grab from a YouTube video showing a bat roller that runs the rollers
parallel to the bat length.
The photographs of two rolling devices at right were taken from website of individuals who advertise their services on eBay. Some people put tape on the
rollers in an attempt to conceal the marks that are typically left on the barrel as a result of rolling it. The ASA is currently using a similar rolling device to
break-in bats prior to sending them out for certification testing to see if they pass the 98-mph performance standard. Almost every single composite bat model
from 2007-2008 failed to pass the 98-mph test after being rolled, which means that a rolled bat is no longer legal for play in an ASA sanctioned game.
Barrel Compression Technique (BCT)
A second popular technique involves applying compression to squeeze the barrel of the bat, but without rolling. The photograph at right is from an eBay auction
(November 2006) in which a guy was auctioning off his bat compression services. It looks like he built a portable hydraulic barrel compression device that he
can operate from the back of his truck. In December 2006 I received a letter from another person offering me his services with a special technique for
compressing composite bats (developed by some friends of his who handle composite materials) which involves a specially shaped compression surface,
rotating the bat at 60o intervals around the circumference and heating the bat walls between each compression.
On discussion boards I have seen some debate regarding the use of heat. Just like the rolling process, the reason that this compression technique succeeds in
improving bat performance is because the barrel is squeezed enough that the fibers and bonds between the layers in the composite material are broken. The
barrel wall of this broken-in bat has decreased stiffness - and thus increased flexibility - and therefore the trampoline effect is greater. Composite materials
become soft at high temperatures (ie, greater than 170oF), so the use of heat would allow the barrel to compress more easily, which would allow it to squeeze
without breaking the fibers and bonds. Then when the bat barrel cools off, it would return to its pre-squeezed condition and the benefit of squeezing would be
lost.
Compressing the Bat Barrel in a Vise
Composite Bats, Break-in, and the Amateur Softball Association
Anyone who has played with an all-composite bat knows that composite bats are often not as hot "out of the wrapper" as they are after a few hundred hits
have been put on the bat. In fact, this is the principle reason that "artificial break-in" techniques are applied to a bat - players want to reduce the time required
to get their new bat to its highest playing performance. The amount of improvement in performance varies from bat to bat, but most composite bats tend to
improve noticeably the more they are used. This is true despite marketing claims that a particular composite bat is "hot right out of the wrapper." This fact
poses a problem for governing associations who are trying to reduce the problem of illegally altered bats because it can sometimes be difficult to determine
whether the increase in performance is due to the bat having been doctored or just to its natural break-in. Some of the associations are putting considerable
pressure on manufacturers to design bats that do not increase in performance over time. And while some of the techniques being developed for detecting bats
which perform higher than the set performance standard may not be able to distinguish between an altered bat and a naturally broken-in bat, the associations'
viewpoint is that if a bat bears a certification stamp then it must perform at or below the performance limit represented by that stamp throughout the bat's
entire life. It doesn't matter how the bat increased in performance; any increase in performance after production is not allowed.
As an example of how seriously associations are taking this issue, the ASA recently changed their bat certification policy. When the ASA certifies a bat as
passing its 98-mph Batted-Ball Speed standard, that bat is expected to pass the standard forever, even after being broken-in. As of October, 2007 all
composite bats are now being artificially broken-in using a barrel rolling technique before they are sent to the Sports Science Laboratory at Washington State
University to be performance tested for certification. I'm not sure what it means for the future of ASA softball, or for the future of composite bats, but at the end
of January, 2008, only one composite bat (including all 2007-2008 composite bat models that had previously been certified "out of the wrapper") has passed
the 98-mph ASA cerfication test after being broken in by rolling. I would expect to see some changes in the design of composite bats in 2009 in accordance
with the ASA policy change.
How Much Does a Composite Bat's Performance Improve as it is Broken-in?
By how much might a typical bat improve with use? A recent Master's Thesis from the Washington State University[1] studied the performance of composite
slow-pitch softball bats and the performance improvements gained through various ways a bat might be modidified. The bar chart at right shows test
results[1,2] for three bats that were broken-in naturally by hitting balls. Bats JN05 and JE04 are multi-walled composite bats and JA05 is a multi-walled
aluminum bat. First, the bats were performance tested brand new, right out of the wrapper, in accordance with the high-speed cannon test (ASTM F2219) used
by the ASA to certify bats. Then each bat was used to hit ASA certified 0.44 COR 375lb softballs 500 times in an indoor batting cage. Balls were pitched
slow-pitch style, and batters were experience amateurs. After 500 hits the bats were performance tested again. Then another 500 hits and another
performance check, and so on until 2000 hits were accumlated.
The results in the bar graph show that all three of the bats showed noticeable improvement of 2.5-3.5 mph in batted-ball speed after the first 500 hits, followed
by a slight decrease in performance after 1000 hits. The experimental evidence seems clear - the performance of a bat can improve significantly after the bat
has been broken in naturally by using it to hit balls. What does a 3.5mph increase in batted-ball speed mean in terms of performance? The difference between a
softball leaving a bat at 98-mph and a softball leaving a bat at 101.5-mph is about 27feet in distance travelled. That could very easily be the difference
between a pop fly to the outfield and a homerun.
This improvement after break-in poses a problem for associations with bat performance standards and certification. All three bats started out meeting the
98-mph criteria (although the JN05 bat was pushing the limit) when tested brand new. However, after 500 hits, all three bats are now above the 98-mph
threshold. The ASA requires that a bat pass the certification test at any time during its useful life. So, from the ASA viewpoint, these bats three bats are no
longer legal bats after they have been broken in. This is largely why the ASA has moved to begin breaking in bats prior to sending them out for certification
testing - and why very few composite bats are able to pass the 98-mph certification performance standard after being broken-in.
Accelerated Break-In Processes
So, there is data showing that the performance of composite bats improves as they are broken. Unfortunately, it takes 300-500 hits before a bat is fully
broken-in, and many players are not willing to wait that long before bringing their composite bat to its full potential. Accelerated Break-In (ABI) Processes are
methods used to break-in a bat quickly and bring it to its maximum performance without having to actually put 500 hits on a bat. I will mention here that the
ASA considers ABI processes to be a form of bat doctoring[4] and holds that bats must meet the 98-mph performance standard at any time. I don't know if the
USSSA and other associations apply their standards the same way - though USSSA does have a pretty strong stance against bat doctoring.
After perusing several websites and discussion boards, it is apparent that there are several popular methods of acclerating the break-in process. Below I'll
describe some of the more popular techniques, discuss some data showing how effective they are, and then I'll offer some comments on the issue of whether
advanced break-in techniques should be considered bat doctoring techniques. Rolling
One of the most popular ABI techniques is bat rolling. The technique of rolling the bat involves inserting the bat between two rollers, using a press to squeeze
the rollers together, and pushing the bat back and forth between the rollers. This squeezes the barrel of the bat enough that the composite fibers and the bonds
between the multiple layers making up barrel walls are physically broken. This decreases the stiffness of the bat walls and increases the trampoline effect.
Most rollers put the bat long-ways between rollers. The photo below right shows a screen grab from a YouTube video showing a bat roller that runs the rollers
parallel to the bat length.
The photographs of two rolling devices at right were taken from website of individuals who advertise their services on eBay. Some people put tape on the
rollers in an attempt to conceal the marks that are typically left on the barrel as a result of rolling it. The ASA is currently using a similar rolling device to
break-in bats prior to sending them out for certification testing to see if they pass the 98-mph performance standard. Almost every single composite bat model
from 2007-2008 failed to pass the 98-mph test after being rolled, which means that a rolled bat is no longer legal for play in an ASA sanctioned game.
Barrel Compression Technique (BCT)
A second popular technique involves applying compression to squeeze the barrel of the bat, but without rolling. The photograph at right is from an eBay auction
(November 2006) in which a guy was auctioning off his bat compression services. It looks like he built a portable hydraulic barrel compression device that he
can operate from the back of his truck. In December 2006 I received a letter from another person offering me his services with a special technique for
compressing composite bats (developed by some friends of his who handle composite materials) which involves a specially shaped compression surface,
rotating the bat at 60o intervals around the circumference and heating the bat walls between each compression.
On discussion boards I have seen some debate regarding the use of heat. Just like the rolling process, the reason that this compression technique succeeds in
improving bat performance is because the barrel is squeezed enough that the fibers and bonds between the layers in the composite material are broken. The
barrel wall of this broken-in bat has decreased stiffness - and thus increased flexibility - and therefore the trampoline effect is greater. Composite materials
become soft at high temperatures (ie, greater than 170oF), so the use of heat would allow the barrel to compress more easily, which would allow it to squeeze
without breaking the fibers and bonds. Then when the bat barrel cools off, it would return to its pre-squeezed condition and the benefit of squeezing would be
lost.
Compressing the Bat Barrel in a Vise
THE DOCTOR IS IN SO LETS START LEARNING
Are Composite Bats better than Aluminum Bats?
The choice of bats shown above does not reflect any preference for brand names. These just happen to be two bats that I currently have in my laboratory.
Using the high speed impact test, wood bats produce batted-ball speeds between 88-90mph (there are no data points for wood bats because a solid wood
bat does not have a hoop frequency).
Single-walled aluminum slow-pitch softball bats produce batted-ball speeds between 90-96mph.
The best double-walled aluminum slow-pitch softball bats on the market have batted-ball speeds between 96-100mph.
In 1993 Easton, Worth and Louisville Slugger each introduced titanium softball bats (Worth had kept theirs under wraps for several years because they knew it
would radically change the game and only released it when Easton did). At the time titanium bats were introduced, the best single-wall aluminum bats were
performing around 93-94mph, so when the titanium bats with batted-ball speeds between 100-103mph entered the game they made an immediate impact.
In fact, titanium bats were so much hotter than anything else available that they were quickly banned by all governing organizations within three months of
their introduction.
Composite bats actually cover the entire range of performance. The early ones (which were not tested in this study) performed like an average single-walled
aluminum bat. There is a group of recent composite models which compete in performance with the best double-walled aluminum slow-pitch softball bats,
having batted-ball speeds between 96-100mph.
And then there is a select group of super high performance composite slow-pitch softball bats, including the famous Miken Ultra, which are capable of producing
batted ball speeds in excess of 105-107mph.
The choice of bats shown above does not reflect any preference for brand names. These just happen to be two bats that I currently have in my laboratory.
Using the high speed impact test, wood bats produce batted-ball speeds between 88-90mph (there are no data points for wood bats because a solid wood
bat does not have a hoop frequency).
Single-walled aluminum slow-pitch softball bats produce batted-ball speeds between 90-96mph.
The best double-walled aluminum slow-pitch softball bats on the market have batted-ball speeds between 96-100mph.
In 1993 Easton, Worth and Louisville Slugger each introduced titanium softball bats (Worth had kept theirs under wraps for several years because they knew it
would radically change the game and only released it when Easton did). At the time titanium bats were introduced, the best single-wall aluminum bats were
performing around 93-94mph, so when the titanium bats with batted-ball speeds between 100-103mph entered the game they made an immediate impact.
In fact, titanium bats were so much hotter than anything else available that they were quickly banned by all governing organizations within three months of
their introduction.
Composite bats actually cover the entire range of performance. The early ones (which were not tested in this study) performed like an average single-walled
aluminum bat. There is a group of recent composite models which compete in performance with the best double-walled aluminum slow-pitch softball bats,
having batted-ball speeds between 96-100mph.
And then there is a select group of super high performance composite slow-pitch softball bats, including the famous Miken Ultra, which are capable of producing
batted ball speeds in excess of 105-107mph.
COMPOSITE VS. ALUMINUM BATS !
Theoretical Model Says Stiff Bats Might Have Wider Sweet Spots
Physicist Alan Nathan published an important paper[10] in which he investigates the bat-ball interaction (for a wood bat) and addresses the issue of bat
flexibility by looking at how important the vibrational behavior of the bat is to the final exit speed of the ball.
One key feature of Nathan's theoretical model is that it obeys the Conservation of Energy. Simply stated, this means that the initial kinetic energy of the ball is
shared among . . .
the final kinetic energy of the ball
the energy contained in rigid body modes (translation and rotation) of the bat
the vibrational energy of the bat
and the energy lost in the compression and expansion of the ball.
If we can assume the energy associated with translation/rotation of the bat and the energy dissipated in ball are independent of impact location, then the
conservation of energy implies that the more energy transferred to bat vibrations, the less kinetic energy is returned to the ball. We would expect the
batted-ball speed to be greatest in the region where the bat does not vibrate after impact. This is illustrated in the graph at right which shows the distribution of
energy after impact as a function of location along the bat barrel. The graph shows that the energy returned to the ball peaks at about the same location where
the energy associated with bending vibrations is minimum.
The effect of bat vibrations is to decrease the effective bat mass, which reduces the exit speed of the ball. "On the time scale of the collision, the bat is not a
rigid body and the ball `sees' only a fraction of the bat mass."
The graphs at right compare Dr. Nathan's theoretical predictions with actual measured hit-ball speeds; the fit is very good both the low impact velocities
(2.2mph) and for higher, more realistic impact velocities (100mph). The graphs also show that if the bat is modeled as a rigid bat with no vibration, then the
rigid model and experimental data only agree at the sweet spot. Bending vibrations and bat flex must be implemented in a theoretical model of the bat-ball
collision in order for it to accurately predict performance.
Assuming all other properties being equal (i.e., two bats have the same weight, the same moment-of-inertia and the same trampoline effect in the barrel), Dr.
Nathan's paper suggests that a rigid bat and a flexible bat would produce the same batted-ball speeds for impacts at the sweet spot. However, his results also
suggest that stiffer bats could have a WIDER sweet spot. If a stiffer bat is more rigid and does not vibrate as easily, so that less energy is transferred to bat
vibrations, then the final ball speed might be higher for impacts away from the sweet spot, than for a flexible bat.
Physicist Alan Nathan published an important paper[10] in which he investigates the bat-ball interaction (for a wood bat) and addresses the issue of bat
flexibility by looking at how important the vibrational behavior of the bat is to the final exit speed of the ball.
One key feature of Nathan's theoretical model is that it obeys the Conservation of Energy. Simply stated, this means that the initial kinetic energy of the ball is
shared among . . .
the final kinetic energy of the ball
the energy contained in rigid body modes (translation and rotation) of the bat
the vibrational energy of the bat
and the energy lost in the compression and expansion of the ball.
If we can assume the energy associated with translation/rotation of the bat and the energy dissipated in ball are independent of impact location, then the
conservation of energy implies that the more energy transferred to bat vibrations, the less kinetic energy is returned to the ball. We would expect the
batted-ball speed to be greatest in the region where the bat does not vibrate after impact. This is illustrated in the graph at right which shows the distribution of
energy after impact as a function of location along the bat barrel. The graph shows that the energy returned to the ball peaks at about the same location where
the energy associated with bending vibrations is minimum.
The effect of bat vibrations is to decrease the effective bat mass, which reduces the exit speed of the ball. "On the time scale of the collision, the bat is not a
rigid body and the ball `sees' only a fraction of the bat mass."
The graphs at right compare Dr. Nathan's theoretical predictions with actual measured hit-ball speeds; the fit is very good both the low impact velocities
(2.2mph) and for higher, more realistic impact velocities (100mph). The graphs also show that if the bat is modeled as a rigid bat with no vibration, then the
rigid model and experimental data only agree at the sweet spot. Bending vibrations and bat flex must be implemented in a theoretical model of the bat-ball
collision in order for it to accurately predict performance.
Assuming all other properties being equal (i.e., two bats have the same weight, the same moment-of-inertia and the same trampoline effect in the barrel), Dr.
Nathan's paper suggests that a rigid bat and a flexible bat would produce the same batted-ball speeds for impacts at the sweet spot. However, his results also
suggest that stiffer bats could have a WIDER sweet spot. If a stiffer bat is more rigid and does not vibrate as easily, so that less energy is transferred to bat
vibrations, then the final ball speed might be higher for impacts away from the sweet spot, than for a flexible bat.
STIFFER SHAFT = BIGGER SWEET SPOT
Many tests have shown that rotational mechanics are far more efficient than linear mechanics in developing bat speed. In order to understand why this is true,
it is important to understand the forces acting on the bat.
Other than the effects of gravity, drag (due to airflow) and other minor factors, there are two forces acting on the bat that create bat speed:
Circular Hand Path (CHP) - The transfer of the body's rotational momentum that occurs when the hands are taken in a circular path.
Torque - Torque is applied at the handle of the bat by the push/pull of the hands/arms/shoulders.
Circular Hand Path
The bat will undergo angular displacement (i.e., bat speed) when the path of the hands is also undergoing angular displacement (i.e., a circular hand path). In
other words, as long as the path of the hands stays in a circular path as the body rotates, the circular hand path will transfer the body's rotational momentum
into bat-head acceleration.
In technical terms, we often refer to bat-head acceleration generated from the CHP as the "Pendulum Effect" so as to distinguish it from the "Crack of the
Whip" theory. (We'll take a brief digression to better explain this topic.) A pendulum is simply an object that swings freely back and forth in a circular arc (i.e.,
pendulum clock). However, in the baseball swing, there are two pendulums: 1) the lead-arm swings the hands in a circular arc, and 2) the end of the bat
swings around the hands. This is referred to as the Double Pendulum Effect of a CHP. A double pendulum consists of one pendulum attached to another. (To see
an example of the Double Pendulum Effect of a CHP, Click Here.)
Linear mechanics is much different in that it does not rely on a circular arc (or Pendulum Effect), as it is based on a theory that when the hands are extended in
a straight line, the bat-head will suddenly accelerate to contact like the crack of a whip ("Whip Effect".) However, this theory is flawed since there is no whip
effect in the baseball swing (a bat is not flexible like a whip), and consequently, efforts to produce a whip effect has stalled many hitters progress for decades.
To better grasp linear mechanics and the Whip Effect, it would be helpful to review the Crack of the Whip Theory at this time (and review the video clip at the
bottom).
A substantial portion of a good hitter's bat speed is derived from the circular path of his hands (think of swinging a ball on the end of a string). As long as we
keep our hand in a circular path, the ball will continue to accelerate in a circle. However, if the path of the hand straightens, the ball on the end of the string
loses angular velocity and trails behind the hands.
The same rational applies when a hitter is swinging a bat. If the hands are kept in a circular path, the bat will continue to accelerate. But if the hands straighten,
the batter loses the circular path and the bat will lose speed. With a straighter hand path, the bat-head trails behind the hands well into the swing. This is often
referred to as "knob of the bat first" and results in poor bat speed.
Torque
Torque is the result of two forces being applied to an object from opposing directions that cause the object to rotate about a point. Forces in the same direction
may cause the object to accelerate, but will not cause the object to rotate about a point (no angular displacement). For example, when loosening a lug nut with
a 4-prong tire wrench, you push down with one hand while pulling up with the other (torque). However, if you push down (or pull up) with both hands, you
would not cause the nut to rotate (no torque).
Torque is applied in the swing by the push/pull action of the forearms and hands. The bat-head is accelerated from torque when the direction of force applied
by the hands is from opposing directions.
To reach maximum bat speed, the batter must apply torque from initiation to contact and keep the hands in a circular path.
Forces initiated by the AVERAGE hitters. Forces initiated by the GREAT hitters.
Average hitters' usually have very little circular hand path in their swing (no pendulum effect) due to the straighter hand-path. As a result, average hitters rely
mainly on torque to accelerate the bat-head. (Remember, there are only two forces acting on the bat - a circular hand path and torque. If one of the forces is
missing, the batter will have to rely on the other force to move the bat.)
For a batter to attain his maximum potential, his mechanics must make efficient use of both - CHP and torque. Great hitters generate great bat speed because
their swing mechanics efficiently apply torque at the handle that compliments the their circular hand path.
it is important to understand the forces acting on the bat.
Other than the effects of gravity, drag (due to airflow) and other minor factors, there are two forces acting on the bat that create bat speed:
Circular Hand Path (CHP) - The transfer of the body's rotational momentum that occurs when the hands are taken in a circular path.
Torque - Torque is applied at the handle of the bat by the push/pull of the hands/arms/shoulders.
Circular Hand Path
The bat will undergo angular displacement (i.e., bat speed) when the path of the hands is also undergoing angular displacement (i.e., a circular hand path). In
other words, as long as the path of the hands stays in a circular path as the body rotates, the circular hand path will transfer the body's rotational momentum
into bat-head acceleration.
In technical terms, we often refer to bat-head acceleration generated from the CHP as the "Pendulum Effect" so as to distinguish it from the "Crack of the
Whip" theory. (We'll take a brief digression to better explain this topic.) A pendulum is simply an object that swings freely back and forth in a circular arc (i.e.,
pendulum clock). However, in the baseball swing, there are two pendulums: 1) the lead-arm swings the hands in a circular arc, and 2) the end of the bat
swings around the hands. This is referred to as the Double Pendulum Effect of a CHP. A double pendulum consists of one pendulum attached to another. (To see
an example of the Double Pendulum Effect of a CHP, Click Here.)
Linear mechanics is much different in that it does not rely on a circular arc (or Pendulum Effect), as it is based on a theory that when the hands are extended in
a straight line, the bat-head will suddenly accelerate to contact like the crack of a whip ("Whip Effect".) However, this theory is flawed since there is no whip
effect in the baseball swing (a bat is not flexible like a whip), and consequently, efforts to produce a whip effect has stalled many hitters progress for decades.
To better grasp linear mechanics and the Whip Effect, it would be helpful to review the Crack of the Whip Theory at this time (and review the video clip at the
bottom).
A substantial portion of a good hitter's bat speed is derived from the circular path of his hands (think of swinging a ball on the end of a string). As long as we
keep our hand in a circular path, the ball will continue to accelerate in a circle. However, if the path of the hand straightens, the ball on the end of the string
loses angular velocity and trails behind the hands.
The same rational applies when a hitter is swinging a bat. If the hands are kept in a circular path, the bat will continue to accelerate. But if the hands straighten,
the batter loses the circular path and the bat will lose speed. With a straighter hand path, the bat-head trails behind the hands well into the swing. This is often
referred to as "knob of the bat first" and results in poor bat speed.
Torque
Torque is the result of two forces being applied to an object from opposing directions that cause the object to rotate about a point. Forces in the same direction
may cause the object to accelerate, but will not cause the object to rotate about a point (no angular displacement). For example, when loosening a lug nut with
a 4-prong tire wrench, you push down with one hand while pulling up with the other (torque). However, if you push down (or pull up) with both hands, you
would not cause the nut to rotate (no torque).
Torque is applied in the swing by the push/pull action of the forearms and hands. The bat-head is accelerated from torque when the direction of force applied
by the hands is from opposing directions.
To reach maximum bat speed, the batter must apply torque from initiation to contact and keep the hands in a circular path.
Forces initiated by the AVERAGE hitters. Forces initiated by the GREAT hitters.
Average hitters' usually have very little circular hand path in their swing (no pendulum effect) due to the straighter hand-path. As a result, average hitters rely
mainly on torque to accelerate the bat-head. (Remember, there are only two forces acting on the bat - a circular hand path and torque. If one of the forces is
missing, the batter will have to rely on the other force to move the bat.)
For a batter to attain his maximum potential, his mechanics must make efficient use of both - CHP and torque. Great hitters generate great bat speed because
their swing mechanics efficiently apply torque at the handle that compliments the their circular hand path.
BAT TORQUE AND ROTATIONAL MOMENTUM
More data showing post-impact flexing of bats - this time for Baseball Bats
Here are some more examples of bat flexing after impact. The following three sequences of images were cropped from frames of high speed movies (1000 fps) of a
player hitting pitched baseballs. Each pair of images corresponds to the instant of collision with the ball and 0.004 seconds after the collision. I've added some red
straight lines to help showcase the flexing of the bat. The important thing about these photos is that they illustrate clearly the differences in bat flex for impacts at or
away from the sweet spot.
Flexible Bat - Impact AT Sweet Spot
When the impact occurs at the sweet spot, the bat does not vibrate after impact. As a result, the bat remains straight after impact and does not flex one way or the
other. A frame-by-frame analysis of the ball motion after impact results in a measured batted-ball speed of 40 m/s (89-mph).
Flexible Bat - Impact OUTSIDE Sweet Spot
When the impact occurs away from the sweet spot, bending vibrations are set up in the bat after the ball leaves. Impacts outside the sweet spot make the barrel of
the bat initially bend away from the ball, while the taper moves towards the ball. This impact outside the sweet spot resulted in a batted-ball speed of 26 m/s
(58-mph).
Flexible Bat - Impact INSIDE Sweet Spot
When the impact occurs inside the sweet spot, the bending vibrational modes combine differently so that the taper region of the bat moves away from the ball, while
the barrel and handle ends initially move in the same direction as the ball. This impact inside the sweet spot resulted in a batted-ball speed of 28 m/s (62-mph).
Here are some more examples of bat flexing after impact. The following three sequences of images were cropped from frames of high speed movies (1000 fps) of a
player hitting pitched baseballs. Each pair of images corresponds to the instant of collision with the ball and 0.004 seconds after the collision. I've added some red
straight lines to help showcase the flexing of the bat. The important thing about these photos is that they illustrate clearly the differences in bat flex for impacts at or
away from the sweet spot.
Flexible Bat - Impact AT Sweet Spot
When the impact occurs at the sweet spot, the bat does not vibrate after impact. As a result, the bat remains straight after impact and does not flex one way or the
other. A frame-by-frame analysis of the ball motion after impact results in a measured batted-ball speed of 40 m/s (89-mph).
Flexible Bat - Impact OUTSIDE Sweet Spot
When the impact occurs away from the sweet spot, bending vibrations are set up in the bat after the ball leaves. Impacts outside the sweet spot make the barrel of
the bat initially bend away from the ball, while the taper moves towards the ball. This impact outside the sweet spot resulted in a batted-ball speed of 26 m/s
(58-mph).
Flexible Bat - Impact INSIDE Sweet Spot
When the impact occurs inside the sweet spot, the bending vibrational modes combine differently so that the taper region of the bat moves away from the ball, while
the barrel and handle ends initially move in the same direction as the ball. This impact inside the sweet spot resulted in a batted-ball speed of 28 m/s (62-mph).
89 MPH IN SWEET
SPOT
SPOT
62 MPH INSIDE
SWEET SPOT
SWEET SPOT
58 MPH OUTSIDE
SWEET SPOT
SWEET SPOT
The data appears to show that the flexible handle bat had about 1-MPH better performance than the stiff bat, which contradicts the experimental results
of just discussed above. However, we need more than two impacts at each location to provide statistical confidence in the results. With the built-in uncertainty
in the test, this result does not suggest a significant difference between a flexible, medium and stiff handled softball bat, either in terms of the batted-ball speed
or the effective width of the sweet spot. BUT HITTING IT ON THE SWEET SPOT OF THE BAT IS STILL THE BEST..
of just discussed above. However, we need more than two impacts at each location to provide statistical confidence in the results. With the built-in uncertainty
in the test, this result does not suggest a significant difference between a flexible, medium and stiff handled softball bat, either in terms of the batted-ball speed
or the effective width of the sweet spot. BUT HITTING IT ON THE SWEET SPOT OF THE BAT IS STILL THE BEST..
FLEX HANDEL VS. STIFF DOES IT HELP ?
ITS ALL ABOUT BALLS
Testing has shown two main things as it relates to softball COR and compression and on-field performance. First, a change from a .47 COR, 525 pound ball to a .44
COR, 375 pound ball decreases performance by up to 6%. All other things being equal, this means that a 305 foot home run using a .47 COR, 525 pound ball would
be a 290 foot fly out using a .44 COR, 375 pound ball. Second, reductions in compression have a much greater impact in on-field performance than reductions in COR.
As a player, you should also be aware that weather has an enormous impact on the compression of a softball. Studies have shown that when the temperature is 100
degrees, an average softball looses 200 pounds of compression as compared with the same softball at 60 degrees. This means that a softball that is a 525 pound
compression ball at 60 degrees may play like a 375 pound ball at 100 degrees. In addition, clouds, rain, and humidity also affect the compression of a ball. 70
degrees and sunny creates lower compression balls than if it was 70 degrees and cloudy. Leather balls generally take on more moisture in rainy or humid conditions
than synthetic balls. This will generally raise the compression and level of play up to a point, then performance will decline once the ball takes on too much water and
becomes too heavy.
Keep these factors in mind when deciding which bat to use and when determining your approach for each at-bat. If it is hot and humid, it may be best not to try for a
home run, but instead try for a base hit.
COR, 375 pound ball decreases performance by up to 6%. All other things being equal, this means that a 305 foot home run using a .47 COR, 525 pound ball would
be a 290 foot fly out using a .44 COR, 375 pound ball. Second, reductions in compression have a much greater impact in on-field performance than reductions in COR.
As a player, you should also be aware that weather has an enormous impact on the compression of a softball. Studies have shown that when the temperature is 100
degrees, an average softball looses 200 pounds of compression as compared with the same softball at 60 degrees. This means that a softball that is a 525 pound
compression ball at 60 degrees may play like a 375 pound ball at 100 degrees. In addition, clouds, rain, and humidity also affect the compression of a ball. 70
degrees and sunny creates lower compression balls than if it was 70 degrees and cloudy. Leather balls generally take on more moisture in rainy or humid conditions
than synthetic balls. This will generally raise the compression and level of play up to a point, then performance will decline once the ball takes on too much water and
becomes too heavy.
Keep these factors in mind when deciding which bat to use and when determining your approach for each at-bat. If it is hot and humid, it may be best not to try for a
home run, but instead try for a base hit.
HEAT EFFECTS ON YOUR BALLS? THATS A BAD THING
TO CLARIFY THE INFORMATION WHICH RELATES TO SOFTBALLS AND TEMPERATURE EFFECT ON THE COMPRESSION. IT WAS PREVIOUSLY MENTIONED THAT FOR
EVERY ONE DEGREE TEMPERATURE CHANGE THERE IS A 5% CHANGE IN COMPRESSION. THIS IS NOT QUITE ACCURATE. FOR EVERY ONE DEGREE CHANGE THERE
IS A 5 LB. COMPRESSION CHANGE. BALLS ARE TESTED AT 72 DEGREES. AT 92 DEGREES A 400 COMPRESSION BALL CHANGES TO APPROXIMATELY 300
COMPRESSION. INVERSELY THE SAME HAPPENS IF THE TEMPERATURE IS 52 DEGREES THE COMPRESSION GOES TO APPROXIMATELY 500. I'M A
MANUFACTURERS REP FOR WORTH SPORTS AND WE HAVE DONE MANY TESTS ON OUR PRODUCTS TO INSURE CONSISTENCY AND BALL QUALITY. I ALSO PLAY
SENIOR BALL AND ENJOY A HIGH PERFORMANCE BAT AND A BALL THAT IS CONSISTENT
EVERY ONE DEGREE TEMPERATURE CHANGE THERE IS A 5% CHANGE IN COMPRESSION. THIS IS NOT QUITE ACCURATE. FOR EVERY ONE DEGREE CHANGE THERE
IS A 5 LB. COMPRESSION CHANGE. BALLS ARE TESTED AT 72 DEGREES. AT 92 DEGREES A 400 COMPRESSION BALL CHANGES TO APPROXIMATELY 300
COMPRESSION. INVERSELY THE SAME HAPPENS IF THE TEMPERATURE IS 52 DEGREES THE COMPRESSION GOES TO APPROXIMATELY 500. I'M A
MANUFACTURERS REP FOR WORTH SPORTS AND WE HAVE DONE MANY TESTS ON OUR PRODUCTS TO INSURE CONSISTENCY AND BALL QUALITY. I ALSO PLAY
SENIOR BALL AND ENJOY A HIGH PERFORMANCE BAT AND A BALL THAT IS CONSISTENT
COR versus Compression
Both baseballs and softballs come in a variety of stiffnesses. Softer balls are often used for younger less experience players because if a player is hit with a softer ball
it doesn't do as much damage and the game is thus a little safer. More experience players usually don't like to play with these "dead" balls and prefer harder, more
lively balls. Sometimes, the weather conditions - especially the temperature - may dictate choosing a certain type of ball over another. Weather conditions can be a
problem since the elastic properties of baseballs and softballs change significantly dependening on the temperature and humidity of the environment in which the balls
are kept.[8-10]
When you pick up a softball you will usually find two numbers printed on the ball as ratio, something like 375/.44. These two numbers represent the compression and
Coefficient-of-Restitution (COR), respectively. The compression is simply the amount of force in pounds that is required to compress the ball a quarter of an inch, and
it represents the "hardness" of the ball. Compression is measured by performing a static compression test on the ball. A compression value of 375 means that if
375-lbs of force were applied to the ball it would compress by 0.25-inches. If you held a 375/.44 softball in your hand tried to squeeze it as hard as you can, and then
try the same thing with a 575/.44 ball, the 575 ball would feel harder because 200 more pounds of force are required to compress the ball the same amount. The
second number stands for the coefficient-of-restitution, or COR, and represents the elasticity or springiness of the ball. The COR is measured by firing a ball from an
air cannon at 60-mph (or 90-mph) towards a rigid surface and measuring the ratio of rebound speed to initial speed. You could compare two balls by dropping them
from the same height onto a flat cement floor. If you compared a 375/.47 ball with a 375/.40 ball you would find that the .47 COR ball would bounce slightly higher.
Recently, several bat manufacturers and some scientists have suggested that a better (and safer) way to control the game would be to regulate the balls used in a
game (ie, choosing a deader or softer ball) instead of banning bats as is the current practice.
Summary of Nonlinear Behaviors Needed to Correctly Model the Ball
So, in order to develop a model which adequately describes the behavior of the ball during the collision with a bat, the model of the ball must produce the following
behaviors:
The stiffness of the ball model must behave like a hardening spring, becoming stiffer as more force is applied.
The nonlinear stiffness must be different for the compression and relaxation portions of the force-compression cycle.
As the speed of the ball increases, both the COR and the contact duration must decrease.
The model must accurately predict the effect of changes in stiffness (compression) and elasticity (COR).
Both baseballs and softballs come in a variety of stiffnesses. Softer balls are often used for younger less experience players because if a player is hit with a softer ball
it doesn't do as much damage and the game is thus a little safer. More experience players usually don't like to play with these "dead" balls and prefer harder, more
lively balls. Sometimes, the weather conditions - especially the temperature - may dictate choosing a certain type of ball over another. Weather conditions can be a
problem since the elastic properties of baseballs and softballs change significantly dependening on the temperature and humidity of the environment in which the balls
are kept.[8-10]
When you pick up a softball you will usually find two numbers printed on the ball as ratio, something like 375/.44. These two numbers represent the compression and
Coefficient-of-Restitution (COR), respectively. The compression is simply the amount of force in pounds that is required to compress the ball a quarter of an inch, and
it represents the "hardness" of the ball. Compression is measured by performing a static compression test on the ball. A compression value of 375 means that if
375-lbs of force were applied to the ball it would compress by 0.25-inches. If you held a 375/.44 softball in your hand tried to squeeze it as hard as you can, and then
try the same thing with a 575/.44 ball, the 575 ball would feel harder because 200 more pounds of force are required to compress the ball the same amount. The
second number stands for the coefficient-of-restitution, or COR, and represents the elasticity or springiness of the ball. The COR is measured by firing a ball from an
air cannon at 60-mph (or 90-mph) towards a rigid surface and measuring the ratio of rebound speed to initial speed. You could compare two balls by dropping them
from the same height onto a flat cement floor. If you compared a 375/.47 ball with a 375/.40 ball you would find that the .47 COR ball would bounce slightly higher.
Recently, several bat manufacturers and some scientists have suggested that a better (and safer) way to control the game would be to regulate the balls used in a
game (ie, choosing a deader or softer ball) instead of banning bats as is the current practice.
Summary of Nonlinear Behaviors Needed to Correctly Model the Ball
So, in order to develop a model which adequately describes the behavior of the ball during the collision with a bat, the model of the ball must produce the following
behaviors:
The stiffness of the ball model must behave like a hardening spring, becoming stiffer as more force is applied.
The nonlinear stiffness must be different for the compression and relaxation portions of the force-compression cycle.
As the speed of the ball increases, both the COR and the contact duration must decrease.
The model must accurately predict the effect of changes in stiffness (compression) and elasticity (COR).
Ball Hype
By Craig Opal
I will try here to simplify a complex issue. We all know about the hype surrounding bats and their bannings etc., but what about balls? It's probably more confusion
rather than hype. First whats more important ball core or compression?
Answer: compression
COR is simply the rate at which a ball will reflect back after being cast against an immovable object. So the higher the core the higher the reflectivity or the higher the
bounce if you will. Core 47 has a higher bounce than a core 40, but core is not as important as compression, although if you could choose a core 47 with low
compression (which would be the ultimate mush ball) this would be a good ball for a stiff walled bat like a stock techzilla to hit for example.
Unfortunately low compression balls (375lbs.) are many times paired up with 44 and 47 COR making the ball that much softer. This is why it is important to separate
the two. The compression is much more important and it's as simple as this: 375lb. comp balls are softer or "compress" more than 525 lb. balls. It takes 525lbs. of
pressure per sq.inch to compress a 525lb. ball 1/4". It takes only 375lbs. of pressure to compress a 375lb. ball 1/4". So the higher the compression the harder the
ball and the harder the ball the farther it will fly with the right bat. What is the right bat? Well lets look at a bit more.
If you could choose and I know many times you can't unless it's your own practice, but if you could the ultimate ball for lets say a Miken Ultra or another high flex bat
it would be high comp. 525lb.ball with 40 COR as opposed to 47 COR. Most times though 525's are paired up with 47 COR and most people think its the core 47 that
is allowing the ball to fly farther, but it is in fact the compression not the core.
Lets look at a low comp ball 375lbs. and a bat with a lot of flex(ultra, rocket tech, synergy, pst, etc.). Typically a low comp ball and a bat with a lot of flex is not a
good combo especially over time(time being the more the ball is hit the mushier it gets). A better pairing is those above named bats and a hi comp 525lb. ball. Hard
ball meets 'soft' bat = long hit. Simple.
So what would a better bat be for the low comp 375lb. with core 44 and 47 balls? Something that dosen't flex as much and guess what, this is how the world record
of 530 some feet was broken back in the 70's. A 'hard' bat (no flex) was used with what kind of ball?
Answer: Back in the 70's the balls flexed incredibly and were made of a type of 'Surilyn'. The flex on the ball was incredible and rivaled what a superball is like today.
They quickly were outlawed and now the bats of today are the focus of bannings like the balls were in the 70's.
So now we as players, should find out what comp balls are being used in our leagues and tournaments so we can match a better bat to the ball we are using. In fact a
better bat now for the low comp balls, which are becoming more prevalent may in fact be the bats of long ago that didn't flex as much. What new bats out there now
don't flex as much? The original Techzilla comes to mind immediately. It flex's for the very hard hitter, but for the average hitter who can't flex it as much, it may be
exactly the bat that the doctor ordered for these low comp. balls, for even the average hitter.
The New Anderson CK(Composite Killer) line however, is a bat expressly made for hitting mush balls like no other. The new Rocket Tech CK is a bat that is a must
have if you play asa and hit mush balls. It is rated in the top ten of all bats of all time already, on bat review sites and it hit the market in August of 2004. It is the only
ASA bat rated this high.
Now having said all of this what is the real difference in distance between a low comp and a high comp ball? My experience has been around 25 ft. or so It may not
sound like a lot, but for some it's the difference between hitting a HR and hitting a long fly out. Also different ball manufacturers will make a difference in
performance. There are too many to mention here, but suffice it to say, some companies put out pure junk while others even though they are low comp. still may fly
pretty good.
The following should help you in understanding the ball compression and how it relates to certain bats. I have broken it down to what I hope is an easier to
understand format, because I know it can be confusing.
375lbs low compression = more flexible or 'mushy' does not perform well with high flex bats.
400lb-475lbs. mid compression = medium flexibility still performs OK with most bats.
525lb. compression= harder ball-performs well with almost any bat on the market, but especially juiced or high flex models etc.
Core 47= more flexible bouncy or 'mushy'
Core 44= medium flexibility
Core 40= less flexible
As you can see here if you were to have a core 40 with a low compression ball you still will have decent almost mid performance, which I have found to be true in my
own testing as well. But as soon as you pair up low comp with core 44 or 47 now you have much more loss in performance with the high flex bats and why I now
recommend the RT CK with those balls. Anything mid and above will perform well with high flex bats and juiced bats. The ultimate for ball hardness would be 525lbs.
paired up with core 40 not 47. I know many balls are paired more with 525lbs. and core 47, but the 47 is not what makes those balls fly so far, it is the compression.
Endloaded bats will in all instances make any ball fly farther, but in the case of low compression with core 44 and 47, it may not be enough to overcome the loss in
performance that is experienced from the flexibility of the ball.
Outside temperature and the climate you may play in will also effect performance. Cooler temps will keep the ball harder and flying farther. Warmer temps will keep
the ball more flexible and mushier.
Also bat weight also factors into hitting a ball for distance. The heavier the bat and the heavier the endload you can swing the better for distance, even and or
especially on the mush balls. This is proven with the players who hit 14" & 16" balls. If you have ever hit a 16" softball you know it is very soft and flexible to where
you don't even need fielding gloves to catch it. Using a Miken Ultra with these balls is almost useless. Most players using these balls go with the heaviest stiff walled
bats they can find.
By Craig Opal
I will try here to simplify a complex issue. We all know about the hype surrounding bats and their bannings etc., but what about balls? It's probably more confusion
rather than hype. First whats more important ball core or compression?
Answer: compression
COR is simply the rate at which a ball will reflect back after being cast against an immovable object. So the higher the core the higher the reflectivity or the higher the
bounce if you will. Core 47 has a higher bounce than a core 40, but core is not as important as compression, although if you could choose a core 47 with low
compression (which would be the ultimate mush ball) this would be a good ball for a stiff walled bat like a stock techzilla to hit for example.
Unfortunately low compression balls (375lbs.) are many times paired up with 44 and 47 COR making the ball that much softer. This is why it is important to separate
the two. The compression is much more important and it's as simple as this: 375lb. comp balls are softer or "compress" more than 525 lb. balls. It takes 525lbs. of
pressure per sq.inch to compress a 525lb. ball 1/4". It takes only 375lbs. of pressure to compress a 375lb. ball 1/4". So the higher the compression the harder the
ball and the harder the ball the farther it will fly with the right bat. What is the right bat? Well lets look at a bit more.
If you could choose and I know many times you can't unless it's your own practice, but if you could the ultimate ball for lets say a Miken Ultra or another high flex bat
it would be high comp. 525lb.ball with 40 COR as opposed to 47 COR. Most times though 525's are paired up with 47 COR and most people think its the core 47 that
is allowing the ball to fly farther, but it is in fact the compression not the core.
Lets look at a low comp ball 375lbs. and a bat with a lot of flex(ultra, rocket tech, synergy, pst, etc.). Typically a low comp ball and a bat with a lot of flex is not a
good combo especially over time(time being the more the ball is hit the mushier it gets). A better pairing is those above named bats and a hi comp 525lb. ball. Hard
ball meets 'soft' bat = long hit. Simple.
So what would a better bat be for the low comp 375lb. with core 44 and 47 balls? Something that dosen't flex as much and guess what, this is how the world record
of 530 some feet was broken back in the 70's. A 'hard' bat (no flex) was used with what kind of ball?
Answer: Back in the 70's the balls flexed incredibly and were made of a type of 'Surilyn'. The flex on the ball was incredible and rivaled what a superball is like today.
They quickly were outlawed and now the bats of today are the focus of bannings like the balls were in the 70's.
So now we as players, should find out what comp balls are being used in our leagues and tournaments so we can match a better bat to the ball we are using. In fact a
better bat now for the low comp balls, which are becoming more prevalent may in fact be the bats of long ago that didn't flex as much. What new bats out there now
don't flex as much? The original Techzilla comes to mind immediately. It flex's for the very hard hitter, but for the average hitter who can't flex it as much, it may be
exactly the bat that the doctor ordered for these low comp. balls, for even the average hitter.
The New Anderson CK(Composite Killer) line however, is a bat expressly made for hitting mush balls like no other. The new Rocket Tech CK is a bat that is a must
have if you play asa and hit mush balls. It is rated in the top ten of all bats of all time already, on bat review sites and it hit the market in August of 2004. It is the only
ASA bat rated this high.
Now having said all of this what is the real difference in distance between a low comp and a high comp ball? My experience has been around 25 ft. or so It may not
sound like a lot, but for some it's the difference between hitting a HR and hitting a long fly out. Also different ball manufacturers will make a difference in
performance. There are too many to mention here, but suffice it to say, some companies put out pure junk while others even though they are low comp. still may fly
pretty good.
The following should help you in understanding the ball compression and how it relates to certain bats. I have broken it down to what I hope is an easier to
understand format, because I know it can be confusing.
375lbs low compression = more flexible or 'mushy' does not perform well with high flex bats.
400lb-475lbs. mid compression = medium flexibility still performs OK with most bats.
525lb. compression= harder ball-performs well with almost any bat on the market, but especially juiced or high flex models etc.
Core 47= more flexible bouncy or 'mushy'
Core 44= medium flexibility
Core 40= less flexible
As you can see here if you were to have a core 40 with a low compression ball you still will have decent almost mid performance, which I have found to be true in my
own testing as well. But as soon as you pair up low comp with core 44 or 47 now you have much more loss in performance with the high flex bats and why I now
recommend the RT CK with those balls. Anything mid and above will perform well with high flex bats and juiced bats. The ultimate for ball hardness would be 525lbs.
paired up with core 40 not 47. I know many balls are paired more with 525lbs. and core 47, but the 47 is not what makes those balls fly so far, it is the compression.
Endloaded bats will in all instances make any ball fly farther, but in the case of low compression with core 44 and 47, it may not be enough to overcome the loss in
performance that is experienced from the flexibility of the ball.
Outside temperature and the climate you may play in will also effect performance. Cooler temps will keep the ball harder and flying farther. Warmer temps will keep
the ball more flexible and mushier.
Also bat weight also factors into hitting a ball for distance. The heavier the bat and the heavier the endload you can swing the better for distance, even and or
especially on the mush balls. This is proven with the players who hit 14" & 16" balls. If you have ever hit a 16" softball you know it is very soft and flexible to where
you don't even need fielding gloves to catch it. Using a Miken Ultra with these balls is almost useless. Most players using these balls go with the heaviest stiff walled
bats they can find.