For a hitter, the most critical decision you can make to help or
hurt your chances in the box is the choice of which size bat to use.
Ted Williams always advocated using the lighest bat you could and
that was good enough for many, but with the use of aluminum bats I
think we see a trend toward the use of bats that are, in many
instances, too light for players. The mechanics that are being wired
into youth hitters are "aluminmum bat" swings. They don't generate
enough power from the lower body since bat speed can come from just
a flick of the wrists.
Chipper Jones, speaking at an ABCA Convention recently related how
he was told as a young player to "swing the heaviest bat you can get
around on a 90-mph pitch". If he's facing a real hard-thrower, he
may drop down an ounce from his regular game bat.
Chipper is also noted to have developed his great bat speed during
an off-season by swinging heavy bats to develop strength and speed.
This is the type of training popularized by Coope DeRenne and Tom
House in "Power Baseball". Very underrated publication, but one of
my all-time personal favorite books for player development.
In youth leagues, given the disparity in sizes of kids, it seems
silly for all kids to use the same size bat. The bigger, stronger
kids are using the same 30in/19 oz bats as the smaller, quicker kids.
The bats in many of the big kids hands just look like toothpicks and
many times the swing is done before the pitch arrives, they seem to
overpower the bat size.
A. Terry Bahill posted the following study re: bat selection.
http://tucson.sie.arizona.edu/sysengr/talks/ideal.html
Ideal Bat Weight:TM
Engineering the Sport of Baseball
A. Terry Bahill
Systems and Industrial Engineering
PO Box 210020
University of Arizona
Tucson, AZ 85721-0020, USA
terry@...
© 1998 Bahill
Baseball players swung very light and very heavy bats through our
instrument (called the Bat ChooserTM) and we recorded the speed of
the center of mass of the bat. These data were used to make
mathematical models for each individual human. These models were
then coupled to the equations of physics for bat-ball collisions to
compute the Ideal Bat Weight for each individual baseball player. We
measured 28 members of the San Francisco Giants baseball team and
found that 80% of them were using bats in their correct range. But
10% were using bats that were too light for them, and 10% were using
bats that were too heavy for them. However, only 25% of the 200 less
experienced baseball players that we studied, e.g. Little Leaguers,
were using bats in their correct range.
The force-velocity relationships of some of our subjects were best
modeled with hyperbolic equations. However, for others a straight
line provided the best fit. We divided our subjects into two
groups: "quick" people with large slopes that are fit best with Hill-
type hyperbolas, and others with flatter data that are fit best with
straight lines. He hypothesize that some people have rigid
unchanging control strategies, they swing all bats the same. Whereas
quick people adapt well and change their control strategies to take
advantage of the varying bat weights.
We developed a more complex model for the swing of the baseball bat
that entails one translation and two rotations. We also constructed
a set of bats where each bat had the same mass but a different
inertia. With our new model and bats we can determine the best shape
of the baseball bat for individual players.
But so far all of these recommendations depend on the ball player
using the Bat Chooser in Tucson. At the finale of this talk I will
present rules of thumb that anyone can use to estimate his or her
optimal bat weight.
References [43, 45 and 50]. I can adapt this lecture to make it
suitable for engineers or the general public. This talk requires an
overhead projector, a VHS video tape player and a 35mm Carousel
slide projector. This talk takes one hour.
Ideal Bat WeightTM and Bat ChooserTM are trade marks of Bahill
Intelligent Computer Systems (BICS), 1622 W. Montenegro, Tucson, AZ,
85704-1822.
and this article from the Arizona Daily Wildcat:
http://wildcat.arizona.edu/papers/93/109/01_2_m.html
UA professor examines science of baseball
Arizona Daily Wildcat
Photo by: GAVIN STEVENS
UA professor Terry Bahill takes a swing through his "bat-chooser"
machine Monday afternoon in an engineering lab. The machine
calculates the batter's swing speed and helps players to find the
most effective bat weight.
By Blake Smith
Arizona Daily Wildcat,
March 1, 2000 Talk about this story
Many professional baseball players have long contended that hitting
home runs is as much of a science as a physical skill.
Now, a University of Arizona professor has found a way for baseball
players to hit more of them.
UA systems and industrial engineering professor Terry Bahill has
examined the physical aspects of baseball, from the way batters
perceive pitches to how the weight of the bat can drastically affect
the speed of a ball.
Bahill found that a pitch is naturally broken into thirds by a
batter. The first part of the pitch is sensory gathering, the second
is computing how fast the ball is traveling and when to swing, and
the third is the actual swing.
Batters often complain that a fastball "jumps" as it crosses the
plate, causing them to swing under the ball, but Bahill contends
that defies the laws of physics.
"When the batter starts to swing, he takes his eyes off the ball to
look at the predicted bat-ball collision point," he stated in a news
release. "When the ball comes back into his view, it is higher than
his mental model predicted, and he sees it 'jump' higher than where
he calculated that it would be."
Bahill contends the way to solve the problem is not to change the
psychological process of the batter, but to change the weight of the
bat.
"We're talking about momentum here," he said, while showing off the
collection of weighted bats in his laboratory.
Bahill said his main objective has been to determine how the weight
of a bat affects the speed of bat-to-ball contact.
Bahill operates a "bat chooser" machine in his engineering lab.
The simple machine consists of two bars. The lower bar has two laser
beams set at a standard distance apart from each other, while a
string dangles from the upper bar.
The player swings through the machine, attempting to hit the string.
A computer attached to the laser beams records the time it takes for
the bat to travel from one laser beam to the other and calculates
the swing speed.
Different weights of bats are used by the batter, and then, a graph
is created to find a balance between greatest bat weight and fastest
swing speed, Bahill said.
For instance, a player can hit a ball with a whiffleball stick - low
weight, but fast speed - and never hit a home run. On the other
hand, when hitting a ball with a bat made of solid lead, the weight
of the bat would be great and the swing speed would be hampered
drastically, Bahill said.
The purpose of the bat chooser machine is to find the best bat for
each individual hitter, he added.
Bahill also studied the advantages of aluminum bats over wooden
bats.
A misconception is that aluminum bats generate higher bat-to-ball
speeds, which could endanger the safety of a pitcher, Bahill said.
He disproved the theory by looking at basic tendencies of baseball
players.
"To go from an aluminum bat of one length to a wooden bat of the
same length, the weight of the bat will have to increase," Bahill
added.
Bat speed then decreases because of the increased weight. That
increased weight overcomes the speed deficit, giving the ball more
momentum. Hence, the ball travels faster to the pitcher.
Bahill is now examining the effects of an end-loaded bat - with
weight shifted from the mid-section of the bat to the end - on a
batter's bat-to-ball collision speed.
The theory is that momentum will increase because of the weighted
end, causing the batter to hit the ball with greater force, Bahill
said.
Since 1987, Bahill has worked with the UA softball team to help them
determine the best bat weight for each player.
"I recommended that they use 25 ounce bats, but the lightest bats
they had were 31 ounces. I checked back with them a few years later
and come to find out they had 26 ounce bats," he said.
UA softball player Nicole Giordano used Bahill's "bat chooser"
machine last semester.
"What he recommended helped some," said Giordano, a junior
centerfielder. "I'm getting more distance on the ball this year, but
I think it's more mental and not so much the bat."
This spring, Bahill hopes to test his findings on Chicago White Sox
first baseman Frank Thomas. Thomas is not his first choice, however.
"Mark McGwire would be ideal," he said.
According to Bahill, the St. Louis Cardinals' first baseman is
interested in the science of baseball but fears that altering his
bat weight - and in turn his swing speed - might change his record-
high home run production.
Currently, Bahill is beginning a study on the vibrations of a bat
after making contact with the baseball.
To this point, his studies have focused on how to make the hitter
better. Now, he will look at how to make the bat better.
While Bahill studies all aspects of baseball in the lab, he said the
only time he watches the sport is when his children have it on the
television.
"I'm not a baseball fan," he said. "I'm just trying to figure out
the science behind it."
From Professor Bahill's work, Worth Sports came up with it's Bat
Guide for baseball/Softball players. This one you'll have to click
on yourself as it does not tranfer well. The formulas to determine
the best bat weight are shown below.
http://www.worthsports.com/aboutworth/batguide.html
WORTHSPORTS.COM: BAT GUIDE
Worth conducted a project with a University of Arizona research
group to determine the best bat weight for players in youth league
and adult baseball, and slowpitch and fastpitch softball. The
research included precise measurement of bat speed for numerous
individuals in each category. Measured bat speeds were then used in
conservations of momentum calculation to determine hit ball speed.
Formulas were then developed to predict the optimum or best bat
weight for maximum hit ball speed in each category. It should be
noted that for baseball and fastpitch softball ball weights, the
ideal bat weight for maximum hit ball speed is approximately 1 ounce
heavier than the standard recommendation. The research showed there
is negligible loss of hit ball speed by reducing the bat weight 1
ounce below the ideal. Because of this, the lighter weight increases
bat control which becomes an essential ingredient in making ball
contact in both baseball and fastpitch softball.
In three of the categories, the experimental data correlated best to
player weight while in the other two, the best correlation was to
player height.
BEST BAT WEIGHTS:
A. High School & College Baseball Formula: Height/3 + 5
B. Youth League Baseball (11-12 yrs) Formula: Weight/18 + 14
C. Youth League Baseball (8-10 yr. olds) Formula: Height/4 + 14
D. Fastpitch Softball (Women) Formula: Weight/15 + 17
E. Slowpitch Softball (Men and Women) Formula: Weight/19 + 17
Ted Williams always advocated using the lighest bat you could and
that was good enough for many, but with the use of aluminum bats I
think we see a trend toward the use of bats that are, in many
instances, too light for players. The mechanics that are being wired
into youth hitters are "aluminmum bat" swings. They don't generate
enough power from the lower body since bat speed can come from just
a flick of the wrists.
Chipper Jones, speaking at an ABCA Convention recently related how
he was told as a young player to "swing the heaviest bat you can get
around on a 90-mph pitch". If he's facing a real hard-thrower, he
may drop down an ounce from his regular game bat.
Chipper is also noted to have developed his great bat speed during
an off-season by swinging heavy bats to develop strength and speed.
This is the type of training popularized by Coope DeRenne and Tom
House in "Power Baseball". Very underrated publication, but one of
my all-time personal favorite books for player development.
In youth leagues, given the disparity in sizes of kids, it seems
silly for all kids to use the same size bat. The bigger, stronger
kids are using the same 30in/19 oz bats as the smaller, quicker kids.
The bats in many of the big kids hands just look like toothpicks and
many times the swing is done before the pitch arrives, they seem to
overpower the bat size.
A. Terry Bahill posted the following study re: bat selection.
http://tucson.sie.arizona.edu/sysengr/talks/ideal.html
Ideal Bat Weight:TM
Engineering the Sport of Baseball
A. Terry Bahill
Systems and Industrial Engineering
PO Box 210020
University of Arizona
Tucson, AZ 85721-0020, USA
terry@...
© 1998 Bahill
Baseball players swung very light and very heavy bats through our
instrument (called the Bat ChooserTM) and we recorded the speed of
the center of mass of the bat. These data were used to make
mathematical models for each individual human. These models were
then coupled to the equations of physics for bat-ball collisions to
compute the Ideal Bat Weight for each individual baseball player. We
measured 28 members of the San Francisco Giants baseball team and
found that 80% of them were using bats in their correct range. But
10% were using bats that were too light for them, and 10% were using
bats that were too heavy for them. However, only 25% of the 200 less
experienced baseball players that we studied, e.g. Little Leaguers,
were using bats in their correct range.
The force-velocity relationships of some of our subjects were best
modeled with hyperbolic equations. However, for others a straight
line provided the best fit. We divided our subjects into two
groups: "quick" people with large slopes that are fit best with Hill-
type hyperbolas, and others with flatter data that are fit best with
straight lines. He hypothesize that some people have rigid
unchanging control strategies, they swing all bats the same. Whereas
quick people adapt well and change their control strategies to take
advantage of the varying bat weights.
We developed a more complex model for the swing of the baseball bat
that entails one translation and two rotations. We also constructed
a set of bats where each bat had the same mass but a different
inertia. With our new model and bats we can determine the best shape
of the baseball bat for individual players.
But so far all of these recommendations depend on the ball player
using the Bat Chooser in Tucson. At the finale of this talk I will
present rules of thumb that anyone can use to estimate his or her
optimal bat weight.
References [43, 45 and 50]. I can adapt this lecture to make it
suitable for engineers or the general public. This talk requires an
overhead projector, a VHS video tape player and a 35mm Carousel
slide projector. This talk takes one hour.
Ideal Bat WeightTM and Bat ChooserTM are trade marks of Bahill
Intelligent Computer Systems (BICS), 1622 W. Montenegro, Tucson, AZ,
85704-1822.
and this article from the Arizona Daily Wildcat:
http://wildcat.arizona.edu/papers/93/109/01_2_m.html
UA professor examines science of baseball
Arizona Daily Wildcat
Photo by: GAVIN STEVENS
UA professor Terry Bahill takes a swing through his "bat-chooser"
machine Monday afternoon in an engineering lab. The machine
calculates the batter's swing speed and helps players to find the
most effective bat weight.
By Blake Smith
Arizona Daily Wildcat,
March 1, 2000 Talk about this story
Many professional baseball players have long contended that hitting
home runs is as much of a science as a physical skill.
Now, a University of Arizona professor has found a way for baseball
players to hit more of them.
UA systems and industrial engineering professor Terry Bahill has
examined the physical aspects of baseball, from the way batters
perceive pitches to how the weight of the bat can drastically affect
the speed of a ball.
Bahill found that a pitch is naturally broken into thirds by a
batter. The first part of the pitch is sensory gathering, the second
is computing how fast the ball is traveling and when to swing, and
the third is the actual swing.
Batters often complain that a fastball "jumps" as it crosses the
plate, causing them to swing under the ball, but Bahill contends
that defies the laws of physics.
"When the batter starts to swing, he takes his eyes off the ball to
look at the predicted bat-ball collision point," he stated in a news
release. "When the ball comes back into his view, it is higher than
his mental model predicted, and he sees it 'jump' higher than where
he calculated that it would be."
Bahill contends the way to solve the problem is not to change the
psychological process of the batter, but to change the weight of the
bat.
"We're talking about momentum here," he said, while showing off the
collection of weighted bats in his laboratory.
Bahill said his main objective has been to determine how the weight
of a bat affects the speed of bat-to-ball contact.
Bahill operates a "bat chooser" machine in his engineering lab.
The simple machine consists of two bars. The lower bar has two laser
beams set at a standard distance apart from each other, while a
string dangles from the upper bar.
The player swings through the machine, attempting to hit the string.
A computer attached to the laser beams records the time it takes for
the bat to travel from one laser beam to the other and calculates
the swing speed.
Different weights of bats are used by the batter, and then, a graph
is created to find a balance between greatest bat weight and fastest
swing speed, Bahill said.
For instance, a player can hit a ball with a whiffleball stick - low
weight, but fast speed - and never hit a home run. On the other
hand, when hitting a ball with a bat made of solid lead, the weight
of the bat would be great and the swing speed would be hampered
drastically, Bahill said.
The purpose of the bat chooser machine is to find the best bat for
each individual hitter, he added.
Bahill also studied the advantages of aluminum bats over wooden
bats.
A misconception is that aluminum bats generate higher bat-to-ball
speeds, which could endanger the safety of a pitcher, Bahill said.
He disproved the theory by looking at basic tendencies of baseball
players.
"To go from an aluminum bat of one length to a wooden bat of the
same length, the weight of the bat will have to increase," Bahill
added.
Bat speed then decreases because of the increased weight. That
increased weight overcomes the speed deficit, giving the ball more
momentum. Hence, the ball travels faster to the pitcher.
Bahill is now examining the effects of an end-loaded bat - with
weight shifted from the mid-section of the bat to the end - on a
batter's bat-to-ball collision speed.
The theory is that momentum will increase because of the weighted
end, causing the batter to hit the ball with greater force, Bahill
said.
Since 1987, Bahill has worked with the UA softball team to help them
determine the best bat weight for each player.
"I recommended that they use 25 ounce bats, but the lightest bats
they had were 31 ounces. I checked back with them a few years later
and come to find out they had 26 ounce bats," he said.
UA softball player Nicole Giordano used Bahill's "bat chooser"
machine last semester.
"What he recommended helped some," said Giordano, a junior
centerfielder. "I'm getting more distance on the ball this year, but
I think it's more mental and not so much the bat."
This spring, Bahill hopes to test his findings on Chicago White Sox
first baseman Frank Thomas. Thomas is not his first choice, however.
"Mark McGwire would be ideal," he said.
According to Bahill, the St. Louis Cardinals' first baseman is
interested in the science of baseball but fears that altering his
bat weight - and in turn his swing speed - might change his record-
high home run production.
Currently, Bahill is beginning a study on the vibrations of a bat
after making contact with the baseball.
To this point, his studies have focused on how to make the hitter
better. Now, he will look at how to make the bat better.
While Bahill studies all aspects of baseball in the lab, he said the
only time he watches the sport is when his children have it on the
television.
"I'm not a baseball fan," he said. "I'm just trying to figure out
the science behind it."
From Professor Bahill's work, Worth Sports came up with it's Bat
Guide for baseball/Softball players. This one you'll have to click
on yourself as it does not tranfer well. The formulas to determine
the best bat weight are shown below.
http://www.worthsports.com/aboutworth/batguide.html
WORTHSPORTS.COM: BAT GUIDE
Worth conducted a project with a University of Arizona research
group to determine the best bat weight for players in youth league
and adult baseball, and slowpitch and fastpitch softball. The
research included precise measurement of bat speed for numerous
individuals in each category. Measured bat speeds were then used in
conservations of momentum calculation to determine hit ball speed.
Formulas were then developed to predict the optimum or best bat
weight for maximum hit ball speed in each category. It should be
noted that for baseball and fastpitch softball ball weights, the
ideal bat weight for maximum hit ball speed is approximately 1 ounce
heavier than the standard recommendation. The research showed there
is negligible loss of hit ball speed by reducing the bat weight 1
ounce below the ideal. Because of this, the lighter weight increases
bat control which becomes an essential ingredient in making ball
contact in both baseball and fastpitch softball.
In three of the categories, the experimental data correlated best to
player weight while in the other two, the best correlation was to
player height.
BEST BAT WEIGHTS:
A. High School & College Baseball Formula: Height/3 + 5
B. Youth League Baseball (11-12 yrs) Formula: Weight/18 + 14
C. Youth League Baseball (8-10 yr. olds) Formula: Height/4 + 14
D. Fastpitch Softball (Women) Formula: Weight/15 + 17
E. Slowpitch Softball (Men and Women) Formula: Weight/19 + 17
2 comments:
Do you have an update to "Choosing the Right Bat" and the "Bat Guide" itself?
The Bat Guide seems out of whack, especially for the 8-10 year old range. Do the computation yourself. They suggest my 11 year old use a 21 ounce bat, but my 10 year old use a 28 ounce bat.
Lastly, the link to WorthSports.com does not work.
Do you have an update to "Choosing the Right Bat" and the "Bat Guide" itself?
The Bat Guide seems out of whack, especially for the 8-10 year old range. Do the computation yourself. They suggest my 11 year old use a 21 ounce bat, but my 10 year old use a 28 ounce bat.
Lastly, the link to WorthSports.com does not work.
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