Golf
When
it comes to improving your golf game, you can spend thousands of
dollars buying the latest titanium-induced, Tiger-promoted golf clubs;
taking private lessons from the local "I used to be on the Tour" pro;
or trying every slice-correcting, swing-speed-estimating,
GPS-distance-guessing gadget. But, in the end, it’s about getting that
little white sphere to go where you intended it to go. Don't worry,
there are many very smart people trying to help you by designing the
ultimate golf ball. Of course, they are also after a slice of this
billion dollar industry, as any technological advancement that can grab
a few more market share points is worth the investment.
In
fact, the golf ball wars can get nasty. Earlier this month, Callaway
Golf won a court order permanently halting sales of the industry's
leading ball, Titleist's Pro V1, arguing patent infringements involving
its solid core technology which Callaway acquired when it bought
Spaulding/Top Flite in 2003. Titleist disagrees with the decision and
will appeal, but in the meantime has altered its manufacturing process
so that the patents in question are not used.
The
challenge for golf ball manufacturers is to design a better performing
ball within the constraints set by United States Golf Association. The
USGA enforces limits on the size, weight and initial performance
characteristics in an attempt to keep the playing field somewhat level.
Every "sanctioned" golf ball must weigh less than 1.62 ounces with a
diameter smaller than 1.68 inches. It also must have a similar initial
velocity when hit with a metal striker, and rebound at the same angle
and speed when hit against a metal block. So, what is left to tinker
with? Manufacturers have focused on the internal materials in the ball
and its cover design.
Today's
balls have 2, 3 or 4 layers of different internal polymer materials to
be able to respond differently when hit with a driver versus, say, a
wedge. When hit with a driver at much higher swing speed, the energy
transfer goes all the way to the core by compressing ball, reducing
backspin. During a slower swing with a club that has more angle loft,
the energy stays closer to the surface of the ball and allows the
grooves of the club to grab onto the ball's cover producing more spin.
When driving the ball off of the tee, the preference is more distance
and less loft, so a lower backspin is required. For closer shots, more
backspin and control are needed.
The Science of Dimples
Which
brings us to the cover of the ball and all of the design possibilities.
Two forces affect the flight and distance of flying spheres, gravity
and aerodynamics. Eventually, gravity wins once the momentum of the
ball is slowed by the aerodynamic drag. Since all golf clubs have some
angular loft to their clubface, the struck ball will have backspin. As
explained by the Magnus Force effect, the air pressure will be lower on
the top of the ball since that side is moving slower relative to the
air around it. This creates lift as the ball will go in the direction
of the lower air pressure. Counteracting this lift is the friction or
drag the ball experiences while flying through the air.
Think about a boat moving through
water. At the front of the boat, the water moves smoothly around the
sides of the boat, but eventually separates from the boat on the back
side. This leaves behind a turbulent wake where the water is agitated
and creates a lower pressure area. The larger the wake, the more drag
is created. A ball in flight has the same properties.
The
secret then is how to reduce this wake behind the ball. Enter the
infamous golf ball dimples. Dimples on a golf ball create a thin
turbulent boundary layer of air molecules that sticks to the ball's
contour longer than on a smooth ball. This allows the flowing air to
follow the ball's surface farther around the back of the ball, which
decreases the size of the wake. In fact, research has shown that a
dimpled ball travels about twice as far as a smooth ball.
So,
the design competition comes down to perfecting the dimple, since not
all dimples are created equal! The number, size and shape can have a
dramatic impact on performance. Typically, today's balls have 300-500
spherically shaped dimples, each with a depth of about .010 inch.
However, varying just the depth by .001 inch can have dramatic effects
on the ball's flight.
Regarding shape, these traditional round dimple patterns cover up to 86
percent of the surface of the golf ball. To create better coverage,
Callaway Golf's HX ball uses hexagon shaped dimples that can create a
denser lattice of dimples leaving fewer flat spots. Creating just the
right design has traditionally been a trial-and-error process of
creating a prototype then testing in a wind tunnel. This time-consuming
process does not allow for the extreme fine-tuning of the variables.
Simulation Solution
At
the 61st Meeting of the American Physical Society's Division of Fluid
Dynamics last month in San Antonio, a team of researchers from Arizona
State University and the University of Maryland is reporting new
findings that may soon give golf ball manufacturers a more efficient
method of testing their designs. Their research takes a different
approach, using mathematical equations that model the physics of a golf
ball in flight. ASU's Clinton Smith, a Ph.D. student and his advisor
Kyle Squires collaborated with Nikolaos Beratlis and Elias Balaras at
the University of Maryland and Masaya Tsunoda of Sumitomo Rubber
Industries, Ltd. The team has been developing highly efficient
algorithms and software to solve these equations on parallel
supercomputers, which can reduce the simulation time from years to
hours.
Now
that the model and process is in place, the next step is to begin the
quest for the ultimate dimple. In the meantime, when someone asks you,
"What's your handicap?" you can confidently tell them, "Well, my golf
ball's design does not optimize its drag coefficient which results in a
lower loft and spin rate from its poor aerodynamics."
Related Articles on Sports Are 80 Percent Mental:
Putt With Your Brain - Part 2
From: Sports Are 80 Percent Mental
If there is a poster child sport for our favorite phrase, "Sports Are 80 Percent Mental",
it must be golf. Maybe its the slow pace of play that gives us plenty
of time to think between shots. Maybe its the "on stage" performance
feeling we get when we step up to that first tee in front of our
friends (or strangers!) Maybe its the "high" of an amazing approach
shot that lands 3 feet from the cup followed by the "low" of missing
the birdie putt.
From any angle, a golf course is the sport
psychologist's laboratory to study the mix of emotions, confidence,
skill execution and internal cognitive processes that are needed to
avoid buying rounds at the 19th hole. Last time, we looked at some of
the recent research on putting mechanics, but, as promised, we now turn to the mental side of putting.
Sian Beilock and her team at the University of Chicago's Human Performance Lab
recently released the latest of a string of research studies on sports
performance, or more specifically, how not to choke under pressure.
Lucky for us, they chose putting as their sport skill of choice. This
ties in with Dr. Beilock's theory of embodied cognition that we
featured in Watching Sports Is Good For Your Brain.
An underlying theme to this work is the concept of automaticity,
or the ability to carry out sport skills without consciously thinking
about them. Performing below expectations (i.e. choking) starts when we
allow our minds to step out of this automatic mode and start thinking
about the steps to our putting stroke and all of those "swing thoughts"
that come with it ("keep your elbows in", "head down", "straight
back").
Our brain over analyzes and second-guesses the motor skills we
have learned from hundreds of practice putts. Previously, we looked at automaticity in other sports.
Of course, a key distinction to the definition of choking is that you
are playing "well below expectations". If you normally shoot par, but
now start missing easy putts, then there may be distractions that are
taking you out of your normal flow. Choking implies a temporary and
abnormal event. Automaticity theory would claim that it is these
distractions from some perceived pressure to perform that are affecting
your game.
Most research into sport skill performance divides the world into two
groups, novices and experts. Most sports have their own measures of
where the dividing line is between these groups. Expertise would imply
performance results not just experience. So, a golfer who has been
hacking away for 20 years but still can't break 100 would still be put
in the "novice" category.
Sport scientists design experiments that
compare performance between the groups given some variables, and then
hypothesize on the reason for the observed differences. Beilock, et al
have looked at golf putting from several different angles over the
years. Their research builds on itself, so let's review in reverse
chronological order.
Back in 2001, they began by comparing the two competing theories
of choking, distraction theory vs. explicit monitoring theory, and
designed a putting experiment to find the better explanation.
Distraction theory explains choking by assuming that the task of
putting requires your direct attention and that high pressure
situations will cause you to perform dual tasks - focus on your putting
but also think about the pressure. This theory assumes there is no
automaticity in skill learning and that we have to focus our attention
on the skill every time.
Explicit monitoring theory claims that over
time, as we practice a skill to the point of becoming an "expert", we
proceduralize the task so that it becomes "automatic". Then, during a
high pressure situation, our brain becomes so concerned about
performance that it takes us out of automatic mode and tries to focus
on each step of the task. The research supported the explicit
monitoring theory as it was shown that the golf putting task was
affected by distractions and pressure for the experts but not the
novice putters.
So, how do we block out the pressure, so that our automaticity can kick in? Another 2001 study by Beilock
looked at mental imagery during putting. Using the same explicit
monitoring theory, should we try to think positive thoughts, like "this
ball is going in the hole" or "I have made this putt many times"? Also,
what happens if a stray negative thought, "don't miss this one!" enters
our brain? Should we try to suppress it and replace it with happy
self-talk?
She set up four groups, one receiving positive comments, one
receiving negative comments, one receiving negative comments followed
by positive comments and one receiving none as a control group. As
expected, the happy people did improve their putting over the course of
the trials, while the negative imagery hurt performance.
But, the
negative replaced with positive thought group did not show any more
improvement over the control group. So, when faced with a high
pressure, stressful situation ripe with the possibilities of choking,
try to repeat positive thoughts, but don't worry too much if the
occasional doubt creeps in.
Our strategy towards putting should also vary depending on our current
skill level. While learning the intricacies of putting, novices should
use different methods than experts, according to a 2004 study by Beilock, et al.
Novice golfers need to pay attention to the step by step components of
their swing, and they perform better when they do focus on the
declarative knowledge required.
Expert golfers, however, have practiced
their swing or putt so often that it has become "second nature" to the
point that if they are told to focus on the individual components of
their swing, they perform poorly. The experiment asked both novices and
expert golfers to first focus on their actual putting stroke by saying
the word "straight" when hitting the ball and to notice the alignment
of the putter face with the ball.
Next, they were asked to putt while
also listening for a certain tone played in the background. When they
heard the tone they were to call it out while putting. The first
scenario, known as "skill-focused", caused the novices to putt more
accurately but the experts to struggle. The second scenario, called
"dual-task", distracted the novices enough to affect their putts, while
the experts were not bothered and their putting accuracy was better.
Beilock showed that novices need the task focus to succeed while they
are learning to putt, while experts have internalized the putting
stroke so that even when asked to do two things, the putting stroke can
be put on "auto-pilot".
Finally, in 2008, Beilock's team added one more twist
to this debate. Does a stress factor even affect a golfer's performance
in their mind before they putt? This time, golfers, divided into the
usual novice and expert groups, were asked to first imagine or "image
execute" themselves making a putt followed by an actual putt. The
stress factor was to perform one trial under a normal, "take all the
time you need" time scenario and then another under a speeded or
time-limited scenario.
The novices performed better under the
non-hurried scenario in imagining the putt first followed by the actual
putt. The experts, however, actually did better in the hurried scenario
and worse in the relaxed setting. Again, the automaticity factor
explains the differences between the groups.
The bottom line throughout all of these studies is that if you're
learning to play golf, which includes putting, you should focus on your
swing/stroke but beware of the distractions which will take away your
concentration. That seems pretty logical, but for those that normally
putt very well, if you feel stress to sink that birdie putt, don't try
to focus in on the mechanics of your stroke. Trust the years of
experience that has taught your brain the combination of sensorimotor
skills of putting.
Just remember the Chevy Chase/Ty Webb philosophy;
"I'm going to give you a little advice. There's a force in the universe
that makes things happen. And all you have to do is get in touch with
it, stop thinking, let things happen, and be the ball.... Nah-na-na-na,
Ma-na-na-na...."
Sian L. Beilock, Thomas H. Carr (2001). On the fragility of skilled performance: What governs choking under pressure? Journal of Experimental Psychology: General, 130 (4), 701-725 DOI: 10.1037//0096-3445.130.4.701
Sian
L. Beilock; James A. Afremow; Amy L. Rabe; Thomas H. Carr (2001).
"Don't Miss!" The Debilitating Effects of Suppressive Imagery on Golf
Putting Performance Journal of Sport and Exercise Psychology, 23 (3)
Beilock
S.L.; Bertenthal B.I.; McCoy A.M.; Carr T.H. (2004). Haste does not
always make waste: Expertise, direction of attention, and speed versus
accuracy in performing sensorimotor skills Psychonomic Bulletin & Review, 11 (2), 373-379
Sian
Beilock, Sara Gonso (2008). Putting in the mind versus putting on the
green: Expertise, performance time, and the linking of imagery and
action The Quarterly Journal of Experimental Psychology, 61 (6), 920-932 DOI: 10.1080/17470210701625626
From: Sports Are 80 Percent Mental
If
Mark Twain thinks golf is "a good walk spoiled", then putting must be a
brief pause to make you reconsider ever walking again. With about 50%
of our score being determined on the green, we are constantly in search
of the "secret" to getting the little white ball to disappear into the
cup.
Lucky for us, there is no shortage of really smart people also
looking for the answer. The first 8 months of 2008 have been no
exception, with a golf cart full of research papers on just the topic
of putting.
Is the secret in the mechanics of the putt stroke or maybe
the cognitive set-up to the putt or even the golfer's psyche when
stepping up to the ball? This first post will focus on the mechanical
side and then we'll follow-up next time with a look inside the golfer's
mind.
Let's start with a tip that most golf instructors would give, "Keep
your head still when you putt". Jack Nicklaus said it in 1974, "the
premier technical cause of missed putts is head movement" (from "Golf My Way") and Tiger Woods said it in 2001, "Every good putter keeps the head absolutely still from start to finish" (from "How I Play Golf").
Who would argue with the two greatest golfers of all time? His name is Professor Timothy Lee,
from McMaster University, and he wanted to test that observation. So,
he gathered two groups of golfers, amateurs with handicaps of 12-40,
and professionals with scratch handicaps. Using an infrared tracking
system, his team tracked the motion of the putter head and the golfer's
head during sixty putts.
As predicted, the amateurs' head moved back in unison with their putter
head, something Lee calls an "allocentric" movement, which agrees with
the advice that novice golfers move their head. However, the expert
golfers did not keep their head still, but rather moved their heads
slightly in the opposite direction of the putter head.
On the
backswing, the golfer's head moved slightly forward; on the forward
stroke, the head moved slightly backward. This "egocentric" movement
may be the more natural response to maintain a centered, balanced
stance throughout the stroke. "The exact reasons for the opposite
coordination patterns are not entirely clear," explains Lee. "However,
we suspect that the duffers tend to just sway their body with the
motions of the putter.
In contrast, the good golfers probably are
trying to maintain a stable, central body position by counteracting the
destabilization caused by the putter backswing with a forward motion of
the head. The direction of head motion is then reversed when the putter
moves forward to strike the ball." Does that mean that pro golfers like
Tiger are not keeping their heads still? No, just that you may not have to keep your head perfectly still to putt effectively.
So, what if you do have the bad habit of moving your head? Just teach
yourself to change your putting motion and you will be cutting strokes
off of your score, right? Well, not so fast. Simon Jenkins of Leeds Metropolitan University tested 15
members of the PGA European Tour to see if they could break old
physical habits during putting. His team found that players who usually
use shoulder movement in their putting action were not able to change
their ways even when instructed to use a different motion. Old habits
die hard.
Let's say you do keep your head still (nice job!), but you still 3-putt
most greens? What's the next step on the road to birdie putts? Of the
three main components of a putt, (angle of the face of the putter head
on contact, putting stroke path and the impact point on the putter),
which has the greatest effect on success?
Back in February, Jon Karlsen of the Norwegian School of Sport Sciences
in Oslo, asked 71 elite golfers (mean handicap of 1.8) to make a total
of 1301 putts (why not just 1300?) from about 12 feet to find out. His
results showed that face angle was the most important (80%), followed
by putter path (17%) and impact point (3%).
OK, forget the moving head thing and work on your putter blade angle at
contact and you will be taking honors at every tee. Wait, Jon Karlsen
came back in July with an update.
This time he compared green reading, putting technique and green
surface inconsistencies to see which of those variables we should
discuss with our golf pro. Forty-three expert golfers putted 50 times
from varying distances. Results showed that green reading (60%) was the
most dominant factor for success with technique (34%) and green
inconsistency (6%) trailing significantly.
So, after reading all of this, all you really need is something like the BreakMaster,
which will help you read the breaks and the slope to the hole! Then,
keep the putter blade square to the ball and don't move your head, at
least not in an allocentric way, that is if you can break your bad
habit of doing it. No problem, right? Well, next time we'll talk about
your brain's attitude towards putting and all the ways your putt could
go wrong before you even hit it!
Timothy
D. Lee, Tadao Ishikura, Stefan Kegel, Dave Gonzalez, Steven Passmore
(2008). Head–Putter Coordination Patterns in Expert and Less Skilled
Golfers Journal of Motor Behavior, 40 (4), 267-272 DOI: 10.3200/JMBR.40.4.267-272
Jenkins, Simon (2008). Can Elite Tournament Professional Golfers Prevent Habitual Actions in Their Putting Actions? International Journal of Sports Science & Coaching, 3 (1), 117-127
Jon
Karlsen, Gerald Smith, Johnny Nilsson (2007). The stroke has only a
minor influence on direction consistency in golf putting among elite
players Journal of Sports Sciences, 26 (3), 243-250 DOI: 10.1080/02640410701530902
Sports Are 80 Percent Mental
Here are some quotes we have all heard (or said ourselves) on the golf course or at the ball diamond.
On a good day:
"It was like putting into the Grand Canyon"
"The baseball looked like a beach ball up there today"
On a bad day:
"The hole was as small as a thimble"
"I don't know, it looked like he was throwing marbles"
The
baseball and the golf hole are the same size every day, so are these
comments meaningless or do we really perceive these objects differently
depending on the day's performance? And, does our performance
influence our perception or does our perception help our performance?
Jessica Witt,
an assistant professor of psychological science at the University of
Virginia has made two attempts at the answer. First, in a 2005 study, "See the Ball, Hit the Ball",
her team studied softball players by designing an experiment that tried
to correlate perceived softball size to performance. She interviewed
players immediately after a game and asked them to estimate the size of
the softball by picking a circle off of a board that contained several
different sizes. She then found out how that player had done at the
plate that day. As expected, the players that were hitting well chose
the larger sized circles to represent the ball size, while the
underperforming hitters chose the smaller circles. The team was not
able to answer the question of causality, so they expanded the research
to other sports.
Fast forward to July, 2008 and Witt and her team have just released a very similar study focused on golf, "Putting to a bigger hole: Golf performance relates to perceived size".
Using the same experiment format, players who had just finished a round
of golf were asked to pick out the perceived size of the hole from a
collection of holes that varied in diameter by a few centimeters. Once
again, the players who had scored well that day picked the larger holes
and vice versa for that day's hackers. So, the team came to the same
conclusion that there is some relationship between perception and
performance, but could not figure out the direction of the effect.
Ideally, a player could "imagine" a larger hole and then play better
because of that visual cue.
Researchers at Vanderbilt University may have the answer. In a study, "The Functional Impact of Mental Imagery on Conscious Perception", the team led by Joel Pearson,
wanted to see what influence our "Mind's Eye" has on our actual
perception. In their experiment, they asked volunteers to imagine
simple patterns of vertical or horizontal stripes. Then, they showed
each person a pattern of green horizontal stripes in one eye and red
vertical stripes in the other eye. This would induce what is known as
the "binocular rivalry" condition where each image would fight for
control of perception and would appear to alternate from one to the
other. In this experiment, however, the subjects reported seeing the
image they had first imagined more often. So, if they had imagined
vertical stripes originally, they would report seeing the red vertical
stripes predominantly.
The team concluded that mental
imagery does have an influence over what is later seen. They also
believe that the brain actually processes imagined mental images the
same way it handles actual scenes. "More recently, with advances in
human brain imaging, we now know that when you imagine something parts
of the visual brain do light up and you see activity there," Pearson
says. "So there's more and more evidence suggesting that there is a
huge overlap between mental imagery and seeing the same thing. Our work
shows that not only are imagery and vision related, but imagery
directly influences what we see."
So, back to our
sports example, if we were able to imagine a large golf hole or a huge
baseball, this might affect our actual perception of the real thing and
increase our performance. This link has not been tested, but its a
step in the right direction. Another open question is the effect that
our emotions and confidence have on our perceived task. That hole may
look like the Grand Canyon, but the sand trap might look like the
Sahara Desert!
Witt, J.K. (2008). Putting to a bigger hole: golf performance relates to perceived size. Psychonomic Bulletin & Review, 15(3), 581-585.
