Ben Hogan, Lee Comeaux, and the Right Hand Hit
-- November 27, 2010
Ben Hogan advocated hitting with
the right hand (even both hands) at impact. Recently, Texas instructor
Lee Comeaux has been teaching his students a "right-hand slap", which
seems very Hogan-esque. One of his students, who has seen marked
improvement in his distance, asked me to investigate the physical
basis of the improvement. My brief study concludes that it's not what
the proponents believe, and the extra distance might not have any
explanation in simple physics. Hitting with the hands at
impact produces no additional clubhead speed -- none.
That might not prevent it from being effective instruction,
A Little Background
Before I start, let me apologize to my left-handed readers. Hogan and
Comeaux use 'right' and 'left' in describing a right-handed swing. I
will follow suit. You lefties will have to mentally transpose. (It's
not that I don't sympathize; my own son is left-handed. But trying to
accommodate it in the wording gets very clumsy.)
Hogan and Comeaux
Hogan made no
bones about it! He believed in hitting the ball with
the hands at the point of impact. Quoting from his classic book "Five Lessons: The Modern
Fundamentals of Golf":
study the correct
motion of the right arm and hand in the impact area....
a full shot you
want to hit the ball as hard as you can with your
right hand. But this is only half the story. HIT THE BALL AS HARD AS
YOU CAN WITH BOTH HANDS. The left is a power hand also. If you hit hard
with only the right and let the left go to sleep, you will not only
lose much valuable power, you also will run into all the errors that
result when the right hand overpowers the left."
About a month ago (early November 2010), I got email
from Doug "Rock"
Burke, telling me about Leecommotion, his name for the swing
by Lee Comeaux. Lee is a teaching pro, and he teaches a motion that he
calls a "shovel move"
or "right hand slap". You can see a video of his swing on YouTube by
clicking on the thumbnail to the right.
Rock is a low-handicap golfer who reports that the Leecommotion has
increased his distance significantly. "I have picked up 30 yards on my
drives and 1 club on my irons. It feels a lot more effortless also."
It wasn't a trivial change; he
practiced it for weeks before he got better. At the time of this
writing, he has been at it for 12 weeks, still practicing, and feels it
has made a major improvement in his game.
My initial impression of Leecommotion is that its essence is the
right-hand hit in the impact area, and Rock and I agreed that I should
start by studying that. It
turns out to be a lot more than that, and
I'll do a separate study for "the whole package". But it is worth
mentioning in this study, since Hogan's book is not the only school of
thought that feels hand action near impact will increase clubhead speed.
Rock asked me to
explain the benefit in terms of physics. It's one thing to make an
improvement; it's quite another to understand why -- and Rock wanted to
understand why. This article applies more to Hogan's "hit the ball hard
with both hands" Than to Comeaux's "right hand slap", but was mostly
motivated by Rock's question.
Golf Swing Physics
we go on to analyze the slap swing, let's review what we know about the
physics of the swing. The illustrations are taken from my tutorial article on
golf physics. For more detail than is given in that article, see Rod White's article.
For more detail on the mathematical model used to analyze the swing,
see my article on the
golf swing is analyzed by physicists as a double pendulum. The inner
member of the double pendulum is the triangle of the shoulders and the
two arms (green
in the diagrams). The outer member is the club itself (black
in the diagrams). The variables in the analysis are the lengths of the
two arms, and the forces on them. Well, not exactly forces; they are
turning forces, more precisely known as "torques".
(1) The body rotation exerts a torque on the shoulders, which turns the
shoulders and arms.
(2) The forearms, wrists, and hands might exert a torque on the club
via the grip.
If you are not
certain you understand the model, its applicability is discussed in more detail
in another of my articles. In particular, you may be concerned that the
role of the hips or the right arm might not be properly modeled if this
is my tool for analysis. You would be right to be concerned. But
whether that concern will doom the analysis is a different story. So
understand that article before you dismiss the results out of hand.
The most notable of the analyses using the double pendulum model is
that by Ted Jorgensen ("The Physics of Golf").
He, and just about every other engineer or physicist who has studied
the swing, has concluded
that the basic efficient swing is one that depends completely on body
rotation (shoulder torque), and lets the wrists hinge freely (that is, zero wrist torque).
In other words, you get a very efficient swing from turning the body
allowing the inertial forces on the club to cause the release. (Those
inertial forces are usually referred to as centrifugal force. This is a
vague and undisciplined use of the language, but we'll stick with it
unless the distinction needs to be made for pragmatic reasons.)
Hitting with the hands constitutes the
addition of wrist torque late in the
downswing. This is the basis of our physical analysis of the Hogan and
What It Might do
I used three distinct approaches to determining the value of adding
wrist torque late in the downswing:
- Stand on the
shoulders of giants. Specifically, see what people
concluded who had seriously looked at the problem before.
- Try it myself.
Of course, this will only be anecdotal -- hardly a controlled
scientific experiment. But it will give me a feel for how the swing
works, an insight into the analytic results,
and ideas for what to try next.
- Do the math.
I used a computer program that simulates the swing, where the torque
profiles can be varied over the downswing.
Shoulders Of Giants
I admit that I started this investigation with a lot of skepticism
because I had read what several "giants" had to say about it.
So we have found
a general consensus among those who have investigated
- Let's start with Rod White's analysis. He devotes a
subchapter to what happens if you add wrist torque to the
standard swing. The graph he presents is unequivocal. Positive wrist
torque (torque to uncock the wrists) results in less distance, not
more. It may seem paradoxical, but that's what physics says. It is
worth noting that negative wrist torque (to hold the wrist cock angle)
results in more
clubhead speed and more distance.
- Tom Wishon has been the Chief Technical Officer of
Golfsmith, and now has his own golf club component company. His company
is recognized as an innovator, and he is the world's foremost advocate
custom fitted golf clubs. In his book "Common
Sense Clubfitting" (chapter five on shaft
fitting), he writes:
condition of the shaft being slightly bent backward with the head
lagging behind the shaft is very rare in the game. This is because the
swing skill plus strength that is required to maintain radial
acceleration and the wrist-cock angle until very late in the downswing
is such that very, very, VERY few golfers can do this. Far more common
are the conditions in which the shaft arrives at impact either straight
or slightly bent/curved forward with the head in front of the forward
curve of the shaft."
In other words, it takes more athletic ability than almost anybody
possesses to apply a positive wrist torque late enough in the swing to
be helpful. (If I may add my own opinion, not Wishon's words: It
strength; it's also speed. Late in the swing, centrifugal
whipping the clubhead toward impact. The wrist-cock angle is being
dragged out very fast, so it takes a lot of hand speed to even keep up,
much less help it along.) One other thing he mentions: we can tell if the wrist torque
is negative or positive on the basis of shaft bend.
That is important, and we will come back to it later.
book is a bit more optimistic. In his chapter
4, some of the points he makes are:
Before we move on, let's take a look at why helping
(positive) wrist torque hurts the ultimate clubhead speed, while
(negative) torque increases clubhead speed. Here are three "strobe
view" simulations of the swing for us to compare. When viewing them,
bear in mind that the release is powered, at least in part, by
centrifugal force -- and centrifugal clubhead acceleration depends on:
strong shoulder turn increases clubhead speed. (The model does not say
whether the turn should be a product of the shoulders, the torso, the
hips, the legs,... Just that a strong turn powers the swing well.)
torque that helps release usually winds up hurting clubhead speed at
impact. You may get higher clubhead speeds earlier in the downswing,
speeds don't hit the ball; by the time of impact, the clubhead speed is
lower than with no wrist torque at all.
- Wrist torque that retards or delays
release usually winds up increasing clubhead speed at impact. #2 and #3
are recognized as paradoxical, but they work time and time again on the
computer -- and also on the driving range.
- When it comes to a
"pulse" of helping torque just before impact, there is no consensus.
Jorgensen found there is some small advantage to be gained. Wishon
believes it is nearly impossible for a real, live human being to
achieve that gain. And White didn't even look at the question. (We will
look at it
a bit later.)
Of course, body rotation is faster later in the downswing. So we can
the best acceleration from centrifugal force if we hold the wrist cock
angle until late in the downswing when fast rotation does the most
look at the pictures:
speed. The faster the golfer rotates, the more the force.
- Wrist cock
angle. The more
acute the wrist cock angle, the more the centrifugal force is
contributing to clubhead speed, by throwing the club outward.
Conversely, the more the wrist cock is already released, the
less the clubhead can be thrown outward (accelerated) by centrifugal
(The pictures were generated by the SwingPerfect
We'll be using it more in a later section.)
wrist torque (the "standard swing")
- Release is driven only by centrifugal force in this
- Maximum acceleration is 60msec before impact. (The
red-dot clubhead is the point of maximum acceleration.)
(helping) wrist torque
- Maximum acceleration is early, 80msec before impact.
- Very little wrist cock is left late in the downswing,
stealing centrifugal acceleration.
- The clubhead positions are closer together at impact,
indicating less clubhead speed.
(retarding) wrist torque
- Maximum acceleration is late, only 40msec before
- Wrists stay cocked late into the downswing,
encouraging centrifugal acceleration.
- The clubhead positions are farther apart, indicating
more clubhead speed.
interesting observation: Jorgensen found that "late wrist torque"
should be applied to a "standard swing" beginning "seven hundredths of
a second" (70msec) before impact, and continuing through impact. That
corresponds almost exactly to the point of maximum acceleration. So his
conclusion might be restated, "As long as inertial acceleration is
increasing, don't mess with it. Once it starts to fall off, you might
help it along with wrist torque." That actually makes sense!
I took it to the practice field and then the course.
It integrated more quickly and easily than I expected. I've been using
it for a couple of weeks, and every round is the same experience. I hit
a bunch of really bad shots early in the round, then find my [new?]
swing and hit some very good shots. Some shots are significantly
longer than I am used to; I have to believe the new swing has
something to do with it.
Specific things I have observed while integrating a push/slap.
round I have played since adopting the motion has included at least one
shot that I didn't know I had in me. So it is doing something good. As
noted before, this report is anecdotal, not scientific. But it is
encouraging, and adds some urgency to find out why it works.
is not a silver bullet. It only works if my fundamental swing is sound.
faults in the basic swing seem to be magnified by the slap.
the slap is introduced early, some very bad results occur. The most
common and worst result is a seriously left hit. The ball flight
indicates a closed face. This makes some sense, since the slap includes
a rotation of the club. Early slap means early rotation, which means
rotated past square at impact.
- Even many of the good impacts were pulls or even
pull-hooks. That means a closed face at impact.
- I started by thinking of it as a
slap or throw with the right hand. Lee Comeaux has a video that
describes the move as, "Right hand closest to the body starting the
downswing. Right hand farthest from the body through impact." This was
a reasonable visualization, and did help.
- Practicing with it
for a while, my body was telling me that an energetic straightening of
the right arm was the real driving force behind the motion. A little
thought told me that both motions had the same effect on the double
pendulum model; they added positive wrist torque. (See my article on the double pendulum and the right
arm to see why.)
- Is it physics? We'll
do some modeling and other
investigation to find out why.
it biomechanics or kinesiology? Sometimes a swing
key has no good
explanation in physics, but encourages other good things to happen in
the swing. One example: "Accelerate through the ball." Physics says
that acceleration makes no difference once the clubface reaches the
ball. But experience shows that a body that expects to accelerate
through the ball does a bunch of other things right.
- Is it the
placebo effect -- or, more accurately, the "Hawthorne Effect"? This
ain't just physics; it's human experience. Note
that we need to treat any swing
experiments as human factors experiments, not physics experiments.
Hawthorne effect comes from an experiment by Western Electric
the 1920s, where they changed things like the lighting in the
Hawthorne, Illinois factory
to see what effect it had on productivity. Turns out anything they did
improved productivity. More light? Productivity went up. Less light?
Productivity went up. The fact that they were changing things and
watching results was more important than exactly what it was they were
changing. The "takeaway" for golf: Consistent attention to one thing
-- almost anything, as long as it's not actually detrimental -- is
going to help your golf performance. It's called disciplined practice.
Do The Math
OK, time to do the math. Fortunately, I don't have to do it by hand. I
have Max Dupilka's SwingPerfect
program, which simulates Jorgensen's model of the swing. You can even
control the profile of the torques, varying it over the duration of the
swing -- both shoulder torque and
wrist torque. We are going to use it to see what effect we get from a
helping wrist torque late in the downswing.
is a screenshot of what SwingPerfect looks like on my computer. It
shows both the main window and the controls to set the wrist torque by
20-millisecond intervals during the downswing. There are also controls
for the shoulder torque during the downswing and lots of other physical
parameters: the golf club dimensions and weights, the golfer's relevant
dimensions and weight, and properties of the computation like how
frequently to calculate a new point in the downswing.
OK, let's compute the effect of a swing with no wrist torque until very
late in the downswing; Jorgensen says the last 70 milliseconds helps,
and any earlier hurts. So we will try swings with zero wrist torque
(the "standard swing"), and a few different helping torques for the
last 70msec and the last 110msec. The torques we will try are:
for the use of SwingPerfect
If you're not going to actually do studies using SwingPerfect, then you
can skip this note altogether.
Most studies that are good golf science will be variational studies.
That is, you are not looking for absolute numbers but rather, "What
happens when I change this parameter by that amount?" So want to set it
up before the variations are introduced so that:
- The swing is as realistic as possible for the class of
player you are trying to simulate.
- Small variations in parameters give small variations in the
answers, related only
to your parameter variations and not to any artifact of the way you do
(1) The most important hint is to reduce the time interval to the
the program supports, a half millisecond. This greatly improves the
accuracy, as well as the
stability of the answer in the face of small variations. It will not
give as pretty a display, because the strobes are only a
half-millisecond apart, but the numerical answers are much better.
(2) In the earlier pictures illustrating centrifugal acceleration, I
the swing without "Lateral Acceleration"
(see Physical Parameters, page 3, in the program) to keep the diagram
simple. But a more realistic
swing would have lateral acceleration turned on, and that is how I did
the numerical studies that follow.
For most of the parameters, I used the default values. I changed the
club parameters to reflect how drivers are different in 2010 from what
they were in 1999 when Max wrote the program. I used club length = 45",
head weight = 200g, and shaft weight = 65g. I also made sure the
initial arm angle and wrist cock were 180º and 90º, which is about what
most decent golfers do.
(4) One final note: Jorgensen uses the opposite sense of plus and minus
for wrist torque. SwingPerfect
follows the Jorgensen definition. I chose the "wrong" sense for my
narrative in this article. Mine is "wrong" to do the math, but makes
more sense when talking to golfers who aren't going to look at the
differential equations. So, if you're using SwingPerfect
what I call "positive torque" is minus, and vice versa.
Here is a chart of the results. The entries in the chart are:
- 2 foot-pounds.
Jorgensen used this number, and thought it was quite a lot. I'm not
sure it's so big, but perhaps he's right.
Rod White thought that 10% of the shoulder torque was kind of an upper
limit on the wrist torque a golfer could apply. I tend to agree. The
shoulder torque for SwingPerfect is 57 foot-pounds, and 10% of that is
- 12 foot-pounds.
Suppose the golfer were actually able to convert all the shoulder
torque into arm-piston force (instead of triangle-turning force). This
is clearly an upper bound on the wrist torque,
and unrealistically high. But let's compute it just to see
happen. I used a shoulder width of 24" (exactly 2
feet) and a maximum distance between the hand pressure points (using a
10-finger grip) of 5". 57 ft-lb divided by 2ft gives 28.5 pounds of
force in the arm piston. Applied over a 5" grip spread, this is 12
foot-pounds of torque.
- Clubhead speed, in mph. (Black on white)
- Clubhead speed compared to standard swing, in percent. (Red
- Wrist cock angle at impact, in degrees. (Black on yellow)
of helping torque
||Zero wrist torque
|Helping torque starting
70msec before impact
|Helping torque starting
110msec before impact
(Full arm piston)
Before you talk about how much there is to be gained at 12 foot-pounds,
let me remind you that 12 ft-lbs is a theoretical upper bound. You're
going to get anywhere close to this number. It is based on converting
shoulder torque into wrist torque. I went back and used SwingPerfect to
simulate that more accurately; I reduced the shoulder torque to zero
when the wrist torque kicked in. When
you do that, the clubhead speed drops to 97mph, and the wrist is cupped
about 60º at impact. That's a recipe for total disaster;
don't even think about it.
So lets consider the first two rows only, to see what might happen with
added wrist torque.
First clubhead speed:
There's perhaps a couple of miles per hour of clubhead speed to be
gained. That translates into no more than five extra yards -- certainly
not enough to explain the 30-yard gains Rock reports. Not only is the
pretty small, but the slap has to be timed very precisely! If you start
the slap 40msec earlier than you should, you lose the whole gain and
Next wrist cock angle:
The standard swing has a slightly bowed wrist at impact, with 8.8º of
wrist cock angle remaining to be released. As you crank in helping
torque, you decrease the wrist cock angle. If you crank enough wrist
torque to make a noticeable difference in distance, the wrist angle at
impact becomes somewhat cupped. Because this change is due to a
rotation of the forearms, the result is a clubface pointing more to the
pull-hook side than usual. Whether it is a pull-hook or just a pull
depends on what adding the torque does to your clubhead path; that's
swing mechanics that the double pendulum does not address. But there is
no doubt that the ball will
go left of where it would go with the standard swing, unless you do
something else to counteract it. And indeed I experienced that in
I did one more mini-study with SwingPerfect. Because of things
discovered later in this article, I wanted to answer the question:
Suppose the golfer is exercising retarding torque for
most of the
downswing. We know this produces more clubhead speed. But... Would
releasing this negative torque just before impact
increase the clubhead speed further?
This would appear to be reasonable, in light of the numbers above, so
let's check it out:
Cock at impact
(no wrist torque)
|2 ft-lb of negative wrist torque
|2 ft-lb of negative wrist torque,
released to 0 at 70msec
|2 ft-lb of negative wrist torque,
released to 0 at 110msec
tells us that negative wrist torque is a good thing for clubhead speed.
By itself, it gives more than a 5% increase in clubhead speed, enough
for a gain of about 17 yards. We knew it would give us an improvement,
but that's big.
Releasing that negative wrist torque 70
milliseconds before impact buys us a tiny bit more clubhead speed --
but not enough for even one more yard. Definitely not worth learning.
And if you do your release too early, you lose that gain and a lot more.
What It Doesn't Do
So far, we have found out that a right hand
hit or slap is modeled for analysis purposes as a wrist torque
introduced very late in the downswing. If it is applied for the last 70
milliseconds of the downswing, we may see a small increase in clubhead
speed. Not enough for an extra ten yards, but probably a measurable
increase. It must be applied at a precise time; much earlier than 70
msec does more harm than good, and much later just doesn't
is that the mechanism for the increased distance experienced by users
of the right-hand hit? Is there an objective way to find out?
It would almost seem foolish to ask this question. There is no doubt in
the minds of those who swing with a slap that they are pushing the
clubhead through impact. But we cannot dismiss lightly Tom Wishon's
admonition that almost nobody can keep up with the releasing
clubhead well enough to supply additional acceleration to the clubhead
with the hands. So let's see if we can verify that the positive wrist
torque is actually being applied to the grip.
It turns out there is a way to find
out whether the slap actually causes a positive wrist torque. We just
look at shaft bend. But first we have to understand shaft bend.
shaft is a spring that transmits wrist torque from the grip to the
clubhead. If you bend the shaft, it transmits a force to the other end
tries to move the object there. Specifically, it tries to move it in a
direction to straighten the shaft. That's what any spring does -- apply
a force so it can get back to its "resting shape". (Just a reminder: we
are bending the shaft in flex, not around its axis -- what shaft specs
refer to as "torque".)
the downswing, three conditions can prevail: a straight shaft, a shaft
bent backward, and a shaft bent forward. All
three show up at one point or another. Let's look at the three
- If the shaft is straight, that means it is conveying no lateral force
to the clubhead. The hands are not applying a wrist torque to the grip,
neither to accelerate nor decelerated the clubhead. For
swing with freely hinging wrists, the shaft would find itself straight
once the wrist cock angle
"left the stop".
So why is there shaft bend in almost every swing we see, and long after
the wrist cock starts to release? The most important reasons are:
- Not many players keep their wrists as frictionless
hinges. They will exert some torque, whether they are trying or not.
- Because the center of gravity of the clubhead is not
in line with the centerline of the shaft, the centrifugal tug of the
clubhead will bend the shaft a little bit.
- There is certainly bending early in the downswing,
where the "stop" of the standard swing is applying torque. Some
"rebound" from this initial bend may occur. But, if the wrists were
truly hinging, then this effect would be small and short-lived; it
would be long
gone well before impact.
backward - If wrist torque is accelerating the clubhead
toward the ball, then the shaft will be bent backward. That is the only
way that the spring of the shaft can apply a helping force to the
clubhead. Remember, the force will be applied in a direction to
straighten the shaft.
So a shaft bent backward -- the clubhead trailing the grip -- is a sure
indicator of a positive or helping wrist torque.
forward - By the same reasoning, a forward shaft bend
shows a negative, or retarding, wrist torque. Again, the force applied
by the shaft is in the direction to straighten the shaft. The force
applied to the clubhead by a forward-bending shaft is slowing the
release of the clubhead.
A little bit of forward bend in the vicinity of impact may be due to
the clubhead's center of gravity. But that will seldom be as much as an
inch of bend, and most swings have a lot more forward bend than that
coming into impact.
How Right-Hand Slappers Bend The Shaft
This is all very interesting, but how can we use it
to learn about the right-hand slap? Let's
go to the videotape! (Always wanted to say that, even
though these days it's an MPEG file or YouTube page, not a tape at
all.) I have face-on videos of several golfers that purport to do a
right-hand slap, including Lee Comeaux and Ben Hogan. Let's look at
freeze-frames near impact. We'll see how the shaft is bent, and deduce
from that whether they are actually applying a helping torque.
The shaft bend in some -- but not all -- of the following pictures may
be an "optical illusion". Many digital cameras and camcorders suffer
from a photographic distortion that
may exaggerate shaft bend, or even create bend where there isn't any. I
have tried to point out the pictures where this might be a problem. To
understand the problem yourself, read my article on Focal
Plane Distortion.Let's start with some frames of Lee from the video we pointed to earlier.
Lee starts down with the wrists well-cocked.
The backward bend of the shaft at this point of the swing is typical,
represents the "stop" that keeps the wrist cock from collapsing inward.
Here centrifugal force has taken over, and is trying to uncock the
wrists. Lee claims to be doing a right-hand push at this point, but the
shaft bend clearly indicates that the hands are actually opposing the
uncocking, not causing it. (In all likelihood, this picture is not affected by focal plane distortion. It reflects what the shaft is actually doing.)
At this point, the ball is gone. With most swings I've observed, the
shaft would be bent backward, at least near the tip, in reaction to
impact with the ball. The fact that Lee's shaft is still bent well
forward suggests that the clubhead came into impact bent well forward
-- with the clubhead's considerable momentum still pulling the hands
and impact caused only partial recovery. (The forward shaft bend in this picture may well be exaggerated or even caused by focal plane distortion.)
In Hogan's peak years, slow-motion video was not nearly as good as
today. In spite of the ample footage of Hogan available, very little is
of high enough quality to look at shaft bend. But I did find one clip on YouTube good enough to try
to draw some conclusions. Here are a couple of frames from that clip.
Fairly late in the downswing, the bright steel shaft is clearly bent
forward. If Hogan was able to "hit the ball hard with both hands", it
kicked in later than this. Our analysis says that is too late to help
clubhead speed measurably.
It is hard to see the shaft in this frame; remember what I said about
video quality from Hogan's heyday. But, if you can make out the blur
that is the shaft, you can see it is still bent forward. No hand-hit
working here, only a few milliseconds before impact.
|If you want a couple more
pictures of shaft bend, here are two of Lee Comeaux's
students, Rock (left) and Karl. Again, you can see that the shaft is
In Rock's case, the picture was a couple of milliseconds
before impact. Any hand hit he can introduce after this does not have
enough time to change the clubhead speed.
has already hit the ball, though less than 2msec before this frame was
snapped. The shaft was deeply bent forward just before impact. You can
see a "deflection wave" of back-bending starting up the shaft, caused
by impact with the ball, but the shaft was bent forward in the extreme
just before impact. In order to develop a big forward bend
this, the clubhead had to be pulling the hands through release; the
hands could not have been pushing the clubhead.
Both of these
are very good swings, and have a lot of power. Both these golfers
credit Lee Comeaux with adding power to their game. But we see here
that, whatever is causing the improvement, it is not because the right
hand is pushing the clubhead through impact. Physics says that just
is possible that the picture of Rock is affected by focal plane
distortion, though it was taken with a fairly fast camera. The picture
of Karl is almost certainly affected, to the point that it probably
does not tell us anything about whether his hands are applying a
release force to the grip.)
How Top Golfers Bend The ShaftWe
have to be careful about using photography to measure shaft bend. There
is, of course, focal plane distortion; we've already mentioned that. It
is also worth noting that the best measurements of what we are looking
for come with the camera perpendicular to the swing plane. You can draw
reasonable conclusions from less careful face-on views, but for
accurate measurement the position of the camera is important.
there are better ways to measure it. In the 1990s, TrueTemper had an
instrument they called ShaftLab, which measured shaft bend directly.
They attached strain gauges to the shaft of an actual club, and
transmitted to a computer samples of the shaft bend during the swing. I
have an article describing in detail what we can learn from the ShaftLab data published by TrueTemper.
review one specific lesson: the fact that the shaft is always bent
forward at impact, and for tens of milliseconds before impact. Here is
a scatter plot for shaft bend at impact; it reflects the swings of nine
PGA Tour pros from the 1990s. Impact always has leading and toe-down
bend. Moreover, it is leading by more than can be explained just from
centrifugal bending -- that is, radial acceleration pulling on the
center of gravity (CG) of the clubhead. There is bending due to dynamic
forces of the swing.
In fact, a leading bend at impact says that
the head is pulling the hands through, so the hands must be exerting
torque that resists the release of the club. If the hands were exerting
releasing torque, then all those dots would show lagging bend, or at
least be positioned to the left of the white "CG" line.
those who feel that Long Drive competitions change the rules, physics
included, here's Jamie Sadlowski just before impact. (Jamie won the
ReMax World Championship the past two years running, and won handily.)
shaft is clearly bent forward, telling us he gets his distance from his
huge body turn in the backswing, inhuman wrist cock, and holding that
wrist cock very
late into his downswing -- and not from forearm or hand
driving the clubhead through the ball.
Likewise for Tiger Woods, as if there were any doubt.
(Both these pictures are probably
unaffected by focal plane distortion. The shaft bend is real. The
Sadlowski picture was taken by Rick Malm using a technique designed to
minimize distortion. The technique is explained in the article.
The picture of Tiger is a frame from the super-slow-motion video used
in a well-known Nike ad a few years ago; the camera scan rate is
very fast, which minimizes distortion.)
Ben Hogan is convinced that
hitting the ball with his hands is a big source of his power. Rock and,
to a lesser extent, Lee Comeaux lean toward that opinion as well. They
have worked and practiced to make it happen. They can feel it
happening. But the
physics and the videos say that the clubhead is pulling the hands into
the ball; their hand-hit is not accelerating the clubhead. What is
going on here?
My take on Tom Wishon's statement is the key. If
you try to add wrist torque late enough in the swing to help (the last
70msec before impact), the hands just can't keep up. Centrifugal
acceleration is turning the hands so fast that the wrist muscles and
right-arm piston can't turn the hands as fast as the club is already
turning them. And if the muscles can't make the hands exceed what the
club is doing, then they can't add any acceleration to the clubhead.
order to test this theory, we need to measure the speed the hands can
rotate a club without the load of a club's moment of inertia. Today's
digital cameras make video the most convenient way to measure such
speeds. So I made a quick video. Click on the photo at the right to
I took a short length of PVC plastic pipe, about the
diameter of a golf grip. I did a 90º back-and-forth whipping of this
baton as fast as I could, simulating the attempt of the hands to uncock
and recock the wrists. Because the baton is short and light, it offers
little resistance to the turning, so I could measure what the hands
would do moving unconstrained at full speed. (An engineer would say
that the baton's moment of inertia is negligible compared to that of a
I examined the video in a movie editor that could
identify frame times to within 10msec. (Actually that is more precise
than the video itself; the inter-frame period of my camera
is 33msec, so I would not trust an answer to be more precise
that.) What I discovered was that it took at least 150msec to make the
move of a nearly 90º release. With a ten-finger grip, it was more like
200msec. True, others
may be able to make a quicker move than I, and perhaps the
back-and-forth is not as fast as a single forward slap (though I
suspect it is). So we may do better, but we are not likely to see an
improvement to twice that speed.
do I mention twice the speed? Let's remember that, when we looked at
the "standard swing" the same change of wrist angle occurred in just
just inertial acceleration, no wrist torque (no hand hit) at all. So
the hands would have to move more than twice the speed they do, just
to keep up with what the clubhead is doing to pull the hands around. In
order to actually push the clubhead (rather than be pulled by it) the
hands would have to go even faster than that.
In fact, this test was tried by Rick Malm
using better cameras and swing analysis software. (One of the lovely
things about science is that it invites others to validate or disprove
results by doing their own testing.) In addition to being a scientist
and researcher, Rick teaches speed training for golf, so if anybody can
demonstrate "fast hands" it should be Rick. Rick was able to create a
90º release using wrist torque much faster than I could. Depending on
the details of the experiment, it took between 60 and 83msec. That is
roughly the same as the 70msec it takes for inertial release. So Rick
can possibly keep the shaft from bending forward, but even he would not
be able to apply much "slap" to the head to increase clubhead speed.
the clubhead is pulling the hands around as fast or faster than the hands
can move under their own muscle power. So the hands just can't keep up
enough to apply a hit that could increase clubhead speed.
What It Probably Does
Expecting a right-hand slap or late
push to give more distance does not have any basis in physics. We know
that now. But there
is a substantial body of anecdotal evidence that says it works. Most
notably, Hogan won a lot of tournaments with a swing intended to do
that (even if it in fact did not do it).
Why does it work? We have
ruled out physics. I think we can rule out the Hawthorne effect. True,
a lot of practice of any swing that is not seriously flawed is going to
improve your game. But I, for one, saw results in the first round I
played with it, after only two practice sessions. So something is going
on there besides just practice.
Let's mention some of the
possibilities, without evaluating them -- yet. I am beginning a study
in conjunction with Lee Comeaux to try to determine what is really
any event, Lee and I are going to see if we can apply physics to other
parts of the golf swing that he teaches.
- Something about the motion encourages some other
good habit. This might result in more shoulder torque or a later
release, or perhaps something else.
- Following up on the first point,
it might be that focusing on forcing a 90º release just before impact
causes the golfer to hold the 90º lag until just before impact. That
synchronizes the release to when it should be, and perhaps causes the
golfer to exercise negative wrist torque earlier, in order to hold the
very late in the downswing.
- A related possibility: Anybody who
has played ball-and-stick sports other than golf has learned to depend
on hand action to supply power. You need it in baseball, stickball (I
grew up in the Bronx), tennis, etc. For someone like that, it's very
hard to train your body and your subconscious to swing through impact
with passive hands (the "standard swing"). If you use a late right-hand
slap it might not help, but at least it won't hurt if it's late
enough. So the slap swing acts as permission
to let the hands get involved,
in the least harmful way. If you had been allowing the hands to get in
way by releasing early, then the slap move might cure the problem. If
this is the answer, the slap move is not so much a powerful move as an
antidote to something you are doing that loses power.
aggressive move through the ball -- like the slap -- might be
encouraging a strong, committed follow-through from a golfer who
normally gives up the swing after impact. (That is sometimes a
problem of mine, but not so much since I started using the slap motion.)
it might be something completely different. Lee's
swing involves a lot more
than just the right-hand slap, and those who have been
everything Lee teaches report big improvements. I started out
suspecting his other advice was in support of the slap, and didn't get
very deeply into them. But I have talked with Lee, and there are lots
of other things he teaches that could have value in their own right. So
maybe one or more of these, and not the right hand slap in the impact
area, is responsible for
From time to
time, someone comes along advocating a hit with the hands in the
vicinity of impact. Hogan was very explicit about it, and Lee Comeaux
is a proponent these days. This study has determined that such
move does not by itself increase clubhead speed. The steps that led us
this conclusion were:
- According to physics studies using the
double pendulum model, it was determined that small improvements in
clubhead speed could indeed be achieved by adding helping wrist torque
late in the downswing. But it has to be added about 70 milliseconds
before impact; any earlier hurts clubhead speed more than it helps, and
any later and the force isn't there long enough to have a significant
effect on clubhead speed. These facts have been reported by previous
investigators and confirmed by our analysis.
- We looked at
frames of videos of golfers who claim to use a right-hand hit. Wherever
we saw the shaft just before impact, it was always bent
That means that, whether the golfer thought so or not, the slap was not
applying any accelerating force to the clubhead.
also looked at video frames and ShaftLab traces of PGA Tour pros and
Long Drive competitors. They also showed a forward bend, meaning a
resisting torque rather than an assisting torque.
- The reason
would appear to be that the grip is rotating too fast approaching
impact, due solely to centrifugal acceleration. The golfer's hands
cannot move fast enough to catch up to the grip and apply pressure to
Last modified -- Nov 9, 2015