Leecommotion, the Right-Side Swing

Part 1 - Discussion

Dave Tutelman  --  December 20, 2010

An earlier article attributed a different sort of swing to Lee Comeaux, as a swing based on a right-hand slap. The previous article showed that a right-hand slap does not actually accelerate the clubhead. But I have since spent some time with Lee, and there is a lot more to Leecommotion than hitting the ball with the right hand at impact. Fundamentally, it is a completely right-sided swing. So, while the study was correct, there is more work to be done to characterize Leecommotion. Here is the next step.

Introduction

Before I start, let me apologize to my left-handed readers. I will use 'right' and 'left' in describing a right-handed swing. 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.)

In early November of 2010, I was contacted by Doug "Rock" Burke. He participates in a golf web forum, Secret In The Dirt, where he met Lee Comeaux and learned about a swing Lee advocated. Everything I have ever seen on the topic is in one huge over-100-page thread on the Dirters' forum, a sort of random collection of YouTube videos, plus private communications with a few participants. (That includes long video meetings with Lee Comeaux, Rock, and Dave Parker.) At the time of this writing, there is no book, no coherent video, no magazine article, not even a web page, explaining or teaching this swing. The Dirters refer to the swing as Leecommotion, an acronym I really like. (I know Lee doesn't much like it, but I will use it until he comes up with another name that is generally accepted.)

Anyway, Rock reported that eight weeks into a swing change to Leecommotion, he has experienced better, crisper ball-striking and a big increase in distance. Quantitatively, his drives have increased by 30 yards, from 250 to 280 -- a 12% difference. That's impressive! Since Rock is a low-handicap golfer who has competed at the national level, I take his claim seriously. He wanted me to see if I could find a scientific explanation for the improvement. I have worked on the problem, and I think I know where the extra distance is coming from. In the process, I learned a lot about the swing in general, sharpened my tools for swing analysis, and may even have bought into a swing change that could improve my game.

This article covers:
According to Lee, there are other potential advantages in addition to more distance. In the main, they have to do with:
They are not directly quantifiable by my engineering physics, so I won't either endorse or deny them here. Anything I say about them will be non-expert and mostly anecdotal.

What Leecommotion Really Is

What and Why


Let's start by looking at Lee Comeaux himself demonstrating the swing. Lee is a big guy and a powerful golfer, and this comes out in the swing. It's fun to watch the video.

While we're watching, let me express a recurrent concern. Lee is an excellent athlete with superb hand-eye coordination. He is big and strong. In evaluating the swing, I had to be constantly mindful of things that work for Lee because of this, and might not work for the average golfer. I have tried to make those distinctions, but I'm not certain how successful I was.
The simplest characterization of Leecommotion is a right-sided swing. Instead of pulling the club around with the left arm, you are pushing with the right. That by itself, while unconventional, is hardly outrageous. There is not much precedent for it in modern instruction, but there are certainly serious treatments of the golf swing that allow for right-sided power:
  • If you look at Homer Kelley's well-known but little-understood book, "The Golfing Machine" (printings from 1969 to 1983), he identifies the extension of the right arm as a source of power. (For instance, see chapter 6-B-1 of the book.)
  • Consider the diagram at the right, a variant of what I often use to illustrate the classic double-pendulum model of the swing. As we all know (at least if we've seen the double pendulum model before), shoulder torque moves the hands in a circular arc, which provides the main power for the swing. But the torque has to be transmitted to the hands from the turning shoulders. Transmitting the torque is the work of the arms. The model assumes the arms to be a single rigid body. But in actuality, the hands can be driven along the circular arc by a pull from the left arm (blue arrow), a push from the right arm (purple arrow), or a combination of the two. Almost all instruction today focuses on the left arm pull, but there is no fundamental reason why any of the three choices could not be used. Just like the left-arm pull, the right-arm push has a component of its force that will move the hands along that circular arc. (Remember this diagram! We are going to use it in the analysis.)
When Lee himself describes the "why" of the swing he has developed, he uses some broad, intuitive arguments. I present them here without any comment from me, just the rationale as I understand it from Lee. (I will give my assessment later in the article.)
  • The dominant side of the body is stronger, so let's make it the dominant side of the swing. For a right-handed golfer, that means you want the right side and the right arm and hand to be dominant. Current instruction teaches a swing where left-arm pull is both the powering and the controlling factor in the swing. The major function of the right arm is to support the action of the left, and otherwise just not to get in the way,
  • A push is stronger than a pull. Most strong moves in sports are more push than pull. So we should expect this to work for golf as well. But current instruction teaches a swing that is much more pull-oriented.
  • More natural (comfortable) body positions means the body isn't resisting the swing. If you put the body (arm, leg, hand, etc.) in a position that human anatomy was not designed for, the body will make compensating moves to minimize the effect of that position. Lee's contention is that the modern golf swing is full of such contradictions, so it takes much effort to achieve any success training the body not to fight it. A swing that avoids such positions should be easier to teach, easier to learn, and more effective for more golfers.
  • More natural body positions means less wear and tear, less injury, and greater golf longevity. This takes the previous point a step further. If the modern golf swing uses positions that human anatomy was not designed for, it may be dangerous to the golfers' health. There is little doubt that golfers suffer more than normal incidence of back problems, and maybe other similar injuries.
 

Keys To The Swing

Here I'll try to give a fair presentation of the fundamentals of the Lee Comeaux swing. I'm not Lee, so I may not present it exactly as he would. But I'm honestly trying to convey the essence as he explained it to me. Later, I'll go through this list again, with my own opinons of the keys. But for now, here's my understanding of the swing Lee is teaching:

Philosophy: Whole motion is (or at least should feel like) a hard right-hand punch downward through the ball, thrown from the right shoulder and reinforced by a triceps-driven right-arm "piston".
 
Grip: Ten-finger grip, with the key fingers the last three of the right hand. (Important note: For the conventional grip, it's the last three of the left hand.)
 
Stance: Lee says "lean" rather than "bend". When asked for a distinction, Lee says to think of an image: "leaning" means you are "reaching" the club to the ball. Your weight will wind up on the balls of your feet instead of centered or back on the heels.

Lee also recommends a stance with the left foot turned out a bit (most instructors recommend this), and the right foot drawn back a few inches. That is, fundamentally, a closed stance. But, unlike most closed stances, Lee keeps shoulders and hips aligned to the target line; only the foot line is closed.
 
Backswing: Lift club up with right hand, rather than one-piece takeaway. Shoulders stay level, right shoulder maybe even lower than left. Club between the hands.

It's OK for the left arm to bend at the top of the backswing.
 
Weight shift: Lee proposes keeping the weight no farther back then the inside of the right foot. But his is clearly a stack'n'tilt move, keeping the weight pretty much left from address on.
 
Downswing: Start by extending right shoulder sharply down. Follow by pistoning the right arm down and across the body. The effort should be extended well past the ball, as if you had "punched through" a boxing opponent. Your body will do whatever weight shift and turn is needed to realize the feeling as motion.

This often turns out as an over-the-top move. Lee claims that over-the-top is the most powerful move a golfer can make.
 
Impact: When the hands reach the vicinity of impact, "Stand the shaft up". A few other terms Lee has used for this move. "Stop the left hand and push the right hand under it." "Slap the ball with the right hand." This amounts to using hands, wrists, and arms to force a release of the club at the ball.
 
 

Experience With The Swing

It is difficult to learn a new swing without instruction. That generally means an instructor present to tell you whether you are doing what you are supposed to. Feedback is crucial for learning a swing. It is vital that someone who knows tell you, "That's it! You've got it," when you do it right.

I've collaborated long-distance on a lot of golf projects using the Internet and United Parcel Service as my collaboration tools. But the need for swing instruction did not show a lot of promise for that limited collection of tools. Lee was talking about the need to get together in person -- meaning significant travel, since he is in Texas and I am in New Jersey.

Fortunately, we were able to make it happen without travel. We used video calls via Skype. That's an amazing service! (And that was an unpaid testimonial. I don't think we could have completed this project without Skype video.) I spent $30 on a good webcam (a High Definition 720p camera, the Logitech C-310), and we were in business. Worked first crack out of the barrel.

Lee and I spent the better part of two hours on a video call, where he drilled me on the basics of the swing. Because of the video connection, he was able to demonstrate what he wanted, then critique whether or not I was doing it. I was indoors in a fairly cramped space, so I couldn't swing a club. I was able to make the moves with a one-foot length of PVC pipe the diameter of a golf grip. It was bright white, so Lee could see exactly what I was doing with it. On the strength of that instruction session, I went out and started my adventure with the Leecommotion swing.

Aha Moment #1 - Right and Left

Lee wanted me to start with right-hand-only swings with an 8-iron. The results were not encouraging. I was hitting the ground several inches behind the ball. Only two out of the first eight balls were struck on the face at all solidly. Even the face hits did not go impressively far, but at least they were not disasters.

I decided not to persevere until I was good with right-hand-only swing. Instead I added the left hand but continued with the same right-hand motion and feeling. Much better results! I hit no fats at all, some hot-trajectory thin shots (what Johnny Miller would call "a few grooves low"), and more than half my shots were solid and high. Almost all were left of where I was aiming. The solid shots went farther than I am used to.

By the time I had hit a dozen balls this way, I had a good mental image of what the swing was doing, and I allowed that image to motivate the swing. I saw my hands on a curved track, the curve defined by the left arm as a radius. My right shoulder and triceps were pushing my hands along that track. The image was extremely helpful in telling me what the swing was doing -- and why I was doing so much better with the left arm involved.

When I swung right-arm-only, there was nothing but the right arm itself to regulate the position of the clubface at the bottom of the swing, and that right arm was also busy powering the swing. Right arm power comes from an extension during the downswing, so the timing of extension and swing has to be really good to get the clubface on the ball. I kept extending past the ground and hitting fat. Then I added the left arm. With the fully extended left arm acting as a guide for the hands, there was no uncertainty where the clubhead was.

This picture is my mental image of the Leecommotion swing, superimposed on a swing by Lee himself. The important thing is the separation of function between the right and left arms. Unlike the currently taught swing, which sees the left arm provide both power and path (and, implicitly, the right arm in a supporting role at most and "just keep the heck out of it" at least):
  • The right arm is completely responsible for power.
  • The left arm is completely responsible for path.
I have found that to be the important fact about Leecommotion. It became apparent in the first twenty balls I hit after the session with Lee. Moreover, when I am having a hard time making good contact, the key that always saves it is the mental image of this swing. ("Left arm determines where you hit the ball, right arm determines how hard you hit the ball.") I have repeatedly been amazed how consistently that image works.

Since that first twenty balls, I have marched through all the keys mentioned above at one time or another. Some days I have tried to stick slavishly to Lee's Keys (has a nice ring to it, don't you think). Other days I play mix'n'match between my old swing and the keys. Some are more essential to the swing than others, but the fundamental essence of Leecommotion is: right hand for power, left hand for path. As long as I keep this as my primary key, almost any other combination of keys works. (Well the grip matters, and we'll discuss that next.)
 

Aha Moment #2 - The Grip

A week later, I spent another hour and a half on a Skype video call with Dave Parker in Australia. Dave is putting together a teaching guide for Leecommotion, and we wanted to compare notes on how to present certain aspects of the swing. (Lee is knowledgeable and passionate about the swing, but his descriptions can be cryptic without very clear video, and sometimes even with it. Proper explanation of Leecommotion remains unsolved. Perhaps this article will also help in that regard.)

At some point in the conversation, Dave and I wondered about the reason for the difference in grip. Lee strongly recommends two significant changes from the commonly-taught grip.
  1. Ten-finger grip rather than the generally favored overlap grip. This is not a wild departure; the ten-finger, overlap (Vardon), and interlock grips are all quite respectable. But most instruction either says, "Do the one that's right for you," or only endorses the overlap. Lee is emphatic that the ten-finger grip is the way to go.
  2. Pressure fingers are the last three on the right hand. Every bit of grip instruction that makes the distinction recommends the last three on the left hand. The difference is shown in the picture at the right.
Why is this unconventional grip recommended for the Leecommotion swing? If the right-hand slap were a big factor, then the ten-finger grip would make sense; it would magnify the wrist torque. But my previous study proves that there is no physical basis for expecting power to come from the right-hand slap at impact. And even if it were, I could not make any sense of the reason for the last three fingers to be key. A slap would come from the right palm or the pad of the thumb.

As Dave and I discussed the swing, the reason for the grip changes suddenly became clear to me!

Let's look again at what I believe to be the fundamental fact of Leecommotion: the right arm pushes the hands around a circular track defined by the left arm. So the right hand must forcefully push the left hand around. This can come either from right-hand pressure on the left hand directly, or from the right hand gripping the shaft with enough force to transmit the pressure through the club itself.
The figure at the left compares the ten-finger grip with the overlap grip, specifically with regard to transmitting force from the right hand (top hand in the pictures) to the left. Note that what holds true for the overlap is at least as true for the interlock grip.

The ten-finger grip butts the edges of the hands against one another, so the force exerted by the right hand (the green arrows) go directly to the left hand. And it is the last three fingers of the right hand providing that force, so it is natural to focus on them as key. But this is not pressure on the handle to hang onto it, but rather to establish a solid base with which to push against the left hand.

The overlap grip is not nearly as efficient. The red question mark indicates most likely point for the force to be transmitted: from the ring finger of the right hand. Take it from a pianist like me that the ring finger is a very weak finger; you don't want to count on it for providing the force in a golf swing. The red X is even less likely as a source of power; there isn't an abutting surface in the proper direction to transmit the force.

Finally, let's consider force transmitted from right hand to left via the handle of the club. The overlap and interlock grips were designed to allow the hands to act as a unit, and specifically to limit the influence of the right hand on the club. So that would be a poor way to convey the force, compared with the ten-finger grip.

I conclude that the purpose of the ten-finger grip is to reinforce the primary element of the swing: the right hand powering the left hand around the circular arc.
 

Aha Moment #3 - Everything Else

I asked a biomechanics specialist to look at Lee's video. No supporting material nor hints, just the video. He came back to me with a pretty good list of what makes up Lee's swing. He got the right-hand push, the stack'n'tilt, and a number of other key points. He also pointed out that none of them are brand new. The history of golf instruction includes every one of them, though perhaps not in this combination.

That gave me the idea (the courage?) to look at the keys as independent, and play mix and match with them as I experimented with Leecommotion. In my assessment below, I evaluate each key as to how essential it is to the principal notion of the right arm driving the hands around a path defined by the left arm. Some seemed to be a matter of personal preference, rather than inherent to the swing.

From my experimentation, one point did come through loud and clear. This is still a golf swing, and your fundamentals still have to be good. You probably can't teach Leecommotion to a raw beginner, without also imparting a lot of conventional fundamentals that are not Leecommotion. Examples:
  • It does not work without a good body turn! In the final analysis, power comes from the body turn. The right (or left) arm just transmits that power from the shoulders to the club.
  • You don't want to release early! That is as much a speed-killer for Leecommotion as for any golf swing. I am just about certain that the right-hand slap to release the club through impact is no more useful here than in the conventional swing. In fact, I suspect it is less useful. In my previous study, the most likely reason for it to help at all was to give the right hand something non-harmful to do. In Leecommotion, the right arm and hand are fully involved in the swing. There is no need for the distraction of a last-instant wrist torque. Multiple timed motions during the downswing are difficult to train, and have to earn their keep. I have stopped trying to force a late release. I may try again someday, if/when the rest of the swing becomes perfectly natural. It's not there yet. But I really don't expect it to be much help.
  • Hit down through the ball! Lee emphasized this in our video call, but it seems to be neither more nor less true than it is for the conventional swing. For years before I ever heard of a right-side swing, this has been a key that I point out to friends and family.
Bottom line: I have found a few important keys to be indispensable. For the rest of the keys, think of the menu at a Chinese restaurant. Leecommotion has been presented as a combination plate: if you pick Leecommotion on the menu, it defines everything you get. But I feel that you can approach the non-indispensable keys as a family dinner: pick one from column A, one from column B, one from column C, and pick your own soup and dessert.

Assessment Of The Swing

Having tried Leecommotion and spent some time analyzing it, I think I understand it well enough to express some opinions on what works and what doesn't, what is necessary and what is a personal option. I'm expert in neither biomechanics nor golf instruction, so my opinions are not expert opinions. But here they are, for what they're worth.

The Basic Principles

I don't buy all of Lee's intuitive arguments for the swing. Some make sense to me, and some do not. Here's one intuitive principle never mentioned by Lee that makes sense to me.

The Keys To The Swing

Here is the list of keys again, together with my assessment of each. I have color-coded the assessments:
Key Description Assessment
Philosophy: Whole motion is (or at least should feel like) a hard right-hand punch downward through the ball, thrown from the right shoulder and reinforced by a triceps-driven right-arm "piston".
 		 This is the entire essence of the swing. See more detail above.
Grip: Ten-finger grip, with the key fingers the last three of the right hand. (Important note: For the conventional grip, it's the last three of the left hand.)
 		 This is important to the swing. It transfers force from the powering right hand to the guiding left hand. See more detail above.
Stance: Lee says "lean" rather than "bend". When asked for a distinction, Lee says to think of an image: "leaning" means you are "reaching" the club to the ball. Your weight will wind up on the balls of your feet instead of centered or back on the heels.

 This presents an "athletic" and "ready" stance. I find it helps. I haven't tried it for a normal, left-side-pull swing, but I am fairly confident it would work equally well there.
Lee also recommends a stance with the left foot turned out a bit (most instructors recommend this), and the right foot drawn back a few inches. That is, fundamentally, a closed stance. But, unlike most closed stances, Lee keeps shoulders and hips aligned with the target line; only the foot line is closed.
 		 The swing is somewhat over-the-top by nature, especially if the right elbow is "flying" instead of tucked in front of the hip. It is possible that the closed stance might counter this a bit, and get the clubhead path back on line. I'm not sure how essential this is; as I practice more, I find it possible to swing down-the-line without it.
Backswing: Lift club up with right hand, rather than one-piece takeaway.

 Seems to be optional. I found a more conventional takeaway left me less prone to the occasional duck-hook. But I'm sure it's fine for some golfers.
Shoulders stay level, right shoulder maybe even lower than left.

 Lee's swing is most emphatically a two-plane swing; he has a fairly normal club plane (55º with a 7-iron), but a very flat plane of shoulder rotation. I don't see that such a shallow shoulder plane is needed for a right arm push.

But I believe it is worse than optional. Lee made the point to me that a level shoulder turn is easier on the back. But I have recently seen two highly respected instructors, Sean Foley and Martin Hall, make precisely the opposite point. They emphatically believe that the left shoulder should go down on the backswing, in order to protect the back.
Club between the hands.
 		 Probably a good idea for a stable swing in general.
It's OK for the left arm to bend at the top of the backswing. I agree with this. It would increase the total club angle for people with flexibility problems, which could increase their distance. A bent left arm is only an issue late in the downswing. As long as it is extended later during inertial release, everything should be just fine.
Weight shift: Lee proposes keeping the weight no farther back then the inside of the right foot.

 There are good reasons for not letting the weight get further back than this, that apply to any golf swing.
His is clearly a stack'n'tilt move, keeping the weight pretty much left from address on.
 		 Stack'n'tilt? Full weight shift? Both work for me. I'm more comfortable with my full weight shift, and it does not seem to hamper the right-side swing. I'm pretty sure this one's optional.
Downswing: Start by extending right shoulder sharply down. Follow by pistoning the right arm down and across the body. The effort should be extended well past the ball, as if you had "punched through" a boxing opponent. Your body will do whatever weight shift and turn is needed to realize the feeling as motion.

 A more detailed description of the essence of Leecommotion.
This often turns out as an over-the-top move. Lee claims that over-the-top is the most powerful move a golfer can make.
 
 I'm not sure about the assertion that over-the-top is  the most powerful move a golfer can make. My biomechanics expert says it is not. But, in support of it, everybody pretty much agrees that straight pulls tend to go a long way. So let's leave it as "whatever works of you".
Impact: When the hands reach the vicinity of impact, "Slap the ball with the right hand." A few other terms Lee has used for this move. "Stand the shaft up". "Stop the left hand and push the right hand under it." This amounts to using hands, wrists, and arms to force a release of the club at the ball.
 		 I suspect this is a bad idea, based on study I have done on the subject. I feel that it does no good at best, and it will hurt clubhead speed if executed at all too early. And "too early" is measured in a few hundredths of a second, so it's easy to be too early.


A Note On Clubfitting

Lee has proposed flattening the lie of the irons substantially (as much as 5º or more). Some (Rock, at least) have interpreted this to mean that Leecommotion produces a flatter swing plane, which calls for a flatter lie. In discussions with Lee, I learned what was really behind the recommendation. Knowing the actual reasoning, let me strongly urge you not to flatten your lie angle without ascertaining the proper lie angle for you. Lee's recommendation has nothing to do with lie fitting. Here's the real story.

Lee sent me this picture of a Hogan iron from many years ago, with Lee's own notes added to it. The clubhead featured an "under-slung" hosel that added some steel behind the heel. The point was to move the center of gravity (CG) closer to the shaft axis, to make it easier to close the clubface.This idea may (or may not) have originated with Hogan, but it has continued to pop up from time to time, especially in the designs of Clay Long. He added weight to the hosel behind the heel in the Peerless PHD. When Long moved to Cobra, he did the same thing with their Gravity Back irons.

Getting back to the marked-up picture, Lee drew his impression of the new CG as a black oval almost 1/4" closer to the shaft axis than Hogan's own staff did. Then he made the logical jump that, (a) this feature increased workability and (b) if your irons did not have this feature, you could acquire it by bending the iron significantly flat. That's correct, to some degree. But I think the whole idea is a bad one. Here is my logic:
  1. There might be a small advantage to a clubhead that turns over more readily. But there is a corresponding disadvantage. You want the ball to strike the clubface near the CG. If you move the CG toward the heel, you are no longer hitting the sweet spot. And, if you compensate for that by hitting closer to the heel, you invite a shank.
  2. Even if you consider the change of CG helpful, it is so small as to be nonexistent for all practical purposes. It certainly isn't anywhere near the 1/4" shown in Lee's diagram. The amount of steel moved in the Hogan design, or by bending the club 5º flat, will move the CG no more than 1/32", probably less. Not enough for anybody to notice. (Clay Long's designs move more steel, but the CG migration is still less than 1/16".)
  3. Lie angle is an important clubfitting specification. If you flatten it 5º worth (compared with your proper fit), you are going to hit the ball well to the right. About 10yd right for a 5-iron, unless you make other compensations. And you don't want to start the fitting process by making swing or setup compensations; that is not a good thing for the golf game.
You are much better off setting your lie by a good dynamic lie test, then strengthen or weaken your grip to square the face. That will be far more reliable and just as workable.

Why It Gives More Distance

Remember that I originally got involved in this to give an engineering answer to why it works. The only aspect that can be attacked directly by engineering analysis is distance. And Rock's experience certainly indicates that there is distance to be gained. It took me a while to figure out why. Here's what I think is going on.

Let's start by reviewing the picture we saw before of the double-pendulum model of the swing. We must remember that the power comes from shoulder torque, which is generated from the ground up. The arms don't create the power, they transmit it from the shoulders to the hands. It is generated by large muscles between the feet (whose function is to provide a stationary base) and the shoulders.

A torque is a push-pull pair of forces, separated by some distance. In the picture, the right arm push and left arm pull are separated by the width of the shoulders. Either or both (right arm push and/or left arm pull) can be used to transmit the torque.

The picture shows a very simple case, where both arms are extended, and the hands are moving in a circular path around the center of rotation. That center is the spine at the base of the neck. This is a pretty accurate picture of what happens late in the downswing, say, the last 100 milliseconds (0.1 seconds) before impact.

But what about early in the downswing? The left arm is extended, but across the chest. The right arm is folded, not extended at all. Is the double-pendulum a useful model there?

Here is a view looking down the spine of the golfer during the early part of the downswing. The shoulder torque is shown as a dotted black arrow, trying to turn the whole assembly of shoulders, arms, hands, and club counter-clockwise. Either arm can be used to transmit the torque, or both can share the load. But, in this position, they act rather differently than when both are extended:

The left arm is extended across the chest. It typically exerts its force from the left shoulder all the way to the grip.[1] So the torque radius (the "lever arm") is the blue arrow.

The right arm is folded next to the torso. If the right side is exerting the force to move the hands, it is the chain of limbs including the right shoulder and [folded] right arm. So the right side lever arm is the red arrow.

Now a key point: The red arrow is shorter than the blue arrow.

Why does that matter? Because the shoulder torque is transmitted to the hands by forces. A torque is a force acting over a distance -- a lever arm. The size of the torque is the force times the distance.

Torque = Force * Distance

Or, applying simple algebra:

Force  = Torque
Distance

Therefore, for a given torque, a shorter lever arm means a bigger force and vice versa.

We have a shoulder torque to be transmitted to the hands. The torque is what it is; left side or right side will not change that. But the force at the hands will not necessarily be the same. The equation tells us that the smaller the lever arm is, the bigger the resulting force. So the shorter lever arm of the right side transmission will provide more force than the long lever arm of the left side.

Getting back to our model of the Leecommotion swing, let's look at what we get from an increased force on the hands. The hands are moving as if on a curved track, the path determined by the radius of the left arm from the left shoulder. As the diagram shows, most of the force  accelerates the hands along that track. So we can expect an increased acceleration early in the downswing, until the arms extend and the force lever arm is the same as the radius of the "track". Later in the downswing, when the lever arm is the same as it would be for a conventional swing, then so is the acceleration.

But more early acceleration means more hand speed (and, obviously, more rotational speed) later. And clubhead speed comes mostly from inertial release, which occurs in the latter stages of the downswing, usually the last 70-100 milliseconds. So what the right-side release does for us is gives us faster rotation by the time the hands start to release as the club is pulled outward by centrifugal force. We know that the formula for centrifugal force is:

Force  = m v2
r		   =  m r ω2

So, whether we look at rotational speed (ω) or just plain velocity (v), the right-side swing gives us a stronger release due to increased early acceleration. And that is where Rock's extra distance comes from. (And mine! I have seen almost a full club's increase in my irons since I started the right-side swing.)

Another way to look at it

...Or two ways!

On March 31, 2011, I exchanged a few emails with Ben Maffitt, who is also working to convert his longtime swing to Leecommotion. (By this time, Leecommotion has been renamed "C-Motion". I respect that, and will call it that in the future. I'm not going back to rewrite the rest of this article, nor all my links to it.) In our conversation, I came up with a few alternative ways to state the previous few paragraphs. It helped Ben, and he encouraged me to include it in the article to make the explanation more accessible.

The first way to paraphrase it is basically a briefer statement of the basic principle:

Lee has reduced the lever arm through which the shoulders convert their torque into force on the hands. A shorter lever arm for the same torque results in more force. More force accelerates the hands faster. By the time the arms are more extended and actual release is occurring, the hands are moving faster than they would be with a conventional swing. That means faster rotation during release, and thus more clubhead speed and more distance.

The second explanation has to do with bicycles. I used to be very much into bicycling, and even got into the technical aspects of it. (Big surprise, eh?) In the mid-1980s quite a few cyclists who were also PC users designed their gearing ratios with a program I developed. So a bicycle gear analogy was a natural for me.

The picture at the right shows how a bike is powered. The short story is:
  • Your foot applies a force to the pedals (red arrow). This force is limited by your strength, technique and weight, and how you are pacing yourself.
  • Eventually, this force is turned into a tension force in the chain (red double arrow), which is used to power the rear (driving) wheel. The more chain tension your pedal force produces, the more driving force you can deliver to the rear wheel.
The picture shows a multi-speed bike with a choice of two front sprockets. If you need more force -- say, to climb a hill -- you need more chain tension. So what would a competent cyclist do? Downshift to the smaller front sprocket.[2] Every experienced cyclist can do this without even thinking. But what is  happening in terms of physics?

When you apply force to the pedals, you are applying a torque to the sprockets. The amount of torque is the pedal force times the length of the pedal crank.
torque = pedal force * pedal crank length
This torque is applied to the sprocket that the chain is on, which causes tension -- a force -- in the chain. How much force. It is created by a torque, and we know:
torque =force * length of lever arm
So the chain tension is given by:
torque = chain tension * sprocket radius

chain tension  =   torque
sprocket radius

Conclusion: You want more chain tension to help power up a hill? Use the smaller front sprocket! The math is easy, the concept is completely sound, and it all agrees with cyclist experience everywhere.

How does this relate back to the golf swing? What C-motion does for the golfer is shift to a smaller sprocket. The torque from the shoulders is applied to the hands through a folded right arm (small sprocket) rather than an extended left arm (big sprocket). Result: an increase in the force available to accelerate the hands in the early part of the downswing.

Numbers please

OK, now we know that the shorter lever arm gives more force to the hands, which makes for higher hand speed when the club is release, And that, in turn, means higher clubhead speed and ultimately more distance.

But how much extra distance? Does the difference in lever arm account for the distance Rock gained?

In a word, yes! I was too lazy to come up with an exact model for the Leecommotion swing and a computer program to simulate it. That is not exceedingly difficult as a physics problem; maybe equivalent to a Masters thesis in mechanical engineering. But that was more effort than I wanted to spend on it. As it turned out, I didn't have to.

I used a couple of modifications to the standard double-pendulum model of the swing, so I could use an already-existing computer program, SwingPerfect by Max Dupilka. As it turned out, the variable lever arm was hard to simulate directly, but it was not hard to come up with a calculation that gave an optimistic estimate and another that gave a conservative estimate. (Engineers do this all the time. It's called finding an "upper bound" and a "lower bound" on the performance of a system.)

In case you're interested in the details of the model, I go through them on the next page. If you just want the executive summary, here is a synopsis of what I did and the results:
  • I took data about Rock's golf game. The most important point was that he drove the ball with a 250yd carry using a conventional swing, and 280yd with Leecommotion. Other pieces of data included specs of his driver and some of his own measurements.
  • I also took a pair of videos that Rock made available to me. They were taken the same day, using essentially the same swing. One was taken face-on and the other down-the-line. After verifying that the swings in the two videos were close enough to identical, I measured the lever arm from single-frame snapshots at various points in the downswing. In that way, I got the radius as a function of time, r(t), for Rock's driver swing.
  • Using two programs, SwingPerfect and Trajectoware Drive, I modeled three swings:
    1. I took Rock's basic dimensions with the conventional swing, and found a shoulder torque that hit the ball 250yd. That was the basis for comparison, and corresponds to Rock's distance before learning Leecommotion.
    2. I modified the shoulder torque to correspond to the optimistic calculation. When I ran that through the computer programs, it said the drive might go as much as 296yd.
    3. I modified the shoulder torque to correspond to the conservative calculation. When I ran that through the computer programs, it said the drive would definitely go more than 268yd.


Here is a chart of the results above, graphed by TrajectoWare Drive. Rock's conventional-swing drive goes 250yd, and his Leecommotion drive goes 280yd. The Leecommotion drive is clearly within the range between the optimistic model (upper bound) and the conservative model (lower bound). So it is reasonable to conclude that Rock's distance gain is real, and is due mainly to the shortened lever arm of the right side, compared with a left-arm swing.
Notes:

[1] The left-side radius does not have to be this long, but it almost always is. Many instructors urge "connection", where the left bicep touches the chest through the backswing and well into the downswing. If the touch were actually a push, where force from the chest is a fulcrum for levering the left arm around, then the lever arm might be shortened. But that is not normally the way "connection" is used; it keeps the relative positions of body and arms, but the chest does not forcefully push the left arm around. In almost all left-sided swings, left arm power comes from the left shoulder -- hence the longer left-side radius.

[2] Actually, many cyclists would shift the rear sprocket rather than the front. For purposes of this article, let's just assume the cyclist is just going to solve the problem with the front derailleur. For instance, assume either the rear derailleur is broken, or the gear increase on the front derailleur is just right.
Last modified -- Mar 16, 2012