Geoff ,sometimes I can't tell if my left shoulder is working correct, is there a way to check to make sure it is moving straight down, I sometimes feel if my shoulder gets down and infront too much, thanks TIM

Dear Tim,

If the "down and back" action of the lead shoulder in the backstroke is a little off, as you describe, that is not a huge worry. What is a bigger worry is how the lead shoulder moves in the stroke coming forward from the bottom of the stroke for a few inches thru and past impact.

The reason is that a "straight stroke" is almost completely about what happens going forward from the bottom of the stroke, and oddities in the backstroke can be sorted out fairly easily. So long as the backstroke is either straight back or slightly inside, the elastic properties of the body will "remember" how to resquare the putter head becoming forward back at the bopttom of the stroke. And even if the forward stroke comes from the inside a bit (not grossly inside, as this would overwhelm the elastic memory of the body), the MOMENTUM of the putter and arms and hands swinging -- as a unit beneath the directionalized (parallal aligned) shoulder frame and a still pivot at the base of the neck in the center of the shoulders' connection via the clavicle bones -- will send the putter head past the bottom rising slightly but square down the line. Holding still atr the top at the pivot with shoulders aligned parallel left of the putt line basically handles the putter path down the line for you. You don't "do" the stroke so much as you "let" the stroke go where it wants, which is rising slightly past the bottom square down the line.

GOING BACK

The two main "oddities" in the backstroke are going inside a bit, and going outside the line. Going outside the line is worse, but not entirely fatal.

Going Across the LIne

The cause of going back across the line is using the hands and arms to take the putter head back from the ball instead of shoving the putter head back with the shoulder (lead) acting thru a fixed-shape lead arm that is otherwise inactive. This is so since the muscles around the elbows move the hands and arms, and activating these limb muscles flexes the elbows, and the elbows are made to hinge only one way (like the knees) and this "way" is to hinge and send the hands farther away from the feet, and this sends the putter head on a path out across the line of the putt, and sets up the need for a corrective looping at the top of the backstroke. (If you start instead by shoving the lead shoulder down thru a fixed left arm to push the putter head back from the ball, the path of the backstroke is biomechanically guaranteed by the parallel alignmment of the shoulder frame NEVER to go across the line -- problem solved. -- See Loren Roberts) So, to "do" the looping effectively to recover, realize that the use of the hands and arms has sent the hands and arms farther from the thighs than they normally hang naturally at address, so they are being held out there by the same arms and hands muscles that sent them there. When there is a slight pause in the motion at the top of the backstroke, simply "quit" holding the hands and arms out there this extra amount and relax to let the hands and arms sink back towards the online position and even a little inside the starting position. Then get on with the forward stroke from an inside beginning of the putter head.

Because the putter head is out from the body and especially the feet, there is inevitably some centripetal force in the swinging of the mass of the putter head from back to front. It's a bit like throwing a bucket of water out a window sideways to your left (right hander). A little swinging back inside doesn't hurt but continuing the swinging inside past the point where the bucket top resquares to the window might get messy on your wall. There is that sense of centripetal force in the forward swing that the body can handle pretty well. But if the body is asked to swing the bucket back headed away from the legs first and then from a position across the line at the top of this backstroke then redirect the bucket's top to throw the water out the window sideways, well, this is awkward. You would be cancelling out the centripetal forces the body otherwise uses for balance and control in the forward stroke by bringing the mass of the bucket from out to in.

If you compare a straight-back, straight-thru stroke with an inside-square-inside stroke or an inside-square-stay square stroke, one of the differences coming forward is in the use of this centripetal-force pattern as a stabilizing factor. There is only a VERTICAL centripetal force in a truly straight-back, straight thru stroke, but in an inside-square-inside stroke there is a mixture of VERTICAL and HORIZONTAL swinging, and the HORIZONTAL component challenges the center of gravity of the golfer, whereas the VERTICAL component does not (the stroke vertical centripetal forces being already aligned with the forces of gravity as is the body center of gravity). There is a tendency in the gating stroke for a "wobble" in the balance of the golfer, and good golfers react to these wobbling forces in a consistent way with well-timed reactive balance-preserving muscle activity. It's mostly in the back of the thighs, I think, at a micromanagement level of activity. The more "around" this horizontal component and the more violent the action, the more the balance is challenged.

Getting back to a non-awkward position coming forward is simply a matter of relaxing and not trying to be perfectly online coming forward and worrying more about sqaure and down the line past the bottom even if the sweetspot is delivered a bit inside and contact with the ball is a bit towards the toe. Once you're in a loop stroke, the priority is get back safely inside the line before coming forward, then throw the bucket of water sideways out the window and don't worry so much about going thru the precise middle of the window -- just don't hit the left wall with the bucketfull of water. Square impact is more important at this point than solid, exactly-on-the-sweetspot contact. You won't be enough off the sweetspot to seriously twist the face offline (your grip pressure may instinctively increase to prevent this) or lose significant distance. Get and stay square is the priority.

Avoid all this by starting the backstroke with the lead shoulder and not the hands.

Going Back Inside the Line

Because there is a certain amount of rubbery body memory in the backstroke that allows the forward stroke to retrace the way coming forward, a little inside going back is not especially hurtful. This means the golfer should NOT try to be a perfectionist in the path of the backstroke, except to avoid going across the line by starting back with the shoulder. But a little inside going back does not change the basic plan of allowing the stroke to "make itself" from the top of the backstroke coming forward. But because of the limited elasticity of the body and because of the issue of challenging balance by coming too far or too fast inside, this coming inside in the backstroke has certain safe limits -- not too much inside and not violent or fast or jerky but smooth and gentle.

So, an inside back stroke needs to be "minor" and "gentle". If so, no worries. The forward stroke will be just fine.

DOORJAMB EXERCISE

With the above in mind, setup in a doorjamb aiming the putter at the vertical plank to the left (right hander) of the jamb from about 10 inches away. This leaves a backstroke space of 20 or 30 inches to the right for most doors. Using the lead shoulder to start the stroke back, focus on letting the stroke take place from the top of the backstroke, resqauring at the bottom, and then rising flush and square into the vertical side of the jamb. You can make an effort to get the backstroke dead straight, but you really don't have to worry that detail to death much.

CHEST ROLLING BACK

The real issue in the back-and-thru stroke is not to follow the putter head with the way the chest "faces" at the top where the shoulder alignment out to be preserved. In your case, the chest seems to get rotated clockwise a bit (looking down) in the backstroke, as the lead shoulder comes forward a bit. That sort of minor, gentle shoulder rotation gets naturally corrected swinging down and forward, due to certain elastic or rubbery constraints in the midsection that get stretched by that backstroke pattern. Just don't OVERCORRECT by voluntary effort -- leave it alone and "let" the body's elasticity do the correction in the proper degree coming forward. The momentum of the forward stroke plus the constraint of holding the top of the chest at the pivot still will REQUIRE the putter head to rise square and down the line past the bottom.

This means don't get caught MAKING a forward stroke. If you LET the stroke happen while holding the top stationary, it works, but if you BRING the putter forward with muscles in an effort to "stay in control", you will mess up the timing and probably send the top of the chest around to the inside in a pull action, or leave the toe open and send the ball offline to the outside.

This generates a rule for the pivot (for right handers). NEVER LEFT OF CENTER. If you drew a line from the bottom of the stroke thru the pivot at the base of the neck, the pivot never goes on the target side of this line -- not in the backstroke, and not in the thru-stroke. It's okay is the pivot curls a bit to the back -- just never let it curl to the front side of this line.

When you dip the shoulders down and back at the start, there is a danger of "leaning" the top of the shoulders, neck and head to the left, and this will send the pivot left of the center. Don't do that -- hold the head still during the backstroke. Coming forward, though, it is okay to allow the head to move slightly back to the right, as this helps leave the base of the neck centered and prevents the pivot from going left across the center following the stroke. Holding the head perfectly still coming forward is done with neck tension at the base of the neck and this is a knot in the way on the left side when the left shoulder tries to "let" the stroke rise down the line. This blockage will either cause a bad stroke or the golfer will instinctively jam thru the blockage to get to a good pattern, with a tight jabby thru-stroke. This may be okay on short putts where distance control is not a big issue, but on mid-range or long putts, holding the head perfectly still thru impact can cause unwanted and hurtful tension.

I like to think of the base of the neck as one end of the top bar of a swing set, and the top bar running the line of the throat. If you move the pivot, you are swinging the top bar os the swing set. While a little swing to the right in the backstroke may be tollerable, a swing to the left in the thru-stroke is pretty harmful. So never left with the pivot, at the start going back or going forward of the bottom.

HEAD ON WALL EXERCISE

If you want, you can plant the top of your head against a wall and this will make the line of your throat stay in place like the top bar of a swing set. The line of the throat also matches the top edge of the putter face at address, as this is the middle / bottom of the stroke, so the throat needs to stay here and never cross to the left. Drive the lead shoulder back and under the fixed line of the throat and then let the stroke swing forward back under the stable throat. Stay back in the thru-stroke.

Cheers!

Geoff Mangum
Putting Coach and Theorist
PuttingZone.com
Golf's most advanced and comprehensive putting instruction.

Hi Geoff ::

Interestingly, you say:

"Because the putter head is out from the body and especially the feet, there is inevitably some centripetal force in the swinging of the mass of the putter head from back to front."


I think that "centripetal force" requires an applied torque to the rotating assembly - putter and arms.

What is the source of this "applied torque" ... ??

From Wikipedia for "centripetal force":

"The centripetal force is the external force required to make the body move in a circular path with uniform speed and directed towards the center. Hence it is a force requirement, not a physical force in its own right. Any physical force (gravity, electrostatics, tension, friction, etc.) can be used to supply the centripetal force. "

Cheers!

Geoff Mangum

Thanks Geoff:

It is my understanding that centripetal force requires an external torque, and it is this external torque in the putting stroke that I am inquiring about.

Perhaps we are converging on the contribution of torque and gravity in the putting stroke, and respectfully, I don't think we have satisfactorily resolved that issue. I tried to raise this same issue in the message entitled "Count Gravity" posted lower down on the forum board, and I hope I have correctly interpreted your explanation there. Your response would be appreciated there too.

Perhaps you could review that post in the context of this post on centrifugal force. Simply put:

Which has the greater effect on the putting stroke .. gravity force or centripetal force? Pendulum action or torque application ??

Dear Sammy,

CIRCULAR MOTIONS

The forces in circular motion do not require torque. A torque "changes" rotational motion either by changing the velocity or the direction of motion.

A ball swinging on a string in a circle around a fixed point is not undergoping torque. To imagine these forces without complications from gravity, first imagine a ball swinging on the end of a string around a pivot (top of pole with frictionless swiveling eye-hook) in "outer space" (i.e., microgravity). The ball is set in circular motion by some initial force. Perhaps this force could come from the hand of an astronaut sending the ball off at the end of the stretched string on a tangent to the circle or a perpendicular direction in relation to the string line. Actually, you would need to attach the ball to a fixed frame holding it out at the end of the stretched string and accelerate it up to the desired angular velocity and then disengage the frame from the ball to leave it alone. An example would be fixing the bottom of a ball to the far edge of a record player turntable, with a string already stretched taut from spindle to ball, starting the turntable up from zero to 33 1/3 rpms, and then disengaging the ball from the turntable. The ball would continue to rotate (revolve) on the end of the string in a circle at the rate of 33 1/3 rpms after detachment from the starter mechanism (turntable).

Then, once a steady rotational "speed" is set, the ball would swing in the same circle at the same angular velocity until the end of time. In this situation, the ball experiences "constant angular acceleration", which is a regular and always-the-same changing of the "direction" of tangential velocity. The tangential velocity (speed and direction of the ball instantaneously along the direction of the tangent) is changing in a steady way -- that is, the ball's tangential direction stays in a circling pattern, always changing in the same manner and extent moment by moment. But the "tangential speed" never changes and neither does the "angular acceleration." So, speaking non-technically, the ball "speeds" around in a circle in a steady or constant "speed."

The "force" here that changes the "velocity" (direction and/or speed) and hence "accelerates" the ball in a circular fashion is the "centripetal force". The centripetal force acts along the line of the string to redirect the ball with a steady "tug" out of the tangential direction back in towards the circular pattern. If you cut the string, the ball would NOT go straight away from the center of the circle, but would travel off on whatever tangent it was headed down at the instant the string was cut. The tension in the string "holds" the ball in the circle by constantly and steadily altering it OUT of its tangential direction.

A "torque" is what changes the circling ball out of its circular pattern, given the ongoing operation of the centripetal force thru the string tension -- knocks it out of a circle into a different direction or set of directions and/or "speeds it up" to a different "angular acceleration" than it has in its steady state.

The "centripetal force" of a string on a ball swinging on earth has to factor in gravity. There is a big difference between swinging a ball in a cirle on a string so that the plane of the circle is a) horizontal to the ground, b) vertical to the ground, or c) somewhere in between.

When the circle is horizontal, the relationship between the tangential velocity and gravity is always the same (90 degrees). Unless the string is at a minimum "tautness" with a minimum "centripetal force", the circle will "droop" out of shape. You have to swing the ball around with a minimum velocity (tangential velocity) and corresponding angular acceleration to keep the string tight enough so the elevation of the ball in its horizontal attitude does not droop. When the string is mimimally tight, it acts like a metal wire or stick instead of a string. Things stay in the same relationship -- no stretching, no drooping.

In the case of a vertical swinging in a circle (say, a golfer swinging his arms and a putter in a circle vertically around a pivot 54 inches off the ground), the relationship or difference in direction of the tangential velocity and the force of gravity is steadily changing in a cycle from "no difference" at 3 o'clock (right hander) as the ball / putter head swings vertically down and gravity also aims vertically down, to 90 degrees at the bottom 6 o'clock as the ball / putter head swings on a line aimed horizontally to the left with gravity aimed vertically down, to "opposite" directions at 9 o'clock when the ball / putter head is aimed vertically straight up but gravity is aimed vertically straight down (sort of "minus" 180 degrees difference), to 90 degrees difference at the top or 12 o'clock position as the ball / putter head moves on a tangent horizontal to gravity to the right. [This is the case with a vertical-plane shoulder stroke.]

In order to swing a ball on a string in a vertical circle in gravity, the "forces" needed to KEEP the string taut and thus KEEP the ball in a circle are constantly cycling thru in this pattern of changing relationship between tangential velocity (speed and direction) and gravitational force of acceleration straight downward. And, there is a "minimum" tangential velocity at the TOP of the swing needed to KEEP the string stretched out taut. This velocity depends on the length of the string, for the same reason that the velocity / acceleration pattern of a pendulum rod and bob depends solely on the length of the rod. The velocity of the ball at the bottom of the swing is a lot faster than it is at the top but the actual velocity at the top determines the velocity at the bottom. If you know one, you know the other. (See Nave's Physics for Centripetal Force in a Vertical Circle Swing)

PENDULAR MOTIONS

For a pendulum swinging in a vertical plane, the difference between swinging in a (complete) circle on a string and swinging like a pendulum on a string is that the pendulum swing has a maximum starting "height" on the circle, and is not therefore subject to the "minimum" tangential velocity at the top. The pendulum does not typically swing all the way over the top around in a complete circle (although it could). This means there is no "necessary" minimum velocity at the bottom. A pendulum swing is free to move only a tiny amount and with only a tiny velocity thru the bottom. What fixes the velocity at the bottom for a pendulum is a) how high up the circle it starts, and b) the length of the rod from pivot to bob. But GRAVITY ALONE "may" be the only force (acting straight down) that starts and accelerates the bob / ball / putter head downward, subject to the constraining "centripetal force" of the string / arms and putter shaft steadily altering the tangential velocity into a more horizontal direction as the putter head swings down and under the pivot thru the bottom of the stroke.

The force of gravity plus centripetal force are the only two forces really required for the pendular swinging. The horizontal momentum of the putter head steadily increases in the downstroke until it peaks right at the bottom, when the tangential velocity is 100% horizontal. This momentum is exactly the momentum required to carry the putter head up in the follow thru to exactly the same height it started down from at the beginning (ignoring air resistance and friction, etc.).

There is a complication though in relating a vertical circular swinging to a pendular swinging, and this shows up if you try to start the pendulum drop from a height above 3 o'clock. The required "tangent" for the first instant of motion of the putter head to send it on a circular path is not in sync with the direction of gravity. From this "above the 9-3 line in the top half of the vertical circle" starting position, a circular motion requires a tangential "direction" that is GREATER the gravitational force -- i.e., aimed somewhat horizontally and not straight down. If you leave the starting to gravity alone, the putter head will "flop" instead of swing out and down on a circle on the correct tangential starting path. That's because the tangential direction and the centripetal direction always have to be perpendicular in a circular motion and when the tangential velocity starts at zero and gets accelerated by gravity, instead of being accelerated by a contraption up to the minimum tangential velocity before release from the contraption, the tangential velocity at the start of the drop is aligned for DIRECTION only with gravity (always vertically down) and this DIRECTIONAL START is LESS OUTWARD than the minimum required by the length of the string to keep things taut on this upper half of the circle. The ball drops straight down, when to stay on a circular path it needs to be sent out and down with a minimum starting speed and direction somewhat horizontally outward, depending on how high above 3 o'clock it starts.

The angle of the tangential velocity above 3 o'clock (top half of the circle) in relation to the direction of gravity is LESS than 90 degrees. The tangential velocity and direction of the centripetal force are perpendicular to one another at 3 o'clock. Below 3 o'clock gravity pulls straight down in angles greater than 90 degrees to the tangential velocity and the taut string instantaneously redirects the fall so that the falling tangential direction and the centripetal "tug" of the string (arms plus shaft) are perpendicular to one another at all times. Above 3 o'clock, the tension in the string and the corresponding centripetal force is inmadequate to keep the ball on a circular path -- it droops. At 3 o'clock for a starting position, the tension is initially zero since the tangential velocity aligns with gravity, so gravity does NOTHING to stretch the string here. But as the ball starts to drop below 3 o'clock, the fact that the string won't reach where the ball is trying to fall creates the tension that corresponds to the centripetal force redirecting the ball not simply down, but down and under. This string tension and centripetal force steadily increases as the ball approaches the bottom of the swing, where the tension is maximal and directly and completely opposed to the line of action of gravity.

You can see the changing relationship between the tangential velocity vector (red) and the increasing tension vector or radial vector (green) as a pendulum bob swings thru the bottom of its arc in this Pendular Motion Java Applet. Notice that the red tangential vector "diminishes to zero" at the bottom. This means that the bob is gaining tangential velocity all the way to the bottom, just increasing its speed at a RATE OF INCREASE that is diminishing. But the tangential velocity at the bottom is ALL horizontal velocity, and this horizontal velocity is therefore at its PEAK velocity at the bottom. The green radial vector increases to a peak at bthe bottom, and this is to say that the string tension builds to a peak at the bottom.

So, a vertical pendular swinging is not the same as a swinging in a full vertical circle. The circular swinging requires some minimum tangential velocity at the top and a corresponding minimum tangential (horizontal) velocity at the bottom or the string will not stay straight and taut in the top half of the circle, whereas a pendulum swinging in the bottom half of a vertical circle does not have these minimums.

TORQUE

A torque is an influence that CHANGES rotational motion from one pattern to another -- from dead still to some rotational "speed" or from rotational "speed" A to "speed" B. (See Nave's Physics Torque Concept.) What is really meant by rotational "speed" is rotational acceleration, and what is meant by that is changing "direction" of the tangential velocity.

A torque is not needed to start a pendulum swing in a vertical plane in gravity from some height less than or equal to a 3 o'clock position, and gravity alone will suffice. Once started, no torque is needed to "accelerate" the putter head from its initial "zero" tangential velocity at the very start to its peak velocity at the bottom, which is the peak tangential velocity in the horizontal direction. The velocity that is increasing is BOTH the vertical velocity and the horizontal velocity. The "string" tension of the arms and putter shaft combine both of these velocity components at every instant into a tangential velocity. Gravity accelerates the putter head straight down and the centripetal force of the "string" constrains this accelerating fall to alter direction along an arc at the end of the "string" more and more horizontally to the exact bottom of the arc.

Suppose a golfer made a backstroke and then "tried" to let gravity make the stroke coming down, but his arms "drooped" out of shape and the stroke looked like crap. What's the explanation? The explanation is that when the golfer in a good stroke "drops", he does so in a way that the shoulder frame stays coordinated with the dropping of the putter head, and this means everything in between is also dropping in a coordinated way or unit -- the proverbial "triangle" remains intact. This takes a minimum body tension to keep the shape of arms and hands coordinated with trhe shoulder frame, but once set, there is no extra MOTION of body parts required to preserve this triangle. The bad stroke is just a golfer dropping ONLY the hands and/or arms, and not in coordination with the turning down and under of the shoulder frame so as to "keep up with" the dropping putter head. That's why it droops. Stay coordinated from shoulders to putter head and there is no droop -- just a nice swinging down and under of the triangle.

This tangential velocity at the bottom when it is horizontal is what determines how "fast" the putter head hits the ball (if impact is right at the bottom), but what determines how much "send" the impact gives the ball is this horizontal velocity PLUS the mass of the putter head. Momentum transfer is mass times velocity (along the direction of motion).

Now, if you wanted to ADD acceleration to the gathering horizontal velocity during the downstroke, THEN you would need a "torque." (Many golfers mistakenly "feel" by niave physcis notions that unless they use the hands and arms to "send" the putter head out there, their arms and hands will come uncoordinated -- not so: just set and keep minimal tension to preserve the triangle shape and drop everything wherever it wants to drop.) The only possible source of this torque is from an animate being, such as the human body. The tell-tale sign of adding torque is that the arms/hands go FASTER than the pure pendular swinging of the putter. The "string" is given ADDED tension for tugging the putter head faster than it would otherwise travel.

You can "feel" the added tension in the arms and hands and in the grip pressure and in the added reactive forces to keep balance. If the putter swings itself and the body keeps up, these tensions and pressures and balance reactions are minimal. That's why great putting is minimalist.

The bottom-line question is whether a 54-inch "string" plus a 350-gram putter head is sufficient to "send" a 45-gram ball far enough on a typical 9-Stimp green to get the usual job done without adding torque to the stroke. Taking a starting angle off vertical of 45 degrees (halfway up to the 3 o'clock position), the starting height is 38 inches. (See Trigonometry Applet.) The peak velocity (V) of an undamped simple pendulum's bob at the bottom of the stroke is V = SQR(2*gH) where g is the acceleration due to gravity (32 feet/sec*sec or 384 inches/sec*sec) and H is the height above the ground of the bob at release. Starting at 38 inches high, this pendulum stroke will impact the ball at a velocity at the bottom of 171 inches per second. A 360-gram putter head sends a ball off with an initial velocity of approximately 1.5 times that of the putter head, so the ball starts off at 257 inches per second (or over 21 feet per second). That's one heck of a blow! A Stimpmeter velocity off the bottom of the ramp that rolls any ball 9 feet is only about 70 inches per second or about 6 feet per second, so this 45-degree half-stroke is over 3 times faster than the Stimp and the ball will surely roll at least three times farther (so, over 27 feet to be sure).

That's a half-stroke powered solely by gravity without any torque at all. Stay relaxed at the top of the backstroke and drop the triangle and it will gather horizontal tangential velocity in a regular accelerating pattern all the way to a peak velocity at the bottom and impact, and this impact velocity plus putter head mass will be more than ample to get the distance covered.

In the rare case where the golfer needs any extra torque, he should not add it until impact is very near. That way, the tension is kept out until nearly too late to misdirect the blow. Addin g torque at this point still has to be done "smoothly" and "evenly," and this means the golfer has to be sensible of the gathering pace of the stroke downward, so he can match and just exceed it to add smooth torque.

I think you are just not quite understanding that "acceleration" for pendular or circular motion is really about the changing direction of the tangent, and not really about "pushing" the mass faster and faster. Gravity will pull the mass down always at the same rate of increase, and in fact pulls ALL different masses down at the same rate of increase for all masses (see Galilleo). That's not the issue -- the issue is whether the putter head mass gets going fast enough for thge required distance. For most greens and most putt distances, the answer is yes, you don't really have to "hit" the ball with torque, and letting the putter swing in its own way in gravity is plenty.

Cheers!

Geoff Mangum
Putting Coach and Theorist
PuttingZone.com
Golf's most advanced and comprehensive putting instruction.

Thanks for all that information, Geoff ... you're thorough as always and you make your case with conviction too.

Let's simplify it for the average golfer, who may not appreciate all the Newtonian Physics and it's effect on the putting stroke. As an example, let us consider a putting stroke that goes back only say 12 inches on a 54 inch overall swing radius ... which amounts to approximately a 12º angular displacement for the backswing. By your concept, we have a 12º pendular swing subject only, or mostly, to the force of gravity.

You will agree that a body 'torque' is required to initially raise the putter, hands and arms into the backswing position. Then at the point of reversal the putter stops instantaneously and the downstroke begins. By your thinking all that is needed is for the hands to support the putter outward at it's 'lie angle' as a cantilever, and then the force of gravity will act on the putter, hands and arms to create a pendular action to impact ... and the body torso and shoulders must be internally torqued to synchronize with the gravity-induced falling putter-hands-arms one-piece assembly.

If additional torque need be added to the arms-hands-putter assembly, it should be applied only towards the end of the stroke approaching impact ... say in the last 6º of downstroke arc. Obviously this added torque can only be generated at the shoulder span to swing the arm-hands-putter assembly.

My question to you is: since maximum torque is required at the end of the backswing, how can one effectively shut off the "torque feeling" at stop reversal point to allow gravity force to take over? If you depend on the initial momentum developed in the first half of the backswing arc, and then gravity decelerating the putter to reversal stop, are you not introducing a combo torque-gravity component to the backswing that is highly complicated, conscious and very subjective?

If the backswing momentum of the putter is not fully defeated by gravity force, then you must use your hands and arms to stop the backswing, which is another torque application that must continue into the downstroke before it can be released to gravity forces. In effect you are creating a mild "lashing" effect at swing reversal that is rife with torque forces.

What I am suggesting is that the putting stroke is a combination of torque and gravity forces, with the torque forces being predominant and the gravity force only secondary if not negligible to the putting effort. I am not able to calculate and quantify the torque-gravity components of the putting stroke, but I believe my intuitive analysis is correct.

I do appreciate your conceptualizing the putting stroke as 'pendular' to psychologically eliminate unwanted physical body stresses, but to abandon the stroke to the force of gravity may not be scientifically correct.

Since we are only considering standard hand-held putters, perhaps your concept of gravity putting should be tested using (a) belly putters, and (b) long putters ... where both are pinned to the body and thus isolating the swing radius to their shaft length. I invite you to extend your analysis to these putters and explain to us how gravity and torque intermingle when the top of the putter is pinned to the still body. (Is this putting stroke one of 'lifting' and then 'shoving' these putters?!) Sincere thanks ...

Dear Sammy,

Your creative insight is pretty sharp! But the biomechanics of human movement is not quite like the "mechanics" that an engineer might envision.

Human movement is powered either by internal forces generated by the biochemical energy and mechanical properties of the human body, by gravity, or by externally applied forces from some other agency. One golfer putting on a green usually has a bit of all three in some combination: his body, gravity, and his putter and ball.

Let me focus on this part of your response:

"My question to you is: since maximum torque is required at the end of the backswing, how can one effectively shut off the "torque feeling" at stop reversal point to allow gravity force to take over? If you depend on the initial momentum developed in the first half of the backswing arc, and then gravity decelerating the putter to reversal stop, are you not introducing a combo torque-gravity component to the backswing that is highly complicated, conscious and very subjective?

If the backswing momentum of the putter is not fully defeated by gravity force, then you must use your hands and arms to stop the backswing, which is another torque application that must continue into the downstroke before it can be released to gravity forces. In effect you are creating a mild "lashing" effect at swing reversal that is rife with torque forces."

In terms of the body's movement by internal forces, what is powering the backstroke are the muscles that send the shoulder assembly lead-side down and under going back. What is bringing the backstroke to a conclusion is some combination of 1) the spent force that started the motion, 2. braking muscles, 3. gravity resisting the upward action of the body and putter. The third contribution is fairly evident, as this is what slows and stops a pendulum swing at the top of the follow-thru. The first two contributions are a bit tricky mechanically, neurophysiologically, and psychologically, but that is "tricky to explain," and not really "tricky to do." Actually, it's very smooth, and precise, and natural, and instinctive, and thoughtless, and repeating, and simple and easy to perform -- once you learn how to do it.

AGONIST AND ANTAGONIST MUSCLE PAIRS

Human movement by internal power is always accomplished mechanically by some combination of "ballistic" agonist muscle action acting to change body parts about a joint and usually but not always coupled with antagonistic muscle action about the same joint to "brake" and counter the ballistic action and thus bring it to a conclusion. Muscles only contract to provide power, so one muscle alone is merely ballistic in action, and controlled and precise movements with definite extents and timing require controlling the LEVEL of the ballistic action and also the BRAKING of the ballistic action.

SPACE SHUTTLE DOCKING

Consider the Space Shuttle trying to dock with the Space Station. The tiny jets on the BACK of the Space Shuttle fire in a controlled burst (such and such a direction, such and such pressure, such and such period of time). This blast (once terminated) accelerates the Shuttle forward from relative zero velocity to an approach velocity of 5.5 feet per second towards the Space Station. This approach velocity in outer space will continue indefinitely until the Shuttle either hits the Space Station or until something slows and stops the Shuttle. So the commander fires tiny jets on the FRONT of the Shuttle in a well-timed and appropriate level of burst, and this BRAKES the Shuttle. If done properly, the front jets slow the Shuttle down to a creep and the Shuttle either STOPS right in contact with the Station's dock or ever-so-slightly BUMPS into the Station and the mass of the Station then STOPS any further motion of the Shuttle as an external force.

Is it possible for the commander to simply calculate the BACK burst to start with, so that he perfectly arrives at the dock when the effect of the burst is spent and the Shuttle stops perfectly at the dock without ever having to fire the FRONT jets and also without bumping the Space Station and using the Space Station to stop the Shuttle? No. The tiniest burst of BACK jets IN OUTER SPACE will impart a perpetual forward motion to the Shuttle that never stops until something else stops it, and in the absense of the Space Station there is nothing else to stop the Shuttle's forward motion -- no gravity, no FRONT jets.

TENNIS SERVE BALL TOSS

A human moving an object on earth with internal forces and gravity, but without help from an external agency, is the tossing of a tennis ball for a serve to a well-practiced height. The player has to toss the ball to a height that is slightly higher than the full upward and stretched reach of the arm and racket and then hit the ball just after it reaches the top and starts falling back down. (See these videos: Tennis Channel and BBC Tennis Instruction.) How does the brain get this toss done consistently the same with the equipment of the human body? TIMING.

The timing is not unlike the timing of the bursts of jets on the Space Shuttle. The upward swing of the tossing arm and hand is powered by agonist muscles operating about the shoulder joint with a minor contrbution of muscles operating about the elbow and wrist and perhaps fingers as well. The calibration of the ballistic action is done by the instinctive processes of the brain in light of the "load" of the tennis ball and the inertial mass of the body segments involved. The braking and release of the ball is mostly TIMED by the braking action of the antagonist muscles in the context of the gravitational resistance to the the arm and ball moving upward. This braking action of muscles at the shoulder joint etc., adds "definition" to the point where the arm and hand STOP and the ball is released to continue upward. The whole business is calculated to send the ball to a well-practiced height that is a bit higher than the tossing hand by at least one tennis racket length (actually, that plus a little more). The TIME it takes the ball to reach the apogee of the toss and then start to fall is also the TIME the player requires to make his racket-hand backswing and deliver the fully stretched swing to meet the ball just after it peaks. The player always knows exactly how long it takes to reach the apogee, and this timing is learned so that it fits the time it takes the player to swing and meet the ball just after it starts to fall back.

CEREBRUM / CORTEX VS CEREBELLAR FORCE CONTROLS

Most people assume movement is handled by the "motor cortex" but this is not an accurate or complete picture. The motor cortex controls the ballistic aspect of muscles, but the cerebellum control the braking action of muscles and also contibutes to the level of ballistic action in the motor cortex. The doctor in testing the health of your cerebellum says "make a fist in front of your nose and resist my pulling your forearm and fist away from your face." As he pulls, you resist the load of his pulling with a steady "ballistic" firing of muscles that counters the pulling. He then suddenly and unexpectedly "releases" his pulling and your fist snaps back at your nose. Your ballistic muscles are uncorked and take off right at your face. IF you stop the fist from hitting your face, you have a cerebellum in normal working order. If, however, your fists pops you in the face, you need to schedule another appointment with the doc. The cerebellum upon the doc's sudden release rapidly takes into account the degree of the ballistic force propelling your fist at your face and calibrates the resisting force of antagonist muscles to stop the fist just short and just in time. Back jets, front jets. Forwards jets, backwards jets.

Likewise, if I ask you to smash your two hands together violently in front of your face like a powerful thunderclap, you accomplish that with "ballistic" action of the cortex, with no concern of thought of ever slowing the hands as they race towards each other. But if I ask you to repeat this action and this time to STOP your hands just short of meeting, and to do so as violently at the start as you are capable, you can also do this, but this action in the braking of the hands before impact is controlled by processes of the cerebellum. Then if I ask you to smoothly wave your hands in the air like a conductor leading his orchestra, then the cerebellum affects both the ballistic aspects and the braking aspects to make the waving hands adhere to the tempo of the music.

That means that the "motor cortex" by itself is controlling "ballistic" action with force and direction of motion without concern for stopping or braking the motion, whereas the cerebellum is concerned with calibrating the level of ballistic action and with TIMING the braking action to define the stopping position of the motion. Between the two processes, the cerebellum has a much more complicated and precise job to perform in estimating the time to impact of the ballistic action, timing the onset and duration of braking muscles, and calibrating the force of braking muscles. Fortunately, the cerebellum is a SUPERIOR TIMING MACHINE for operating the human body for careful movements that get the job done effectively and precisely.

A person suffering degeneration of the cerebellum has "dysmetria," an impairment of controlling the ending of limb motions such as reaching and throwing. This most typically results in "overshoot." In other words, the braking and defining of the motion is impaired (no front jets). "Undershoot" is a problem of the level of ballistic action not being modulated correctly for the loication of the intended target (e.g., a door knob).

The cerebellum does not participate in the conscious processes of the cortex and the "mind." The cerebellum is stuck onto the brain stem at the back of the head, where it influences the cortex and the acting body by "regulating" the signals of the "motor cortex", but you cannot "talk to" the cerebellum with the silent inner voice of your mind. That would be like "talking to" your kidney or your liver. The cerebellum is biological tissue that functions as an organ to process and produce neurochemical impulses. It ain't listening to you. That makes these SUPERIOR TIMING PROCESSES for movement NON-conscious and instinctive. If the processes did ALLOW intrusion from conscious or even cortical processes in the calibrating of movement controls, that would be a TIME-CONSUMING and UNNECESSARILY COMPLICATED mixture of processes that would make human movement the equivalent of the the centipede trying to think how to walk. So evolution has protected our movement processes from the vagaries of our cortical, conscious processes. No think, just putt.

THE SMOOTH BACKSTROKE

So what happens in the sort of smooth backstroke that is instinctive and that gets the size of the backstroke correct for a given putt with the same TIMING every stroke regardless of the length of the putt?

1. The brain is familiar with the inertial "load" of the putter and arms and so accurately knows in advance the sort of forces required for a given backstroke (this is similar to the engineers designing the size and force and positioning of jets in light of the mass and shape of the Space Shuttle).

2. The brain is familiar with the relative masses of your putter head and the ball and so knows in advance what results when putter head moving with velocity A and mass X meets ball at velocity Zero and mass Y (1/7th X or thereabouts), in terms of how fast the ball starts out after impact.

3. The brain is familiar by experience and warmup and other putts etc. with the speed of the green, and thus knows in advance about how far a ball sent off with force and velocity A will roll in total across this green before the friction in the grass brings the roll to a conclusion.

4. The brain is familiar with the TIMING of the backstroke and the TIMING of the downstroke, so that every backstroke is performed by the human agency of the body in a manner such that the movement blasts off and coasts to a stop at SOME or ANY SIZE backstroke in exactly the same amount of time every backstroke, regardless of the SIZE of the backstroke. Every stroke from top of backstroke to impact also always takes the SAME TIME regardless of the size of the stroke.

A short backstroke and a long backstroke both take exactly the same TIME from start to finish. So what determines the SIZE of the backstroke? The interaction of the targeting information supplied to the brain for the intended length of the putt (where the roll needs to stop) with the instinctive movement processes of the brain.

The targeting information is the process that answers this question: "Where am I and where is the location across this green in relation to my position where I want the rolling to come to an end?" Most of this comes in spurts and from memory and experience, while the golfer walks to the green looking at his ball and the hole, while he waits his turn, while he watches the caddie pace his way to the flag to remove the pin, while he watches others putt, while he walks about on the green and reads his putt, aims his putter and adopts his setup, and then he polishes off the business with a "look" or turn of face from the ball to the target location and back. This NECK TURN is tracked by position nerves in the neck that feed straight into the cerebellum, and supplies the final piece of information needed for the instincts to give you the correct backstroke size for this putt, in light of your body, your putter and ball, this green speed, and your TIMING or TEMPO going back and coming down.

Because the instincts KNOW IN ADVANCE the timing coming down to impact, the instincts know that a bigger stroke has to move more quickly coming down to keep the total timing the same from small strokes to big strokes. That is, a bigger stroke has a faster impact speed of the putter head on the ball. Not only does the brain know this in general, but the instincts also KNOW VERY PRECISELY exactly how much "send" will result at impact from backstroke size A and from bigger backstroke size B. And so long as you stick to the TIMING both back and down, EVERY BACKSTROKE SIZE CORRESPONDS TO ONE AND ONLY ONE VELOCITY AT IMPACT. And the relationship between every possible backstroke size and every unique putter head speed at impact that corresponds to each backstroke size effectively constitutes a TOUCH DIAL that never changes. Getting "used to" a green speed on a particular course on a given day is a matter of bringing your machine-like DIAL of touch for backstroke sizes and impact speeds to the green and seeing what size rolls result when you stick to your timing. Once you see this, the green speed gets internalized and you're good to go with your DIAL.

Working this whole system in reverse on a given putt on a given green, the brain / instincts KNOW IN ADVANCE what putter head impact is required and appropriate to send the ball across the green with the correct stopping at the end, and from this the instincts then KNOW IN ADVANCE how big the stroke has to be to match this impact speed, and then working backwards still, the instincts thru the cerebellum control the ballistic muscles and the braking muscles (if any) in the context of gravity resisting the upward action of the backstroke and within the TIME CONSTRAINTS of how long the backstroke can last, so that the golfer simply "pulls the trigger" and the backstroke blasts off and coasts to a stop at the top of the backstroke at a size that is VERY PRECISE AND CORRECT and so that the TIME of the backstroke is not altered.

More specifically, this instinctive process is the management of the ballistic blast off of the backstroke in the context of gravity. Unlike the Space Shuttle docking and more like the tennis serve toss, the golfer can rely upon gravity to brake the backstroke evenly and smoothly so that the backstroke COASTS to a conclusion AT THE RIGHT TIME. The size of the backstroke, then, is not really a matter of braking with muscles but almost entirely if not completely a question of the LEVEL of the BALLISTIC blast off. That makes the backstroke more of a tennis serve toss of the arms and hands and putter as a unit, but not to a predetermined position or top of backstroke as the tennis toss has a same-every-time height of the toss. Instead, the enterprise of the backstroke in putting has as its objective the same TIMING every backstroke.

So, this means that the instincts are accurately managing the "blast off" of the toss back of the arms, hands and putter as a unit. It's like shoving a swing back and up from hanging beneath the swing bar with a mind to make the toss back last a predetermined time, whether the chair of the swing is empty or loaded with a petite two-year-old or strained by a corpulent teenager. Every stroke takes the same time going back. The instincts know how to do this TIMING because of the familiarity of the load of the arms and hands and putter in gravity and how gravity will operate to slow and stop the movement. It's all a matter of the instincts calibrating the blast off for the load, so the backstroke lasts the right / same time before it coasts to a stop. A blast off for an empty swing seat that will last, say, one full second, and coast to a stop under the resistance of gravity at the top of this backstroke at the end of this one second, will NOT BE A LARGE SIZE BACKSTROKE. But shoving a thirty-pound child hard enough to get the backstroke to persist for one full second will take more umph at the start and also WILL RESULT IN A MUCH LARGER BACKSTROKE. In the putting stroke, the required "send" that the instincts recongnize is the equivalent of the weight of the child in the chair, or the "load" in the canon that has to be shot out going back.

So what is the relationship between the calibration of the ballistic force at the "toss back" of the backstroke and the SIZE of backstroke that results? How is that done so the instincts get the blast off LEVEL OF FORCE correct?

Basically, the targeting information acts like a measuring cup loading the canon of the ballistic movement with X amount of gunpowder. Targeting that says impact "send" A is needed, and thus backstroke size X corresponds to that, results in measuring into the canon just the right amount of gunpowder to blast off the stroke backwards so that the stroke lasts the same-as-ever time but reaches the right SIZE. The targeting for a short putt pours in half a cup of gunpowder, whereas a 22-foot putt pours in 2.3 cups of gunpowder. (Yes, the instincts are that precise -- that good at calibrating force and timing.)

A REALLY GOOD BACKSTROKE DOES NOT INVOLVE BRAKING ACTION, JUST THE CEREBELLAR CALIBRATING OF THE TOSS BACK FORCE OF BALLISTIC MUSCLES WITHIN A TIMING PATTERN, A LOAD PATTERN, A GREEN SPEED CONTEXT, AND IN LIGHT OF TARGETING REQUIREMENTS, KNOWING HOW GRAVITY ALONE WILL BRING THE BACKSTROKE TO A COASTING STOP WITH THE RIGHT TIMING AT THE RIGHT SIZE .

This means that the backstroke does not feature intentional defining. The backstroke is NOT stopped by the body, but by gravity alone. The tennis ball is not stopped at the top by anything other than gravity and neither is the backstroke. It's just that the backstroke always has the same TIMING. A tennis toss has the same timing AND the same ending position of the toss every time. Putting is more complex because all putts are the SAME EXCEPT FOR THE SIZE OF THE BACKSTROKE, while tennis serves are pretty much all the same size of arm action.

On a mental level, there is no PLANNING of the size of the backstroke, there is no ANTICIPATION of the size of the backstroke, there is no MONITORING of the size of the backstroke, there is no STOPPING of the backstroke at a predetermined size with braking muscles, and there is no DISSATISFACTION OR REACTION in case the backstroke size does not match some conscious notion. There is never any "trying" to perform a backstroke of the right size. Instead, there is an intention to stick to the timing going back, always the same. And the less conscious this timing becomes, and the more an unvarying habit, the better the touch. A total;ly non-conscious golfer relying on his insttincts will simply look from ball to target and back and then pull the trigger with a toss-back of the putter and his arms and hands in a coordinated manner. If he thinks at all, it is to adhere to his timing.

So, a really good backstroke that is instinctive is coordinated with gravity and this makes it SMOOTH at the start and makes it coast to a stop after the same-every-time period of time. There is no counter-torquing to stop the backstroke.

DOWNSTROKE

Since there is no counter-torquing to STOP the backstroke described, the backstroke simply glides or coasts to a stop after it runs out of steam against the resistance of gravity. At this "pause" at the top of the backstroke, there is a situation the golfer needs to appreciate. The SIZE that has resulted by the instincts was CHOSEN only because the brain assumes you will also have the same-every-time TIMING in the downstroke to impact and this will generate the anticipated putter head velocity at impactr. Whatever motion pattern the golfer uses to time the downstroke, he better stick to it this stroke, or the impact velocity will not be what the instincts are attempting to produce. Sticking to the downstroke timing guarantees that the effort of the instincts is given effect. The size of backstroke will correspond to the correct impact velocity ONLY IF the golfer adheres to the downstroke timing.

WHATEVER TEMPO the golfer is used to, he better stick to it.

But there are tempos and then there are TEMPOS! Especially for the downstroke. Gravity alone will generate a PERFECT downstroke timing that is ALWAYS THE SAME TIMING, whereas a human by "trying" to learn and consistently generate a timing in the downstroke will NEVER EVER BE AS CONSISTENT FOR TIMING AS HE WOULD BE IF HE SIMPLY LEFT THE DOWNSTROKE TO GRAVITY ALONE. So all golfers have a choice: 1. do the downstroke timing yourself, or 2. let gravity do it.

The golfer who chooses to "do" the downstroke timing will inevitably "torque" the downstroke from the top of the backstroke or somewhere further down with internally generated muscle power. That would be you, Sammy.

The golfer who chooses to "trust" the never-changing LAWS OF PHYSICS to work like they are supposed to work simply patiently waits as the downstroke transpires all by itself. The arms, hands and putter at the top of the backstroke arrived without any counter-torquing or braking muscle tension and the ballistic tension that fired the stroke back is all spent, so there is a happy state of relaxation as the arms, hands, and putter arrive at a coasting stop. Withn patience and resistance to the urge to draw or bring or pull the stroke forward, the golfer's stroke simply transitions on its own headed "wherever gravity wants." Each separate piece of mass of the arms, hands, and putter ALL drop straight down towards the center of the earth, towards whatever is directly below that piece. The golfer simply stands there keeping the pivot of this "swing" steady at the base of his neck and "lets" the stroke swing down and under gathering momentum to the bottom of the stroke. He also "lets" the inertial properties of the putter, arms, and hands MOVE themselves past impact on a slightly rising, square trajectory down the line. Somewhere very near or just past the bottom, the forces of gravity begin to resist the upward action of the stroke and the impact with the ball at about 1/7th the mass of the putter head also tends to stall out the upstroke, so for BEAUTY'S SAKE the golfer adds a touch of torque to smooth out the stroke into a coasting finish. But again, the golfer does NOT define or even expect to produce a finish at a predetermined SIZE or POSITION. That takes care of itself. Then the downstroke TIMING to impact is perfect or more closely so than voluntary human effort, and the TOUCH is right.

Golfers who torque the downstroke "feel" in control of their touch on a conscious level, but they really are bypassing an opportunity to do it a different and a better way. Only a very few of the top putters in history ever get a truly instinctive backstroke and downstroke that conforms to gravity. Their superb putting touch is effortless, repeating, and instinctive.

Loren Roberts' downstroke has been timed at 63 beats per minute on the metronome. because a gravity-only stroke would be about 60 beats per minute, Loren Roberts has evolved into a downstroke that is very nearly devoid of human torquing. The only possible evidence of human torquing in his stroke is a mere 3 beats per minute worth of voluntary muscle activity, and this may not be any muscle action at all -- it may simply be that gravity timing with his body etc. IS 63 bpm on the nose.

Likewise, Ben Crenshaw has evolved a very leisurely stroke and he has summed it up in the following quote: "Once I start the putter back, it seems as if the stroke completes itself." That is, he simply witnesses gravity making his stroke for him, without contributing his voluntary try-based muscle action in the downstroke. He "lets" the downstroke happen rather than tries to "bring" the putter thru impact.

WHAT MUSCLES USED HOW

In the backstroke that I am describing, the muscles that send the shoulder frame lead-side down and under the stable neck and throat are those that tug the upper torso down at the pelvis on the lead side. This contraction is not coupled with a braking action of muscles on the opposite side of the upper torso, although there is a natural limit to the stretching of the tissues and structural components on the back side of the torso as the stretch extends. So the backstroke is a toss back of the lead-side contraction that is resisted and ended by gravity and the internal limits of the body, and NOT by a counter-torquing with antagonist muscles. That would be "defining" the backstroke size.

The instincts do not define the backstroke or the follow-thru stopping point in precise motions. Instead, the instincts size the backstroke in light of the downstroke TIMING, and work backwards from the latter to set the SIZE of the backstroke in the context of the backstroke timing. The varying sizes are all generated out of consistent back and down timings that the brain is used to and expects to use on any given occasion.

I would invite you to watch the tennis videos above once again and notice the timings of the toss for the "backstroke" of the toss and for the forward-stroke" of the toss. These timings in each toss are always the same. If you bid a golfer to roll golf balls across a green to a fringe from starting spot A and watch his timings, and then move him to a different starting spot B and again watch his timings, you will see that the backstroke timings and the downstroke timings are all the same, whether he stands at A or stands at B, and whether the SIZE of the backstroke at A is larger or smaller than that at B. And you can also observe that the golfer is NOT defining the tops of the backstroke or the thru-stroke if he looks smooth and fluid, i.e., instinctive.

Now don't get me wrong. Golfers CAN get pretty darn good by using a tempo faster than gravity coupled with torquing and counter-torquing and defining the size of the backstroke and thru-stroke with braking action, but I contend without any reservation at all that this is NOT as good as these golfers can be and that an instinctive approach to touch is MUCH MUCH MORE CONSISTENT AND PRECISE. Yes, it takes a bit of good instruction, astute learning, and getting used to, but if it didn't, the Loren Robertses and Ben Crenshaws wouldn't be as rare in the world of golfers, now would they?

Nor am I saying that a gravity-sponsored stroke is totally devoid of braking action of downward torquing. In the ideal case, this is true. But in reality, golfers are progressing on a learning curve towards the ideal and may get very near it and fluctuate to and fro a bit. The golfer who desires a smooth, instinctive stroke will also DESIRE the feeling of total relaxation at the top of the backstroke and the non-action of patiently waiting for the stroke going down and thru to unfold according to inevitable physics without interference, and he will also DESIRE the coordination throughout the stroke of the shoulders, arms, and hands with the motion of the putter head in a total system back and then down and thru. He will also DESIRE the absence of braking action at the top of the backstroke and the top of the thru-stroke and the absence of downward torquing action at the start of the downstroke and the pleasure of simply "riding" the stroke down and thru without trying to speed it up, knowing that what impact velocity the instincts have chosen will be better than he can come up with by "trying something." If in fact the golfer finds himself with some residual braking tension at the top of the backstroke, he will have to learn how to "relax" and let the stroke drop. But it is better not to develop this braking tension to begin with -- then the stroke is purely effortless once the backstroke tosses back with instinctive force.

Bad golfers have a lot of "lashing" in their putting stroke, as you say. Good putters do not have much violence or "lashing" going back or going down and thru in the putting stroke. The less the better. The best putting is minimalist.

Enough for now. Great question. I hope this helps.

Cheers!

Geoff Mangum
Putting Coach and Theorist
PuttingZone.com
Golf's most advanced and comprehensive putting instruction.

Thank you Geoff for your complete and concise explanation of your "gravity-sponsored" putt stroking concept.

Questions that arise from your posting are:

1. If the ideal stroking is that subject only, or mostly, to gravity forces, this would mean that the longer the putt, the longer the backswing. Have you plotted the typical length of backswings for a given green speed and given weight of putter design, just for illustrative purposes?

2. Instinct seems to be a big factor in the "gravity" putting stroke, which reasonably is a function of the individual golfer's neuro-muscular and brain characteristics. This would imply that your putting method would require substantial practice to ingrain the proper instincts for consistent performance. Given that most recreational golfers do not practice anything, is your method not recommended because it is too instinctive for their uncoordinated body and uneducated mind? Instinct can be chaotic.

3. Learning the "gravity-sponsored" putting stroke requires "relaxation", which brings up the issue of "conscious learning" versus "semi-conscious performance". It would seem that a high degree of kinesthetic ability is required to develop the instinct for this putting method. How does a novice begin the learning process to relax but still control and vary the backswing arc for different distances?

4. Unanswered question from my previous posting:

"Since we are only considering standard hand-held putters, perhaps your concept of gravity putting should be tested using (a) belly putters, and (b) long putters ... where both are pinned to the body and thus isolating the swing radius to their shaft length. I invite you to extend your analysis to these putters and explain to us how gravity and torque intermingle when the top of the putter is pinned to the still body. (Is this putting stroke one of 'lifting' and then 'shoving' these putters?!) Sincere thanks ..."

I may have more hopefully "good questions" that are worthy of discussion and clarification. Thanks again ...

Dear Sammy,

1. If the ideal stroking is that subject only, or mostly, to gravity forces, this would mean that the longer the putt, the longer the backswing. Have you plotted the typical length of backswings for a given green speed and given weight of putter design, just for illustrative purposes?

Yes I have.

2. Instinct seems to be a big factor in the "gravity" putting stroke, which reasonably is a function of the individual golfer's neuro-muscular and brain characteristics. This would imply that your putting method would require substantial practice to ingrain the proper instincts for consistent performance. Given that most recreational golfers do not practice anything, is your method not recommended because it is too instinctive for their uncoordinated body and uneducated mind? Instinct can be chaotic.

No it does not imply the need for substantial practice and it is not at all idiosyncratic to the specific golfer. All human neuromuscular systems get trained by reality and gravity, and these don't vary for one golfer or another. All that varies is the exact physical size, shape, masses, and personal experiences of the individual. But most adult golfers fir within a fairly common range of size and shape for purposes of making a putting stroke, so these individual differences don't make that much difference to the neurological "instincts" for adult human movement in one gravity, one reality. This brute fact is borne out by the numerous successes I have teaching adult novice golfers great touch in one short lesson to the extent these novices are able to lag over 100 feet to a far fringe and stop the ball just short instinctively within about 20 minutes, and know how and why it works that way. It's basically just look and putt with good backstroke tempo and then the putter and arms swing and gather speed down into solid impact -- no speeding up, no slowing down, no shortening the timing or extent of the backstroke.

3. Learning the "gravity-sponsored" putting stroke requires "relaxation", which brings up the issue of "conscious learning" versus "semi-conscious performance". It would seem that a high degree of kinesthetic ability is required to develop the instinct for this putting method. How does a novice begin the learning process to relax but still control and vary the backswing arc for different distances?

The relaxation is strictly only required if something needs relaxing at the top of the backstroke. Ideally, there is nothing to relax, since the moving parts going back don't "clinch" to hold things still at the top of the backstroke. But realistically, the normal human pattern of agonist-antagonist muscle activation is the well-known "tri-phasic" pattern illuminated by researchers such as Hallet 1975 and Hallet and Marsden 1979. One recent researcher describes typical "joint-torque movements" as proceeding according to simple rules for paired muscles:

"Movement is smooth with a velocity profile that has a single peak. Joint torque is a biphasic pulse. The acceleration impulse (integral of torque from onset to peak velocity) increases with distance, load, and speed. Changes in distance or loading do not alter the initial rate of rise of the torque, despite the fact that both affect movement speed. There is a proportional change in the initial rate with deliberate changes in speed. The agonist muscle initiates a fast movement with an EMG burst, the area of which is proportional to the accelerating impulse. The rate of rise of the burst is independent of distance or load and scales with intentional changes in speed in the same way as does the initial rise in joint torque. The duration of the agonist EMG burst increases with distance and load but is not directly affected by speed, although burst duration is a difficult parameter to quantify because the end of the burst is often poorly defined. The antagonist muscle first becomes active at a relatively low level shortly after the agonist and then produces a later, more or less distinct burst of EMG activity to slow and arrest the movement at its endpoint. The onset of this burst is delayed for movements over longer distances or with greater loads and is earlier if the movement is intentionally faster. The area of the antagonist burst increases with inertial load or intended speed and decreases with viscous and elastic loads but has only a weak dependence on distance."

Gottlieb 1998. This movement specialist describes the typical pattern thusly:

"As a concrete example, consider the classic neuromotor implementation of a simple point-to-point target tracking movement involving one joint, such as an elbow flexion-extension movement. From a neuro-control perspective, moving quickly from one point to another is initiated by strongly activating the agonists (prime mover) while relaxing any drive to the antagonists. This causes a muscle-induced moment across the joint, which will cause a movement to be initiated toward the new, desired target position. The acceleration will depend on the inertia of the segment to be rotated (Newton's law) and the velocity will increase as this acceleration is integrated. After reaching roughly the half-way point, there is a need to start decelerating the limb segment, i.e. to start planning how to stop. One approach might be to simply turn off the agonist drive at just the right time and "coast" into the new position (taking advantage of some natural "viscosity" (velocity-dependent friction) within the muslce-joint apparatus. But in general, there is a need for active braking, or "clamping" of the movement through a temporary change in sign of the moment. This is accomplished by activating the antagonist muscles while lowering the neuromotor drive to the agonists. The movement rapidly slows toward zero. But since the new moment is not functioning as a frictional brake, there is often a need for an additional agonist clamping pulse. We've just described the classic "tri-phasic burst" pattern (agonist-antagonist-agonist) for very fast goal-directed tracking movements that has been observed across many joints (e.g., seen in EMG's for isolated movements of the elbow, shoulder, wrist, horizontal head, ankle). Typically the first (agonist) burst is large in both pulse magnitude and width (e.g., over half of the movement time), the second (antagonist) burst starts just before the first agonist burst ends and is nearly as high in magnitude but for less time, and the third (agonist second burst) overlaps some with the end of the second. Also, there is often a degree of coactivation around and shortly after the end of the movement (temporarily "stiffening" the joint) that gradually dies down. Finally, there needs to be a sustained "step" increase, typically small, in the agonist relative to the antagonist so as to maintain the new joint position and not drift back towards the old position."

Jack Winters, Neurorehab Module, Marquette University. The "triphasic" pattern is agaonist to move the body part about the joint, antagonist to slow and stop the movement, and then agonist joinging in with antagonist to "hold" the position.

So, a beginner normally "puts" the putter back to a certain position, where it gets held briefly, and then he "brings" the putter back down and thru and again "puts and holds" the putter at a pre-defined stopping position in the follow-thru. This golfer thinks he is thereby "in control." To teach this golfer a better pattern, I get the golfer to make his normal backstroke and then "freeze" at the top of the backstroke. I then "assassinate" him with a figurative shot thru the head, and his stroke just happens. I also take a golfer and lift his arm up and out to level with the ground and then tell him I am going to let go of his arm and that he should first make his arm go "dead". Then I let go. The student's arm almost always floats there and does not drop. This shows the student what is "not relaxed." I then illustrate relaxing by having them lift and then drop my arm. It drops like a dead thing to my side. This is not a "high degree of kinesthetic ability" as you say, but simply overcoming the ever-present tension we maintain to "present" our bodies in public. Non-movement is inhibition of this holding -- holding in place is both agonist and antagonist muscles in a pair firing to oppose one another in a "balance of power". Relaxing is declaring peace so all the muscles just relax and go home.

But you are right: there is a big difference between a voluntary activiation of muscles to make a movement and a deliberate de-activation of muscles to make a movement, or to "allow" a movement.

4. Unanswered question from my previous posting:

"Since we are only considering standard hand-held putters, perhaps your concept of gravity putting should be tested using (a) belly putters, and (b) long putters ... where both are pinned to the body and thus isolating the swing radius to their shaft length. I invite you to extend your analysis to these putters and explain to us how gravity and torque intermingle when the top of the putter is pinned to the still body. (Is this putting stroke one of 'lifting' and then 'shoving' these putters?!) "

So long as the stroke is made with the shoulders moving in the same manner as they move for a conventional-putter stroke, there is no difference worth talking about. If you use the hands and arms for belly putters and long putters while leaving the shoulders more or less out of the action, then, yes, there is a difference. When you make the stroke with the shoulders, there is no need to make an extra pulling of the top of the handle into the chest to keep it there. Nothing about the shoulder action challenges the top of the handle to do anything other than stay put. But if you move the putter back and thru more with the hands and arms working independently of the shoulders, then this action could easily pull the top of the handle out of contact with the body. So for this sort of stroke, the golfer unreflexively "holds" the top of the handle tucked up against his body. This "set" is made secure before the stroke starts. Then the gripping of the putter itself PREVENTS the hands or arms from lengthening away from the body during the stroke. Even so, the hands can head off track and rise up too high, so there is another dimension to the stroke that has to be respected. Belly putters and long putters need to be swung on a stay-low arc that sweeps no higher than necessary. All of this tugging and pulling basically spoils touch for any appreciable distance. Other than thse comments, I personally have little inclination to pursue this line of thought.

Cheers!

Geoff Mangum
Putting Coach and Theorist
PuttingZone.com
Golf's most advanced and comprehensive putting instruction.

Thank you Geoff for your detailed explanations of your 'gravity-sponsored' putting method, and the supporting science and experiences you have with teaching this method. I have been attempting this style of putting, with satisfactory results. Actually I find little difference in the results between a 'gravity-sponsored' stroke and a 'torqued' putting stroke. I believe my arms are kinestheically superior based on my training in sports and music (playing the violin enhances proprioceptiveness ... as well as rhythm and tempo ..

Can you please share with us your measured data on backswing arc length for varying lengths of putts, together with your usual full explanation of your testing method? This information will provide an interesting comparison for my putting efforts. Thanks and I hope this is a reasonable final request.

Geoff,

Queastion with regards to this: "Loren Roberts' downstroke has been timed at 63 beats per minute on the metronome. because a gravity-only stroke would be about 60 beats per minute," The 60 beats per minute of a gravity stroke would be from top of backstroke past impact and to the top of downstroke or just from top of backstroke to impact?

Thanks

Dear David,

The 63 beats per minute is measured from top to top, from top of backstroke to top of follow-thru. The swinging of a 35-inch putter from top to top is about this also, close to 60 bpm or one full side-to-side swing per second. That's because a "meter stick" was set by humans (in France in 1761) to equal the length of stick that takes 1.0 seconds to swing from side-to-side in earth's gravity.

Cheers!

Geoff Mangum
Putting Coach and Theorist
PuttingZone.com
Golf's most advanced and comprehensive putting instruction.

Just for curiosity, I measured Loren Roberts putting tempo and found the following:
Backswing: 58 beats per minute
Downswing: 78 beats per minute

Geoff, can you explain this? His backswing is essentially gravity (60), but I found his downswing to be much faster. How did you get 63 bpm?

Dear dean,

Could you please explain what you mean by "downswing"? Is that 'to impact" or to "top of follow-thru / end of motion"? And also what were the circumstances of the measurement, in terms of occasion and technology?

I didn't personally measure Loren Roberts. He was measured by others along with other players and the data published in an article. I will get the article and give the exact data, but it will take me a little bit.

Cheers!

Geoff Mangum
Putting Coach and Theorist
PuttingZone.com
Golf's most advanced and comprehensive putting instruction.

Downswing being from the top of the backswing through impact to the end of the followthrough.
I captured the video from a couple of Champions Tour events this year (turtle bay in hawaii and/or the allianz at boca raton). I think almost everyone considers Loren Roberts (and maybe Brad Faxon too) as the best putter on Tour. Most golfers would like to emulate his stroke.
I analyzed two or three good shots of his putting stroke frame by frame to get the data. His backswing is very slow, but his downswing does not seem to match. He is very consistent though. Backswing always right around 60 bpm (1 second for a backswing) and downswing always around .8 seconds (75bpm). If his downswing was pure gravity sponsored or, at least, mostly influenced by gravity with only 3 bpm added by his own torque, shouldn't it be somewhere around 60 bpm?

I was motivated to learn more about the gravity-based stroke based on the heated exchange between yourself and "sammy" under another post. (it made my head hurt!)

thanks,
dean

Dear dean,

That's excellent! That's exactly what I would do if I wanted to know. Can you tell me how you accomplish this frame counting?

My comments are:

First, the impact rebound / slowing of the putter head adds a little time to the thru-stroke, but clearly not as much as 15 bpm (probably 2-5 bpm).

Second, your measurement may reflect his adjusting to a specific green / event and may not be typical, or he may have changed his stroke since the measurements that I am quoting. It's also possible that you measured only certain sorts of putts -- like uphill, or short, or slick, etc. -- and Loren was using a special stroke on the occasion of the measurements (probably not).

Third, you can't really tell whether a golfer has a good instinct for green speed and touch by measuring the backstroke timing and the downstroke timing. The real relationship that needs knowing is the relationship between backstroke SIZE and downstroke TIMING in light of the results of how far the ball rolls in relation to the intended distance of roll. Touch is how a golfer's timing system fits to a green to generate good results from intentions.

Fourth, if this is really his usual downstroke timing, then that's too bad for Loren. That may explain why he has trouble with green speed on occasion. In Greensboro 2 years ago he played the same course Tuesday, Wednesday, Thursday, Friday, Saturday, and Sunday. In competition he shot 71, 68, 81, 70. The weather was the same all six rounds, but his putting went off the rails on Saturday. All he ever works on is the speed of the greens, and he did well in Greensboro the year before (14th), so what was his problem getting the green speed in 2004?

There is a relationship between the golfer's typical downstroke timing and how well the brain knows in advance the force of impact that accompanies a given backstroke. The brain plans the stroke backwards, from the distance and the surface speed to the impact force still further backwards in the process to the backstroke size. But the backstroke size won't be correct unless the brain KNOWS in advance the relationship between the downstroke timing and the backstroke timing, since this is how the brain gets the force of impact correctly adjusted. When a golfer chooses the downstroke timing, 99+% think they should "do" the downstroke in order to stay in control, so they choose a timing that is faster than gravity. In comparison to smoothly allowing gravity to handle the timing versus the golfer "trying" to groove and repeat an adopted intentionally-generated timing, my money is on gravity every time.

Almost all golfers on the PGA Tour think and believe that they should adjust their stroke to a given green speed, and Loren may be one of these guys. Frankly, this is backwards. The golfer needs to appreciate how the green responds to his same-every-time stroke timing, both back and thru (two different timings). If Loren came to Greensboro in 2004 and thought he needed to get his stroke adjusted to the green speed, then he would alter his downstroke timing to "manufacture" what he would hope to be the correct "hit" for the green speed. Then he would vary his backstroke size (not timing) and try to "use" this adjusted downstroke timing in the belief that the given green speed calls for this downstroke timing. If so, then that is backwards and will cause just the sort of problems he had in 2004 playing the same course six times in a row but losing his touch on Saturday. If the golfer gets into a situation where he "tries" to use a specially adjusted and manufactured downstroke timing on the same greens for six days in a row, then this happens:

a) he doesn't really learn and fix the sense of adjusted timing as well as he hopes;

b) he spends hours on the practice green trying to "get it";

c) each day he is a bit worried about whether he "has it" that day; and

d) he can't really tell for sure whether he is in fact "using it" each putt.

Sure, he wants to be consistent in the downstroke timing, and sometimes he is, but over week after week, the cracks in the system show up. How and why?

The whole problem in TOUCH is the consistency of the relationship between the backstroke SIZE and the downstroke TIMING. You can't really tell from measuring the backstroke timing and the downstroke timing whether that relationship between size and downstroke is based on good instincts for the green speed. It may well be that Loren adjusts his downstroke timing to a green but doesn't then use an instinctive backstroke SIZE. This leaves him caught in a trap that some golfers are better at evading than others. But it's still a trap: the idea of manufacturing a certain "hit" pace without regard to a consistent instinctive generation of backstroke SIZE results in questionable touch. The instincts demand that the golfer stay completely out of the backstroke SIZE issue, and that includes staying out of the putter-head speed at impact issue as well. These two are hand-in-glove in the instincts, and if the golfer takes charge of one of them consciously and "tries" to get right, he definitely creates a problem that maybe he can manage and maybe he can't.

Any golfer who really wants consistency and touch had better learn not to adjust his timing in a "hunting" for the green speed. I've never thought that Loren Roberts has learned this lesson, and his writings on putting technique rather clearly indicate otherwise.

So, although I have often pointed to Loren Roberts as an example of someone who seems to use a gravity-sponsored stroke, I have never said that he has "touch" figured out. To the contrary, I have always said that he could benefit mightily from a lesson about touch and the relationship between downstroke timing and backstroke timing and the approach to "getting" the speed of a green in the best way. Even if he is currently "one of the best" in pro golf for touch, he has plenty of room for improvement.

I would caution you from the notion that one or two guys on today's Tour represent the way all amateur golfers should try to putt. The notion that guys on Tour are the "best" is false. Loren Roberts personally learned in San Francisco competing with a friend who routinely whipped him on the greens nearly every day, and still does (ask him). And today's pros are not even close to the best in golf history, despite what commentators like Gary McCord might say on television trying to make the pros look great and sell the Tour to addvertisers with marketing hype. Arnold Palmer in his heydey was a lot better than almost all the golfers on Tour today, even putting on crappy greens. So was Bobby Locke -- immensely better, not just a little better. And there are plenty of others from the past. And in addition, there are guys on Tour today who are day-in and day-out VASTLY better than Loren Roberts or Brad Faxon on their best days, but they don't get talked about on television so amateurs don't regard them as exemplars to emulate. And finally the guys on Tour are usually as good as they are not because of their well-thought-out technique, but because of their genetic gifts that made them successful at pro golf to start with over tens of thousands of others. There is a rather pronounced "freak" element in being a steady success on Tour, and the pros know this and respect it and don't really want to try to question it. Loren Roberts and MOST tour players are "unwilling" to discuss how or why they have success with a given part of their game, and simply hope that the success continues earning them $1 million or more yearly. That means that amateurs don't really know whay a certain approach works for a Tour player, not knowing their "freak" element. Ben Crenshaw is explicit about this, and has written in golf magazine that he does not recommend his style of putting for golfers in general, as its success is perhaps unique to his talents and development as a golfer since childhood. More generally, the fear of getting worse is a lot more powerful at this level than the desire to get better, except for players who just can't stand being low down on the totem pole any longer and are forced to try something.

The better approach is to sort out putting issues generally using "first principles" and then apply these principles to specific golfers in helpful ways. The principles that I am learning and teaching apply to Tour players despite their "freak" element, don't make them go backwards, and will improve any of them above their current level of performance. And they apply directly to amateurs as well.

I also ought to comment on the general folly of using a few measurements of Tour players and thereby thinking you have a "sculpture" of data that represents the player's stroke dynamics for all time. Apparently, the PuttLab folks think that if they have a dozen or so strokes of 100 or so Tour pros, then they have a "database" of how Tour pros make strokes. What in fact they have is a dozen snapshots of 100 players at Time X. It is pretty doubtful that these same players use the same stroke a week or two later, as pros are NOTORIOUS for changing putters and grips etc.

So, while it is very interesting to learn something suggestive about Loren Roberts' downstroke timing, I really don't take any specific measurements as sufficient to invalidate what I am learning about physics and the brain in putting. I've always said he could putt better than he does. The same goes for Brad Faxon.

Cheers!

Geoff Mangum
Putting Coach and Theorist
PuttingZone.com
Golf's most advanced and comprehensive putting instruction.

Thanks for your answer. Geoff, on one of the putts (worm cam view straight on from hole back to Loren's putter), his backswing actually appeared to me as going outside the line (opposite of Stan Utley's inside-out) at the last few frames. I believe it wasn't a camera angle issue, his putter actually went back very straight until the last few inches, then the putterhead went outside! Is this possible or was I seeing things? Anyway, the putt was about 8 feet and he yanked it left and missed (of course I'm no better). Maybe the fast downswing caused it but I'm still confused about his swing path. (I'm not picking on Loren Roberts, but, since everyone looks at his putting stroke as the ideal, I thought I would report what I saw).
Thanks for your overall incredible work. It is amazing to me how much material you find and explain. Take the Infinics Putter/Trainer for instance. I saw it on your website 2-3 weeks before it was announced that Adams Golf was going to distribute it. Great work!

dean1234

Dear Dean,

The Turtle Bay greens in Hawaii use "seashore paspalum" for the greens, and this is significantly slower than tif-dwarf or bent grass greens. (See Turfgrass Trends; Honolulu Advertiser; Green Media Online; Golf Course News; Malaysian Seaside Greens; Mauna Lani green speeds hard to determine; Golfdom Magazine.)

The Broken Sound greens in Boca Raton are bermudagrass, which is aslo usually slower than bent grass greens.

This leads me to suspect Loren Roberts was adding "hit" to his stroke at these venues to adjust his stroke to the slow greens.

Cheers!

Geoff Mangum
Putting Coach and Theorist
PuttingZone.com
Golf's most advanced and comprehensive putting instruction.