Your comment about a second read echoes remarks of Jack Nicklaus to the effect that he never watches another golfer's putt because he doesn't know how hard he strokes the ball and in any event he will probably not stroke the ball with the same speed anyway. To like effect, Loren Roberts has said that he does not want his caddie to read his putts, because the caddie does not know what speed he will give the putt, so he can't know the "line" of the read.
While I appreciate these views, I have come to believe over the years that there really is always only ONE basic speed for any putt, and this speed has to be recognized and appreciated before it is rejected, and in fact this basic speed is almost always the best speed. Generally speaking, if you look for this one speed to begin with, once you find it you will almost never want to look further. This view requires an understanding of how the instincts are pre-set to putt with one tempo based on accurate targeting, so that the ball always arrives at the cup with the same end-of-putt speed at the lip on every putt, regardless of the length of the putt or usual challenges of the contour. Let me explain, as the physics and neuroscience are a little involved but nonetheless basically simple.
PHYSICS OF BALL CAPTURE. In order for a ball rolling at a hole to fall into and stay in the hole, the ball must be on a path across the top of the hole and traveling laterally across the ground at a speed that permits time enough for gravity to pull the ball towards the earth at least one-half of the ball's diameter before the front edge of the ball impacts the back edge or wall of the cup. This involves 1) the ball size, 2) the cup shape and size, 3) the path of the ball across the cup, 4) the manner in which gravity affects the ball once over the rim during the ball's "air time", and 5) any corrections required by the rim of the cup being tilted towrds or away from the roll of the ball, with a "backstop" effect for putts uphill and an "oops" effect for holes tilted away from the ball downhill.
Starting at the beginning of this mouthfull, a "ball" is 1.68 inches in diameter, so 1/2 a ball's diameter is 0.84 inches. (The Rules allow bigger but not smaller balls, and bigger balls are not normal.)
The length of "air time" a ball has across a hole depends on the size and shape of the hole and the trajectory or path the ball takes across the top of the hole and the lateral speed of the ball on that path. In golf, the hole or cup is columnar in shape, with a circular rim that is 4.25 inches in diameter across the center of the cup. If the ball travels across the center of the cup along a "centercut" path, the ball has the maximum length path. As the path of the ball across the cup moves out towards the left or right edge, the effective diameter of the hole for "air time" steadily decreases from 4.25 inches to zero at the far edge. Actually, the maximum path is less than this, since the "air time" is measured from when the bottom dimple of the ball crosses the lip to when the front dimple on the ball's equator hits the back wall. This distance is shorter than 4.25 inches by half a ball, or 0.84 inches, and so at maximum is really only 4.25 - 0.84 = 3.41 inches.
How much "air time" is really required? Gravity makes ALL objects accelerate from zero towards the center of the earth in exactly the same way once the objects run over the edge of a cliff, as a ball does when its bottom dimple rolls over the rim of the cup. In the downward direction, gravity really doesn't give a hoot how fast the ball is traveling horizontally across the ground, and just pulls the ball down exactly the same way every time, once the ball becomes "air borne." If you want to see for yourself how long this is, just hold a ball in the palm of your hand, lift it above your palm one-half its diameter, and drop it and watch. You can drop the ball over and over again, and it will always fall this short distance with EXACTLY the same pattern of acceleration and in exactly the same total amount of time.
Here's a picture of Galileo and the Leaning Tower of Pisa to prove it!
That amount of "air time" is set by gravity under the simple formula:
Distance of Drop = 1/2 x Gravity Acceleration on Earth x Time^2 [Time in seconds, squared].
The Distance is set (0.84 inches) and Gravity Acceleration is set (gravity makes objects speed up at the rate of 32 feet per second faster every second, which is the same as 384 inches per second per second), so TIME is also set for every single putt at a level cup. Solving the equation to find this one and only time for ball capture, the answer is 0.066 seconds, slightly more than 1/2 of 1/10th of a second. Every time, every where, every putt to a level cup.
So the ball "needs" at least 0.066 seconds of "air time" to be captured by the hole. Assuming the ball runs centercut across the widest path across the hole (3.41 inches on a centercut putt), there is plenty of "air time" so long as the ball is not rolling across the ground at the lip too fast. Anything above 0 revolutions per second, up to this maximum speed at the lip, will result in capture for a centercut putt. So what's the upper speed limit for centercut putts?
The answer lies in the normal understanding that
Distance = Speed x Time of Travel.
In this case, we "need" 0.066 seconds of travel time, and the distance is set by the 3.41 inch path across the center of the cup. Solving for the Speed, we get 51.7 inches per second of ball speed at the lip as the MAXIMUM speed for ANY putt to be captured at a level cup.
A ball covers 5.28 inches every roll or revolution (its circumference), so 51.7 inches per seconds is the same as 9.8 revolutions per second at the lip. So the total range of all possible speeds at the lip for ball capture at a level cup is from 0 revolutions per second to 9.8 revolutions per second. Nothing faster will drop (ignoring certain wild possibilities such as the ball popping straight up in the air and then dropping into the cup without bouncing back out). [This wild possibility makes the top speed of 12 revolutions per second the real maximum speed for a centercut putt, but it's too infrequent and special to consider, so the effective, normal top speed is about 9-10 revolutions per second at the lip.]
Once you start considering non-centercut paths across the hole, this TOP speed at the lip steadily decreases. When the speed at the lip is 9-10 revolutions per second, the effective "size" of the hole for capture is really only one dimple wide left-to-right at the centercut line. Anything off to the side of this dimple-sized "hole" will miss because the ball is rolling too fast for the path length available. As the ball slows from 9 at the lip, the effective "hole" widens left-to-right. As the ball speed at the lip slows all the way to zero revolutions per second at the lip, the effective "hole" is finally 4.25 inches broad from left to right, and is the fattest target there is.
All of this physics teaches that there is a RANGE of speeds from 0 to 9 revolutions per second available for the ball's delivery speed at the lip, and not really an infinite number of possible speeds, and that as the ball speed slows towards the low end of the range, the effective size of the hole for capturing the ball increases from one dimple wide out to as much as 4.25 inches wide.
NEUROSCIENCE. The touch system is all about the ending of the roll at a desired position or distance on the green. Controlling the place where the ball STOPS is what the touch system is all about. So, the touch system is about targeting the end of the putt and controlling the ending of the ball's roll speed so it stops at that target. How does that work in the brain?
The cerebellum of the brain coordinates body motion and target locations so the body motion accurately moves (rolls) an object (ball) just the correct direction and distance in space to reach the target. The cerebellum enables an accurate simulation of the putt just like a "flight simulator" is programmed to take into account different factors such as wind speed and flap angle and jet engine thrust. The cerebellum then uses this simulation to make the appropriate movement, coordinating the tempo and size of the motion in light of the green speed and the heft of the ball and putter.
This cerebellar control can be accomplished with any tempo used consistently for moving an object to different targets, or with different tempos from motion to motion. In putting, consistency of performance and accuracy learning from day to day requires that we use only one tempo all the time. Whatever tempo is selected, the cerebellum relies upon that tempo both to visualize and simulate the successful rolling of the ball mentally and then to execute the putt so that the simulated roll occurs.
The cerebellum receives input from the eyes, the inner ear, and the body feelings in gravity to "target" from ball to the selected ending location of the putt, with the tempo of the stroke in mind, and then instinctively selects the backstroke that is required to make that stroke perfect.
Given a fixed and stable tempo, the speed of the putter head at impact depends ONLY on the beginning length of the backstroke. A big stroke takes exactly the same time from side to side because it's smooth acceleration lasts over a longer path and the putter head reaches a higher peak velocity at the bottom of the stroke than is the case with a smaller stroke. But regardless of stroke size, a stable tempo means all strokes take the same amount of time from side to side. This further means that a stable tempo means EXACT variations in putter head speed at impact correlated with backstroke length. In fact, backstroke length with a fixed tempo acts like a reostat dimmer switch on a light bulb, and every increase in backstroke corresponds smoothly with an increase in putter head speed at impact. The neat thing is that the golfer is only concerned about green speed, target distance and tempo, while the cerebellum takes care of the backstroke length and putter head speed at impact, so that the end result is the ball STOPS where the golfer intended for it to stop. Once the golfer gets a handle on green speed, and has a stable tempo, the targeting alone produces the just-right backstroke for accurate touch or distance control instinctively.
So, the touch system properly understood ALWAYS delivers the ball to the target with the SAME end speed. A ten-footer arrives at the lip with the same end speed as a thirty-footer. All the "leaves" are the same on the same green regardless of length of putt. The end-speed of the ball at the lip is ALWAYS THE SAME.
Given the Physics and the Neuroscience above, whatever tempo you choose to make yours ought ALWAYS to enable you to control the stopping of the ball after any distance on a given green. In other words, you are capable of CHOOSING the ONE ball speed you have at the lip for every single putt. What's a good ball speed?
Obviously, 9 revolutions per second at the lip is too fast, and zero is too slow. The "just right" speed ought to be as slow as possible but not too slow as to subject the ball to surface irregularities knocking it off line as it slows nearing the lip. What are the surface irregularities commonly faced, and what speed of the ball is sufficient to overcome them? In my experience, with most greenskeeping practices today, "2 at the lip" is about right for most greens in normal playing condition.
The distance the ball rolls past the cup if it misses at this end-of-putt speed at the lip is not one number (as Pelz claims) but depends on the green speed and condition at the time. On Augusta greens, 2 at the lip might send the ball 20-30 inches past the hole on level ground, whereas at the local Muni course 2 at the lip will send the ball only 6-10 inches past the cup. pros typically have leaves past the hole of 8-12 inches, and on greens Stimping around 10-11, this corresponds with an end-of-putt speed of about 2 at the lip.
Here is a chart showing the Boudaries of ball capture for given speeds. The "Impact Parameter" along the bottom axis means that at 1.0, the effective hole is 100% its actual size, and here the ball speed at the lip is 0; at impact parameter 0 where the hole is not as wide as a dimple, the maximum capture speed is indicated as 1.63 meters / second (12 revolutions per second), which is the case of a pop-up ball that falls back in the hole. The case of "2 at the Lip" is indicated on the vertical axis at 0.27 meters / second end speed and corresponds to an effective hole size of about 90% or 3.825 inches wide left to right:
Here is a chart showing all putts arriving at the hole with the same end speed for different green speeds:
Now, with the touch system and your preselected tempo always delivering the ball at the lip with the same speed regardless of length of putt, when you READ a putt, you should use this delivery speed to simulate how the ball will take the break of the contour. Unless you can see the break of this BASIC normal delivery-speed putt, how can you decide how much "break" to take out of a putt by increasing the ball's speed at the end, if that's what you want to do?
So, for every putt, Physics and Neuroscience suggests that you READ the putt to begin with with a stable tempo and a consistent end-of-putt delivery speed in mind, using this to simulate the ball's reacting to the contour along its path. This establishes your vision of the BASIC, normal putt -- one speed, one break. Because this speed at the lip is at the low end of the range, you usually don't want to go slower at the lip, so variations of your delivery speed will almost always be by speeding up the end-speed. To speed up the end speed, you either have to "gas" the putt by increasing your tempo or target past the hole, and in any event you will make the effective "size" of the hole smaller and increase the comeback distance of any miss.
None of that sounds good to me.
Even if a little extra "firmness" on short putts is a good idea to help "hold the line," the golfer still needs to work within this range of possibilities and appreciate the consequences of speeding up the end-speed. The trade off cannot intelligently be made unless the golfer is clear about where he starts from, and that means ONE SPEED, ONE READ.
In the case of short putts, my experience has taught me NOT to try to take any break out unless I first clearly see what break there is in the normal-speed putt. Then, I would only want to take out just as little break as I can get away with to feel better about "holding the line" without making the hole too much smaller. This usually means that if the initial READ has the start line of the normal-speed putt aimed outside the hole, the extra speed and smaller hole needed to redirect the putt inside the hole is too big a change and too much of a risk to be worth it, and I end up just playing the ONE SPEED, ONE READ I know I need to hit. I just make sure I haven't overestimated the ONE SPEED, ONE READ break to begin with.
But if the ONE SPEED, ONE READ break has the start line of the putt still inside the hole, as an "inside right" or "right edge" putt, then I don't mind a little extra speed at the lip to adjust the start line a little to aim the putt more securely at the fattest part of the hole. I don't have to change the end speed much at all, so the hole size stays pretty close to what it was at first.
All this tells me that it is usually never a good idea to try to take the break out of a putt unless the putt is inside about 4 feet and if the putt's initial start line is inside the hole anyway, and even then, there is not much break that should be taken out.
So, to address caddies reading putts, I personally don't think there is a wide array of putt speeds to use, and normally there is only ONE SPEED, ONE READ. So long as the caddie knows my end-speed (and he certainly will if he stands with me on the practice green every day for hours watching me putt and sees me putting round after round on the course), then the caddie can read the line for me.
I think that in truth top putters DO this even if they don't understand they do.
If you respond that golfers putt "more aggressively" going uphill, then my take is that so long as the golfer gets the ball all the way uphill to the hole with the right end-speed, everything beyond that is just psychological swaddling and is not really helpful and may be hurtful since it reduces the effective size of the hole.
Granted, going uphill, the "backstop" of the hole is tilted at the golfer somewhat so the range of end-speeds is increased a little, this only allows a modicum of faster end-speed going uphill. How much? If the green slope is 3 percent grade uphill, the back edge of the cup is a mere 0.1 (1/10th) of an inch higher than the front edge. That means the ball needs to drop only 0.74 inches instead of 0.84. This gives it a need for 0.062 seconds "air time" (a mere 4/1000ths of a second less than a level cup requires). This reduced "air time" means the maximum centercut speed increases from 9.8 to 10.4 revolutions per second, which is not that much really.
And also, because an uphill putt "dies" more suddenly and the end break is more pronounced, it is not always wise to try to "take the break" out of an uphill putt, as this makes the ball run thru the break. So being "agressive" on uphill putts is probably only a little advisable when the putt is basically straight and the start line is "inside" the hole. But once the uphill is somewhat also sidehill, with break and a strat line outside the hole, the golfer needs to be pretty careful to know and use his end-speed effectively. This normally means to stick with the normal end speed and be sure to get the ball all the way to the hole, but not to blow the putt thru the break.
What about downhill putts -- shouldn't they be sent at a different (slower) speed? I say no. If you "baby" a downhill putt, you have a serious risk of decelerating and missing short or low. If you send a downhill putt firm, you risk blowing the ball thru the break and also risk a rather unwelcome comeback putt. The trick to downhill putts is to use just the right touch to feed the ball onto the proper fall line as it curls down into the lip from the high side of the cup. The right speed to get this done is most consistently attained when you read the putt and execute the putt with your normal tempo and even your normal delivery speed. If you locate a second ball as a target on the fall line above the cup and aim the putt straight at this target ball and make the stroke with the intention of delivering your ball to this target ball with just the right touch so the rolling ball slows and then just bumps the target ball with the same old end speed of 2 revolutions at the point the two balls touch, this downhill speed is going to be the same you use to READ the putt to begin with and will result in correctly feeding the putt onto the fall line for a sink.
Sure you have to be aware of the fact that the ball is headed downhill, but this is more akin to thinking of the putt as taking place on a "slicker" green, and really is used by the brain in this way to make sure your targeting stops the ball where desired and does not mis-gauge the green speed. In other words, all that is required for downhill putts is to think about rolling the ball only as far as the target plus a little, and not farther, so the ball arrives at the lip with the usual end-speed. The downhiller may result in a little more of a comeback, but not enough to worry you unless you're playing Augusta.
In those extreme cases when the green speed on level ground is severe, so that a downhill putt becomes that much "slicker," there comes a point when the normal end-speed is just too much for that green. Then just learn a slower delivery speed, and then you're back to ONE SPEED, ONE READ.
The way I think about it, there is never more than ONE SPEED, and never more than ONE READ. If for some reason that ONE SPEED, ONE READ makes me uncomfortable, then I might consider a faster end-speed, but there is a very strong presumption against incurring the unfamiliarity of the change in stroke pattern (changing tempo, changing backstroke length) and the smaller effective hole size. I'll certainly consider it, but won't usually opt for a change.
People who want to read more about the Physics should see my
Science section > Physical Science > Technique > Ball-Cup Physics and Optimal Speed at Hole and read the paper by AJ Penner on the
Physics of Putting available on my website in Adobe PDF format.
Cheers!
Geoff Mangum
Putting Theorist and Instructor
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