Dear Kevin,
Thanks for the question!
This training device is a little odd visually, but in terms of the MOTION it is desinged to train, it works pretty well. (I don't really understand what is meant by the claim that 20 minutes with this device is worth 2 hours with a regular putter ... and such a fact even if true doesn't matter much to me.)
What's happening here is you are trading in two dynamic features of a regular putter for something else:
1. The sweetspot of the normal putter is somewhere "along" or "on" the putterface, usually a bit out from the hosel towards the toe, on a rectangular "slab" of metal; but on the ball-putter the sweetspot is in the center of a sphere and also directly beneath the straight hosel. So you are "moving" a ball into a ball, instead of moving a slab into a ball.
2. All putters, as "slabs" on a stick, have a certain balancing of heel and toe; some are "face balanced" and some are not; some are "reality balanced" -- which is a step beyond mere face balancing. With the ball-putter, there being no "slab" to balance, the ball as a sphere is perfectly balanced. So whatever tendency exist in a normal putter during the backstroke and throughstroke, these tendencies are eliminated in the ball-putter design.
SO-- here's what difference it makes:
IMPACT: a slab can impact a sphere at any point on the slab but only one point on the sphere. There will still be significant transfer of momentum from the slab to the sphere, and so long as the slab is oriented to the target correctly and the stroke path is online, the line the ball will take will be more or less okay even if the energy is weak. To have "solid" impact, the sweetspot of the slab has to impact the sphere of the ball so that the trajectory of the slab sweetspot is moving directly thru the center of the sphere, which is the sweetspot of the ball. This sweetspot-to-sweetspot stroke probably should be made thru the ball's equator level with the surface, as this probably generates less bouncing or bounding, which takes energy out of the putt, but it's not abslutely necessary for what I mean by "solid." A solid putt is, then, one in which the slab is facing the target, and the path of the slab's sweetspot travels along the puttlline, and the sweetspot of the slab moves thru the sweetspot of the ball. All THREE conditions have to coexist.
By the way, the diameter of the ball-putter design is such that it is possible to make contact with the ball so that the equators of both make contact. This is consonant with the principles of energy transfer in a pendulum bob.
With the ball-putter, however, there is no slab. A sphere-to-sphere contact can occur in one and only one point on the ball-putter AND one and only one point on the ball itself. Still, the other two conditions need to coexist -- path of the ball-putter online and sweetspot-to-sweetspot movement of the ball-putter's center thru the center of the ball. There's only one way to do this, and that is with a stroke path that keeps the center of the ball-putter exactly on the puttline at all times. This is the MOTION you train with this aid.
Consider what happens if you miss this trajectory slightly: a glancing blow that might hit the correct spot on the back of the ball or might not. In either case, the combination of ball-to-ball means there will be tremendously less energy transfer from the ball-putter to the ball because of the shape of the sphere. There's a lot less "behind" the impact point of sphere on sphere when you're off a bit. With a slab, this is not the case, and is the reason for heel-toe weighting schemes that somewhat compensate the energy loss for off-center hits. SO-- you see a dramatic LOSS of energy whenever your stroke path MOTION is offline, and in that way the ball-putter AMPLIFIES the feedback.
BALANCING: Curiously, the balancing of the ball-putter, being perfect in a sense, does not help you. It might help if you used the ball-putter in the game, but you don't. You use your own putter. Your own putter has certain tendencies in the stroke due to the physics of its design and your technique, so that you "learn" subconsciously how to use your own tool to control these tendencies. The ball-putter is free from these tendencies, so it sort of fools you. Hence, it's value as a MOTION trainer comes at a little price by subtly corrupting your ability to manage your own putter. Doesn't seem too serious, though.
VISUAL EYE-HAND COORDINATION: Moving the sweetspot of a "slab" and moving a center-shafted sphere-on-a-stick are two different visual experiences. This tends to alter your sense of the coordination of the arms-hands with the "putterhead" in one case versus the other. Moving the ball-putter is more like pointing a stick, whereas there is more "sweep" sense to moving a "slab" putterhead back. For my money, this is a good effect. You want to emphasize the stability of the shaft's pointing at your putting pivot in the neck area at all times in the stroke, and this is promoted by the ball-on-a-stick design. A "sweep" involves the wrists instinctively, so here the ball-putter is helping with a detail in the stroke MOTION. Still, the proof ends up being in the trajectory of the ball-putter's center: is it online thru the ball's sweetspot or not?
SOOOOOOOO--------- You are training a MOTION. What the heck good is that? For my money, it's pretty good, but only so long as you appreciate the fact that your putting stroke must ALWAYS be the same MOTION. It''s a matter of the stroke always looking and feeling the same in your constant setup positioning. Then, the only thing you need to do is read the putt to identify the start line, setup to the startline, and get the energy right. But the stroke MOTION is always along exactly the same path in relation to your setup. The arc of your stroke is always a certain distance out from your toeline, and a good stroke always sends the ball out along exactly the same starline out from your lead toe. (My putts go out of my setup ver a spot ahead of the ball directly out from my left toe about 5 inches; if it doesn't, I didn't make a good stroke.) In other words, the ball-putter is teaching you the most natural way to make this happen consistently.
What you should disciver, if you want to take the time to notice, is that any sort of "gating" in the stroke path of a ball-putter is automatically a big problem, and you will instinctively try to get rid of it if you want the ball-putter to work well. This ends up teaching you to relax your hands so they hang naturally below the shoulder sockets. This also teaches you how to start the ball-putter back without casting or jerking it off line -- you have to start gently while keeping the hands and wrists out of it, so that means you start back with a shoulderframe push instead of with hand muscles. So the device promotes a dead-hands stroke. The gradualness of the move back has to be matched at the transition from back- to down-stroke and with the increase in speed as the ball-putter falls into impact. In other words, tempo -- slow and smooth. Finally, again the dead-hands are emphasized in the grip pressure, because alteration of grip pressure in the stroke often affects stroke path and energy transfer, so grip-pressure changes (mostly tightening) shows up dramatically with a weak, glancing blow offline.
To sum it up: The ball-putter trains a MOTION in terms of tempo, dead-hands, no-gating, pivot-steady online stroke thru the ball's sweetspot. This is fine, but it won't translate to your putter unless you realize that your putting stroke always has to look and feel the same in a consistent setup. You can't alter the motion from one putt to another, and if your setup is not consistent and aimed the way you need it to be aimed, this is exactly what you have to do to make a putt -- change the motion. So the ball-putter only works if you are committed to a consistent setup, and then it helps you coordinate a good motion IN THAT SETUP. It also teaches that the setup needs to include hands hanging below shoulder sockets to minimize "gating." Even so, there is a slight price to pay when turning back to your real putter and trying to use this new learning. It doesn't look the same, so you have to recognize the tendencies to start back with a different motion (keep your hands dead, keep a constant grip pressure, start back with a shoulderframe push, keep the shaft pointed into your pivot, don't rush the tempo, and don't gate the stroke path). You kind of have to watch how the ball-putter practice transfers to your real putter.
One day someone will create a putting aid that is similar, but shaped more like a tootsie-roll on a stick, so the putterface is the small-diameter end of the tootsie-roll "log" that swings like a battering ram into the ball. perhaps the end of the log can be domed" too, instead of a flat circle shape. This will show you the gating more clearly AND show you the vertical dimension of the stroke arc as it comes into impact -- if the log is not level at impact, you'll have a problem. Know any manufacturers?
Cheers!
Geoff Mangum
The PuttingZone
http://hometown.aol.com/puttmagic
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