Dear David,
That is a keen observation. But there are a few separate issues here (three).
FIRST ISSUE - Eyeline geometry
First, the Eyeline video does not use the laser properly. Your write:
"As Eyeline golf has shown in
this video a square to square stroke does not project a straight line on the ground when a laser is attached to the putter shaft. However, the putter face may be perfectly square to the target line throughout the stroke.
Conversely, an inclined putting plane will project a straight line on the ground; however, a laser attached to the putter head will show an opening and closing putter face."
The problem here is that the location on the shaft is not IN the same space as the putter head. When you make a straight-back and straight-thru stroke, the motion of EVERYTHING from shoulder down to putter head (every separate piece of matter in between) moves in its own vertical plane. And all vertical planes of course are parallel to one another. If you looked at the golfer from behind the line and sliced the image a million times with parallel vertical planes from left to right, from the shoulders outward along the arms and hands and down the shaft to the putter head, each separate plane correlates with the specific piece of the body and putter that that single plane intersects.
The Eyeline video has a laser in plane #203,346 high on the shaft aiming down into the bottom of plane #987,342 at the sweetspot on the putter head. Right at the sweetspot, the laser beam "lands" on the putter head. left and right of this, along the "laser line", the beam is hitting the ground BELOW the height of the top of the putter. Imagine a transparent putter head and a single beam shining thru the sweetspot onto the ground, "burning" a path in the grass along the ground when the putter is moved straight-back and straight-thru. As the putter moves straight back, it also rises. As the beam shines thru the putter head, it hits the ground farther away from the golfer than the putter's sweetspot. As the putter rises higher in the backstroke, this beam meets the ground out past the putter head progressively farther and farther away. A similar thing happens as the putter rises going straight forward past impact into the follow-thru. The end result is a curved path burned into the grass that appears like a "smile" shape.
When you address the inclined plane stroke, you write: "Conversely, an inclined putting plane will project a straight line on the ground; however, a laser attached to the putter head will show an opening and closing putter face." These two lasers are not IN the same space and are not aimed the same direction in their respective planes of motion, either.
I can't really clarify all this completely here, as I am currently making a training aid that gets all this sorted out correctly.
But the punch line is that Eyeline and its video don't really understand what they are talking about. (They probably would if they had read some of my earlier posts on this issue, but alas!)
SECOND ISSUE - Software geometry
The next issue is about the location of the signal emitters on TOMI and the PuttLab. For PuttLab, you are directed to locate the signalling device 10 inches up the shaft, and a template is provided to help. If done properly, combined with the "calibration" signals at the start of a session, the software algorithm is supposed to have the correct geometrical mathematics to "handle" this offsetting of the signalling device from the putter head.
There are a couple of assumptions here, though. One is that the shaft line hits the ground where the sweetspot is located. This is not true for heel-shafted putters. In the near-far dimension on the ground, this doesn't really matter because the golfer sets the sweetspot behind the ball, and the software algorithm simply reports whether there is a difference at impact in terms of the signalling device being nearer or farther than it started at calibration at "impact", and this is used to "infer" how far towards the heel or toe impact occurs in relation to the putter's sweetspot. If you viewed this dimension with a video, this view would be from directly above the putt line looking down. I think PuttLab displays this parameter instead with a star on the putting face as seen from the target side.
In terms of representing the shape of the stroke, the REAL shape is three dimensions in time (total of four dimensions), but PuttLab and all monitors to date display data in the two dimensions of a "screen". The PuttLab presents two data displays in drawing form, and each display is two dimensions (like a drawing in the plane of a sheet of paper), from two different perspectives -- one down from the top, one from across from the golfer looking sideways at ground level. The top-down view shows the left-right and the near-far dimension in the 2D plane of the display. The side-on view shows the left-right and the up-down dimensions in another flat plane of display. There is no display for up-down and near-far combined, as this would be a view from BEHIND the putter looking down the line.
But even so, when there are two displays like this, with the left-right dimension common to both, there is an "overlap" effect where the viewer can sort of infer the putter shape's locations during the stroke in three dimensions separately as well as sort of combine or synthesize them in the mind holistically. That is, the viewer can sort of figure out what the relationship is between up-down and near-far for the stroke. Sort of. But it's no substitute for a hologram in motion in 4D! (Think "Holodeck" on Star Trek with a "pause" button, a "slo-mo" button, an "advance frame one at a time" button, and a "go back" button while watching someone putt.)
The question for both TOMI and PuttLab is whether their software correctly handles the geometry, and whether it handles the geometry for different putter designs. It's entirely possible, since mathematically the software algorithms COULD handle the displays correctly to reflect reality accurately, but do they?
In Las Vegas and Atlantic City, slot machines and other mechanized games of chance are "handled" by software algorithms, just like PuttLab and TOMI. The algorithms determine what combination of fruits show up (Cherry, Cherry, Lemon), what combinations pay out, and how often they come up. These algorithms COULD ROB you or GOUGE you or pay out GENEROUSLY and you can never tell before you put your quarter in the slot what sort of algorithm you're dealing with. Because of this, state government agencies in Nevada and New Jersey CHECK the algorithms and regulate by law how often they can keep the quarter (say 90 times out of 100 quarters). The slots in central Las Vegas are allowed to be greedier than the slots in North Las Vegas. In central LV, the slots are allowed to keep 95 or 100 quarters. In North LV, the slots keep only 90. This is the way the Nevada Gaming Commission recognizes the need of North Las Vegas slot-machine owners and operators to even the competitive field for tourist quarters in comparison to central Las Vegas, with its showgirls and bars and restaurants, whereas North Las Vegas has grocery stores and barber shops.
There is a similar checking of the integrity and fairness of the software algoritms used in online gambling websites, but this is mostly handled at the trade-association level, as most of the big nations "ban" this gambling instead of regulate it for fairness.
The point is that neither TOMI nor PuttLab's algorithms have been examined independently. This is ordinarily the function of a "scientific community" to check the claims or work of others with a communally accepted process. But of course the sport of golf does not really have a real "scientific community." It has independent folks each acting in the manner of a sole scientist, claiming the truth of science, but no community of scientists ever critiques or tests their claims independently for the purpose of granting or withholding communal assent to the claims.
I've written before about why this is so, but it really needs to change. Other sports generally don't have this social-political kind of status-based community of gate keepers, like so many emperors wearing no clothes. In golf, in America more so than elsewhere in the world, it's mostly who do you know, who likes you, do you have quasi-celebrity status in the magazines and on tv, and what are your connections to other big wigs in golf -- all tending to vest individuals as "gate keepers" and "talking heads" who are seldom if ever challenged about the merits of their views and claims and comments. This is not the way science operates, and neither is this the way science operates in other sports, like Olympic sports such as shooting and track and field, NASCAR, and about all strength-and-endurance sports.
THIRD ISSUE - Stroke geometry
The third issue is from your point #2 above. You write: "David
Posted Mar 5, 2007 9:44 PM
"2) This is one of the main problems with putting (other than we can not aim). All strokes have some form of rotation in them...either the putter face itself (inclined plane stroke) or the grip and shaft of the putter (square to square stroke). I guess one needs to experiment with each to see which produces the best accuracy and roll. I think the square to square stroke has the potential (for us messy humans) to produce a lower quality roll as it tends to return the putter to impact with to much dynamic loft on average (unless one likes playing the ball 2" - 3" back in their stance)."
Your speaking of the rotations of the putter head and of ther grip and shaft separately confuses a more accurate description of what really happens. The notion that the putter face itself rotates when the stroke proceeds in an inclined plane is not accurate. if you run a putter heel along an inclined surface, the point of contact during the stroke describes a certain shape in space (a "smile" leaned back out of vertical). If you looked down the plane along the same angle the plane leans, however, you will see a straight line traced by the heel on the plane, and the putter face NEVER changes out of perpendicularity to the surface of the plane at any point in the "smile" of the stroke. So the putter face does NOT open or closed in relation to the plane of motion.
The trouble is in your thinking about the "line" of the putt. In relation to the "line" on the ground that represents the line of intended roll of a straight putt, the putter face in an inclined stroke motion "appears" to open and close, but only from the perspective of the eyes looking across the putter and comparing the image of the putter to the line on the ground. The golfer does not MAKE the shape on the ground by moving the putter head in a matching arc -- he makes the shape on the ground by moving the putter straight back and straight thru on a specifically angled incline plane of motion, without the putter face changing with respect to the plane of motion.
The analysis of strokes in terms of the "line" of the putt and the "plane" of the stroke is mixing apples and oranges in a deceptive and confusing way. If instead you speak of the "Sidewall" of the putt "line" like a vertical plane arising out of the ground along the line of the putt, and the inclined plane of the stroke motion, then you can really see and understand what is happening. Yes, in an inclined plane, the sweetspot of the putter starts IN the Sidewall plane and immediately as the backstroke progresses, the sweetspot comes out of this plane and moves "inside" it into a closer space as the putter rises up the leaning plane. This does not mean, however, that the putter face is rotating with respect to the Sidewall. IT IS NOT. It "appears" to rotate with respect to the "line" at the bottom of the "Sidewall", but this is an illusion created by perspective of the eyes and focus on the wrong relationship. The correct relationship is shown by making a stroke on an inclined plane next to a wall and hanving someone check at all points in the stroke to see whether the putter face is staying square to the plane of the wall -- IT DOES. This is not opinion; this is geometry.
ANY stroke that is generated by a motion in a plane does NOT rotate the putter head any at all with respect to the plane of motion OR the vertical plane out of the line of the putt, whether the plane of motion is vertically oriented and considered a "straight back and straight thru" stroke or whether the plane is tilted off vertical or inclined and considered something that "looks" like the putter head is fanning open and closed in comparison to a "line" on the ground. People who describe this inclined plane stroke as "arcing" with the putter face opening and closing in relation to the line of the putt while it stays square to the plane of the stroke are, frankly, confused people and their descriptions of stroke geometry confuses others, to the spreading harm of playing golf intelligently.
The rotation of the grip and shaft DOES rotate the putter head out of square to the "wall" of the putt (seen as a vertical plane arising out of the "line" of the putt). This is accomplished not by choices of stroke plane but by the golfer's conscious or unknowing rolling of the arms and hands during the stroke. In a dead-hands stroke, this doesn't happen.
There is another way to get the putter face coming out of square to the putt plane, but it is not really a "rotation" of the putter head or of the grip and shaft. If you curl the pivot in the body around back and thru during the stroke, the putter head will follow.
But in general, if the pivot of the stroke at the base of the neck does not wander about in the stroke, and the arms and hands do not rotate the putter, the putter head will stay square to BOTH the stroke plane and the putt plane.
Cheers!
Geoff Mangum
Putting Coach and Theorist
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