Dear Larry,
The way I teach, the golfer is basically moving only to prevent the putter from getting slowed down, stalling out, or flopping in towards the feet. The "follow through" (what the heck is that, actually? what is getting followed?) is the forward stroke. The forward stroke is mostly a self-propelled gravity drop from the top of the backstroke. This will return the shoulder frame to level without effort by the golfer. The golfer follows or "rides" the putter down with nothing other than relaxation. Once the putter reaches the bottom and the shoulders are level, the putter head is at its maximum speed.
This speed and momentum is not really enough to send the putter up to a symmetrical finish. The impact itself takes some of the momentum out. The tissues of the body stall out the tendency of the putter and arms to rise up past the bottom to a symmetrical finish. So, a symmetrical finish WITHOUT some effort by the golfer near the bottom of the stroke is not happening. If you really used ONLY gravity to power the stroke from the top of the backstroke, the putter head would fall into impact and then stall out awkwardly. That very well MIGHT result in a great putt!
But for sake of "riding" the putter through the impact zone (between the feet, and at least 4-5 inches past the bottom of the stroke), it is advisable to actually move the shoulder frame IN COORDINATION with the putter head. So what I teach is that the golfer wants the shoulders to stay in coordination with the putter head down and thru the impact zone. Once the putter head rises and gets past the bottom by as much as the left foot (right-hander), then I don't really care about the so-called "follow-through" -- the putt is essentially finished.
The reason other instructors talk about making the follow-through a certain size in relation (or in proportion) to the backstroke is because they are trying to a) avoid deceleration in the impact zone, or b) they think there is a relationship between follow-through and "touch." Because I teach a naturally accelerating stroke that always reaches peak speed exactly at the bottom in exactly the same timing every stroke, I don't have any need to worry about a); and because I think I have a pretty good handle on what is responsible for distance control or "touch" and don't think the size of the follow-through has much if anything to do with it, I also don't worry about b). (I do think that a fearful golfer might curtail the follow-through out of unfounded fear of going too long -- these fearful golfers need to learn more about the built-in limit of a well-timed stroke tempo, as the fear is baseless and acting on it makes the putt's roll shorter than it should and needs to be. So if you are a fearful golfer who might curtail the follow-through, this will make you short, and the cure is to stop being fearful and therefore to stop curtailing the follow-through.)
The only thing to worry about in the forward stroke past the bottom of the stroke is to keep the putter square (a "form" matter) and to move just enough in "riding" the putter head that the shoulders and the putter head stay in coordination thru the impact zone. After that, you can do what you want or what you need to do.
Some golfers need to keep the putter head moving so that it actually coasts to a stop at the top of the forward stroke. This "coasting to a stop" mirrors the way the putter head reaches the top of the backstroke. (If your backstroke stops abruptly, that's not a good thing -- it means you aren't putting with instincts but out of fear and worry.) The putter really won't "coast to the top" on the forward stroke without some effort by the golfer to help it get there. But this sense is helpful to many golfers. Also, many golfers really ought to keep the forward stroke going a ways past the impact zone, because otherwise the golfer doesn't fully appreciate how the line of the putt heads AWAY from the center of his stance. The farther a golfer keeps the forward stroke going past impact, the more of a stretch it is as the putter head gets farther and farther away from the middle of the stance. The alternative is to casually allow the putter head to curl inward offline as the forward stroke gets bigger (no stretch, all nice and comfy, but wrong). This inward curling is the tendency of the putter head to STAY the same distance from the middle of the stance. This inward curling is OK, but only so long as you allow it ONLY after the putter head clears the impact zone (I say "passes the lead foot"). An inexperienced golfer who thinks this is OK will actually end up having the putter curl inside BEFORE clearing the impact zone, and this sends the ball off line (usually a "pull"). So, in general, it is best to extend the forward stroke a little past the impact zone just to make sure you're not getting too casual about it.
If you want to "ride" the putter the same length up going forward as the top of the backstroke, that's fine, but let the "riding" come to a coasting stop. Don't artificially pick a point in space for the so-called "follow-through" to end and then simply "stick" the putter there. This does serious damage to your timing and distance control -- the very thing people think they are trying to help. This sort of "controlled follow through" is (in my opinion) pretty dumb. Wherever the putter comes to a coasting stop is perfect. Don't pick it in advance and don't try to make anything specific happen.
As to the idea that the forward stroke should be twice as long as the backstroke, that relates to avoiding deceleration. Forget that, so long as you have a naturally accelerating down stroke.
Cheers!
Geoff Mangum
Putting Coach and Theorist
PuttingZone.com
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