Dear Neville,
The "natural" motion of the torso is the one that is most common at times of inattention. This is a turning of the shoulders back around to the left as if hearing someone enter the room to the left and turning instinctively to see who it is. This is a motion of the upright body powered by the gut and lower back muscles that connect the upper torso as a whole to the lower body by strapping the spine and rib cage to the pelvis bones. The shoulder gridle and pec muscles are generally relaxed and uninvolved in this "natural" motion. In the context of a putt from a putting posture, this "natural" move is a pull as the left shoulder gets rotated around to the back of the original setup alignment of the shoulderframe. That is the "lateral" motion of the shoulder back behind the body.
Golfers who believe the best stroke arcs inside-square-inside (regardless of the argument that keeping the putter face square longer in a straight stroke is better) usually TRY to move their shoulderframe laterally so that the left shoulder goes forward and then back "around the spine." If you define a plane that connects the shoulder frame to the ground vertically beneath the shoulder sockets, this "plane" in an arcing stroke twists about the vertical axis of the plane. The alternative is to move the sockets either so they stay inside the vertical plane or so they stay inside a plane from the shoulder sockets down to a line on the ground that is the same as or parallels the intended putt line. Either way, this plane of motion does not twist laterally around any vertical axis, and the plane of motion stays still.
In Europe, putting guru teaches that the shoulders move in a single fixed plane (without twist) and this results in an appearance that the left shoulder rises vertically in the through-stroke and this sends the putter face square down the line through impact. He has recently released an excellent CD-ROM in association with Quintic, a sports biomechanics company in Coventry, England [avaliable via
http://www.quintic.com]. This CD includes Swash's teachings and technique, and also includes videos of the top European PGA Tour putters, such as Padraig Harrington, Bjorn, Fasth, Langer, Poulter, Price, and many others. They all do NOT have a left shoulder moving laterally back in the through-stroke. My technique looks the same, but there are a few differences in the way the body is managed, and my technique is dovetailed with the neuroscience of targeting perceptual processes and the motor movement processes throughout the routine and setup. Notwithstanding these differences, I heartily recommend that you obtain Harold Swash's CD-ROM, as he and I are fighting the same battle for HOW to move in a good putting technique.
The short answer, then, to your precise query, is that I believe a "pull" is by far the most frequent form of a flawed stroke due to its being "natural" in the sense of most frequent when the golfer is inattentive. (I'm not aware right now of specific statistics, but I'll hunt around and see what's out there.) Inattentiveness in putting is usually fatal, and the notion that a golfer simply needs to practice a motion enough until it is "engrained" by rote repetition (as Pelz teaches) plays right into this condition of failure. Putting excellence always requires a knowledge of what works and what sort of movement is necessary to make the stroke correctly, and this need for "cognitive vigilance" never dissipates regardless of how long you practice.
Cheers!
Geoff Mangum
Putting Theorist and Instructor
The PuttingZone
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