Dear Mark,
The "open" shoulder alignment complicates the consistency of a "straight" putt. A "straight" putt is one that rolls the ball wherever the putter face aims at address, regardless of whether that aims at the target or not. An "open" shoulder alignment does not usually promote a straight stroke in that sense, but more often accompanies a stroke in which the putter face aims outside the true intended line of roll and target line but the stroke action itself has some "pull" aspect to it that corrects this aim and results in a roll down the line that aims at the target. Golfers who putt this way (and they are legion, being a clear if not vast majority of all golfers) don't really KNOW they aim outside and stroke inside, and hence don't know what exactly is supposed to happen in the stroke or why a particular stroke doesn't work out as hoped.
So, a golfer who adheres to a strict definition of an acceptable "straight stroke" will want to know whether an "open" alignment is better for him than a square (parallel) alignment of the shoulders with the target line. My opinion is that a parallel alignment of the shoulders is better in the long run for consistency and accuracy because it forces certain decisions about a consistent ball position and a consistent pattern of stroke motion. In contrast, an "open" shoulder alignment may vary in the degree of openness (there is only ONE setup that is parallel) and the ball position / stroke motion combination can also vary as the golfer seeks strokes that go where intended or even that go wherever the putter face is aimed. It is possible to putt well with an open shoulder alignment, but ultimately I think it is better to set the shoulders parallel to the target line.
To experiment with the difference yourself, try this:
Aim the putter face thru the ball and draw a start-line in front of the ball for 3 to 5 inches. Then try setting up with shoulders parallel to this start-line and making strokes and comparing that with setting up with shoulders aligned "open" to this start-line and making strokes. I believe you will find that the open shoulders exacerbate the degree of opening and closing that must get done in order to roll the ball down this start-line. Jack Nicklaus had a specific sort of shoulder rock that did NOT follow his shoulder alignment, but that is a learned trick of how to rock the shoulder frame vertically despite the alignment being athwart the target line. Ordinarily, there is more "arcing" around in the backstroke and thru-stroke than in the other setup. When the shoulders are parallel, sending the ball straight down the start-line is simpler, as all it takes is a vertical rocking of the shoulders back and thru, or a mild inside arcing in the backstroke followed by re-squaring with the shoulder alignment coming forward and then a vertical up-rocking thru impact.
Cheers!
Geoff Mangum
Putting Coach and Theorist
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