Dear Bastiaan,
The spine angle for putting probably out to be defined a little. The spine is actually not a line but an S-curve looked at from the person's right side. The curves are in 3 sections, cervical at top, thoracic in the middle, and lumbar down low.
Treating the "spine" as a line from the base of the back to the center of the neck is probably more what you have in mind. But actually, there are some very important curvatures that can be used right at the top or cervical section of the spine.
Harold Swash teaches that the top section of the spine needs to be oriented horizontally to the surface. In "line angle" lingo, this would be 90 degrees.
Harold has a putting trainer device called "The Rack" that is sort of a robot frame for guiding a person's stroke. (You can see it at
Yes! Golf if you click on Training Aids.) The base of the frame has a rod extending out that swivel up and down on its attachment at the top of the stand. This rod adjusts the frame that holds the golfer's putter. When the golfer makes strokes over a grid on the ground, you see different stroke path shapes depending upon how the rod is oriented. If the rod is horizontal, the stroke path generated is stright back and straight thru above the ground (while also rising on either side of the bottom). This setting corresponds to having the top of the spine horizontal, matching the rod orientation.
If the rod is tilted or angled down, this corresponds to the golfer having his top spine up off horizontal at various degrees. The resulting strokes appear to arc above the grid indicating that the stroke plane is tilted.
Stan Utley and others appear to believe that the fact that the spine tilts is the sole factor that causes an arc-shaped putting stroke. He thinks the shoulders "naturally" rotate around the spine like a record turns around a spindle. I believe this is a little confused.
The shoulder frame is not really connected to the spine. The shoulder frame really is the shoulder joints and bones connecting these joints to the sternum via the clavicle "struts." While the ribs branch out from the spine and curve around to the front of the chest, the ribcage is only indirectly connected by tissue to the sternum. So in a sense, the whole torso is kind of all connected together, but there is quite a bit of independent range of motion of each shoulder and of the shoulder frame as a unit independent of the spine. In particular, just because the spine is tilted at a certain angle (as ifit were a "line"), this does not determine how the shoulder frame must be moved, and the shoulders can be moved in an independent direction other than "around" the spine as tilted.
There really are two separate sorts of shoulder frame movements that may be involved in side-on putting. First, the torso as a whole may be tilted from side to side, as in performing side "crunches" in an exercise class in which the head goes with the shoulders and so does the spine (including the lower spine), all as a unit. Second, the head and spine may be kept more or less stationary while the shoulder frame rocks, one shoulder down as the other rises in coordination, leaving the whole spine more or less unaffected and motionless. The greater the amplitude of the stroke, the more the spine becomes involved in the tilting side to side.
Regardless, the important point is whether the motion of the shoulder frame moves in a plane that remains oriented to the ground so that the plane intersetcs the ground in a line that is the same as or parallels the putt line, at least thru the crucial segment of the stroke path on either side of the ball for about 3 to 6 inches. The plane of motion may be vertical or tilted to some varying degree, or even horizontal. But in none of these cases is the motion entirely fixed by the spine angle. The planar character of the shoulder frame motion determines the stroke path, not the spine angle.
The spine is very flexible. The ordinary range of motion tilting down sideways to touch the floor beside the foot is a full 90 degrees. The twisting of the spine and torso around while standing upright is more than 90 degrees left around or right around, as is obvious in a full swing.
The real determinant of spine angle is a) setting the eyes and skull line square to the putter face as aimed, b) the need to reduce conflict between the bottom of the ribcage and the pelvis bones at the extremes of stroke ranges, c) comfort and d) balance. You can make a perfectly good putting stroke standing upright or bending very far out and down over the ball. The most important of these are a) and d), and b) is probably least important.
The reason the spine angle usually gets bent is because the golfer wants to look down near his feet to see the ball. This bends the top of the spine. Too radical a bend is uncomfortable, so the rest of the spine is also bent to ease the strain for increased comfort. The more the upper torso bends, the more the golfer's balance is challenged. A nice place to stop bending the upper torso is when you feel very stable in balance in your stance. This usually occurs when the shoulder joints are out over the balls of the feet, with a slight bend at the hips and a flex in the knees. Whether the head is "flat" with the top of the spine horizontal, or whether the head is a little forehead-up does not prevent you from having a straight-out gaze that sees the ball and sets the skull line square to the putter face, but is really a matter of comfort and choice.
If the top of the spine is horizontal, it may be marginally easier and more consistently repeating when the golfer moves the shoulder frame vertically in a rocking planar action. But when the top of the spine is slightly up-angled off horizontal, it is still entirely possible to move the shoulder joints vertically by directing them at or away from the balls of the feet.
I don't recommend a tilted stroke plane because the body cues for where the shoulders need to head are not as clear as with a vertical action, and because the tilted action makes ball position something of an issue for whether the ball will be sent straight or right or left.
Generally speaking, given the fact that most people have pretty much similar proportions in body parts, a "normal" setup for a good shoulder stroke has a "line" angle for the spine probably in the range of 30 degrees. (It would not surprise me to learn that this angle is about the same for a good full-shot setup.) The greater the curvature, the more the strain in the body, and hence the discomfort and restriction on movement. But people have different ranges of limberness, and some tolerate more curvature than others. If you bend over too far at the hips so that the lower back tightens and has some discomfort, you have gone to far. Similarly, if you bend the top of the spine too much, you will tighten the muscles along the top of the back to a point of discomfort and restiction. So let balance and comfort and ease of motion be your general guide to spine angle.
Cheers!
Geoff Mangum
Putting Theorist and Instructor
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