Dear James,
That's a fabulous question! Thanks for asking it and giving me a chance to talk some anatomy!
The bottom line is that a little head movement or leg action is not hurtful to an accomplished putter, but if you prefer, it can be eliminated fairly simply. I personally haven't been able to decide which I think is "best" -- a still head and legs or a little informality in the head and legs -- but I don't see it as an either / or choice or really all that much of a problem. The really important stuff in the putting stroke is going on in the shoulders, arms, and hands, not the head or the legs.
Let me backtrack a bit and talk about the spine, with a special focus on its relation to the head and legs.
In the full swing, the standard lore is that the "spine angle" needs to be constant going back and coming thru. The angle being referred to is the tilt -- which is both forward (perhaps 30-45 degrees or so) and slightly to the rear (maybe 15 degrees?) in the K-shaped setup commonly recommended. Once set, this angle should structure the turn in the swing, or so the teaching goes.
This so-called "spine angle," though, is really just an imaginary line up the back. The spine is hardly a line, but is curved in an S-shape: curved inward at the bottom lumbar region -- lordosis -- and curved outward in the middle thoracic region -- kyphosis -- with the top cervical region being the inward end of the thoracic curvature. And the spine is also not a unitary structure, but is a series of vertebral sections, and each section has its independent freedom of motion to a limited extent -- like one of those wooden articulated snakes in the novelty shops. The bottom vertebrae have different structural properties that tend to keep motion in a flexion-extention orientation and not in a lateral bending, whereas other higher vertebrae are structured differently and allow more sideways bending. And the connectedness of the bottom, middle and top of the spine to other body structures differs greatly and differently restricts or conditions the freedom of motion for that part of the spine, so the spine does not move as a unit, but has different movement capabilities depending on the section of the spine and the direction of the motion.
Actually, in the full swing, the golfer's head moves laterally back an inch or two in the backstroke, while the hips and knees both turn and shift back and forth.
FULL SWING RESOURCES:
Using Your Head to Improve Your Golf Swing, CoachesInfo.com
Managing Golf Injuries, The Physician and Sportsmedicine
Golf Swing Misconceptions
Rolf and Golf
Shoulder motions during the golf swing in male amateur golfers, J Orthopedic and Sports Physical Therapy
Golf Injuries, Sports Medicine Clinic, Laval University, Quebec
Preventing low back pain from golf
Spinal anatomy and back pain
Levelhead Golf Necktie
Golfers with Spine: On and Off the Golf Course
Managing Golf Injuries, The Physician and Sports Medicine
SPINE DOCTOR - Exercise
Science Blog, Chiropractic: keeping golfers in the swing of things, American Chiropractic Association
Golf and Your Back
Combat low back pain with conditioning exercises, HealthSouth Sports Medicine Van, PGA Tour
Golf Fitness Academy, The Golf Channel
Timothy Agnew: The Kinesiology of Golf
The Golf Channel - Dealing With a Reverse Spine Angle, The Golf Channel
In putting, the lateral motion of the spine and the twisting motion are the ones we are concerned with, and not so much with the bending forward properties (flexion). Measuring range of motion in the spine is not a straightforward proposition, because the spine is not one structure but many. Looked at (roughly) as a whole, most adults have a lateral range of motion in the cervical spine of about 45 degrees, while lateral bending of the lumbar spine is around 25-30 degrees. This makes the spine look and act a bit like a small tree that is willowy but thicker at the bottom. In the middle, the thoracic spine is not designed so much for connecting the top and the bottom of the body but with containing the chest in a stable, same structure for vital organs. The rib cage is built out of ribs emanating from the thoracic spine and wrapping around the chest protectively to the front, where the ribs are then connected to the sternum by costal fiber processes. This enclosure has some flexibility, but overall the thoracic spine and chest tend to move as a unit and the thoracic spine does not really have a lot of freedom for changing shape. All together, the spine "moves" in different ways.
These sources have movies showing a vertical shoulder stroke:
Dean Thompson's shoulder stroke straight back and straight thru
Innovative Golf Technologies -- Vertical Shoulder Stroke Training Aid
Here are some typical "norms" for range of motion of parts of the spine (in degrees):
Lumbar:
Flexion 60 (forward bending),
Extension 25 (backward bending),
Lateral bending 25 (sideways bending)
Thoracic:
Flexion 50,
Rotation 30 (twisting)
Cervical:
Flexion 60,
Extension 75,
Lateral bending 45,
Rotation 80
SPINE RANGE OF MOTION RESOURCES:
Range of motion, Chiro.org
Spine Research Institute of San Diego
Mayfield Clinic - Anatomy of the Spine
Joint Range of Motion, Ball State University
Compensation and Pension Examination, Spinal Examination, Veterans Administration
A new, comprehensive normative database of lumbar spine ranges of motion, Clinical Rehabilitation
Stability Provided by the Sternum and Rib Cage In the Thoracic Spine.
Spine. 30(11):1283-1286, June 1, 2005
AcuROM Videos of Spinal Motion
Stretches for the cervical area, Human Kinetics
Spine Mechanics, Sports Medicine and Rehabilitation International, Bradenton FL
Trunk Range of Motion in Golf, Biomechanics Listserv
Spinal Range Of Motion, Oregon Department of Workers Compensation
Steelcase - Ergonomics - Seating - Investigating lower back strain while sitting
Steelcase - Ergonomics - Seating - Supporting the lower back while sitting
Steelcase - Ergonomics - Seating - Back Basics
The Spine -- Lab 3, USC Kinesiology
Let's look first at the head and eyes in the stroke:
A typical putting stroke with the shouder frame has the lead shoulder dropping about 3-4 inches below its level starting position. Typically, adult male shoulders are about 15-18 inches across. An shoulder that drops 4 inches from the pivot at the base of the meck 9 inches away makes an angle of 24 degrees with level. A shoukder stroke (no arms or hands) that sends the putter back 24 degrees, for a golfer with the base of the neck (pivot) 4.5 feet off the ground, sends the putter back 24 inches.
Looking at the spine, head and legs in this typical stroke:
The "face" will roll back 24 degrees if it follows the shoulder frame. A typical "face" is about 8-10 inches wide, so this means that the lead-side ear will drop about 4 inches in this stroke. The eyes are 2.25 inches on center, usually, so the lead-side eye will lower about one inch. Ordinarily, the eyeball gaze will stay put on the same focal point at the ball or the ground behind the ball, due to the vestibular-ocular reflex (VOR), but at worst the gaze's fixation point will wander back from the ball along the line of the putt the same 24 inches the putter sweetspot moves. More normally, if the head rolls some, it doesn't roll all the way with the putter head but only a short distance -- something closer to 5-10 degrees off vertical. The eye can easily manage this head roll by staying fixed on the original spot. That is, even if the head rolls, the fixation of vision will remain steady at the back of the ball or on the ground behind the ball. Going forward, the same kind of rolling occurs.
Here is Fredrik Jacobson with his face rolling with his shoulders into the thru-stroke:
This head and eye motion implicates the visual, balance, and proprioceptive (body-sense) systems in the brain. (These are the three systems that the cerebellum coordinates for smooth movement.) In contrast, when the head is kept motionless so that the "face" does not follow the shoulder frame back and thru, the inner ear, the visual system, and the body-sense system remain unchanged so far as the head and eyes are concerned.
What difference does it make? The more accomplished the golfer, the less these changes in the three systems are hurtful to the accuracy of the stroke form. In other words, the very experienced golfer knows what to expect in these changes and has learned how to accommodate these changes in a stroke that still preserves its accuracy to the same or nearly the same level as that in a stroke with the head kept motionless.
The main accommodation to this face rolling is to keep the gaze fixed on a single spot, as this eliminates visual changes -- hence my tip to fix the gaze on a blade of grass directly behind the ball and to keep the gaze there throughout the stroke. The inner ear balance system and body-in-space sense will still experience the rolling of the head, and this may challenge the sense of the exact bottom of the stroke (the key to accurate form in the stroke). As the head tilts going back from the ball, this balance change tends to blur the sense of the initial address position. The accomplished putter has a clear focus on body symmetry at the start of the stroke and has a strong sense of returning to the bottom of the stroke, in terms of when (tempo timing always returns the putter to the bottom with exactly the same timing regardless of size of stroke), where (when the sweetspot again returns to the visual fixation at the bottom of the stroke), and the how (the shoulder frame, arms, and hands all return to the neutral setup relationships they started with at address when the putter returns to the bottom f the stroke), and other cues. These cues and skills in executing the stroke in the context of these cues renders a little inner-ear head roll inconsequential, or at least substantially less so than otherwise for the intermediate or beginning golfer.
If you want to eliminate head and face roll, you can simply "point your face" or your nose at a location on the ground. The neck muscles "point" the face or nose, so doing this sets a muscle tone that keeps the head still even as the cervical spine and shoulder frame bends laterally. The very top of the cervical spine will twist or rotate because the head is not rolling with the lateral bend, but the head is naturally structured for just this sort of rotation anyway, so the spine twist is not very noticeable.
Here is a photo of a golfer keeping his face aimed down at the ball even into the thru-stroke:
Nick Faldo does the same:
When Harold Swash places his hand on the top of the spine of a golfer at the putting setup, he is basically getting the golfer to point his face, flatten the top of the spine, and quieten the action in the top of the spine more to a twisting or rotating without lateral bending.
Picture of Swash and student Padraig Harrington:
I'm not sure I really agree with this, because the pivot is the base of the neck, and this point is well below the top of the spine. If the pivot is held steady in the stroke, there is something of a sciccors action about the pivot: the very top of the spine and the head goes left of the pivot while the right shoulder goes up, then the top of the spine and head goes right as the left shoulder goes up, but the pivot point in the base of the neck (like the pivot of the scissors) stays in place.
So, keeping the head still is important to a begining or intermediate golfer on the green, and may or may not be important to an advanced golfer -- at least not to one who has learned the changes and accommodated them to preserve stroke form.
What is the spine doing in this sort of stroke? If the shoulder action follows a vertical plane, with the lead shoulder dropping down and back along the line of the balls of the feet, this motion is accomplished by abdomenal muscles that tug the lead shoulder and side down at the lead pelvis. The willowy tree-like response of the spine sees the top of the spine bend laterally (probably 12.5 degrees), the thoracic spine bend less, and the lumbar spine bend laterally not much at all. There is very little "twisting" of the spinal column, if any, unless the head and face are held motionless -- in which case the cervical spine will twist by virtue of the head not rolling with the shoulder frame. In so many words, a little head and face roll in the stroke is less complicated for the spine.
What is the response of the hips and legs to the action of the spine in this sort of stroke? The tilting of the upper torso and the lateral bending of the spine puts a counter sideways force from the lumbar spine into the pelvis -- dipping the shoulder frame left-side down tends to shove the pelvis to the right laterally. A minor lateral slide of the body's center of gravity (COG) is the reaction. The center of gravity is below the navel and inside the lower abdomen a little. Watching this spot in a vertical shoulder stroke would show a minor shift back and then forward off ther initial centering.
This COG shift can either be eliminated or accommodated. To eliminate or drastically restrict it, some golfers widen the stance (Padraig Harrington), and some go pigeon-toed (Arnold Palmer). Other golfers accommodate the COG motion (Ben Crenshaw). The principal accommodation is to regulate the conflict between the bottom of the rib cage (and thoracic spinal action) and the top of the pelvis. So long as the conflict does not send the thoracic spine and chest out of plane, there is no-harm, no-foul. The chest goes out of plane only when the conflict is avoided by the bottom of the rib cage on the rear-side sliding in front of the top of the pelvis. The chest remains in plane when the conflict is either avoided (by the rear knee giving and thus lowering the pelvis out of the way of the rib cage -- as Crenshaw does) or positively encouraged (as I teach -- its just a minor crimping in the rear waist, but a valuable signal that the chest is remaining in plane).
The real issue is more than balance, though, and is motion-in-balance. Static balance by restricting the COG does not fully address motion-in-balance, and this is why I teach "putting from the top." Whatever approach you take to the COG in the lower abdomen (stlling it or allowing it to respond to spine action), what matters in the stroke is what happens in the shoulders, arms, and hands in space. The focus needs to be at the pivot at the base of the neck and on the shoulder frame, not in the abdomen. Keeping the shoulder frame in plane with quiet hands and arms and a nice slow tempo makes putting with motion-in-balance a lot easier and more consistent.
Does resticting the head or the COG between the hips help or hurt the stroke in comparison to a focus on the pivot at the base of the neck and the action of the shoulder frame in space? I think that it is a matter of personal style, but a choice that needs to be made mindfully. estricting one part of the body's motion tends to exacerbate control of another part -- at least, it makes the motion in the other part less "natural" and subject to voluntarily adopted constraints. So long as you realize this, the effort to still the head and the hips and legs in the stroke can be made, but not at the expense of moving the pivot and shoulders astutely. Putt from the top.
Cheers!
Geoff Mangum
Putting Theorist and Instructor
Geoff Mangum's PuttingZone
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