bargolf, on 20 January 2013 - 07:25 AM, said:
indyvai, on 19 January 2013 - 07:48 PM, said:
bargolf, on 19 January 2013 - 07:05 PM, said:
Is it possible the point of rotation is not the spine but the base of the neck? Geoff Mangum explained this in detail in his work and depending on the players distance from the ball is correct.
In 2D sbst is easy to achieve. In 3D really hard, there is a vertical component you have to deal with unless you can make your arms longer during the stroke. SBST takes specific posture requirements, you can't just walk up and decide you are sbst. Putter path is a result not a choice.
The problem isn't whether one is possible or not. It is what fits your posture and perception. Justin Leonard would really be a bad putter with a SBST perception. Indyvai can't make it arc if he wanted to.
Can I post a picture? I have hundreds of Puttlab measurements showing a very straight path in 2D. All from very successful putters.
The rotation point only comes into play when deterrents of SBST claim it's impossible and the human body can't physiologically execute what Pelz describes in his book. Simple arms under the shoulders, vertical pendulum... putter stays square SBST.
I'm extremely interested in the vertical component, because my linear thinking just defines the result of a vertical pendulum as a vertical arc that accounts for the putter face "closing" to the ground on the backstroke, but staying square to the target line...
I think what catches most people in this discussion is the assumption that the putter shaft defines the plane of the stroke. It doesn't, it is only a component of the whole mechanism. If the HANDS are under the shoulders and the shoulders rotate or move on a vertical plane, the putter HEAD will move on a vertical plane that visually looks SBST. The only influence of an arc is as the putter comes up on the backswing and up past the apex of the arc on the forward swing. The drawing represents a model of the mechanical requirements of the sbst method.
Bruce, I love having your input here. Between you and Putting Doctor, there is a wealth of knowledge in this thread.
While geometrically it is possible to putt SBST, I don't see a way that it's phyiscally (or, maybe more appropriately, physiologically) possible. Here are two points of contention between indyvai and me.
1. Look at the line defining the axis of shoulder rotation. It is parallel to the ground. I have consistently stated that SBST would be possible IF your shoudlers could rotate around the spine in an angle that was parallel with the ground. This is what is clearly shown. What indyvai has retorted is that it is possible to rotate your shoulders in a vertical plane even if your spine is not parallel to the ground. I have stated it is theoretically possible (but practically impossible because of item 2 below), but it is no more repeatable than putting with some other type of mechanical correction such as timing wrists or weight shifts.
2. The stick figure is a perfectly fine representation but it lacks the physiology of a human being. Where is the stick figure's stomache, chest, forarms, and other things that "get in the way" when a person is not swinging around his or her body? If a person were actually to try and rotate in this plane, so many things are in the way that the person's arms would run into the person's sides, unless, of course, the person addressed the ball with his or her elbows pointed out away from the body. To date, I haven't seen anyone putt that way. The only way to accomplish this is by shifting weight, bending the back, extending the arms, or otherwise "correcting" to get the putter to move straight.
While your SAM lab results show it's possible to make a straight stroke, they do not show the user's stroke or if he/she has any corrective action. Moreover, as Putting Doctor has pointed out previously in this forum, many pros do not have a truly "shoulders only" stroke. Many of those that do not are nonetheless exceptional putters and are capable of repeating a timed stroke to near perfect success.
I would love to see DTL and front facing videos of one of these putters to see exactly how he/she is accomplishing this motion.