Dear Bastiaan,
Yes, and yes.
I believe the true plane tool actually teaches a VERTICAL-PLANE stroke action of the shoulder sockets and that the statement that the putterhead will swing naturally inside on the backswing and on the follow through" cannot literally be true. The heel of the putterhead afterall is resting against a plane of plexiglass, so it cannot possibly come closer to the golfer's feet. But with a TILTED-PLANE shoulder action, the heel of the putter will in fact come closer to the feet as the backstroke progresses, even as the intersection of the plane of motion with the green surface is parallel to or matches the line of the putt. The trajectory of the putterhead and putter heel in that case would come closer to the feet as the backstroke (or thrustroke) progresses. I believe that Dr Brooks simply makes a slight misstatement here.
If this is unclear, let me know and I'll try to be clearer.
Cheers!
Geoff Mangum
Putting Theorist and Instructor
The PuttingZone.com
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