Day three - May 30, 2009

Coordinates
In order to move on it is necessary to introduce a concise language for discussion based on an x, y, z coordinate system. This is just so we can talk about your swing.

Align yourself toward your target. Your shoulders and feet now point along what we will call the 'x' axis. Now address the ball with a club such that the club is pointing symmetrically away from your body. The shadow of the club, at mid day, will fall perpendicular to the x axis. The shadow is defined as the 'y' axis. Where x and y cross (at 90 degrees) is defined as the 'origin'. A vertical line drawn up from the origin is defined as the 'z' axis. So there we have it: x, y, and z.

No z!
On your backstroke when you dip your left knee toward your right you should be rotating only about the y axis. Your left shoulder moves down and your right shoulder moves up at the start of the back swing and should remain in line with the x axis (y rotation only).

In contrast, if you are trying to hit a baseball you swing horizontally about the z axis. But this is not baseball! You do not want to rotate about the z vertical axis.

If you are rotating both about the y axis and the z axis then on the down swing you must undo what you did in order to hit the ball square, but this means that the muscles controlling the y rotation must be in sync with the muscles controlling the z rotation and that is difficult to do!

By rotating only about the y axis, you only have one degree of freedom to control which is far simpler than controlling two degrees of freedom.

Another way of thinking about this is to hold you right hand out in front of you with your thumb pointing up. Rotate the thumb to the left. That is a rotation about the y axis. Put the thumb back up. Now move you wrist such that the fingers move left and right. That is rotation is about the z axis. That is 'fish tailing'. You don't want to fish tail in golf!

The consequences of fish tailing are poor ball striking, hooks, slices, draws, or fades.

When you rotate only about the y axis, with a little knee dip so you are looking slightly back at the ball at the top of your swing, the swing plane passes through the ball. Left and right errors are minimized. The knee dip enhances the likelihood that you will hit down on the ball and avoid 'thin' strikes.

Remember, no z!