[Mathew]

Low point of the clubHEAD is at the left shoulder. Low point of 'thrust' (force) is at both arms straight per 1-L 13 and 1-L 15.

I think this is a good post but I however have been itching to write a responce to this....

The low point of the clubhead however relative to the ground is not technically speaking directly under the left shoulder (although a useful simplification) because the left shoulder is also moving in a circle that moves its location progressively upwards (plotting this circle is geometrically complex and perhaps make a good lab thread). So it is actually a lil bit further back of directly under the left shoulder. Another point of note is that after impact and low point -----into followthrough the clubhead goes upwards (even with horizontal hinging) more than most appreciate due to the fact that now the left arm and the left shoulder are now going upwards as opposed to the downstroke where the left arm is swinging downwards and the left shoulder going upwards.....

To go into real detail about this though would be extremely complicated....maybe a good future lab thread....