[SECGolf]

I'm just thinking here, could be wrong...

If you have a obviously whippy shaft, and hold the club up, the shaft will droop because the weight of the clubhead. No continuous movement. Things just are. The hands feel the pressure generated by this initial lag.

Trying to think back to physics, isn't weight a measure of pressure (as opposed to mass - a measure of the "stuff" inside an object)?

Then you must move the club in a way to maintain this initial pressure (or else there is no way you can maintain control of the club - the club then dictates movement). I think this is how the hands are sensors, how they dictate body movement - they know to maintain the pressure and will instruct the body to move in a way that keeps the pressure (for example, if the right hip is in the way, blocking hand movement, pressure can't be maintained, educated hands that feel pressure tell the hip to get the heck out of the way).