The sonic golf system can be used for various purposes. Definitely as a golf swing aid  using the audio biofeedback feature, as sold presently. But it will eventually, with future expansions planned, allow many serious amateurs and instructors, for a reasonable cost, to have a simple yet sophisticated research tool at their disposal.

There is still a nmgolfer, who after polluting this forum and others, continues to ridicule Brian and mandrin elsewhere for their apparent nonsensical ideas regarding hands slowing down during the downswing and the role of the kinetic chain in the golf swing.  Well, with future versions of the sonic golf system everyone can determine for his own swing the validity of these ideas.

This fellow very stubbornly keeps hammering on the fact that slowing down of the hands is a myth. In effect that they actually accelerate though impact. However just simply looking at the super slow sequences on TV of any pro golfer shows clearly that their hands slow down. But some simply can't see it even when you rub their nose forcefully into the obvious truth. It shows the dangerous and suprising power when neurons are poorly aligned.

Let's have a closer look at our hypothetical example, based on typical signals such as measured by Dr. Grober. The two torques derived by inverse dynamics are shown again but now both as a function of time, Figs2a/b and as a function of angle θ of inner segment in  Figs3a/b.  In all figures the dashed magenta line represents 'impact'. Notice especially that the main 'shoulder' torque is only really effective only during the early part of the  down swing. The same is true for the 'wrist' torque which is primarily used in the model to prevent back knifing of the outer segment.

Figs 4a and 4b show the acceleration and speed of the 'hands'. In Fig4a the red emphasized part shows clearly the large deceleration (braking) of the 'hands' for a substantial part of the  down swing and the corresponding slowing down of the hands in Fig4b.

Intuitively one might indeed think that this slowing down of the hands will produce less clubhead speed. However it is just the opposite. It allows the clubhead to  increase its velocity as shown clearly in Figs 4b and 5. The mechanism behind it ? The kinetic chain action !  

Observe in Fig5 that from about 0.22 sec the total kinetic energy remains approximately constant. Only a small increase due to gravity. However there is clearly a vigorous redistribution of kinetic energy taking place. The arms lose most of their kinetic energy whereas the clubshaft but primarily the clubhead receive this kinetic energy. Someone who forcefully keeps applying 'shoulder' and 'wrist' torque through the 2nd half of the down swing prevents this natural energy exchange to occur optimally.

The down swing reflects life. First we hang on tight but later on we better learn to let go.