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. Especially for lag's sudents with the emphasis on pivot acceleration prior to, through and beyond impact.
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 tightly but later on we better learn to let go.