New Millennium Golf Science
where golf myths get debunked

"It's not what you don't know that hurts you, it's what you know that just ain't so." -- Mark Twain

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why a golf club releases and how to
delay the release in order to get more clubhead speed
are the stuff of modern golf myths

You're asking: how can pingman (or a pure swinger) release the club if there is no wrist torque or "centrifugal force"?

We start with the lexicon... a definition of terms:

· position: location in space at a given instant in time

· velocity: time rate of change of position... has both direction and magnitude

· acceleration: time rate of change of velocity... has both direction and magnitude

· kinematics: the study of motion without considering forces and torques

· dynamics: the study of rigid bodies in motion including forces and torques

· statics: the study of rigid bodies at rest including forces and torques

To begin to understand the golf stroke and how club release is affected, one must have a basic understanding of these simple physics principles. If you don't then begin here: http://www.glenbrook.k12.il.us/gbssci/phys/mmedia/index.html

AT ANY GIVEN INSTANT IN TIME

I have stated that the only forces (not withstanding the small contribution due to gravity) that the club experiences are those which are imparted by the golfer at the grip. He/she can apply a linear (swinger) force or a torque (push/pull exerted between the two hands... ie hitter) or some combination of the two. Most likely everyone is some combination of the two.. but lets simplify and assume he/she is a "pure swinger" (like pingman) and does not apply wrist torque.

We calculate the acceleration of the hands from the change in velocity. This can be done analytically or graphically using vectors as shown in figure 1.

Now that we know the magnitude and direction of the acceleration of the hands as shown in figure 2

We can use what's known as d'Alembert's principle to solve the dynamics problem as if it were a simple statics problem.

d'Alembert's principle says: the resultant motion of a rigid body is completely defined by the resultant and moment resultant about the mass center of the external forces acting on it.

Remember, in the real world there is only one external force acting on the club and that is what's caused by the hands moving along their path at an ever-increasing velocity.

Now its a simple statics problem to solve for the (linear) accelerations ma_x and ma_y as well as the angular acceleration alpha. Angular acceleration IS the release!

What have we learned? Lets review...

· The only force necessary to cause the club to release is imparted to the club by the golfer's hands

· The kinematics of the golfer's hands are key to knowing when and where the club will release.

· There is absolutely no need to resort to patently wrong magical mystical totally nonsensical centrifugal force theories to explain how and why a club releases. Classical mechanics and a firm grasp of technical concepts are all that are needed.

Now.... TIME-MARCH THE SOLUTION

What I've shown you is how the instantaneous angular acceleration of the club-head can be calculated for a brief snapshot in time given only the hand velocity profile and trajectory. But we're after club-head speed at impact not club-head acceleration at a single instant.

The next step is for you to set the problem up to time-march the solution forward then optimize. How and what to optimize are left as an exercise for the reader. When you've done that, add the effect of gravity and a wrist torque profile. You'll get out of it what you put into it.

Here's a hint... the only tool you'll need is something like Microsoft Excel.