Scigolf Presents Jack Kuykendall's Myths of Golf - #5 - What Really Produces club head Speed

The Body Does Not Produce Speed
The Body is a Stabilizer.

You cannot produce speed where there is no speed. The body is moving at very low speeds. Experiments show that the hips are moving less than 2 mile per hour. They are also moving on a plane that is at an angle between 55 and 65 degrees to the plane of the club head.

Simple physics 101 shows the following:

A body rotates about an axis through point "o" with angular speed "w".

The velocity of a point "P" is (v = w r)

Since "P" travels in a circle of radius "r sin o" , the magnitude of the velocity is "w ( r sin o )".

Scientific experiments show that tour professionals have hip velocity around 1.8 mph. This is 2.7 ft/sec. Assuming hips to be an average of 14 inches wide, the radius of the hips will be 7 inches ( 0.6 ft).


           v           2.7 ft/sec
   w  =  -------  =  ------------- = 4.5 radians/sec
           r            0.6 ft

Hand velocity due to body rotation:

v = w ( r sin o) = 4.5 rad/sec ( 3 ft) (sin 35o) = (4.5)(3)(.57) = 7.7 ft/sec = 5.2 mph.

The "Search for the perfect Swing" scientists, and the "Physics of Golf" physicist and many instructors believe that the feet, legs, hips, body or big muscles create club head speed. Why are all of these people making the wrong assumptions and coming to the wrong conclusion?

One of the answers lies in the plane that the body and the arms move on during the downstroke. The body and hips rotate on a plane parallel to the ground - blue line in figure 1.

The right shoulder, right hand and club head (RRC) move on a plane that is around a 60 degree angle to the ground - red line in figure 1.

A scientific observation of figure 1 and 2 shows that if the hip plane controlled the position of the RRC plane during the downstroke: - the RRC plane would only be in the ideal position if the hip plane was exactly parallel to the target line at ball impact.

If the shoulders followed the hips, the RRC plane would have the greatest probability to be in a non-ideal position at ball impact (figure 2). You would have the over-the-top outside-in swing that produces the weak slice.

SUMMARY:

A. On the movement of the hip and RRC plane.
The hip plane and the RRC plane rotate independent of each other.
B. Torque on the back due the hip and RRC plane.
The hip plane can and does create high twisting torque on the back if it gets more than 10 degrees ahead of the RRC plane during the downstroke. Many players experience back pain by rotating the hip plane ahead of the RRC plane during the downswing. This is due to the incorrect belief that hip rotation can produce a dramatic increase in club head speed.
C. On the contribution to club head speed by rotation of the hips.
The rotation of the hip plane contributes less than 10% toward club head speed.
D. The body plays an important role in a golf stroke.
It is a stabilizer for the fast moving hands and arms.