The Physics of Golf, Theodore P. Jorgensen

The author quotes Bobby Jones:

“There are a number of players who devote enough thought, time, and practice to the game to make them reasonably good golfers if they might start out with an accurate conception of what they want to do; but in many instances there is a confusion of ideas making intelligent progress impossible”

And thus I proceeded into the book with the hope that it would provide me that accurate conception, well-founded on Newtonian Dynamics. Like my university physics books, this is not one you sit down and just read. This is one for study.

The author presents a basic model conceptualized according to a pendulum and refined by those of the bullwhip. He tests the model against actual performance of a professional golfer, refines it with computer modelling and confirms the results with the writings of well-known golfers such as Bobby Jones, San Snead, etc.

The primary objective of the golfer is to increase clubhead speed and thus ball flight distance. Clubhead speed is proportional to power. The models presented explain the sources and generation of power. According to the author, 71% of the power comes from the golfer’s muscles, 13% from gravity, 16% from the lateral shift towards the target.

The book provides some additional insights, such as:

• Distinguishing between stroke characteristics that are well-founded on physical principles over style.
• Trying to hit the ball “harder” does not proportionally increase clubhead speed. According to the author’s calculations, a 5% increase in power yields a 1.8% increase in clubhead speed. He points out that increasing power comes at the expense of accuracy.
• The optimum wrist cock at impact is 15.3 degrees
• A golfer may reduce his back swing up to 30 degrees and only impact clubhead speed by 2.5%
• A professional golfer will hit the golf ball with approximately 2 HP force. To produce that amount of power requires about 32lbs of muscle. That amount of muscle is found in the legs, thighs and back; not the arms and shoulders.
• The lateral shift as measured by the left should is around 15″ albeit along a somewhat curved path
• The estimated efficiency of the club swing, the ratio of energy transferred to the ball as it leaves the club face, is estimated for the standard swing to be about 30%.
• On an average length course, if the golfer can drive only 160 yards they should expect to loose 15 strokes to par. However, if they are able to drive 230 yards then they should not loose any strokes to par due to their lack of distance. For the yards in between: 170 (12); 180 (9); 190 (7); 200 (5); 210 (3); 220 (1).

While the book accomplishes its mission, it is a technical book. Even with university-level physicals, albeit some 35 years in the past, it takes some level of concentration to get through the material. I think with a few simple alterations the material could be much more consumable by a wider audience.