I am a physicist and a keen golfer. A few years ago I was under
doctor’s orders to stay away from golf for at least 3 months in order
to recover from a shoulder injury. So instead of playing, I trawled
through golf books and papers to figure out what actually happens in
the golf swing. After many months, I had a good pile of paper
describing a lot of things about golf, but nothing simple to tell me
how the swing really works. Even the best of the classic
books like Cochrane and Stobbs, Daish, and Jorgensen fail on this
point. Once I was back playing, the problem continued to nag.
The underlying problem with golf-swing physics is the complexity of the
math. The equations explain everything and nothing. Sure it is possible
to solve the equations, produce animations, and carry out numerical
experiments, which is what most researchers have done, including me.
However, the equations are so complex that it is not possible to look
and say, “Ah ha! – I understand.”
Eventually I found the simplification that provides the insight, and
this presentation is the result.
The presentation builds the whole of the golf stroke including the
swing and the club-ball collision. The key points of technique
identified here are simple but so counterintuitive that they are hard
to believe and execute when you are standing over a ball. The physics
explanation helped me to defeat my intuition. I’m in my 50’s now and 30
years of bad wiring in the brain is hard to change, but over a period
of two years I have gained 30-50 m distance on my drives, and improved
the accuracy on all of my shots, all with less effort. Hopefully these
pages will help you to do the same.
A careful reading of the presentation will take about an hour, and for
most people it’s probably necessary to view the animations to really
understand how the swing works. If you don’t have an hour, you can try
reading the technique section by itself, but you may find some of the
advice hard to believe.
The golf swing
is a combination of two physical processes: most obviously, a
between the club and ball, and perhaps less
obviously, the unfolding of a simple machine called a double-pendulum
Although simple, the double pendulum has very complicated behavior. In
recent years, it has received a lot of attention because is a simple
example of a system exhibiting chaotic behavior (which may explain some
of my golf shots). The double pendulum also turns
up in a lot of different places because it is an efficient way of
transferring energy from a heavy slow-moving object to a light
- Baseball, tennis, hockey, and wood chopping are obvious
- Football (kicking), javelin, and discus are not so obvious
- Old war machines: Trebuchet (like a catapult), sling,
atlatl or spear thrower (also known as the woomera in Australia).
- Builders and shipping cranes (especially on ships where it
causes trouble), and the threshing flail.