How to throw a shot

Shot putters throw furthest at an angle of 37–38°

By Nicola Guttridge

Wimbledon? The World Cup? The Open Championship? Sport isn’t a great interest of mine, but despite my general ineptitude at most athletic activities, a recent paper caught my eye today in which two researchers studied the optimum angle of release in shotput – a problem that has baffled scientists since the 1970s. It’s not 45°, as you might expect. Instead, it turns out that athletes can throw a shot furthest when launched at a lower angle of about 37–38°. So why this difference in angle?

Alexander Lenz at the Technical University of Dortmund and Florian Rappl of the University of Regensburg in Germany puzzled over this and now believe that they have an explanation. It seems that the limitations aren’t in the mechanics but are to do with the human body. What it boils down to is that we humans are much better at pushing outwards than upwards, and so throwing the shot at a slightly lower angle than the expected 45° makes it travel further. To read more about this study, try the arXiv blog post.

As they point out, the human body’s preference for low angles of release is also apparent in weightlifting where weight records for bench pressing are much higher than for when the athlete tries to lift when standing.

Perhaps I should not have been surprised by the non-45° angle for shotputting. Back in 2006 scientists at the University of Brunel calculated the best angle to launch a football at during a throw-in and found it to be 30° to the horizontal – again, disagreeing with the expected angle of 45°. Most of these mistaken predicted angles can be explained by the theoretical calculations treating humans like perfect machines, a little reminiscent of superman – something that I’m sure many footballers would appreciate!

Another post I stumbled upon while reading around the shotput study was one about a completely different type of putting – golf. Robert Grober, an expert on the physics of golf at Yale University, has come up with a model to describe the perfect putt. Apparently the secret to golfing success lies in the behaviour of a simple pendulum being driven at twice its resonant frequency – I’m not sure how practical it’d be to attempt to use Grober’s model on a golf course, but even so it’s quite an interesting read. But then what do I know? I don’t like sport.

About the author
Nicola Guttridge is an intern with physicsworld.com