Can we design sports shoes that don’t squeak? Here’s what the science says

The unofficial soundtrack of every basketball, squash or hard-court tennis match is the constant high-pitched squeak or shreak of the players’ shoes. But can this squeak be designed out of them while retaining the grip?

That’s the question an international team of engineers and applied physicists, including me, have been investigating. It sounds like a small design tweak. In fact, it cuts to a deep physics problem: how a soft body slides against a rigid one.

Perhaps surprisingly, the mechanism that produces sound when a soft solid slides against a stiffer one has long been the subject of scientific debate. Most theories are linked to the concept of “stick-slip”: when, instead of sliding smoothly, the sliding object rapidly alternates between sticking and slipping.