Unravelling [yes, pun intended] the mysteries of the unknotting shoelace. See also Ian’s Shoelace Site [ https://www.fieggen.com/shoelace/knots.htm ], posted by Ed S for different ways to tie a shoelace. I’m a happy user of Ian’s Secure Shoelace Knot; no shoelace has ever come loose after switching to it. “Things can start to unravel at any moment, but when failure occurs it is swift and catastrophic. This is the conclusion of a scientific investigation into what might be described as Sod’s law of shoelaces.
The study focused on the mysterious phenomenon by which a shoe is neatly and securely tied one moment, and the next a flapping lace is threatening to trip you up – possibly as you are running for the bus or striding with professional purpose across your open-plan office.
In a series of experiments involving a human runner on a treadmill and a mechanical leg designed to swing and stomp, the scientists revealed that shoelace knot failure happens in a matter of seconds, triggered by a complex interaction of forces.
Oliver O’Reilly, a professor of mechanical engineering at the University of California Berkeley and the study’s senior author, said: “It’s unpredictable but when it happens, it’s in two or three strides and it’s catastrophic. There’s no way of coming back from it.””
https://www.theguardian.com/science/2017/apr/12/scientists-unravel-mystery-of-the-loose-shoelace
I didn’t know how to tie my shoes correctly (at age 60) until I saw this:
ted.com – How to tie your shoes