There's a possibility such work could shed light on the mechanics of other kinds of knotty structures, such as suture knots used in surgery, or the folding of DNA and proteins -and especially how they fail.
It is a question that everyone asks, often after stopping to retie their shoes, yet one that nobody had investigated, until now.
In a series of experiments involving a human runner on a treadmill and a mechanical leg created to swing and stomp, the scientists revealed that shoelace knot failure happens in a matter of seconds, triggered by a complex interaction of forces.
In his 2005 TED talk on how to tie shoelaces correctly, Terry Moore, director of the Radius Foundation, told an audience: 'I would have thought that, by age 50, one of the life skills that I had really nailed was tying my shoes, but not so'. However, the study proves that physics will untie all knots eventually.
The majority of people are taught to tie their laces incorrectly which means they're more likely to come undone, mechanical engineers have discovered. The researchers' strong knot is a version of the "square knot", made by crossing left over right as before but crossing right over left the second time.
"But we still do not understand why there's a fundamental mechanical difference", he added, leaving another knotty mystery to be solved.
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Christine Gregg, also a Berkeley graduate student and coauthor of the study like Daily-Diamond, slapped on some running shoes and proceeded to run on a treadmill as her colleagues captured footage of her motions with a slo-mo camera.
During running, the impact of one foot striking the ground stretches and relaxes the knot. Their study found that unwanted untying comes from two forces combining to replicate the effect of the wearer intentionally pulling the laces undone.
Also, the type of knot and lace and tightness all play a big factor in terms of how long it'll take before the shoelaces will come undone. According to researchers from the University of California Berkley, it's inertia that whips the laces forward coupled with the stomping of the foot that causes the knot to loosen.
In simple words, what happens is this: a combination of "stomping and whipping forces" behaves the same way a hand would, making the knot grow loose and then pulling on the laces to unravel the knot.
As the knot loosens, the swinging leg applies an inertial force on the free ends of the laces, leading to rapid unravelling in as little as two strides. "You can't seem to get knot failure without both", Daily-Diamond said.
Of course, when a person goes walking or running, their shoelaces don't always come untied.
Still, if you're going to take anything from this piece of news, make sure you tuck your laces into your shoes in future, that might just save you from tying your shoes over and over again. More research needs to be carried out to understand all the variables involved, they said.