We have all been here asking how do these shoelaces untie themselves. It used to be an unsolved mystery till professor Oliver O’Reilly and his team conducted a few experiments to understand why shoelaces come untied when we are on the move.
Scientists reported that the failure of the knot happens in a matter of seconds, often without warning and it turns out to be catastrophic. They have aptly termed it catastrophic – complete, or total collapse and once the loosening begins, it is inevitable to keep them in place.
To tackle this enigma, a trio of mechanical engineers at University of California, Berkeley filmed a knot on the shoe of a person running on the treadmill. They explained that a double whammy of stomping and whipping forces act like an invisible hand, loosen the knot in slow motion and then tugg on the free ends of your laces until it unravels completely. After a couple of re-runs they spotted that there are two types of knots and various types of laces. Weak and Strong knots, both fail the same way but one takes longer than the other. And some laces were better than the others but none were impervious to failure.
Millions of shoelaces come undone every day and yet the mechanics of it has never been thoroughly examined. When running, your foot strikes the ground seven times the force of gravity which stretch and relax the knot. As the knot relaxes, the legs swings into motion; applying additional force.
Despite being an everyday circumstance, the consequences could be devastating. Lace-related accidents trend on social media every other day. A van driver who killed a motorcyclist because his shoelace wrapped around the accelerator blocked him to lift his foot off the gas. A boy whose leg got pulled into the gears of an escalator suffered fatal injury. A cyclist sailed over handlebars into traffic due to his untied shoelaces.
The cost of a pair of strangling shoelace is rarely higher than a scraped knee or the amount of time it takes to bend down to re-tie a bow.