Science and Shoelaces

If you run, hike, cycle or partake in any other activity that requires shoes, you’ve probably wondered how shoelaces come undone without human interference.

Wonder no longer, for a team of mechanical engineers from the University at California Berkeley investigated this phenomenon in search of an answer.

To study the laces up close, the team of engineers filmed a runner on a treadmill and reviewed the footage in slow-motion. The results weren’t shocking, but interesting nevertheless. When a person runs, their feet strike the ground at 7G, which means the foot weighs seven times as much as it usually does. That amount of forces results in the knot stretching out and settling within the space of a few milliseconds.

The motion of swinging legs also applies inertial forces on the aglets, which pulls the knot further apart. It’s known as the Avalanche Effect.

Obviously the team also studied various shoelaces in the hopes of finding the perfect Avalanche Effect-proof pair, but it was not to be. Some shoelaces fared better than others, but it was simply a matter of time in the end.

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