We all have tied shoe laces many of the times in a day. No matter how firmly or tightly you tie, it ends falling apart. And with this, we were left with a question “What makes the laces to loosen up all through the day?”. Well, NLC have you covered. Read on as what makes you tie shoelaces all day.
A study showed that when you run or walk, the force of a foot striking the ground stretches and then relaxes the knot.
As the knot loosens, a second force caused by the swinging leg acts on the ends of the laces, like an invisible hand, which rapidly leads to a failure of the knot in as few as two strides after inertia acts on the laces.
“When you talk about knotted structures, if you can start to understand the shoelace, then you can apply it to other things, like DNA or microstructures, which fail under dynamic forces,” said Christopher Daily-Diamond, a graduate student at the University of California-Berkeley.
The researchers assessed a pair of running shoes that were laced-up and were on a treadmill with the help of a slow-motion camera.
The researchers find that the shoelaces knot failure happens in just the matter of seconds, followed by complex forces. While running, the foot strikes the ground at seven times the force of the gravity.
Researchers also found that some laces are better than other, and might hold the laces for a longer period of time, but the fundamental mechanics causing them to fail is the same.
“The interesting thing about this mechanism is that your laces can be fine for a really long time, and it’s not until you get one little bit of motion to cause loosening that starts this avalanche effect leading to knot failure,” said Christine Gregg, a graduate student at the University of California-Berkeley.