Finally clarified: this is why laces come loose
Mechanical engineers at UC Berkeley have solved an ancient mystery of mankind: Why shoelaces come untied when we walk.
No matter how tightly you tie them, at some point every shoelace comes loose when you walk - and the risk of tripping increases. Engineers at the U.S. University of Berkeley have now investigated the mystery of why shoelaces suddenly come undone.
Kick and swing
According to the study results, it is a combination of two forces that act on the shoe during walking and running: Treading and momentum. The stomping motion during treading loosens the knot, while the momentum forces tug on the ends of the laces like a hand as the foot moves forward.
The complex interaction of the forces mean that the knot can come loose within seconds. According to mechanics professor and study author Oliver O'Reilly, however, it is unpredictable exactly when it will happen - only that it can happen within a few steps is clear.
O'Reilly and his team studied the process using slow-motion cameras that recorded walking and running movements of dummies and real people, and a series of experiments; such as adding weights to the ends of shoelaces.
https://www.youtube.com/watch?v=_-aiynIphTw
Unfortunately, these results do not prevent tripping accidents. Instead, it provides the insight that our traditional way of tying shoes is not particularly good. Remedy offers, for example, the good old double knot.
