Study untangles theory of why laces loosen

SAN FRANCISCO - A new study shows why your shoelaces may keep coming untied.

It suggests that a double whammy of stomping and whipping forces acts like an invisible hand, loosening the knot and then tugging on the free ends of your laces until the whole thing unravels.

Using a slow-motion camera and a series of experiments, the study by mechanical engineers at the University of California, Berkeley, and published this week in the journal Proceedings of the Royal Society London A shows that shoelace knot failure happens in a matter of seconds, triggered by a complex interaction of forces.