In the race to the top, zigzagging is more efficient than a straight line

Trails used by humans exhibit zigzags, or switchbacks, when they traverse steep hillsides, such as this on in Mallorca, Spain. Click here for more information.

A straight line may be the shortest distance between two points, but it isn’t necessarily the fastest or easiest path to follow.

That’s particularly true when terrain is not level, and now American and British researchers have developed a mathematical model showing that a zigzag course provides the most efficient way for humans to go up or down steep slopes.

“I think zigzagging is something people do intuitively,” said Marcos Llobera, a University of Washington assistant professor of anthropology who is a landscape archaeologist. “People recognize that zigzagging, or switchbacks, help but they don’t realize why they came about.”

Llobera, who is interested in reconstructing patterns of movement within past landscapes, said the model and a study that describes it stem from earlier research that looked at the emergence of trail systems. That research focused on flat terrain.