By Ben Harder
A new backpack design that uses elastic cords to minimize the pack’s vertical motion could lessen bodily strain on wearers and reduce the effort required to carry a load. It could be useful to schoolchildren encumbered with books or to emergency personnel and soldiers who sometimes need to sprint while carrying heavy loads, says the pack’s inventor, locomotion researcher Lawrence Rome of the University of Pennsylvania in Philadelphia.
Walking and especially running with a conventional backpack put strain on joints and muscles because, with each footfall, the wearer must reverse the downward momentum of both body and load. “When you run with a normal pack, it bounces up and down,” and the wearer repeatedly gets “squeezed in the vise between the load and the ground,” Rome says.