Podcast: Play in new window
BOB HIRSHON (host):
Back relief from bungee cords. I’m Bob Hirshon and this is Science Update.
Whether you’re a hiker, a paramedic, or a third grader, a heavy backpack can be a real pain. Now, University of Pennsylvania muscle physiologist Larry Rome has designed an ergonomic pack that can lighten the load and potentially prevent injuries. It’s rigged with a springy, stretchy bungee cord, which allows the load to glide up and down on a frame as you walk. That eliminates the exertion of lifting the pack a few inches every time you take a step.
LARRY ROME (University of Pennsylvania):
If the load doesn’t move with respect to the ground, then it doesn’t have to be accelerated, and there’s no accelerative force.
HIRSHON:
That may sound trivial, but Rome says these peak forces can double or even triple a pack’s load while you’re walking or running. In contrast, the bungee pack’s effective load stays very close to its actual weight.
I’m Bob Hirshon, for AAAS, the science society.