Ergonomic backpack
When biologists meet backpacks, the result can take a load off your shoulders.
Three biologists have worked up a prototype backpack frame that uses bungee cords and pulleys to reduce the amount of stress a loaded pack can place on its wearer.
The trio took its inspiration from Asian merchants who can run carrying their wares on the ends of flexible bamboo poles. Standing still, a person holding a load adjusts only to the weight gravity imposes on the object. But when people walk or run, their hips rise and fall by up to 3 inches with each step, the team notes. This adds up-and-down acceleration forces with each step. This added force is up to twice the force that a load imposes when a person stands still, the team estimates. The trio noticed that the flexing bamboo poles, in effect, hold the loads at a fairly constant height even as the bearer trots along. The pole reduced the acceleration forces the bearer feels.
They applied the same principle to design a new backpack frame and found that it would allow a person to carry a 60-pound load and expend no more energy than a 48-pound load requires.
The trio, from the University of Pennsylvania in Philadelphia and the Woods Hole Oceanographic Institution in Woods Hole, Mass., suggest that their approach could significantly reduce the load children feel as they wear book-laden packs to school. It also could cut the load emergency workers confront as they carry gear to disaster sites. The results appear in the current issue of the journal Nature.
When biologists meet backpacks, the result can take a load off your shoulders.
Three biologists have worked up a prototype backpack frame that uses bungee cords and pulleys to reduce the amount of stress a loaded pack can place on its wearer.
The trio took its inspiration from Asian merchants who can run carrying their wares on the ends of flexible bamboo poles. Standing still, a person holding a load adjusts only to the weight gravity imposes on the object. But when people walk or run, their hips rise and fall by up to 3 inches with each step, the team notes. This adds up-and-down acceleration forces with each step. This added force is up to twice the force that a load imposes when a person stands still, the team estimates. The trio noticed that the flexing bamboo poles, in effect, hold the loads at a fairly constant height even as the bearer trots along. The pole reduced the acceleration forces the bearer feels.
They applied the same principle to design a new backpack frame and found that it would allow a person to carry a 60-pound load and expend no more energy than a 48-pound load requires.
The trio, from the University of Pennsylvania in Philadelphia and the Woods Hole Oceanographic Institution in Woods Hole, Mass., suggest that their approach could significantly reduce the load children feel as they wear book-laden packs to school. It also could cut the load emergency workers confront as they carry gear to disaster sites. The results appear in the current issue of the journal Nature.
