The experts said the bungee backpack, invented by a U.S. biologist, could reduce the force exerted on children's shoulders, backs and hips by more than 80 percent, ANSA said Friday.

The backpack reduces the force by allowing the weight to be attached to two short bungee cords instead of inflexible straps. The cords suspend the load at a constant level from the ground, scientists said.

Lawrence Rome, a biology professor at the University of Pennsylvania, said he got his idea for modifying the backpack after watching Asian merchants carrying loads suspended from bamboo poles, which maintain the load at the same height from the ground because of their elasticity.

Rome said the design could be useful for students, hikers, athletes and emergency workers.