An American biologist has developed a backpack that reduces the weight students and hikers carry.

The bungee backpack, invented by Lawrence Rome, a biology professor at the University of Pennsylvania , could be useful for students, hikers, athletes and emergency workers, reported UPI news wire.

It uses two short bungee cords instead of inflexible straps to reduce the burden of weight. The cords suspend the load at a constant level from the ground.

The scientist 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.

The new design could reduce the force exerted on children's shoulders, backs and hips by more than 80 percent.