Harvesting Energy by Improving the Economy of Human Walking

Mobile power sources such as batteries often add great additional weight to a backpacker9s load. As a result, there is great interest in harvesting electrical power from the energy expended during walking in a variety of situations. In his Perspective, Kuo discusses results reported in the same issue by Rome et al., in which a backpack with a spring-loaded weight was found to permit generation of electrical power with unexpected efficiency. Analysis of the biomechanics of walking indicates that the oscillating payload enables generation of useful amounts of power while costing less metabolic energy than expected.