The Foot's Arch and the Energetics of Human Locomotion

Sci Rep. 2016 Jan 19;6:19403. doi: 10.1038/srep19403.

Abstract

The energy-sparing spring theory of the foot's arch has become central to interpretations of the foot's mechanical function and evolution. Using a novel insole technique that restricted compression of the foot's longitudinal arch, this study provides the first direct evidence that arch compression/recoil during locomotion contributes to lowering energy cost. Restricting arch compression near maximally (~80%) during moderate-speed (2.7 ms(-1)) level running increased metabolic cost by + 6.0% (p < 0.001, d = 0.67; unaffected by foot strike technique). A simple model shows that the metabolic energy saved by the arch is largely explained by the passive-elastic work it supplies that would otherwise be done by active muscle. Both experimental and model data confirm that it is the end-range of arch compression that dictates the energy-saving role of the arch. Restricting arch compression had no effect on the cost of walking or incline running (3°), commensurate with the smaller role of passive-elastic mechanics in these gaits. These findings substantiate the elastic energy-saving role of the longitudinal arch during running, and suggest that arch supports used in some footwear and orthotics may increase the cost of running.

MeSH terms

  • Biomechanical Phenomena*
  • Humans
  • Locomotion*
  • Metatarsus / anatomy & histology*
  • Metatarsus / physiology*
  • Models, Biological*
  • Motor Activity*
  • Running
  • Walking