A structural mechanics model for sports shoes: the heel strike

For a shod heel-striking runner, classical mechanics was used to predict the stresses and displacements for the shoe's heel, with and without reinforcement. The shoe's heel loading was based on a typical runner's measured plantar pressure distribution fitted to a hemispheric pressure dome. Experiments showed that the shoe's heel region was approximately linearly elastic, so that classical solutions were appropriate for an elastic half-space heel model. Here, the surface dome heel pressure within the heel area and image point loads beyond the heel boundary were superimposed to predict realistic heel boundary stresses and displacements. Results for two limiting boundary conditions were investigated: a vanishing radial boundary stress with maximum lateral heel bulging, and complete suppression of lateral bulging using radial heel reinforcement. The theoretical results herein can serve as guidelines for the development of a new class of running shoes with optimal heel reinforcement between these two boundary limits. This optimisation would lead to more comfortable and efficient running.