Sports footwear having a sole studded with a plurality of directional studs, said directional studs being shaped to present a higher resistance to movement through a flowable ground surface in one radial direction of the stud than in the opposite radial direction of the stud, by means of stud conformation...http://www.google.fr/patents/US6357146?utm_source=gb-gplus-shareBrevet US6357146 - Sports footwear and studs therefor
