Midsole for sports shoes

Claim 1

A sports shoe comprising: (a) a shoe upper; (b) an outsole; and (c) a midsole comprising a soft elastic member and a hard elastic member having a greater hardness than that of the soft elastic member, the hard elastic member being disposed at one of a foot-contacting side of the midsole and a ground-contacting side of the midsole in a portion of at least lateral edge area of a heel portion of the midsole, the soft elastic member having an upper surface to which said shoe upper is joined, a lower surface to which said outsole is joined, and a joint surface joined to a joint surface of the hard elastic member and extending between the upper surface and the lower surface so as to face to one of the upper surface and the lower surface, the joint surface of the soft elastic member and the joint surface of the hard elastic member each having a complementary wavy configuration along a direction of longitudinal center axis line of the shoe for mollifying and reducing a strong reaction force produced by an impact to the shoe in a horizontal or oblique direction, the wavy configuration having at least two cycles of waves between a fore end of the heel portion and an aft end of the heel portion, the cycles of the waves having substantially the same wavelength and substantially the same amplitude.