The sole comprises three layers, including (a) an outer or ground contact
sole (7) having flexibility, ground-gripping, and abrasion-resistance
properties, (b) an upper or comfort layer (8) positioned directly beneath
the foot and having elastic shock-absorption properties, and (c) an
intermediate layer or rib (9) positioned directly between the upper
portion of the contact layer (7) and the lower portion of the comfort
layer (8) and having torsional rigidity properties which provide both for
the distribution of shocks sensed by the contact layer (7) and for their
diffusion over the comfort layer (8) before they come into contact with
the foot (4).