Abstract: An insole for shoes for soccer, running or similar sports having a contoured plate-like element made of plastics, which has a first through slot composed of a transverse portion which lies ahead of the position of the line of optimum flexing of the foot, and of two longitudinal portions which protrude from the preceding portion toward the plantar arch. The insole further having a second through slot which extends from the outward region of the heel, adjacent to the plantar arch, and has a first portion directed forward, a second portion directed backward, and a wider end portion arranged in a central rear region.