Support structure (1) of a foot articulation that comprises a body in which a foot articulation can be arranged, a lung body (3), associated with the body, which defines a deformable chamber (4). The lung body comprises a first portion (5) which extends in a direction substantially longitudinal and a second portion (6) which extends in a direction substantially orthogonal with respect to the first portion arranged between the body and the ankle of the foot articulation, such that when occurs a foot support inclined at an angle with respect to a ground plane, is generates a first force on said first portion defined by a first vector (T1) substantially orthogonal with respect to said ground plane (P) that causes—；in feedback—；a subsequent expansion of said second portion which generates a second force, defined by a second vector (T2) substantially parallel to said ground plane, that is adapted to provide a support for ankle.
