The invention relates to a dynamic orthosis (1, 101) comprising: a sole plate (7, 107) for a foot (8) and a leg brace (2, 102). The sole plate and the brace are connected together by means of a structure (11), the structure comprising: a resilient cylinder (12, 112) borne on the rear of the leg and foot an axial extension of said cylinder, said extension enabling the foot sole plate to pivot around a patient ankle joint (19). The orthosis is characterized in that the structure (11) comprises a strap (20.2, 123) connected to the brace on each side edge of the leg, each of said straps being both flexible and non-stretchable, each of said straps being designed so as to enable a pull on a rear portion of the sole plate, said rear portion being between a line vertically perpendicular to the toes and a line vertically perpendicular to the arch of the foot (8).
