Abstract: An athletic leg brace apparatus of the type operable to be connected to the sides of a ski boot wherein the apparatus includes a first and second lower leg brace member and a first and second upper leg brace member. Each of the first upper and lower leg brace members and the second upper and lower leg brace members are connected by a ball joint hinge structure which preferably includes nested hemispherical shell members which are connected to respective portions of the leg brace members by a laterally extending axle positioned coaxially through the center of the hemispherical shells. A front portion of the first and second lower leg brace members and the first and second upper brace members are connected by a rigid semicylindrical member while the rear portion of the first and second lower brace members and the first and second upper leg brace members are interconnected by a flexible, adjustable connecting means.