A laterally applied orthosis has a dynamic flexible stiffener that is configured to extend across a joint and to impede joint movement caused by muscle contractions by resisting flexing but allowing some movement in the joint. The stiffener is elastic so that it rebounds to its original form under its inherent bias after flexing due to movement of the joint. The stiffener is housed within a brace having a plurality of adjustable straps extending from the brace. The straps can be fastened to one another or the brace itself to form a substantially tubular structure for securing the brace to a limb. At least one of the plurality of straps is semi-rigid and malleable.
