In a lower limb prosthesis an ankle unit has a combination of an hydraulic piston and cylinder assembly providing a continuously damped range of ankle flexion and a resilient telescopic shock absorber. The damping resistance of the piston and cylinder assembly is the predominant resistance to ankle flexion and is provided by a piston which is axially moveable in a cylinder centered on the shin axis. The wall of the cylinder has a cylindrical outer bearing surface for a sleeve which is translationally displaceable relative to the piston and cylinder assembly according to the axial load, the sleeve being resiliently mounted by a compression spring which extends axially within the sleeve and has an integral end portion forming an upper bulkhead of the cylinder. The sleeve is also rotatable on the cylinder wall, the spring providing torsional resistance.
