Mechanical linkage

A rehabilitation apparatus comprising:

• a force provider;
• a recipient object, wherein the recipient object is a body part support;
• and
• a linkage configured to transfer a force from the force provider to the recipient object, the linkage comprising a first link and a second link;
• the first link having a first rotational joint defining a first link axis, and a second rotational joint defining a second link axis, the first and second link axes being at a first link angle to each other, which first link is pivotably attached to the recipient object for rotation about the first axis;
• and,
• the second link having a third rotational joint defining a third link axis, and a fourth rotational joint defining a fourth link axis, the third and fourth link axes being at a second link angle to each other, the second link being pivotably attached to the first link such that the second and third link axes coincide, the second link being pivotably mounted at the fourth link axis to transfer a force from the force provider,
• in which the first, second, third and fourth axes intersect at a predetermined point such that the recipient object can rotate about the predetermined point by articulation of the linkage;
• in which the first and second link angles are each less than 45 degrees;
• and
• in which the body part support is a foot support, and the force provider is configured to exert the force in a fore-aft direction of a subject's foot in use.