Abstract: Exercise apparatus (1) in which a person exercising exerts a force against a movable actuator (6) to which is applied an adjustable force by a load system which resists or assists the movement of the actuator and is connected to the actuator by cables (9). The load system comprises a fixed, longitudinally arranged coaxial series of coil units (15), each coil unit being independently connectible to a source of electric current. The series of coils provides an elongate passage (18), and a shuttle (19) of ferromagnetic material is mounted for relative longitudinal movement within the passage, in response to movement of the actuator. Passage of a current through a coil unit exerts a force on the shuttle when in that coil unit, and is controlled by a microprocessor (22).

Abstract: The paving system has a perforated pavement covering a deep substrate of mainly hard nodules or shells, the whole being surrounded by impervious walls to provide temporary storage in the interstices for chemical spillage or flood water, wherein liquids may be chemically treated or biologically decomposed, and from whence the rate of outflow may be regulated, the pavement consisting of preformed pavings of brick, concrete or other material, laid edge to edge without mortar or cement, and these pavings can be perforated or notched to allow liquids to run down into the substrate. The pavings are laid on a screen which filters out solid particles to reduce clogging. The system allows biological substances to grow, or be introduced, with or without additional nutrients, and allows chemical treatments to be introduced, from above, when needed. The whole pavement system can be lifted out for cleaning or, substitution, and relaid as new.