Described are novel armature kits, constructions and elements, providing increased flexibility in design and ease of use. In one aspect, inventive armatures include adaptations to isolate the tensioning of ball-and-socket joints occurring at either end of a motion segment. In other aspects, inventive armatures and kits include uniquely shaped plates, providing interchangeability among chest and hip areas of a human form. Novel threaded and tie-down armature elements are also described.