Shape of hand tools, and shape and positioning of control levers, wheels and other such elements of larger equipment have a major impact of the the position and nature of movement of limbs while using such tools and equipments. Often it is possible to reduce the uncomfortable and awkward positions and movements involving bending of various limbs of body by suitable design of such elements. Such design, at times, may require replacing some straight elements with some bends and curves. The phrase "better to bend metal then bend the arm", refers to the the advantages of designing tools and equipment to eliminate awkward human positions and movements. even when it makes the design of the tools and equipments more complicated.