Ergonomics is concerned with the design of working systems in which human beings interact with machines. It is a science drawing upon various other sciences (e.g. anatomy, physiology, physical anthropology, applied psychology), that deals with the design and positioning of machines, instruments, and controls so that they may be used with maximum efficiency by human beings.
Ergomomics is the science of fitting the job to the worker. When there is a mismatch between the physical requirements of the job and the physical capacity of the worker, repetitive stress injuries (RSIs) can result.