Something that is designed to work smoothly with the human body is designed to be ergonomic. If your fingers ache after using the computer, you may need an ergonomic keyboard. Or you could play fewer video games.
Ergon, the Latin word for "work." The study of ergonomics looks at making man and machine work together most efficiently, especially in the workplace. An ergonomic design is one that offers a worker comfort while using it. It can be considered important for everything from an office chair to a keyboard, as Designer Yves Behar commented that "Ergonomics is about design that treats the body well." The word appeared in 1950, when the study of efficiency in the workplace became a science (even if your lumpy desk chair tells you otherwise).