Ergonomics

Ergonomics is, essentially, the study of how things interact with the human body. It is most often used to make products that are easier or more comfortable for a human to use.

 For example, designing a pen that is more comfortable to hold for long periods of time that does not cause hand cramps because the design will eliminate stress on the hand muscles. Or designing a chair that gives better lower back support.For anything like that you must first study ergonomics and find out what does or does not work well with the human body. 

What it is

Example