During my workstation assessments, I often use the concept of base of support to explain which position is the least stressful for your body while working. During my occupational therapy studies, it was one of the most important concepts I learnt. I think it is a useful concept for everyone to understand!
Physicists also use the word and – of course – explain it in the least number of words: the base of support is the area around the outside edge of the sections of your body in contact with the ground/surface.
That definition may sound a bit abstract. How I often explain it to computer workers: if you are standing and you draw an imaginary line around your feet, that line is your base of support. If you are sitting, the base of support is the line around your feet and chair.
The smaller your base of support area is, the more your muscles have to strain. This is more tiring for your body. So when you are working, always try to make your support surface as large as possible and stay within your support surface as much as possible. Both when standing and sitting. And also in everyday life, of course, it helps.
For example, if you put your feet under your chair while working, which a lot of people do, you reduce the base of support. Not good!
The biggest base of support you can have is when you lie horizontally. This is partly why lying on a bed is so nice! Unfortunately not the ideal working position for many other reasons….