What does ergonomic mean? Let's get the science out of the way first.
There is a science discipline known as "human factors and ergonomics" (HF&E). It's all to do with how we humans interact with the things around us, predominantly machines and technology, but significantly, furniture. It's best illustrated by some common examples.
A full size bicycle would be difficult (if not impossible) for a six-year-old child to use, just as a full grown adult would find it difficult and uncomfortable to ride the six-year-old's bike. But when in the right hands, each machine is ideally suited to its rider; in other words, they are both ergonomically appropriate and efficient but user and machine need to be tailored to one another.
In the world of furniture, particularly in the office environment, ergonomic suitability or efficiency is usually measured (if comfort and discomfort can be measured) by how comfortable the furniture item is, and for how long.
In essence HF&E is the study of designing machinery, devices and equipment (in this context, "equipment" includes furniture) that suit the human body they have been designed for. The two terms "human factors" and "ergonomics" are essentially the same thing.
Ergonomics have an important part to play in the fields of occupational health and safety and productivity. If an object is difficult or uncomfortable to use, mistakes could be made leading to mental or physical injury, or excessive strain could be placed on the user, resulting in the same unfortunate outcome.
What makes an ergonomic office chair?
Its design, its suitability to the user, and its adaptability to one or more users. A properly designed office chair will prevent lumbar strain and back pain; when adjusted to the correct height for the user it can also be instrumental in minimising the risk of repetitive strain injury (RSI) by ensuring that computer keyboards are set at the optimum height.
