The word ergonomics is formed from two Greek words: ergon meaning 'work' and nomos meaning 'laws'. The practice of ergonomics today is a science concerned with products, systems and environments and improving people's interaction with them. "The application of scientific information concerning humans to the design of objects, system and environment for human use".

Strains put on parts of the body; joints, muscles, tendons and bones unnecessarily. Factors conducive to these strains include repetitive motions like typing or continual use of a pair of heavy scissors; the use of excessive force, for example lifting a heavy box; and handling a vibrating instrument for a long period of time.

Outside influences apart from the body that may have an effect on such things as hearing, eye-sight, and general health and comfort. These can include working in an excessively loud environment, poor lighting, bad air quality and uncomfortable working conditions.

Visual Display Unit, also known as Visual Display Terminal (VDT) in America.

Display Screen Equipment - Alphanumeric or graphic display screen, regardless of the display process involved.

A person who uses display screen equipment as a significant part of their normal work.

A workspace comprised of display screen equipment and any optional accessories to its operator or user. It may or may not include a disc drive, telephone, modem, printer, document holder, chair, desk, work surface, or any other item supplementary to the display screen equipment, and the immediate environment around the display screen equipment.

Repetitive Strain Injuries (RSIs) are caused by movements made repeatedly, but that would not cause damage or discomfort if performed only once. They include many different conditions from carpel tunnel syndrome to various back disorders.

The position which best supports the natural and normal curve of the spine, and guards against undue pressure to any part of the body.

For example:

"The optimum seat height is the distance from the back of your knee to the floor when your feet are flat on the ground......the arms should be bent at right angles or lower at the keyboard - this position reduces strain on the arms whilst typing......you should be able to put your feet flat on the floor directly below your knees. It is important that you have an adjustable seat and backrest to achieve this position"

Health and Safety Executive.