Screen work is not just a professional activity anymore: your muscles and joints are overloaded both by your private and by your professional lives. 

Remember the three rules of posture:

1. three back shapes are unhealthy (slouched, hollow, twisted). Your goal should therefore be have a "flat back" posture (monkey posture) during all prolonged, frequent or hazardous activities;
2. the neck should always be relaxed;
3. posture is built from feet to head.

When you work on a computer

• rule #1 requires that you sit on the sitting bones, with your belt against the lumbar support. To achieve this, the heels must be firmly on the floor (or a footrest). If your chair does not have lumbar support, a cushion will help. In this article you will find out why we do not recommend Swiss balls as office chairs.
• rule #2 requires that you place the mouse and keyboard just under your fingers tips when your elbows fall loosely along your body. The screen is just below the eye line, slightly tilted towards you. If the neck flexes more than 20° (e.g. laptop), use a detachable keyboard and mouse and raise the screen.

Even though good posture is essential, you can't sit still for long: if you sit well, you can hold on for about 30 minutes. Beyond that, you have to stand up, whether you are working (telephone, meeting) or not (break, coffee).

The relaxation exercise illustrated below should be practiced as often as possible to relax the muscles, decompress the joints and facilitate the oxygenation of the tissues.

Then  comes the question of the daily duration of use of the screens. For an adult, take as a benchmark a total credit of 360 minutes (6 hours) per day on a desktop computer; each minute spent on a laptop consumes 3, and each minute spent on a smartphone or tablet consumes 6... Do the math for yourself!

Last but not least: an ergonomic office chair cannot be bought from a catalogue or the web! Here are a few tips to help you make the right choice.