Your web questions answered

Send your WebWorld queries to pcollins@irishtimes.com or by post to Padraig Collins, The Irish Times New Media, 4th Floor, Ballast House, Aston Quay, Dublin 2

After a question on health concerns related to possible injuries from typing (known as RSI, or repetitive strain injury) was dealt with here a few months ago, several people have asked other health questions related to computer use. Some people have also e-mailed this column with suggestions for websites which deal with similar problems.

Most helpful was an e-mail from Mr Robert Canavan. His first suggestion was that people should contact their safety department at work, if there is one, when they have questions on health issues. He also recommended a website, www.morencyrest.com, which is good on these issues. I will summarise some of its tips below, but do visit this excellent site for further information.

Posture is very important when using a computer for any length of time. The web ergonomists recommend: the monitor should be at or below eye level; your wrists should be straight; your forearms and back supported; forearms and thighs should be parallel to the floor; and your feet on the floor or a foot rest.

On work surface height, it recommends that the proper height for a computer work surface is about 3 or 4 inches lower than the average writing desk. If the desk your computer is on is not adjustable, raising your chair and using a foot rest for support should help. Your elbows should be at an angle of between 90 and 110 degrees (don't worry about the exact dimensions of the angle, you'll know what feels best for you). Keep your wrists straight. Using a computer while your wrists are bent up, down, left, or right could lead to discomfort and injury.

Your monitor should be directly in front of you, not slightly to the left or right. It should be 18 to 28 inches from your eyes (about an arm's length is a good measure for most people).

It also recommends stretching and taking screen breaks. Taking a break from typing will improve blood flow. You also need to stretch your neck (an everyday problem for this reporter), hands and wrists, back and shoulders, eyes and legs.

Other good advice given here is that you should adjust your chair height and seat pitch slightly throughout the day. The reason is that slight position changes will change the muscles required to hold a position, alleviating fatigue and improving comfort.

For further information see IBM's site at www.pc.ibm.com/ ww/healthycomputing and the University of Waterloo at www.safetyoffice.uwaterloo.ca (go to the Office/Computer Ergonomics section).