An Introduction to Ergonomics
An Introduction to Ergonomics
How to avoid RSI
November 11, 2002
Ergonomics is the science of adjusting your work environment to fit your body and make it as comfortable and healthy as possible. Despite its 51-year history as a branch of science, ergonomics (often referred to as "human factors" or "human engineering") is frequently disregarded as a part of office safety. But proper ergonomics will help you eliminate the problems associated with Repetitive Strain Injuries.
RSI (Repetitive Strain Injuries) are more often a result of bad posture while operating a computer than any other tool operation in the workplace. Unlike carpal tunnel syndrome, which is a diagnosis, RSI is a description that encompasses many diagnoses including carpal tunnel syndrome, ulnar nerve entrapment, deQuervain's syndrome, thoracic outlet syndrome, tennis elbow, and tendonitis.
RSI is caused by many factors, including physical fitness, body size, muscle tension, work habits, stress, long hours, lack of breaks, bad ergonomics, and poor, static posture.
RSI does not occur only in data-entry jobs. In fact, Web surfing is a common cause of RSI. Think about the hours of time you spend leisurely surfing the Web. Although you may be thoroughly relaxed, your posture may be just as damaging to your body as that of a high-pressure computer job. For example, while waiting for a Web page to load, you may leave your mousing arm stretched out. You may slouch during a Web-surfing session. You may also rest your elbow on your chair armrest or workstation desk, resulting in direct contact pressure. For a complete analysis of Web-surfing ergonomics see this Web Browsing Study .
It is important to remain aware of your body while you surf. If possible, print up the list below for some simple posture guidelines and place it in front of your workstation.
The basic precept to follow is to have good posture. This is no easy feat, unless you are educated in the proper techniques. As I sit and write this article, I am reminded of how years of bad posture have created my own bad sitting habits.
Here are some posture guidelines to get you thinking about good posture:
- Let your shoulders relax and roll back towards your back.
- Keep your arms on your chair's armrests as often as possible.
- When you are not mousing, return you arm to your armrests; do not keep it hovering on or above the mouse.
- Your back should be slightly angled back so as not to slouch, but not so far that you are leaning way back.
- Your neck position should be upright and at a neutral position -- not leaning forward, not turned in either direction.
- Feet should be flat on the ground or if you're short, on a footstool.
- Feet should be positioned about one foot apart from each other.
- Wrists should be straight and neutral (not tilted down or up).
- Do not ever slouch or slump in your seat.
- Adjust the tilt function of your chair, or alter your posture once every two hours.
- Pull your chin in when looking down.
- Always be looking forward at your monitor; do not have it placed to one side.
- Keep your monitor between 18 and 28 inches away from you.
- Your monitor should be raised or lowered so that you can work without raising or lowering your head. Bifocal wearers need to be especially careful that their monitors are positioned to avoid neck strain.
- Keep your chin parallel to the floor and pulled back slightly.
- Get up from your seat and move once an hour.
The last rule is important for your circulation. You should also either squeeze an ergonomic ball or do simple hand clenches to promote good circulation in your hands. If you find that you have numb or tingling hands, aching wrists, or the loss of hand coordination, you are probably suffering from RSI. Hand exercises are an essential means of RSI prevention. However, if you find that you are already injured (hurting), don't grab for that squeeze ball. Your tendons need a rest, not increased strain. A qualified physical therapist will be able to work with you to develop an appropriate exercise routine.
The important thing to remember is that these stretches should be gentle, just to the point where you feel a stretch. If you try to stretch as far as you can possibly stretch, you will over-stretch your tendons and do more damage than good. It may feel good for you, but it probably isn't.
Note: If you are feeling numbness, tingling or pain in your arms, wrists or hands, you are already injured!
Many people try to live with the pain or work through it in the spirit of some twisted gym coach telling you to "walk it off." This is not an option. Get yourself to a qualified health practitioner as soon as possible. Talk to your regular doctor and see if he or she can recommend a specialist for you. If you don't have a regular doctor, try talking to your HR manager. If you go this route, your HR manager is legally obligated to start a Workers Compensation claim and get you in to see a doctor.
If you want to avoid RSI try taking a break for five minutes every hour.
The two most important things to do if you are injured are to take regular breaks and get plenty of exercise. If you need software to remind you to take breaks check out BreakTime . It is also important that the breaks be much more frequent than fifteen minutes every four hours or even once per hour. If you are in pain now try five minute breaks every twenty minutes and work up from there.
Regular exercise of at least twenty minutes per day will help you more than almost everything else. Avoid things that strain your arms. Good cardiovascular exercise such as using recumbent bikes, stair climbers, or just going for a walk every couple of hours will get much needed circulation to your strained muscles and tendons.
Check your monitor for glare by holding a white piece of paper in front it. You should not be able to see the monitor's reflection in the paper. Quick fix: tape a manila file folder on the top or side of your monitor to shield out excess light. Here are some other guidelines that may help:
- Lower background lighting.
- Adjust monitor to eye level.
- Blink often to lubricate the eyes.
- Keep the computer screen clean.
- Look away from the screen every five minutes.
- Consider PRIO-based correction glasses for the computer (even if you don't already wear spectacles).
Your ophthalmologist can determine if you need special computer glasses by using the PRIO test. The PRIO Vision Tester is a backlit box, about 5" by 7" by 1", that attaches to the doctor's side of the eye-examination system. It displays green and amber text against a black background, and green text against a white background. The process is quick: You read the text over and over for a couple of minutes to start your eyes' focus-swapping routine, and then the doctor measures your ocular movement.
Finding It Difficult to Imagine Being This Ergonomically Perfect?
Think about your body as a series of right angles. Your feet should be flat on the floor and your calves should be at a right angle to your feet (perpendicular to the floor). Your back should make another right angle with your thighs (but make sure you are leaning back about 10 degrees.) Your arms should hang relaxed at your sides, and your forearms should bend at right angles at the elbow. Your wrists should be straight, and not angled upwards or downwards.
The Coalition on New Office Technology has assembled the following Computer User's Bill of Rights.
Every computer user has the right to:
- Work without pain
- A reasonable workload
- A Workers Compensation system that works
- Adequate breaks from computer use (at least 15 minutes every 2 hours, or 10 minutes per hour of intensive typing)
- Job design with a variety of tasks
- An ergonomic workstation
- Ongoing ergonomic training
- Access to adaptive technologies and information
- Recover from injury before returning to work at the same task
The key to preventing pain and injury is a combined therapy of ergonomics and developing and sustaining healthy habits such as breathing and stretching, and taking breaks.
About the Author:
Susan Tenby is Online Community Manager at TechSoup.
Copyright © 2002 CompuMentor. This work is published under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 License.