Atlantic Women in Law Enforcement Les Femmes Policiere des Provinces de L'Atlantique

Fitness & Lifestyles

The term ergonomics is being tossed around the office as often as computers, copiers and fax machines. But what does it mean. Why is there so much hype surrounding this term? Can ergonomics help alleviate some of the pain being felt by employees required to sit for prolonged periods?

The term ergonomics comes from the Greek words ergon meaning work and nomos meaning law. Ergonomics focuses on the study of work performance, with an emphasis on worker safety and productivity. The primary goal of ergonomics is to assist workers in attaining their highest functional performance in all areas of life, including work, recreation and home. Adapting the work environment to the worker! Keeping in mind that the field of ergonomics is very broad, this months theme will focus on office ergonomics and practical tips to ensure that you are working towards an ergonomically correct work station. This information is only a small part of what exists in the field. For more information, check out the web sites sited in the reference list.

Four areas will be discussed:

1. Computer monitor
2. Keyboard and mouse
3. Computer chair
4. Rest breaks

Computer Monitor

• When sitting comfortably back in the chair in a typical posture, place the monitor at an appropriate reading distance. Generally, this means “as far away as possible without affecting legibility.” You should be able to read the monitor and see the cursor without peering. The farther away the object of view, the less strain there is on both accommodation (eyes change focus) and convergence (eyes turn inward). Therefore, the distance between your eyes and the screen should be between 33-70 cm (13-28 in). Most people find 20" to be the most comfortable.

• Adjust the monitor height so the entire viewing area is somewhere below eye level (the eyes should be in line with a point on the screen about 2-3" below the top of the monitor casing (not the screen). Often this means putting the monitor directly on the work surface (removing the hard drive, stand or books from under your monitor). And if you are short it might mean removing the tilt-swivel base

Keep it Close! Make sure that those things you use most frequently are placed closest to you so that they can be conveniently and comfortably reached. Phones should be close if you spend a lot of time on it! Consider using a headset.

• Adjust the monitor angle so the centre of the monitor is about 17-18 degrees below horizontal for optimal viewing (tilted down). You actually see more visual field below the horizon than above this (look down a corridor and you’ll see more of the floor than the ceiling), so at this position you should comfortably be able to see more of the screen. If the monitor is too low, you will crane your neck forward, if it’s too high you’ll tilt your head backwards and end up with neck/shoulder pain.

• Check for monitor glare and correct it by changing or shielding the light source, installing a good quality (glass, polarized and optically-coated) glare screen, and/or changing the computer’s position so that light sources strike it from the side.

• Check for direct glare – light sources that shine directly in the user’s eyes when the user is at the monitor. Possibilities are ceiling lights beyond the monitor and nearby task lights. Block or turn off those lights or change the monitor’s location to eliminate them.

• Check the brightness of the area around the monitor, especially if the monitor’s display is white-on- black. If the surrounding area seems significantly brighter than the monitor, reduce it if possible, especially if eyestrain is a common complaint. Usually, this means keeping monitors away from windows.

Take a Break! All Ergonomists agree that it’s a good idea to take frequent, brief rest breaks: Practice the following: Eye breaks - looking at a computer screen for a while causes some changes in how the eyes work, causes you to blink less often, and exposes more of the eye surface to the air. Every 15 minutes you should briefly look away from the screen for a minute or two to a more distant scene, preferably something more than 20 feet away. This lets the muscles inside the eye relax. Also, blink your eyes rapidly for a few seconds. This refreshes the tear film and clears dust from the eye surface. Micro-breaks - most typing is done in bursts rather than continuously. Between these bursts of activity you should rest your hands in a relaxed, flat, straight posture. During a micro-break (< 2minutes) you can briefly stretch, stand up, move around, or do a different work task (e.g. make a phone call). A micro-break isn’t necessarily a break from work, but it’s a break from the use of a particular set of muscles that’s doing most of the work (e.g. the finger flexors if you’re doing a lot of typing). Rest breaks - every 30 to 60 minutes you should take a brief rest break. During this break stand up, move around and do something else. Go and get a drink of water. This allows you to rest and exercise different muscles and you’ll feel less tired. Exercise breaks - there are many stretching and gentle exercises that you can do to help relieve muscle fatigue. You should do these every 1-2 hours. Contact your DFLA for stretching exercises that can be performed at your desk.

Keyboard and Mouse

• Adjust the keyboard height and angle so you are comfortable and your wrists are in a neutral (straight) position. This does not necessarily mean having the keyboard at elbow height as long as the keyboard’s angle reflects the angle of the forearms. In other words, a very low keyboard position can be used if the keyboard is tilted back. If the keyboard cannot be lowered appropriately, the chair may have to be raised and a footrest added. This, however should be a last resort – try to adjust keyboard height rather than chair height.

• Place the mouse where it can be used without reaching, preferably next the to keyboard. This requires using a keyboard tray that has room to accommodate the mouse. The best kind of keyboard tray is one that can adjust up and down, in and out and has room for the mouse. These are more expensive than the standard tray that can only pull in and out, but worth the extra dollars. In some situations a keyboard tray is not appropriate if it’s not possible to make room for the mouse on it. It might be best to remove the keyboard tray entirely and put everything on the work surface, which hopefully can be adjusted to an appropriate height.
• The height of mouse should be such that the wrist is fairly straight when using it.

Chair

• When selecting your chair, the most important feature you can have is adjustability. The adjustments need to be easy to make and the controls must be accessible to the worker while they are seated in the chair. Adjustable chairs improve body position and blood circulation, reduce muscular effort and decrease pressure on your back.

• Start with the chair. Adjust the chair height to a comfortable position that keeps the feet on the floor, thighs approximately parallel to floor. Forward sitters may prefer to sit higher than this, recliners may prefer to sit lower. People with knee-tilt chairs (with the tilt hinge forward of the seat post) tend to prefer higher positions than people with center-tilt chairs. This is because center-tilt chairs lift the knees when reclining.

• Move all the way back in the chair and adjust the backrest height to a comfortable position. There is no correct height, and the most pronounced part of the backrest does not have to correspond to the most pronounced curve of the sitter’s spine. Comfort is the most important thing.

• Move the backrest in or out so that the depth of the seat is appropriate. Newer model chairs have adjustable seat pans than can be moved forward or backward to adjust the seat depth. You should be able to reach the backrest without experiencing any pressure behind the knees at the front of the seat cushion. Large users on the other hand should not feel that the seat depth is short and unstable. If the chair is too shallow (front to back), a backrest cushion can help.

• If the backrest angle can be changed, adjust it to a comfortable angle. A reclined position of 100-110 degrees is preferred NOT the upright 90 degree posture that is often portrayed. Erect sitting is NOT relaxed, sustainable sitting, whereas reclined sitting is.

• Adjust the chair tilt tension so that you can recline mostly by shifting weight rather than by pushing with the feet. If you have to raise your heels to push with the toes, then the tension is probably too stiff. If, on the other hand, you prefer not to recline, the tension can be kept tight. In some chairs the seat and backrest can be locked in the upright position.

• Adjust the height of the armrests, if possible. They should be high enough so the elbows are supported without having to slouch or lean to one side. Armrests should be low enough to avoid uncomfortable pressure under the forearms or raising the shoulders. Too-low fixed-height armrests can be raised by wrapping them with foam or fabric.

• Adjust the width (distance between) the armrests, if possible. They should be close enough to avoid splaying of the elbows. They should be far enough apart to allow the user to easily get into and out of the chair. Some non-adjustable armrests can be changed by tinkering with the attachment points under the seat.

• Chair support. For safety reasons, the base should have 5 points or castors.

Sources: Chris Grant 313.994.0066, IOHS/Atlantic OT Conference 1996 www.office-ergo.com/setting.html Jacobs, K. & Bettencourt, C. (1995). Ergonomics for therapists. Butterworth-Heinemann: Boston: USA . www.ergo.human.cornell.edu/ergoguide.html

Home | President's Message | Executive | Membership | Contacts | | Topics of Interest | Conferences | Contact Us |