Injury Prevention for Computer Users

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Repetitive Strain Injuries (RSIs)

When working on a computer; improper posture, work habits or workstation set-up can:

· aggravate pre-existing health conditions (e.g. arthritis)

· contribute to new conditions known as RSIs

RSIs are painful injuries that are the result of muscle, tendon or joint overuse.

What you may feel

• ache, pain

• joint stiffness, muscle tightness

• loss of strength, “clumsiness”

• redness, swelling of affected area

• tingling, "pins & needles", numbness

Where you may feel it

• head/eyes

• neck/shoulder

• arms/hands

• low back

• legs/feet

To avoid these outcomes, it is important to follow the advice outlined below.

What you should do

RSIs develop slowly, beginning with mild symptoms that become more frequent and intense. Unfortunately, many cases are reported very late when joint use is already severely restricted. The key to preventing disability is early intervention, so tell your supervisor and consult a health care professional when you first suspect a problem. Your Joint Health and Safety Committee and the Department of Occupational Health & Safety can help address work-related causes.

Prevention Is The Best Treatment

Early intervention is good, prevention is better. Here’s how.

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Physical Fitness

With proper diet, rest and exercise, your joints and associated structures will be more resistant to overuse.

Workstation Layout

If you cannot adjust your workstation to achieve the posture described below, inform your supervisor or check online for more information.

There is no such thing as a perfect posture that you should maintain all day long. Find two or more postures similar to what is described below and rotate among them.

Chair (#1, 2, 3 on cover photo)

• Seat Height & Angle: Feet flat on floor. Thighs about parallel to floor or sloping slightly down (#1).

• Backrest Height & Angle: Vertical curve of backrest over curve of low back. Angle between thighs and torso should be 90 degrees or more. However, reclining too much can create awkward neck postures (#2).

• Seat depth: You should be able to fit a fist and not much more between the front edge of your seat and your lower leg (#3).

• Armrests (if present): With arms hanging comfortably at your side and elbows bent, elbows should be able to swing freely without hitting armrests.

Keyboard/Mouse Platform (#4 on cover photo)

· Height & Tilt: While holding the mouse or with fingers on the keyboard, set platform height and tilt to achieve

• Elbows close to sides. Forearms about parallel to floor or sloping slightly down. Wrists straight. (#4 )

• Tilt of platform should match slope of forearms.

• Hands should float above keyboard while typing, only rest on palm/wrist rest (if present) during typing pauses

· Keyboard position: Home row directly in front of you. Centre yourself on g/h keys.

• Mouse position: As close as possible beside keyboard. (Note: Placing mouse on left side of keyboard eliminates the reach over number keypad. Although mousing left-handed may seem strange at first, it could be a positive long term change.)

Monitor

• Lighting: To reduce glare, keep light sources beside, not in front or behind you.

• Viewing Distance: Varies among individuals. Test different distances for optimum screen visibility. Less than an arm’s length away is generally too close. (Note: If you wear glasses or contact lenses, check with your eye doctor about a prescription for your specific viewing distance.)

• Height: Ensure you’re not tipping your head back to view top of screen. If monitor is on your CPU, it may be too high. What you’re looking at should be between eye level and 30 degrees below eye level. Bifocal users may need it even lower.

• Tilt: Distance from eyes to top of screen should be as close as possible to distance from eyes to bottom of screen.

•     Position: Directly in front of you. Ensure your neck isn’t twisted.

Paper Documents

• Position: As close as possible to monitor. Beside or below display.

• Tilt: Distance from eyes to top of document should be as close as possible to distance from eyes to bottom of document.

Telephone & Other Work Station Components

• Position work station components to minimize reaching and twisting. Keep frequently accessed objects as close as possible to body centre.

• To facilitate note taking while on the phone, place telephone closest to your non-writing hand. Then dial and lift handset with non-writing hand.

• Hold phone with hands, not neck and shoulders.

Work Organization

Ways to rest your joints while you work.

• Rest by performing alternate activities that utilize different muscles, stretch, or relax

• Mouse with your left hand.

• Use keyboard shortcuts instead of mouse.

• Stand whenever you don't have to sit.

• Learn timesaving features in programs you use (e.g. macros, templates).

• Frequent short rest is better than infrequent long rest.

• Avoid prolonged repetitive activities by performing at least 5 minutes of alternate activity per hour.

• Take micro stretch breaks for 10 seconds every 10 minutes.

• Rest at regular intervals before discomfort occurs, not in response to it.

Preventive Stretches

If you are seeing a health care professional for a musculoskeletal problem, ask for his/her recommendations.

Perform each movement slowly until you feel a gentle stretch, then hold it for 5 seconds. If you feel pain, you’ve gone too far.

Eyes

• Close your eyes to help keep them moist.

• Look away from monitor at something at least 20 feet away. (Looking at close objects is harder on the eyes than far objects.)

Neck

• Move head forward by sticking neck out, then bring it back to form a double chin. Relax.

• Turn head to left then to right.

Shoulders

• Raise shoulders towards ears, then lower them.

• Place hands on shoulders with elbows out to side, then try to touch elbows together behind you.

Hands

• Make a fist, then spread your fingers.

• Hang arms at sides. Shake hands slowly.

Back

• Stand up. Join hands over head and reach for the sky. Look up at hands.

For more information

Mike Papakyriakou, Occupational Hygienist-Human Factors

Department of Occupational Health & Safety

C37 East Office Building

Phone: 33477

E-mail: mikepapa@yorku.ca

http://www.yorku.ca/dohs/ergonomics/vdtinjuryprevent.htm

Revised October 26, 2005