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If you were asked to name the biggest injury risk for workers who perform desk jobs, what would your answer be?
If you are like most people, you would likely answer repetitive motion.
However, the actual answer is poor posture.
Poor posture includes not just your back or sitting posture, but how you hold your arms, where your legs/feet are placed and how your workstation relates to you.
The study of ergonomics means fitting the workplace to the person. If you look around your work environment, you will notice work areas are set up almost the same. The desk heights, chairs, computer and keyboards are identical. However, if you now look at people, none of us are the same. Even if we are the same height, our body proportions may be different.
Let’s review strategies to reduce the risk of injury:
Chair: Review the adjustments the chair may/may not have. Some chairs have only height adjustments, while others may have many adjustments. Start with sitting back in the chair with your back supported against the back rest. Place feet flat on the floor and check that hips and knees are the same height. If not, adjust the chair up/down until they are even, or your knees are slightly lower than your hips. You should be able to put two fingers between the back of your knees and the front of your chair. Too little space can cut off the blood flow to your lower legs. Too much space may leave your legs unsupported.
Now, sit back and place your elbows at your sides bent to 90 degrees and make your wrists/forearms straight and level. Turn your chair to your keyboard and see where your keyboard lines up. If the keyboard is above your hands, it is too high. If it is below your hands, it is too low. Remember: arm rests are for resting, not for supporting arms as you type.
Keyboard: The keyboard should be placed where your hands are when you are sitting back in the chair with elbows at your sides and forearm/wrists are level. Be sure to put the tabs down on the back of the keyboard. Using the tabs on a keyboard forces wrist extension, which leads to fatigue in forearms, wrist and elbows and increases pressure in the carpal tunnel area. The ideal keyboard should be angled down away from you (a negative tilt) to allow wrists to remain in neutral while typing. The mouse should be close to you and not where you have to reach away from your side to use it.
There are many ergonomic keyboards and mice to choose from. The best way to choose is to go to an office supply store and look at the different options. Try them out and see which ones fit you best. Do you use the numbers pad often? If so, try moving the mouse to your left side. This will decrease the overuse of your right hand. If you don’t use the numbers pad, you may want to consider a smaller keyboard without a numbers pad so you can keep the mouse closer to you.
The standard desk height is 29” to accommodate a two-drawer file cabinet underneath, which can cause the keyboard to be too high. An adjustable keyboard tray may be the best answer as they can be adjusted to fit many different heights. Look for one with controls that are easy to reach and use. Also, look for a tray that can be angled to a negative tilt. It should be large enough to hold the keyboard and mouse. If you can’t get or use a keyboard tray, you can raise your chair, so your arms are properly positioned and add a footrest to support your legs.
Monitor: For normal vision, the monitor(s) should be adjusted so the top of the monitor is at eye level and the distance is arm length away from you. If you wear progressive or bifocal lens, you will need to lower the monitor so you can focus without having to extend your neck. Adjust the distance so it is comfortable for you to read without having to lean forward away from the back of your chair.
If you use two or more monitors and use them equally, centre the keyboard and angle the outside of the monitors toward you slightly to decrease head turning. If you use one more than the other, centre your keyboard at your dominant monitor and place the other one on the side of your dominant eye. Angle it toward you to decrease neck rotation. Place the items on your desk that you use the closest to you.
Lastly, let’s touch on postures and positions to avoid.
- Slouching forward
- Neck extension (looking up) and over rotation (looking side to side)
- Wrist extension (when in position to type, hands are higher than the forearms)
- Prolonged positions
- Bending elbows past 90 degrees
- Leaning on elbows
- Crossing legs
- Sitting without good back support
While we can’t stay in perfect position all the time, using good postures and positions when you can, and taking micro breaks every 30 minutes, can make a big difference in how you feel.