We will assist you in improving your computer workstations set-up. Let’s begin by looking at chair adjustments. Please locate your chair’s instruction manual. First, we’ll adjust the seat height. Keep your feet flat on the floor, with your knees and hips at the same height. Your thighs should be parallel to the floor. Now let’s talk about adjusting the backrest height. The lumbar curve of the backrest should be adjusted so that it is positioned at the lumbar spine, sometimes called the small of your back. This diagram shows where the chair cushion should be positioned, in relation to your spine. There are several ways to adjust your chair’s back height: by tab (pull the tab in and pull up), by knob (unscrew the knob and move the backrest up or down and tighten), by ratchet (lift the backrest up as it clicks, and pull it all the way up to move the backrest back down), and finally, by pull and release (simply pull out the button and lift or lower to the right height and release). Take a moment to determine if and how your chair’s backrest height adjusts.
Adjusting the seat pan depth: The space between the front of the chair and the back of the knee should be approximately 2-3 inches. As you can see here, this gap is too large. By adjusting the seat pan, you can achieve an appropriate gap. The chair should have a lever or handle either in front or to one side, to adjust the seat pan depth. This is an example of a lever on the side, and this is an example of a lever on the front.
Adjusting the keyboard and mouse height: Neutral typing posture is achieved with the upper and lower arm creating a right angle, and flat, straight wrists. Notice, in this picture, the right angle the elbow creates. A keyboard and mouse placed on top of the desk is too high in many instances, and requires adjustment. In this example, the keyboard and mouse are too high when placed on the desk, not allowing for a comfortable right angle in the elbows.
Several undesirable effects are caused by such a setup, when the keyboard and mouse are too high. The body leans forward in the chair, losing the support of the backrest. Notice a loss of support due to the gap between the chair and the back. The forearms and wrists rest on the hard edge of the desk, creating contact stress; notice the contact points between the forearms and sharp edge of the desk. And finally, the shoulders work in a shrugged position, often causing fatigue and soreness. Notice the shrugged shoulders.
The height of your keyboard and mouse can be lowered by implementing a keyboard and mouse tray underneath the desk. By using a keyboard tray to get your keyboard at the right height, you can gain the support of your backrest on your chair, you can avoid unnecessary contract stress on your arms, and you can relax your shoulders. Note that your mouse should be at the same height as the keyboard, and positioned directly next to the keyboard. If a keyboard tray is not an option, raise your chair high enough to allow neutral typing posture and mousing posture with your keyboard and mouse on the desk. After raising your chair, a footrest may be necessary to properly support your feet, and to help you avoid resting your feet on the legs of the chair. In this instance, a footrest is needed. After the footrest is added, the feet and legs are supported properly.
Adjusting the monitor: Proper monitor height results in a neutral, comfortable neck posture while viewing the screen. Your neck should not be tilted up, or tilted down. It should be in a neutral position, as shown by the picture. Adjusting your monitor too high or too low can create uncomfortable neck positions. Neutral neck posture is achieved by positioning the top of your monitor screen at eye level. You can increase the height of your monitor by adding books or monitor risers underneath your monitor. The distance from the monitor to your eyes should be no more than an arm’s length.
Telephone use: Individuals who must work on the phone and computer at the same time often cradle the telephone handset between their neck and shoulder, resulting in poor neck posture; you can see the poor neck posture in this example. A telephone headset allows for a more neutral neck posture. Observe the difference in neck posture while using a headset, vs. cradling the phone as we saw in the previous example.
Finally, let’s take a look at document holders. Referring back and forth between a source document and the computer screen often results in non-neutral neck posture. The constant twist and flexion of the neck can create neck pain. This can be resolved by using a document holder directly next to your monitor, or just beneath it. Observe the difference in neck posture.