Sitting erect is all very well, but a straight back is not going to make for comfortable sitting all day long. It is best to have the back inclined a bit at about a 100 or 110 degree angle. An important thing is to rest the feet comfortably on the ground and not craning the neck forward at an uncomfortable angle.
If you have to strain your eyes to read what is on your computer screen then it is time you increased the font size of your display. Often we lean forward not for any other reason but to actually read what is displayed on the screen.
An ergonomic chair will not function as designed unless you know how to operate the adjustable features correctly. To adjust your task chair, follow the steps:
1) Sitting in the chair, raise or lower the seat so that your feet rest comfortably on the floor. Your knees should be slightly lower than your hips.
2) Sit as far back in the chair as possible, and adjust the backrest height or lumbar support so that it fits into the curve in your lower back.
3) If you have a seat slider, adjust the seat pan depth so that a closed fist fits between your knee and the edge of the seat.
4) Adjust the backrest angle to achieve a torso-to-thigh angle of 93-113 degrees (have someone else look at you from the side).
5) Adjust the seatpan tilt angle to a comfortable position.
6) Adjust the armrest so that it is at your elbow height. If the armrests swivel, place the armrests in line with your forearm when you are using the mouse.
7) Once you have adjusted the rest of your workstation, if your feet do not reach the floor, use a footrest.
8) Remember to adjust your chair throughout the day to help relieve muscle tension in specific muscle groups.
Keyboard & Mouse
There are numerous keyboard and mouse configurations and models available, however it is important to correctly position these tools to prevent overuse injuries. To properly position your keyboard and mouse, follow these steps:
1) Sit close to the keyboard and mouse so that your upper arms hang in a relaxed position.
2) Center yourself so that you are aligned with both the keyboard and mouse, depending on what is most frequently used. Position the mouse as close as possible to the keyboard to avoid rotating the shoulder.
Adjust the height of the keyboard platform (or chair if there is not an adjustable platform), so that your shoulders are relaxed and elbow angle is 90 degrees or slightly greater.
3) Adjust the angle of the keyboard platform slightly downward in a negative tilt, if able. This will help to keep your wrists straight.
4) Do not put the mouse where you must stretch to the desk or out to the side of a keyboard to reach it.
Proper monitor positioning is important in avoiding vision and neck problems. Follow these steps
1) The monitor should be positioned so that your natural gaze falls about one-third down the length of the screen.
2) The distance should be about arm's length (45 to 60 cm). Font size, specific applications and personal visual acuity and sensitivity will also determine the correct distance, however placing the monitor too far away can cause the user to lean forward and can lead to eyestrain.
3) Bifocal users should lower the monitor so that text can be viewed through the proper prescription. Increasing the distance away from you also increases the field of vision available without moving the head. Tilting the screen upward slightly can also help.
4) The monitor should be directly in front you, aligned with the area of the keyboard that you use most.
5) Adjust contrast and brightness to your personal needs to reduce eyestrain.
6) Look away from your screen periodically - focus on a distant object to exercise eye muscles.
Reference documents, especially when used frequently, should not be placed flat on the work surface. Instead, use a document holder. Traditional holders position the document adjacent to the monitor, however there are models that allow the user to place several items directly between your keyboard and monitor, avoiding awkward neck postures and maximizing productivity.
In a general office environment, the recommended lighting level for computer work is 500 lux. These lighting levels can be adjusted for personal preference, and paper work may be augmented by task lighting.
Glare is the main lighting concern when working with computers. To help minimize glare:
Position monitors parallel to overhead lights and perpendicular to the windows.
Ensure wall colour is neutral (not too bright).
Remove or cover shiny surfaces and objects.
Use blinds or curtains to minimize window glare.
Install diffusers on overhead fluorescent lights.
Adjust the angle of the monitor, so that the screen is vertical.
Use incandescent task lights over source documents, but direct them away from monitor.
Setting up a Laptop Workstation
Laptops are a popular and often necessary addition to the traditional office. However, the attributes that make laptops so portable also create ergonomic hazards that users should be aware of. The main concerns with laptop use is the fact that the keyboard and the screen are contained in one unit. This goes against the ergonomic principle that the keyboard should be located at elbow height, and the screen at eye level.
Using a laptop in an awkward posture for over 1-2 hours can cause temporary discomfort, and prolonged or repeated use can cause musculoskeletal injury.
1) Sit in a comfortable chair that supports your back, preferably one that reclines slightly.
2) If the laptop is on a table, try to position it so that your wrists and elbows are in a neutral position. Avoid high counters or tables if you are sitting - consider standing at a suitable counter if needed.
3) Tilt the screen away from you, to place it in line with your natural line of sight - it is usually necessary to tilt the neck slightly. Try to work in an area that limits glare on the screen.
For long-term use, the following steps should be followed to avoid discomfort or injury:
1) At a minimum, place the laptop on a worksurface that allows your wrists, elbows and shoulders to remain in a relaxed and neutral posture. Tilt the screen to your line of sight.
2) Better yet, plug in an external monitor or keyboard and mouse to separate the two components. Position all components correctly using a monitor riser, laptop holder or keyboard platform.
3) Laptop docking stations are another way to accommodate and improve ergonomics. They serve to position the laptop at an angle that elevates the screen, but keeps the keyboard at a reasonable angle.