Office Ergonomics

An adjustable, ergonomically designed chair can help you position yourself at the proper height for your workstation and allow you to more easily maintain a natural and comfortable posture. A well designed and fitted chair will have a back rest that provides you with proper lower back support. The chair should be able to be adjusted to suit your specific body dimensions and the types of tasks that you perform. It is important to know how to adjust your chair for maximum comfort.

Take some time to familiarize yourself with the adjustable features of your chair (e.g. chair height, tilt, arm rests).

Chair Height And Tilt

• Adjust the height of your chair so that your feet rest flat on the floor.
• If your keyboard/mouse tray is not height adjustable and you have to raise your chair to comfortably use these devices, use a footrest to fully support your feet and eliminate any discomfort due to pressure on the underside of your thighs.
• Your thighs should be parallel to the floor with about a 90-110 degree angle at the hips.

Backrest

• The backrest should provide adequate support for the natural curve of your back, especially in the lower back or lumbar region.
• Some chairs allow you to adjust the backrest height and angle to improve comfort and support.
• An adjustable backrest angle allows you to adopt different postures while still maintaining good lumbar support.

Seat Pan

• The depth of the seat pan should be such that you can sit with your back fully supported against the chair’s backrest and have about 2-3 finger-widths clearance between the back of your knees and the front edge of the seat.
• The front edge of the seat should be rounded or downward-curving to reduce the pressure on the underside of your thighs.
• The chair should be made out of breathable materials that can dissipate moisture and heat.

Armrests

• The chair’s armrests should not impede natural arm movements while typing or using the mouse and should not interfere with positioning the chair close in to the workstation.
• Position the height of the armrests to just below elbow level so you do not have to raise your shoulders while resting.
• While resting, avoid leaning your body to one side and supporting your upper body weight on one armrest only.

Stability

• For proper stability and mobility, the chair should have a five-prong base with appropriate casters.

It is important to consider the placement of your computer monitor. Improper viewing distances may contribute to visual fatigue or eye strain. If the monitor is placed too high or too low, your neck muscles will have to work harder to hold your head in viewing position which may result in fatigue and discomfort over time.

Monitor Position

• The viewing distance between your eyes and the computer monitor should be in the range of 40 cm to 74 cm, or approximately one arm’s length away.
• Center the computer monitor directly in front of you so you do not have to turn your head to one side or the other to view the screen.
• If working with two monitors, it is usually recommended that the monitors be equally centered in front of you. If one of the two monitors is used only occasionally, it may be more comfortable to place the frequently used monitor directly in front of you, with the other monitor immediately to the side of the first. Both monitors should be placed at the same viewing distance.

Monitor Height

• Adjust the height of the monitor so that you can look at the monitor with your head and neck in an upright and relaxed position.
• When looking at the computer monitor, the top line of text should be at approximately eye level.
• If you wear bifocals/trifocals and are viewing the monitor through the bottom half of your glasses, you will need to position the monitor at a lower height than you otherwise would; avoid tilting your neck upwards to view through the bottom section of your glasses.
• If your monitor is not height adjustable, an adjustable monitor stand can be used to support the monitor at the desired height.
• In addition to proper monitor position and height, the monitor should also be adjusted to comfortable levels of brightness, contrast, and font.

In an office environment, it is important to consider both the overall lighting level and the position of lights and windows. For computer work, excessively bright lighting can cause visual discomfort, especially when it creates glare on the computer monitor. Inadequate lighting can also result in eye strain particularly when working with paper documents. Compared to computer work, paper-based work often requires a higher lighting level, such that additional task lighting may be necessary. Older workers may need a higher lighting level to compensate for visual limitations due to age.

Glare

Glare occurs when there is a large difference in light levels within the visual field. Glare can lead to visual fatigue and discomfort as the eyes try to adapt to the differences in light levels. You may also adopt an awkward body position in order to avoid either direct or indirect glare.

Direct glare occurs when a source of bright light, such as a task light or an unshaded window, is directly in your field of view. Indirect/reflected glare occurs when light bounces off nearby surfaces into your field of view. Both types of glare can be distracting and impair your ability to view the computer monitor.

To optimize the office environment with respect to lighting, the following should be considered:

• Lighting levels should be adequate for the type of tasks performed at the workstation.
• The monitor should be free from glare or reflections from other light sources such as windows and overhead lighting.
• If task lighting is used, it should be positioned so that it does not shine directly in your eyes and does not cause shadow or glare on the computer monitor or source documents.
• Your line of sight should be parallel to the plane of the window; curtains and blinds can also be used to control light from windows.
• Walls, floors, and work surfaces should have low reflectance (matte finish) to reduce reflections.

The way your workstation is organized will affect your body position, posture and overall efficiency. How the task is designed may also affect risk factors associated with musculoskeletal injuries. Task design, or work scheduling, that allows for adequate rest breaks and the opportunity to stretch and change body position may help to reduce the risk of developing work-related musculoskeletal fatigue and injury due to repetitive and static muscle loading.

Workstation Organization

The following recommendations are made to improve the overall organization of your workstation:

• Place frequently used items such as telephones and calculators within easy reach. This will help to minimize long reaches, awkward stretches, and the need to frequently twist or turn your spine to reach the required item.
• Keep heavy reference materials such as large binders and manuals near waist level so that you can more easily manage the weight.
• There should be sufficient leg room underneath your desk and/or keyboard tray so that you can move freely; avoid storing boxes or other materials underneath your desk that could interfere with your body position.

Task Design

The following are recommendations related to work scheduling and task design:

• Pace work activities over the entire shift, whenever possible.
• Take regular breaks (e.g. 5 minutes every hour) away from the computer, when computer work is prolonged or intensive; a break does not mean you cannot do any work, but could mean switching to a different task that allows you to change position, move your muscles or use different muscle groups.
• Try taking micro-pauses (5 to 10 seconds every 5 to 10 minutes) by looking away from the computer monitor to a distant object so that your eyes have a chance to relax and change focal distance; this will help to avoid eye fatigue.

If work tasks involve extensive data entry from source documents, or frequent or prolonged phone conversations, computer accessories such as document holders and hands-free phones or headsets can be used to reduce muscular and visual fatigue.

Document Holders

A document holder should be used if you frequently transcribe information from hard copy to the computer.
The document holder should be adjustable and positioned between the monitor and the keyboard, or adjacent to and at the same height as the monitor, to reduce head and neck movement.

Hands-Free Phones And Headsets

A hands-free phone option or a headset can be used when it is necessary to access or input information on the computer and talk on the telephone at the same time. This will prevent awkward head, neck, and back postures caused by holding the phone receiver between your shoulder and head.