Know-How: Ergonomics
Apr 1, 2006 12:00 PM, By Mike Kennedy
As students and instructors rely more on computers to complete assignments and teach lessons, having furniture and equipment that allows users to work efficiently and comfortably is a critical component of creating a sound environment for learning.
Ergonomically designed furnishings can help users adapt chairs, tables, keyboards and other computer equipment to match their size, shape and individual preferences.
The University of California, Los Angeles, has set up an ergonomics website (www.ergonomics.ucla.edu) that offers guidance on safe and comfortable computer workstations:
Chair: It should have adjustable height, arms and seat back, and include lumbar support. For someone who is tall, a chair should have an adjustable seat pan or a deeper seat pan so that more of the person's legs are supported by the chair.
Sitting in a chair, users should have their feet touching the ground. If they don't, a footrest should be used. The seat should adjust to allow for changing positions and postures for different tasks. A rocking mechanism can provide continuous active repositioning while working. Armrests should be adjustable. A user's forearms should be able to rest on the armrests with shoulders relaxed.
Table: An adjustable model that will accommodate many users is the best option. Here are some recommended features: If a keyboard tray is not being used, the table should be at a height that correctly positions the keyboard and the mouse. Generally, this height ranges from 23 to 28 inches. A table without a keyboard tray should be deep enough to have the monitor centered, and the keyboard and mouse at the same level.
Monitor: It needs to be centered in front of the user, not to the side or corner. If glare guards are on the screen, the monitor should be positioned where no light source shines into it. A slightly downward gaze should be maintained to view the screen. The distance should be at least 18 to 30 inches; the farther away one can place the monitor to see comfortably, the better for the eyes.
Keyboard and mouse: A keyboard should be relatively flat, not banked up into a high positive tilt. If a keyboard is split or spread out, users still should be able to reach the mouse without straining their shoulders. The mouse should fit in a user's hand and have easy-to-reach buttons. The hand and fingers should rest on it comfortably. Wrists should be straight and aligned, and fingers relaxed when using the mouse or keying.
Keyboard tray: It should hold both the keyboard and the mouse, and should adjust easily. There should be enough leg clearance under it to get it very close to the user's lap without banging knees into any knobs or levers. The tray should be positioned so that a user's arms are in a relaxed position when keying. The wrists should be aligned with the forearms, and the elbows should be in a slightly open (100 to 110 degrees) position.
NOTABLE
18 to 30
In inches, the recommended distance between a computer screen and the user's eyes.
23 to 28
In inches, the recommended height of a com-puter table (without a keyboard tray).
Source: UCLA Ergonomics
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