Published on March 5, 2008
Computer Workstation Ergonomics: Computer Workstation Ergonomics For Use by UMKC Employees Ergonomics: Ergonomics Ergonomics can be described as the study of adapting the environment to the individual. The aim of ergonomics is to reduce the amount of physical stress caused by improper body mechanics, repetitive motor movements, static positions, vibrations, lighting and impact or contact with objects. Slide3: To modify our environment properly we first need to identify the sources of physical stress at the computer work station. The Eyes: The Eyes As we get older we tend to be more comfortable focusing on objects further away. While focusing on the monitor, we tend to blink less, causing the eyes to dry out. This is especially critical for those who wear contact lenses. Glare or dirt on the screen makes it difficult to focus and causes additional eye strain. Static Positions: Static Positions Static sitting positions, especially when coupled with poor body mechanics, can cause stress to the back, neck, shoulders and legs. Repetitive Motion: Repetitive Motion Repetitive fine motor movements related to keyboarding have been associated with certain medical conditions involving the hands, wrists, thumbs and fingers. Thresholds vary greatly between individuals before pain or injury takes place, thus contributing to a sense of complacency among some workers. Workers should also examine activities outside of the work environment when trying to limit repetitive stress. Activities such as knitting, playing musical instruments, painting and other activities may also contribute to the total load of repetitive motion. Contact with Objects: Contact with Objects Highly localized pressure caused by an object against the body can cause numbness and loss of blood circulation. Common examples are across the back of the legs from the edge of a chair, across the forearms or at the elbows from leaning on a table or desk, and on the inside of the wrists from leaning on them while keyboarding. Poor Body Mechanics: Poor Body Mechanics Awkward body positions can amplify stress caused by repetitive motion, static positions and pressure contacts with objects. Intervention Strategies: Intervention Strategies Periodic “mini-breaks” from repetitive movements allow the body to recuperate. Work does not have to stop. Rather, identify duties that do not require the same type of effort and take a break by doing something different. A kitchen timer can be used as a reminder to take a “mini-break.” Intervention Strategies: Intervention Strategies For dry eyes, use an over-the-counter eye lubricant (sometimes known as artificial tears). Don’t wait until your eyes begin to burn, apply the eye drops each time you take a “mini-break.” Avoid using eye drops that “get the red out.” Prolonged use of this type of eye drop can cause damage to the eye. Intervention Strategies: Intervention Strategies For those having difficulty seeing the monitor screen with bi-focal or tri-focal lenses, speak with your optometrist about a pair of single vision lenses for use at the computer. Take a measurement from the bridge of your nose to the top line of the monitor screen. Give this information to your eye doctor. Intervention Strategies: Intervention Strategies Proper posture and body mechanics can reduce the amount of physical stress. At the keyboard; adjustment of the seat height, lumbar support, monitor height, monitor distance, and mouse placement encourage good posture and proper positioning of the hand and wrists. Intervention Strategies: Intervention Strategies If you regularly enter information while on the telephone, consider a speaker phone or headset telephone. Never cradle the phone between your shoulder and ear. Making the Adjustments: Making the Adjustments First, adjust the chair height so that you can reach the keyboard with the upper arms falling naturally by your side and with your forearm and upper arm forming a right angle. Making the Adjustments: Making the Adjustments Adjust the lumbar support so that it fits into the curvature of your back just above the buttocks. Some lumbar supports can also be adjusted for firmness. Making the Adjustments: Making the Adjustments The hand should extend straight out from the forearm. Place a pencil across the back of the hand. The pencil should be able to lie nearly flat across the back of the hand. The pencil will also help you see if you have the hand turned out or inward. Making the Adjustments: Making the Adjustments This is known as “neutral positioning” of the hand. This position allows for the greatest amount of room for tendons and the median nerve that run through the carpal tunnel in your wrist. Making the Adjustments: Making the Adjustments The mouse should be placed as close to the keyboard as possible. Mouse platforms are available that straddle the far right side of the keyboard. For those who do not use the numeric keypad, this may be a viable option. Move the mouse by using your whole arm, not just your wrist. Making the Adjustments: Making the Adjustments For those with “normal” vision, the monitor should be between 18” and 24” from your eyes. Those with single vision glasses, adjust the distance to your comfort. The top line of the monitor should be at the same height as your eyes. The monitor should be tilted back slightly (about 15 degrees from vertical). Making the Adjustments: Making the Adjustments Those with bi-focal or tri-focal glasses must approach monitor adjustment differently. Making the Adjustments: Making the Adjustments First, lower your head forward. Slowly raise your head until very little effort is required to hold your head in position. Making the Adjustments: Making the Adjustments Then, position the monitor height and distance so that you can see the monitor through the appropriate lens while your head is in the low effort position. Making the Adjustments: Making the Adjustments If you key from “hard copy” material, use a swing-arm copy holder or position your easel so that the “hard copy” material is at the same height and distance as your monitor. Making the Adjustments: Making the Adjustments Do not place the “hard copy” material on the flat desk and twist your neck so that you can read. Making the Adjustments: Making the Adjustments It is important to have your feet placed flat on the floor. With your feet flat on the floor you are anchored. This allows you to push off, keeping your torso up-right so as to avoid slouching or reclining. If necessary, use a foot rest to provide this support. Making the Adjustments: Making the Adjustments Glare on the monitor screen can be eliminated by use of drapes, placing the screen at a 90 degree angle from the light source and use of a glare hood or glare screen. Avoiding light colored clothes that may reflect in the screen can also help. Keep the screen clean. Purchasing Decisions: Purchasing Decisions The chair is one of your most important ergonomic purchases. The comfort and adjustability of your chair will affect your entire posture and body mechanics. Purchasing Decisions: Purchasing Decisions The seat pan should have a “waterfall” front edge. Adjustments for both seat height and lumbar support should be simple and easy to get to. Avoid arm rests. Most are not well designed and they tend to make it difficult to pull up close to the desk. The chair should have 5 casters for ease of movement and stability. The casters should be designed for the type of floor surface on which they will roll. Purchasing Decisions: Purchasing Decisions The more you look at the monitor while computing, the more you should consider a larger monitor. The price differential between a 15” monitor and 17” monitor is quite small when compared to the overall cost of a personal computer. Pixel size also will affect the clarity of the screen images. Smaller pixels = greater clarity. Purchasing Decisions: Purchasing Decisions In order to raise the monitor height, you can use telephone books or other things around the office to create a raised platform. There are also inexpensive devices that can create a raised platform with some offering storage for diskettes, paper or other supplies you might want to keep at hand. Purchasing Decisions: Purchasing Decisions The cost of split keyboards is now comparable to the cost of replacement keyboards. The broader your shoulders are the more difficult it is to maintain your hands and wrists in “neutral position.” Split keyboards help some to attain “neutral positioning” and reduce the micro traumas associated with keyboarding. Purchasing Decisions: Purchasing Decisions If you have a computer workstation that will be used by multiple people, an easily adjustable chair is a must. You should also consider a height adjustable table or a keyboard tray that is height adjustable. Treatment of Repetitive Stress Injuries: Treatment of Repetitive Stress Injuries Do not try to self treat by purchasing over the counter wrist splints. Wrist splints are also known as occupational splits and are designed for specific occupational duties. Splints should be fitted by a physician and are often used in conjunction with medication. Early appropriate treatment is important to avoid long term physical damage. Treatment of Repetitive Stress Injuries: Treatment of Repetitive Stress Injuries If you believe that you are experiencing a repetitive stress injury due to your work or if your physician indicates that you have a medical condition that is as a result of your work, you should report this to your supervisor immediately. Your supervisor should complete a “UMKC Report of Employee Injury” form. Review: Review The back should be vertical with the shoulders positioned over the hips. Support should be given to the lumbar curve in the spine. The head should be positioned so that it rests comfortably over the spinal column. Little effort should be necessary to maintain the position. The monitor and “hard copy” should be placed directly in front of you. Review: Review The upper arms should hang naturally at your side. Pull your chair up close to the keyboard so that you can avoid reaching out for the keyboard. The forearms and the upper arms should form a right angle. Your hands and wrists should be in “neutral position.” Hips should be against the back of the seat. Feet should be flat on the floor, not stretched out or wrapped under.