Ergonomic office furniture ... |
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Ergonomic office
Workstation set up The first defense against workplace injuries is to create a working environment that positively influences behavior and therefore minimizes risk. Such a working environment is made up of four key elements with which the user will interact on a daily basis: the chair; keyboard and mouse; monitor and documents; lighting and glare. These elements are interactive, and must be considered together for a truly comprehensive approach to ergonomics. In other words, the way a person sits effects how they will use their keyboard and mouse, and how they view their computer screen or documents. Likewise, awkward positioning of the keyboard and mouse will have an impact on the ability to achieve appropriate positioning in the chair. These components, their interactions and appropriate uses are outlined in the following pages. The Chair – The most important piece of office equipment, from an ergonomics standpoint, is the chair. According to the Liberty Mutual Insurance Company, “Low back pain remains the most prevalent and costly work-related musculoskeletal disorder facing industry, both in the United States and in other Western industrialized countries.” Low back pain is, more often than not, the direct result of sitting for days, months and years in poorly adjusted chairs. The typical office worker will spend more time sitting in their office chair than they’ll spend anywhere else, with the possible exception of their own bed. With such tremendous user-equipment interaction, it’s critical that task chairs meet the following important criteria.
1) Task chairs should encourage movement. As we now know, frequent movement and positional changes are critical to long-term health and comfort, yet most chairs on the market encourage users, by default, to fix themselves into one position. While some current generation chairs have weight-sensitive mechanisms that alleviate this problem, traditional task chairs still have recline springs and tension controls which must be manually set to accommodate the user’s particular weight and body proportions. Unfortunately, this is easier said than done. According to a 1995 study performed by Martin Helander, less than 2% of the subjects in a laboratory setting were able to identify the purpose of the back tension adjustment knob on a variety of chairs. The problem is, if the tension spring is set too firm, the user won’t be able to recline, and will be forced to sit in an upright posture. Likewise, if the spring is set too loose, the chair will typically fall back to its most reclined position, which is where the user will likely sit for hours at a time. Even if set properly for the user’s particular body weight, the tension spring will only provide optimal support in the middle of the recline range. So, to accommodate for these inherent failings of the tension spring, many chairs are equipped with recline locks. However, locks can be extremely dangerous because, by definition, they are designed to keep the chair in a fixed position, which we know is not healthy for the user. As written by Galen Cranz in The Chair, “Ergonomic furniture has created back problems because it succeeds too well in supporting the body in one position.” The solution? i) Adjust the spring tension to best support the user, ii) use locks with caution and conscientiously unlock them on a fairly frequent basis to change recline positions, or iii) choose one of the newer breeds of task chairs that utilize weight-sensitive mechanisms to provide optimal support, while avoiding the inadequacies of tension springs and the danger of locks. 2) Task chairs should fit the user. In addition to offering proper recline support, it’s important that a task chair provide good body fit for the user. No one would consider wearing a pair of shoes that didn’t properly fit their feet, yet day in and day out, millions of office workers sit in chairs that are maladjusted to their body size and shape. Not surprisingly, such workers are at high-risk of injury. It’s not news that office workers come in all shapes and sizes, so it’s vital that each worker’s chair be sized to fit. The most common size adjustment is seat height. Ideally, the seat height should be set so that the user’s feet rest comfortably on the floor while the upper body is high enough so that work can be done comfortably at the desk. However, because the height of most desks is fixed, petite users will usually have to raise their chair to a point where their feet get lifted off the floor. Maintaining such a position for any length of time will put undue stress on the undersides of the thighs, which can cause circulation problems and nerve damage. In this case, placing a height-adjustable footrest under the desk will solve the problem and give petite workers proper support for their feet and legs. Creating a Healthy Workstation by Rhonda Crenshaw, Director of Humanscale’s National Ergonomic Group >> Workstation set up continued
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