Computer workplace ergonomics

In an ideal world, every workstation would be equipped with the right accessories and materials to create a good and ergonomic workstation. A good place to work prevents the occurrence of physical discomforts. It also protects people's minds. Taking frequent breaks and momentarily disengaging yourself from your monitor is important. Afterwards, you can return to work feeling fitter, more focussed and more creative. All this makes people more productive. What are the requirements of a good workstation? What aspects should be taken into account?


 

 

Considering the requirements of the NEN_EN 1335-1 standard and preferably the NPR 1813:2003 as well, a chair should be able to tilt backwards at least 15°. A chair should be comfortable and its dimensions should be right for the person sitting on it. Since no two people have the same build or preferences, desk chairs are adjustable. The NEN standards dictate the functionality a desk chair should offer. A good desk chair is adjustable based on the parameters shown below. Another - equally important - aspect is that sitting in the same posture for too long can put excessive strain on your body. It is therefore best to pick a chair that can be used in various ways and while sitting in different postures. Given the popularity of flexible workstations, being able to easily adjust a chair to your preferences is an absolute must. 

Armrests: while doing computer-based work, your arms must be properly supported by comfortable and height-adjustable armrests or, alternatively, the surface of your desk. Good arm support reduces the strain on your neck (Aaras, 2001, Cook, 1998, Karlqvist,1998), partly because of improved circulation (Hagberg M, 1984). Furthermore, armrests make you feel less fatigued as you work (Arndt, 1983).


 

Positioning documents: it is advisable to position your documents between your monitor and keyboard and at a slight angle. When reading or entering data, the same aspects that were mentioned before - regarding viewing angle and distance - should be taken into account. An angled surface reduces the bending and rotation of your neck (Dul 1992) and contributes to a better position of the neck, thereby reducing the risk of discomfort.

A document holder helps to organise your workstation and create a comfortable viewing distance, which is also better for your eyes. The downside is that a document holder takes up space on your desk, so you may sometimes have to set it aside when you have to write.
 

Footrest: a footrest has to meet the requirements of the DIN 4556 standard. If your desk is not (sufficiently) height adjustable, you need a footrest. It should be at least 45 cm wide and 35 cm deep and have an adjustable range of at least 11 cm. The angle of the support surface must be adjustable from at least 5-15 degrees (DIN 4556). For flex workstations, it is important that the footrest can be adjusted quickly and easily.

A lesser-known effect of footrests is that they impact your posture as you work. By placing your legs forward and resting your feet on a stable surface, you push your torso backwards. If you have lower-back pain or experience instability, a footrest can literally and figuratively support you. Lastly, the footrest's support surface is anti-slip.
 

Resolution, size and number of monitors: When using multiple applications at the same time, it is advisable to use two monitors or a widescreen monitor. A monitor's resolution indicates how many pixels the image consists of; the higher the resolution (i.e. The number of pixels), the sharper the image. However, increasing the resolution without increasing the screen size will result in smaller on-screen text. The size of the pixels is indicated by the pixelpitch. Ideally, it should be no smaller than 0.25 mm and preferably bigger than 0.28 mm.

The other key specifications are:

• Good readability (contrast ratio preferably 1,000:1)
• A clear image (brightness: at least 250 cd/m2; higher is better in well-lit environments)
• Easily adjustable to suit your personal preference.

Dual screen?
Using multiple monitors side by side gives you a better overview and results in less switching between applications.
Scientific research shows that users are 10-15% more productive and make 33% fewer mistakes when using two or three monitors (Research Productivity and Multiscreen Computer Displays - Janet Colvin ea). Instead of using two monitors, it is also possible to use a widescreen monitor.

Viewing distance: With a flatscreen arm, any flexible workstation can be set to the correct viewing height and distance for all users. The viewing distance should be at least 50 cm, but preferably more. The character height determines the viewing distance. The viewing distance should be at least 200 and preferably 150 times the character height (i.e. A character height of 4 mm corresponds to a viewing distance of 60 cm).

A relatively large viewing distance is less taxing for your eyes, because they do not have to accommodate as much. One requirement is that the characters on screen increase in size accordingly (Owens and Wolf Kelly 1987). In some cases, you can increase the size of the on-screen characters. For example, Word offers a zoom function that you can use to zoom in or out on the document you are working on. Larger characters are easier to read than smaller characters (Tullis et al, 1995), which means small on-screen characters have a negative impact on your productivity (Jaschinski-Kruza, 1988).

Viewing angle: The ideal viewing angle allows your neck to be in a neutral position (i.e. not bending or stretching in any direction). The ideal viewing distance is as far away as possible, while creating a tendency to lean forward. When using multiple displays, the angle between the outer edge of both screens and the centre of your eyes should be no more than 60 degrees (see image).
 

A compact keyboard, mouse, laptop stand and external monitor make using a laptop more comfortable.  A laptop stand has a positive effect on your posture and contributes to increased comfort (Boersma 2003. Lindblad 2003).

To create an optimal workstation, it is important to connect a 19” external monitor to your laptop. This is especially recommended if you use your laptop extensively (more than 4-5 hours per day).
 

Clicking and scrolling: On an average workday, you make extensive use of your mouse. While using your mouse, it is important to avoid static unnatural postures (stretching or bending sideways or rotating your wrist inward). Furthermore, it is best to position your mouse as close to your body as possible.

Excessive mouse usage and positioning the mouse too far away can lead to discomfort in your wrist and lower arm. (Jensen 1998, Fernstrom 1997, Burgess-Limmerick 1999, Armstrom 1994). Positioning your mouse closer to your body reduces the strain on your neck and shoulders (Armstrom 1995, Cook 1998, Harvey 1997). Using trackballs and trackpoints may be extra taxing for your thumb.
 
When using your mouse, it is important to take frequent breaks; the so-called pitstops. To do so, take your hand off your mouse and allow the tension to drain away for ten seconds or so.
 

Your keyboard is an essential piece of hardware. The characteristics of a good keyboard are clear legibility, logical functions and a comfortable keystroke. The same rule that applies to using a mouse also applies to using a keyboard: give your hands frequent breaks (every ten minutes or so).

The keyboard: The horizontal and vertical distance of the keys should be at least 19 mm. While typing, the keys should produce feedback that can be clearly felt and/or heard. A compact keyboard reduces the distance you have to cover to reach your mouse.

If a keyboard does not provide sufficient feedback, users have a tendency to hit the keys up to 3.9 times harder than necessary. Doing so can lead to physical discomfort in the lower arms and hands (Feuerstein, 1997, Gerard, 1996, 1999). Furthermore, it makes the user more prone to making mistakes, thereby reducing their productivity (Feuerstein, 1997, Yoshitake, 1995).

Compact keyboards (keyboards without a numpad, yet with a key spacing similar to standard keyboards) reduce the distance you have to cover to reach your mouse (Cook, 1998), they reduce the strain on your lower arms and users generally find them more comfortable than standard keyboards (Van Lingen, 2003). A compact keyboard is a worthy alternative to a full-size keyboard. If you frequently have to enter numerical data, you can use a separate numerical keyboard or a compact keyboard that does include a numpad.

A well-shaped keyboard can contribute to the prevention of physical discomfort (Moore and Swanson, 2003) because the posture of the user's lower arms and wrists is better (Riezebos, 1997).