Are You Sitting Comfortably?
There are many factors that contribute to a comfortable position when seated at a workstation. Some of these depend on the equipment used and environmental factors, but many can be improved by the user. Before you start work ensure that your workstation is arranged so that you are able to work without any discomfort.
1. The Chair
The small of your back needs to be supported by the backrest of the chair, if not, you won’t get the necessary support for your back. Adjust the backrest so that the most rounded aspect of the backrest is at waist level. The backrest should then be tilted slightly backwards from the vertical position. Always sit well back in the chair to ensure the lower back is adequately supported.
Adjust the height of the chair so that with your shoulders relaxed, forearms horizontal and wrists straight, your fingertips are at the same level as the desk. If, at this height, your feet are not flat on the floor then, and only then, is a footstool required. If a footstool is used inappropriately then it reverses the curve in the lower back, which could then lead to spinal damage. If, on the other hand, once the chair is adjusted with the desk being at the correct height, your knees are higher than your hips then the desk is too low and either needs to be adjusted in height. The hips and knees should be at right angles whilst sitting at the desk at the correct height.
Whether or not you should have armrests is largely a matter of personal preference. In general, it seems that those users who are touch typists prefer not to use them while those who are not prefer to use them.
For non-trained typists, whilst using either the keyboard or the mouse, it is essential that the forearms be supported by either armrests or the front of the desk as this encourages the neck and shoulders to be in a relaxed state. If armrests are used they should be large enough to support your forearms without discomfort and positioned so that they do not interfere with keying or push up your shoulders. With the shoulders relaxed and the spine straight, the armrests should meet the elbows with the forearms horizontal. If they are too high then this will cause the shoulders to hunch and cause unnecessary tension and consequent discomfort, too low and they obviously offer little or no support to the arms and may also encourage the spine to twist to enable the arms to reach them. The same principles apply when using the mouse; always ensure the forearm is supported either on the desk or the armrest and the hand is relaxed over the mouse and not gripping it.
Whilst using the keyboard, the wrists should be in a neutral horizontal position. It is therefore usual that the ‘legs’ underneath the keyboard, at the back, be laid flat so that the neutral wrist position can be maintained. To achieve this ‘neutral’ position it is also essential that the chair height is correct.
The ideal position for the screen is slightly below head height so that you are looking down at an angle of 10-15º below the horizontal when you are looking at the middle of the screen. The screen position will also depend on how you work. If you need to refer to the keyboard frequently you may find it better to have the screen lower so that you don’t need so much neck and eye movement when switching between screen and keyboard. Alternatively, if you are a touch typist then the screen can be set slightly higher. You can alter the height of the screen by placing it on something else, usually the main system unit can be used but other stable alternatives are usually available.
The screen should be positioned directly in front of you whilst working. Working with the screen to one side means that the neck and torso is constantly rotated to one side and can lead to serious musculoskeletal problems.
If you are getting reflections or glare on to your screen then it may help to track down sources by turning the screen off and placing a small mirror where you get interference so that the cause can be seen. A slight angular adjustment may get rid of the reflection without affecting visibility, window coverings may be needed or else the screen may need to be repositioned elsewhere.
It is important that you keep your screen clean because if it is dirty then this may encourage poor neck and back posture through having to lean forward to read it. It is also important that you adjust the brightness and contrast so that you can clearly see what is on the screen. You may need to adjust the brightness during the day to compensate for the changing light conditions.
4. Document Holder
If you are inputting data and do not need to refer to the keyboard then it is important to have such data on a document holder which should be at the same distance and height as the screen. This will minimise head and eye movement and so prevent discomfort or early onset of fatigue. If you need to turn pages on your source documentation then the copy stand should be within arms reach so as to eliminate the need to lean forward.
Rest your eyes properly during your breaks which means avoid reading small print, don’t play computer games but try to focus on distant objects to relax your eyes.
In the correct posture, your head is upright and does not strain forwards or backwards, your neck is elongated slightly and relaxed, your shoulders are kept down with your chest open and your back is upright or inclined slightly forwards from the hips. Establishing this posture is particularly important if you naturally tend to slump in your chair. However, it is not advisable that you should maintain a single rigid posture all day no matter well you sit. Varying your posture throughout the day is beneficial and helps avoid stiffness and encourages blood flow which brings essential nutrients and the energy required. But, a correct chair position should encourage you to return to a healthy, upright posture regularly during the day.
Simple exercises to move joints and stretch muscles and nerves will stimulate circulation, lubricate joints and relieve nerve and muscle tightness. Doing a few stretches several times a day helps to prevent fatigue and so the onset of musculoskeletal disorders.
(a) Stretch head from side to side (x5 each side)
(b) Pull chin in so stretching the back of the neck. Hold for a count of 5 then relax (x10)
(c) In standing, place your hands in the small of the back and gently stretch backwards (x10)
(d) Interlock the fingers, turn palms away from you, stretch arms up so palms face the ceiling (x5)
(e) Stretch arms back to each side at hip level. Keep elbows straight, bend wrists back (palms facing downwards). Take arms back as far as possible (x5)
(f) Put hands together with elbows out keeping the heels of the hands together and stretch (praying stretch) (x5)
If you have any queries with these exercises or any of the information given call Advance Physio Ltd Clinical Specialist in Occupational Health, on 07885 439656 or 0161 832 8797