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Overuse Injury
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This page explains the main principles behind the Setup advice, to help you tailor it to your particular circumstances.

Some more detailed information is also provided on some issues.  You can use the links on the left to go directly to a topic.
Overuse injury, RSI, WRULD There are many different terms and abbreviations for the kind of injury that can happen with intensive computer use.  They include:

RSI - Repetitive Strain Injury
WRULD - Work-Related Upper Limb Disorder
ULD - Upper Limb Disorder
CTD - Cumulative Trauma Disorder
OOS - Occupational Overuse Syndrome
MSD - Musculoskeletal Disorder
and more.

In effect, they all refer to the same thing: stress damage to the bodily tissues which is outstripping recovery.  You can think of it as each day the muscles, tendons, tendon sheaths, ligaments and so on are stressed by the activities, and then each night the body repairs them.  Up to a point, this stress/recovery cycle is good for us, it's the same process that gives fitness in athletes.

With low durations and intensities of stress on the tissues, the recovery process is completed easily, with time to spare as it were.  Especially when we are young and the body heals quickly.

What happens with overuse is that the repair does not get completed in time for the next day, and so the stress damage accumulates.  Each day there is a bit more damage that does not get repaired.  The body responds to protect itself, typically with swelling and/or pain, and these are signs that must not be ignored.

Age is a big factor.  As the bodily healing processes inevitably slow down with age, we can get nearer and nearer to the limit of our body's healing capabilities, but without noticing.  Then when the limit is reached, symptoms appear because the damage is suddenly accumulating, and urgent action is needed. 

You have to reduce the amount of stress damage being done each day, so that the body can catch up.  Typically you have to reduce it by a lot.

Fortunately reducing bodily stresses by a lot is often perfectly achievable, providing you are willing to change some ingrained habits.

In general it is long continuous effort by muscles, or stress repeated all through the day, that is the problem.  Static muscle effort holding a fixed position is particularly difficult, because the blood flow through the muscle is not assisted by the pumping action of the muscle expanding and contracting.  This is why getting yourself set up with a low-effort posture is so important when you are at a computer all day.

Stress Managing your levels of emotional stress is especially important for computer users, because tension in the body can increase the risk of physical overuse injury.

Stress can be brought about by a combination of physical and emotional factors both in and out of work. These signs can be indicators of stress:
  • Fatigue (without an obvious cause).
  • Feelings of isolation.
  • Anxiety and inability to cope.
  • Muscle tension and poor posture.
  • Easily distracted by low level noise.
  • Difficulty concentrating.

Try to improve your sense of control over your life at work. This can include:

  • Planning, prioritising and scheduling
  • Communicating effectively with others
  • Researching stress so you know more about it, e.g. in HSE or Google
  • Improving your skills to increase confidence, such as assertiveness training.

Vision Reading glasses are designed to give you focus at around 40 cm, while distance glasses are designed to give focus at 6 metres and beyond.  A computer screen is between these, at around 50-75 cm.
For this reason the DSE regulations provide for free eye tests to be provided by employers to employees whose job entails extensive computer use.  The Loughborough University policy is here.

Your optician is the best source of advice on glasses for you.  In general you should not be looking at your computer through the bottom half of bifocals or varifocals, because that will tip your head back.  You should be looking through the middle of the lens, and glasses are available that have an enlarged central sweet spot for computer users.

The DSE regulations also provide for your employer to pay for simple single-vision glasses, if you require them for that purpose and for no other reason. 

If you use reading glasses with a laptop where the screen is in the same position as a book - low down and close to you - then that may be alright for you.  Ask your optician, and monitor yourself for signs of fatigue that may be associated with using your eyes in this way.

Alternative Postures The formal advice on how to sit at a computer is an upright seated posture.  If this does not suit you, for one reason or another, you should at least make sure that all the various segments of your body are supported.  Then for example you can have a more open angle at the hip.

The relevant body segments are broadly:

Upper arm
Lower arm
Upper back
Mid back
Low back
Lower leg

Each segment is attached to the adjacent segment(s) with a joint and muscle (disc and ligaments in the case of the spine).  By directly supporting each individual segment - with your chair, armrests, backrest, wrist rest etc. - you save those joints and muscles from continuous strain.

Also you should keep each joint angle well within its normal working range, not at one end of its movement.

Monitors LCD monitors present relatively few problems - they are easy to position and do not flicker.  The main thing to watch out for is the size of the screen in relation to the resolution (number of dots).  In general for desk use you should choose a screen that is relatively large for its resolution, so that text and screen items are large and easy to see.

It is possible to have an LCD screen too far away, depending on its size and resolution, so don't automatically put it at the back of the desk.

The old style CRT tube monitors can be harder to position far enough away, and are prone to flicker if not correctly set up.  Also the picture quality deteriorates over time and most are quite old now.

Touch-Typing It is very worthwhile to learn to touch-type, if you cannot already do so.  Touch typing means you don't have to keep looking down at the keyboard, and this is much better for your neck muscles because your head stays in balance. 

If you regularly type from paper documents, or refer to paper media while computing, you need a document holder, and if you can touch type you can position this alongside the monitor at the same height and distance.  This saves your eyes from having to refocus all the time.

For members of Loughborough University there is a free touch-typing course, also there are many free tutorials online.

Footrests For cost reasons most commercially available footrests are short, narrow, and high.  Some tilt to an unsuitable angle with the weight though the heel, and some have attractive but uncomfortable bumps over the surface.  "Features" are generally misleading.

The effect of all this is to restrict foot movement and raise the feet too much, with potentially some other sources of discomfort as well.  It is often better to find something yourself, a board or an old cushion perhaps.

Do some experimentation with books or magazines, for example, to find the right height, and measure the height, length and width that you want.  Also you should experiment with the angle - this will vary with the shoes you wear and how far away you have it.

Office chairs are often sold with misleading claims, and it can be difficult to know which one is best for you. Here are some tips:


The bottom cushion should not be too long for you to get fully back in the seat, with the back of your buttocks behind the small of your back. This is often a problem in 'executive' chairs.


Separate height adjustment of the back is important if it has lumbar support built in. If the seat has tilt adjustment, it should be a 'knee tilt' design which pivots at the front and so limits the change in height at the front of the cushion.

Armrests should be height-adjustable if they are fitted. Fixed-height armrests are nearly always too low, encouraging you to slump down to them.

Lumbar Support

Your chair back should have effective lumbar (low back) support.  It should be height-adjustable and bulge or curve forwards slightly, with a soft feel and no hard edge at the top and bottom.

Add-on back supports are cushions that attach to the back of seats in order to provide better support to the lower back.


Armrests must be at the correct height for the user. Too high and the user will tend to work with their shoulders hunched. Too low and the users will slouch in their seat. Most fixed armrests are set too low, so adjustability is more or less essential. If you need to you may be able to build up the height of fixed armrests by wrapping foam around them; if not it is better to remove them.  They can nearly always be unbolted from underneath.

Armrests must be short enough to allow the chair to get close enough to the desk. This is generally little more than half the length of the bottom-cushion.

Not everyone likes armrests, but those who do can benefit from the reduction in arm weight hanging from the shoulder. This also reduces the static loads on the spine and buttocks.


The cushion should be flat. Avoid cushions which have a rise at the back as these will compress the buttocks, also avoid 'waterfall front ' seats which have an extended slope at the front - these give no support but can prevent you sitting fully back in the seat.

Ideally the seat-back should have a smooth lumbar support curve which is at least 25 cm in vertical length, and be adjustable for height.  Choose a shape which is simple and spreads support over the largest possible area, to reduce pressure on the skin. If a chair lacks this but is otherwise suitable, you could use an add-on lumbar support. You don't need lateral support in an office chair.


One of the ways cheap chairs are made cheaply is by using low-density foam in a thin layer. Check this by pressing your fist hard into the cushion and backrest. If your knuckles easily 'bottom out' onto the hard surface underneath, the foam won't last.

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