Repetitive Strain Injury (RSI) and Occupational Overuse Syndrome (OOS) are umbrella terms that include many localised injuries such as trigger finger, golfer’s and tennis elbow and carpal tunnel and also more diffuse pain syndromes (those spread over the body) which may be diagnosed as cervicobrachial pain syndrome or chronic pain syndrome. On this website we use the terms RSI and OOS interchangeably.


Symptoms of an overuse injury can be any of the following:

  • burning, aching or shooting pain that can be restricted to small sites, such as fingertips, or settle in a larger area such as the forearm
  • tremors, clumsiness and numbness
  • fatigue or lack of strength
  • weakness in the hands or forearms to the extent that it is difficult to perform even simple tasks such as lifting a bag of shopping
  • difficulty with normal activities like opening doors, chopping vegetables, turning on a tap
  • chronically cold hands, particularly the fingertips.

Early signs

The first signs of an overuse injury may be soreness, tingling or discomfort in the neck, arms, wrists, fingers or shoulders. These symptoms may come on when you do something or appear afterwards. They may disappear when you stop the activity that brought them on. It may take only a few hours for the symptoms to go away, or it may take as long as a couple of days.

Unfortunately, over time a minor condition like this can turn into a crippling injury with little warning. Extra stress in your life, pressure to work harder and longer or take fewer breaks can make your symptoms much more severe and long term.

I was 22 and working as a legal secretary when I first felt pain in my arms. I ignored it, thinking or hoping it would go away, and continued to work at my normal pace. I had recently changed jobs and didn’t want to cause any problems. However, typing for six or seven hours a day I soon realised the pain was getting worse. I continued working for about six months then my employer put me off work. It got to the stage that I couldn’t type more than a few minutes at a time and couldn’t keep up with the workload. They didn’t have any light duties for me nor did they want to re-instate me unless I could type as much as I had previously. In the end, they legally terminated my employment after I had been off work for six months.

What causes RSI?

Many factors acting together lead to RSI. They include:

  • doing something with your arms repeatedly for too long
  • working with equipment that doesn’t fit your body
  • working too fast
  • not having breaks
  • holding your muscles in the same position for a long time
  • lack of training in the safest way to carry out a task
  • long work hours
  • lack of variety in the type of work you do
  • working in cold conditions

The underlying cause common to all RSI-type conditions is damage to muscles and tendons (and the nerves that run through them) through repeated micro-trauma. Whenever muscles are used, tiny tears can occur in muscle tissue. The local area becomes inflamed for a short time as the body attempts to repair the damage.

Thickening and scar tissue form over the torn muscle tissue. At this stage, the area will feel painful. Normally, the body would repair the damage and the pain would go away. However, without enough rest, more activity causes further damage and more inflammation, thickening, scar tissue and pain.

This cycle gets progressively worse if sufficient rest is not taken. Under the microscope, changes can be seen in the structure of a tendon damaged by overuse. Collagen bundles that are normally tight and parallel instead look disorganised and discontinuous. A number of other changes have been noted as well, including a decrease in fibre diameter and fibre loosening.

Nerves are also damaged by RSI. Tingling feelings are caused by the compression of nerves. Nerves run through muscles, and if muscle health is poor, so is nerve health. Damaged nerves can heal but the process is extremely slow.

Treating RSI

RSI, once it’s established, is difficult to cure and can prevent you doing all kinds of things, like playing a musical instrument, carrying out hobbies, or gardening. Some people with RSI may eventually get a chronic pain syndrome that affects every aspect of their life. However, RSI is curable in its early stages, so it’s vital that you get medical help early and that you take this condition seriously! Early action is the key.

For more information on the RSI Basics, see our FAQs or order our book RSI: A Self-Help Guide.

Skip to content