General information
Both students and staff spend a considerable amount of their time every day working with a computer. Whether they are involved in word processing, e-mailing, data processing, producing calculations, carrying out graphic tasks or 3D modelling, the computer is the tool they use in all their activities. In the future, use of the computer is only set to increase, and for many tasks traditionally done by hand, there will be no alternative. In the home, too, more and more information is being digitally transferred, using laptops, PCs and personal organisers.
One major advantage of this development is that information is more easily accessible to everyone, whilst tasks can be carried out more efficiently, on condition you have the necessary skills. However, these developments do not seem to be reducing workloads. This is on the one hand due to the time you need to install the hardware and software and learn how to use it, whilst on the other hand the newly created technology and the resultant productivity improvements very rapidly become viewed as the performance standard. With the newly added possibilities, tasks are also in many cases becoming more and more complex. Viewed against the background of a very productive economy and learning environment, the overall result is high to very high mental burdens. On top of this, working with a computer generates a very specific physical burden because of the way data is input, and the physical position in which the work is carried out.
This combination of physical and mental burdens appears to be the cause of the increased numbers of physical complaints due to VDU (Visual Display Unit) work, also within the Delft University of Technology. This site deals with the fastest-growing group of complaints, namely RSI-related disorders. Because there are many misunderstandings and much confusion about RSI, current knowledge on this subject will be explained by describing the symptoms, explaining the origin and, most important, telling you how you can avoid RSI in connection with VDU work.
What is RSI?
RSI is the abbreviation for Repetitive Strain Injury. It is a collective term for a group of complaints affecting the neck, shoulders, arms, wrists and hands, due to chronic overload. Repetitive injury occurs as a result of making repetitive movements; a common phenomenon in many types of work. The repetitive component of VDU work is above all clicking the mouse (or other pointing device), or rapid typing on the keyboard. Not only VDU workers but also other professional groups have to deal with repetitive movements, including hairdressers, racing drivers, musicians, packers, de-boners and poultry workers. As early as the 16th century, monks who were required to precisely copy books by hand regularly complained of ‘writer’s cramp’, resulting in pain in the shoulders, arms and hands.
What are the symptoms of RSI?
The symptoms of RSI are varied. They range from feelings of cold, cramp, colour change, stiffness, tingling and loss of power, through to pain or specifically loss of feeling, and can occur in the neck, shoulders, arms, wrists, hands and in very exceptional cases, the legs. It is also sometimes difficult to precisely localise the pain. And because there is generally no evidence of a specific injury, it is difficult to determine whether or not somebody is indeed suffering from RSI. The types of complaints listed above are therefore described as non-specific, but that makes them no less serious. A small group of complaints also recognised as RSI are, however, specific. These include tennis elbow and carpal tunnel syndrome.
One common feature of all RSI symptoms is that until the affected body parts are thoroughly rested, they will increase in severity.
RSI is often broken down into three stages (in this case focused on VDU work).
Stage 1
The complaints only occur when working at the computer.
Stage 2
The complaints also occur during other activities. The pain is also felt in the evening, and some sufferers even wake up at night as a result of the pain.
Stage 3
The complaints become continuous. Activities such as dressing and undressing are painful, and opening a door or turning a key becomes practically impossible.
How does RSI originate?
At present, we do not precisely know how RSI starts. There are however a number of hypotheses, many of which share common aspects. Below is a summary of the most recent ideas. It is assumed that the same organisms are underlying aspects of both specific and non-specific complaints.
Dynamic load
The muscles in the hands and fingers are subjected to dynamic load due to the high movement frequency of the fingers while typing or mouse handling. If these muscles are given insufficient opportunity to recover, due to a lack of breaks, the overloading of the muscles can result in damage to the muscle fibre. It is suspected that those muscle fibres that are first used for movement are in fact the last to relax. As a consequence, even when subjected to relatively low load, an overload condition in the muscle fibres can occur. In the case of repetitive movements of the fingers, there is also friction between the muscles, tendons and bones, particularly in the areas of wrist and elbow, which in the long term can also cause complaints. One such example is the carpal tunnel syndrome, whereby the tendons and tendon sheaths become irritated and inflamed as a result of friction between the tendons in the narrow passage (the carpal tunnel, a sort of belt of connective tissue) in the wrist. Nerves which run through this same passage can as a result become trapped, and cause painful complaints.
Static load
In addition, the muscles in arms, shoulders and neck are subject to static load. They are required to constantly tense, in order to keep the body in balance, while working behind the computer. As a result of this load, the muscles tend to be continuously slightly pumped up. The minor blood vessels that supply the muscles become squeezed tight, and blood circulation decreases.
The result is twofold: a shortage of oxygen and nutrients, in combination with an excess of waste matter. As a result, the waste matter irritates the free nerve ends in the muscle. This irritation is painful, and in response, the muscles tense even more. This leads to a vicious circle. The cramping in arms, shoulders and neck not only causes local complaints (painful, hard muscles) but also causes the nerves and blood vessels running to the hand and fingers to be pinched. This often makes its presence felt in the form of cold or tingling fingers. The same vicious circle of irritation as a result of cramping and cramping as a result of further irritation then also occurs in the muscles of the hands and fingers. Only by removing the static load on the muscles and improving the circulation can this vicious circle be interrupted, for example by taking breaks, and through physical exercise.
Mental and physical
As we stated above, mental and physical burdens play a role in the origin of RSI. Current research is therefore focusing more specifically on this combination. It has for example emerged that muscle tension in the arm, shoulder and neck is increased as a result of a range of psychological, physiological and biomechanical factors. Let us explain further. A certain degree of co-contraction is always present, in order to make movement possible. In other words, the simultaneous tensioning of agonists and antagonists (the benders and stretchers) during a movement. This co-contraction increases, as the psychological, physiological and biomechanical factors become stronger. It is perfectly feasible for a situation of this kind to arise during VDU work, as a result of the number and frequency of the repetitive movements, the precision and speed often demanded, the complexity of the work, and the circumstances in which the work is carried out (noise, interruptions, cooperation, etc.). Because the co-contraction effectively makes the movement less efficient, more energy is required to achieve the same result, and the pressure in the muscles simply increases. The consequence of this pressure increase is that the muscles become overburdened, and RSI-related complaints can arise.
Personal factors
It appears that people who are susceptible to RSI share a number of personal characteristics. They often emerge as perfectionists and less extrovert by nature, as a result of which they are less easily able to stop themselves from working, and as a consequence, they are susceptible to stress.
Some people have a higher average muscle tension than others. This too can play a role. In addition, there are suspicions that certain physical characteristics influence the occurrence of RSI. Against this background, the ratio body weight / body length, wrist, lower arm and upper arm size, and joint excursions (elasticity) are currently being further investigated.
What to do when the symptoms first emerge
RSI is caused by a combination of long-term mental and (very specific) physical overload. By reducing this burden in time, taking regular breaks, alternating with other (less specific) physical burdens and taking more rest and relaxation, muscles, tendons and nerves can recover, and the initial RSI complaints will rapidly disappear. In other words, if you take the initial signals seriously, prospects for recovery from RSI are good. However, if you ignore these signals, and the body is subjected to the standard load, the complaints will become worse. Over time, these more serious complaints can become less and will eventually disappear, on condition that muscles, tendons and the nervous system are given sufficient opportunity to recover. Given the seriousness of the complaints, it may be necessary to take complete physical rest. Nonetheless, it is advisable to quickly resume activities to increase the amount of physical load the body can handle, through general physical movement and, albeit in a moderate form, to remain involved in your normal day to day activities. In the final stages of RSI, the overload is such that the complaint becomes chronic, as a result of which recovery is an extremely long-term process, often of months, or even years.
How can you prevent RSI?
The measures you can take to reduce the risk of RSI are often known as the "five Ws", and they are listed below. Alongside these "five Ws", good general physical fitness (sport and sufficient rest) is also key. Physical fitness after all enables your body to cope with more physical load.
RSI is generally caused by a combination of different factors, and can therefore itself generally speaking only be prevented by a combination of measures.
Work assignments
Repetitive work such as typing and mousework can best be varied with other non-repetitive work such as conferring with colleagues or fellow students, reading documents and taking notes, as well as simple tasks like walking to the printer.
Working times
Work must be alternated with relaxation. Listen to your body when it calls for a break. Take breaks on time, although this is not always easy. Therefore, as a rule of thumb, a break of at least 10 minutes is advisable, after 2 hours of uninterrupted working. You can also take a short break (approx. 20 seconds) every 10 minutes, to improve the blood flow through your muscles, by shaking your hands, twisting your upper arms, lifting your shoulders, and tilting and turning the head and neck. You are also advised not to spend more than 6 hours on VDU work, in any given day.
Working method
A good working method is a method focused on a sound physical and psychological work attitude. A poor physical posture will increase the static load on the muscles in the neck and shoulders. With a good physical work posture, the muscles in the body are subjected to the least possible static load. Regularly changing the body position will bring about good blood circulation through the muscles.
A good psychological work attitude involves keeping things in perspective. This attitude means that you do not exceed the maximum working times, that you take breaks when necessary, that the urge to perform when faced with deadlines itself is subject to limits, and that good planning means that peak loads are kept to a minimum. In other words, a working method whereby you also take good care of yourself. This can sometimes mean learning to say 'no', if you have good reason.
Working environment
You will find more information on this aspect under 'organizing your workplace'.
Some people work in awful working conditions and will never suffer from RSI, whilst others have the very best furniture and hardware that money can provide, and still suffer from the complaint. Despite many opinions to the contrary, research has shown that the working environment only has a minimal influence on the occurrence of RSI. It has however been shown that a well-organised workplace can encourage an individual to take up and maintain a good physical working posture. But for both furniture and the type (and adjustment of the) input device you choose, the following always applies: you should experiment to create the optimum working environment for you.
Work pressure
Work pressure is the last point mentioned here, but it is nonetheless viewed as an important factor in the origin of RSI. Severe work pressure brought about by deadlines, for example, can cause psychological stress, which often unnoticed leads to additional tension in the neck and shoulder muscles. As well as RSI, this can cause other complaints such as the so-called 'stress headache'. Another possible cause of psychological stress at work is a lack of cooperation with colleagues, fellow students or your boss (in other words, insufficient social support). The degree to which you can influence the organisation of the work you do can also play a role.
Also remember that psychological stress in your private life can result in greater muscle tension, making you temporarily more susceptible to developing physical complaints. Learn to deal with tension caused by deadlines, and try to prevent extreme peak loads, by carefully planning and setting limits for yourself.
