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Identifying the Hazard

What is RSI?

Repetitive Strain Injury (RSI) is an umbrella term used to describe a range of painful conditions which affect the musculoskeletal system, ie the tendons, tendon sheaths, muscles, joints and nerves, and which are associated with repetitive movements and other forms of overuse. A fuller definition is provided by the Australian National Occupational Health and Safety Commission, as follows:

RSI is a collective term for a range of conditions characterised by discomfort or persistent pain in muscles, tendons and other soft tissues, with or without physical manifestations. RSI is usually caused or aggravated by work and is associated with repetitive movement, sustained or constrained postures and/or forceful movements. Psychosocial factors, including stress in the working environment, may be important in the development of RSI. Some conditions which fall within the scope of RSI are well defined and understood medically, but many are not, and the basis for their cause and development is yet to be determined. It occurs amongst workers performing tasks involving either frequent repetitive and/or forceful movements of the limbs or the maintenance of fixed postures for prolonged periods.

To add confusion, there are a number of alternative umbrella terms in common usage, such as Work-Related Upper Limb Disorder (WRULD), Occupational Overuse Syndrome (OOS), Cumulative Trauma Disorder (CTD) and Occupational Cervicobrachial Disorder (OCD). None describes the disorder fully or perfectly and the proliferation of terminology reflects the difficulty people have in finding a satisfactory explanation for the condition. OOS is the term generally used in Australia, CTD in the USA, OCD in Japan and WRULD or RSI in the UK. The London Hazards Centre continues to use RSI, even though the description is limited to one risk factor, since this is the term in popular usage and is generally recognised.

Our musculoskeletal system consists of muscles, bones, tendons and ligaments. The system also includes nerves running to and from the brain. Our bones are held together by ligaments and our muscles are connected to our bones by tendons. Body movements are produced by the contraction and relaxation of muscles. Tendons do not stretch or contract but transfer force from the muscles to the bones. When a muscle contracts it becomes shorter, pulling on the tendons and allowing our joints and limbs to move. Tendons are smooth and slippery, so that they can glide easily inside the tubes that surround them known as synovial sheaths. These contain a lubricating fluid, synovial fluid, which enables the tendon to move within its sheath without friction. Where a ligament may be subject to particular friction, for example at the shoulder, elbow or knee, a small, fluid-filled sac called a bursa helps reduce the friction.

Although the musculoskeletal system can withstand many stresses and strains upon it, it is not invulnerable. Damage can occur to any part of the system and cause pain. Although our bodies can repair themselves, they need time to do this. When people suffer sports injuries, they usually rest the injured part and allow it time to recover. However, if the injury is work related, people often feel under pressure to carry on. Not only do they not give the injured part the chance to recover but they often continue to perform the work activities which caused the problem in the first place.

The term RSI covers a number of different conditions affecting the musculoskeletal system although there is disagreement amongst the medical profession about what should be included under this general definition. However, it is now generally accepted that RSI falls into two broad categories, although these may overlap. These are:

localised or pathological conditions diffuse conditions

Some of the most common localised conditions are:

tenosynovitis tendinitis epicondylitis bursitis carpal tunnel syndrome

A more detailed list is contained in Table 1, which also describes the nature of the condition and its symptoms more fully. Localised conditions have a specific medical name, are better understood and can be diagnosed relatively easily on examination. They are usually confined to one part of the body and the symptoms are experienced in that area only. Inflammation may be present. The conditions can be grouped as follows: those involving inflammation of the muscles, muscle-tendon junctions or associated tissue (eg tenosynovitis); those involving inflammation of the tissues of the hand, elbow or knee (eg beat conditions such as bursitis); those involving compression of the nerve (eg carpal tunnel syndrome); and those involving fatigue of muscles because of excessive load or awkward posture.

Table 1: Localised RSI Conditions

Diffuse conditions are less localised, spread through areas of the body, much less well understood and hard to diagnose. They are characterised by pain, muscle discomfort, burning and tingling sensations. Because the symptoms are diffuse it may be difficult to identify the site of the problem. They are sometimes described as RSI of obscure pathology.

The two conditions may often overlap, with diffuse muscle discomfort existing alongside a localised condition. Also it should be noted that pain can be referred elsewhere, for example, the symptoms of a shoulder problem may be a pain in the arm, and pains in the hand and fingers may be symptoms of a neck problem. This is because of the way the muscles and nerves are arranged in the upper part of the body.

What are the symptoms?

Some of the commonly reported symptoms of RSI are:

pain tenderness burning sensation pins and needles crepitus (a crackling feeling when tendons are pressed) loss of sensation (numbness) sensation of cold swelling ganglion (cyst-like swelling) muscle weakness muscle spasm joint restriction/loss of movement loss of grip

Not all sufferers experience all these symptoms and they do not necessarily appear in any particular order. They can occur at any stage in the development of RSI and there may be a delay between doing an activity and experiencing the symptoms. Often there are no visible signs at all.

RSI is a progressive condition which can be divided into three broad stages although the symptoms experienced by sufferers do not always fit this tidy scheme:

Pain, aching and tiredness of the wrists, arms, shoulders, neck or legs during work, which improves overnight. This stage may last weeks or months, but is reversible.

Recurrent pain, aching and tiredness occur earlier in the working day, persist at night and may disturb sleep. Physical signs may be visible, such as swelling of the tendon areas. This stage may last several months.

Pain, aching, weakness and fatigue are experienced even when person is resting completely. Sleep is often disturbed and the sufferer may be unable to carry out even light tasks at home or work. This stage may last for months or years. Sometimes it is irreversible and the person never gets back full use of the affected part of their body.

This demonstrates the need to recognise the symptoms of RSI early so that remedial action can be taken when the condition is at the mild stage and can be reversed.

Stage one is virtually impossible to distinguish from aches and pain arising from fatigue and may continue for weeks or months. However, the transition to stage three can take place within weeks and sufferers can be in extreme pain or incapacitated for months or years. It is therefore vital to take all symptoms seriously and take prompt action.

"If only Id realised the long term implications of RSI when I first experienced pains in my hands. But the symptoms were only slight at first and didnt stop me doing things." ( Secretary sacked because she was incapacitated by RSI, and still in pain and unable to work three and a half years later, speaking to a London Hazards Centre advice worker)