Feature

Preventing repetitive strain injury

RSI can bring agony to computer workers. However, it can be prevented by a combination of ergonomic products and common sense

Repetitive strain injury is not a diagnosis but the name assigned to a series of symptoms related to overuse of one or more parts of the body.

RSI encompasses a series of physical disorders and injuries, including carpal tunnel syndrome, ulnar nerve entrapment, deQuervains syndrome, thoracic outlet syndrome, tennis elbow and tendonitis. Diagnosis of RSI is a difficult process since symptoms may be intermittent for many months before becoming continual. General symptoms include a tenderness or aching in a joint (often the wrist), before tingling and loss of strength and movement lead to pain.

Many different factors can contribute to the development of RSI and the presence or otherwise of one or all of these factors does not guarantee whether or not you will be susceptible. They include long hours, lack of breaks, muscle tension, physical fitness and inappropriately placed or unsuitable equipment. The degree of risk can also be influenced by such factors as obesity, a sedentary lifestyle and smoking, as these reduce blood circulation.

Another key cause over strain is the use of small font sizes. Workers using a font size that is too small to be easily viewed tend to lean forward, hunched over their desk. This restricts blood flow to the muscles which can lead to muscle tension and injury. When blood flow is restricted, the tissues are unable to carry the necessary nutrients and oxygen to the joints and muscles. Also, the waste products, lactic acid and carbon dioxide, build up, causing pain for the worker in the affected area.

Once you have injured your hands through restricted circulation, a vicious circle emerges where, to counter the pain or stiffness in one part of the body, the neighbouring muscles tense, which then leads to an even more restrictive blood flow. The only way you can heal muscle damage of this sort is to rest and to take steps to ensure that you do not damage the muscles further.

Repetitive movements can also damage tendons. When muscles and/or tendons are tensed frequently they can become inflamed. If you continually strain your tendons, they will tear and, without rest, will not heal and may become permanently weakened.

Tendons glide within sheaths lubricated by synovial fluid. If this fluid is not free flowing or thickened from overuse or prolonged static postures, friction between the tendon and the sheath may result. The sheath may then swell and be painful. This can lead to further injury as other muscles and tendons attempt to compensate for the injury.

Treatment for RSI ranges from rest and pain relieving pills or gel and wrist braces to correct posture, to physiotherapy and, in some very severe cases, surgery. Once RSI has developed, there are two ways to prevent re-occurrence and the exacerbation of the problem. These include incorporating ergonomics into the working environment and encouraging healthy working practices.

There are many techniques for encouraging healthy working practices both within and outside of the workplace. It's important to take a holistic view of preventing RSI and for this reason I am including methods that can be practised outside the workplace as well as within it. To encourage healthy breathing, posture and improved co-ordination, try the Alexander technique. To improve stretching, yoga or Tai Chi is excellent. For stress reduction, try positive thinking, visualisation or just going for a walk. Remember to treat sore muscles with care, try massage to relieve the stress build up. A healthy diet and lots of water can also help promote good circulation.

It's important to keep your hands warm, perhaps by wearing fingerless gloves or by playing with a stress reliever toy that you can kneed. Most importantly, take frequent work breaks and move around. Sitting in the same position for more that 30 minutes will lead to stiffness. If you have wheels on your chair, use them to swivel round and move your body, and make sure that at least once an hour you leave your chair and stretch.

Poor ergonomics in the workplace can severely damage your company's wealth. Studies suggest that an unergonomic workstation leads to 20 per cent less productivity. One Norwegian company discovered that by re-designing their workers' workstations, they made an 840 per cent return on their investment, simply by reducing the costs of sick leave and staff turnover.

An ergonomically sound workstation set-up involves right angles. The workers feet should be flat on the floor, calves should be parallel to the floor and to the thighs. The angle between thighs and back should be at least 90 degrees. Arms should hang relaxed at the sides, and forearms should project out in front of you, forming another 90 degree angle. Wrists, while typing, should be straight, not arched upwards or with the wrist resting on the desk or keyboard. To achieve this, it's often necessary to adjust either chair and desk height or the height of the keyboard. One of the simplest ways to do this is to use a keyboard shelf. These are literally small metal drawers for the keyboard, which the monitor can then be placed on. This puts both monitor and keyboard at the right height for good posture (assuming that the chair and desk are at the right height). The worker should sit between 1 and 28-in away from the screen. Your screen should be between 15 and 30 degrees below your line of site.

Also consider the effects on the eyes of continual screen use and act accordingly. Take regular screen breaks and ensure that your eyes are regularly checked for deterioration. Backlighting your display can help to prevent eyestrain. Consider the use of glare guards as well to reduce eyestrain.

A change of input device may help aid or prevent RSI. There are a wide range of split and adjustable keyboards on the market. Microsoft and Logitech are now launching a range of infrared keyboards which allow you to work in a comfortable position without cumbersome leads. The replacement of a mouse, with a trackball, can also help, as it doesn't generally require the same muscular strength that can lead to tension.

A lightness of touch on the keyboard can do wonders in reducing the amount of stress exerted on your muscles. If you have poor hand posture, you will probably hammer the keys using the whole of your hand strength to touch one key when the lightest of touches would do the job. Also, use two hands rather than one to press function keys (e.g. ctrl + C for copy). This shares the load on the hands and also allows you to use your strongest fingers rather than stretching (and tearing) the small muscles in the smaller fingers.

Voice recognition software can also help by minimising the amount of typing required. However, this does involve teaching the software how to recognise your voice patterns and also teaching yourself how to speak in a relaxed regular way your computer can recognise.

Wrist pads or rests come in two forms, the first is neoprene or rubber, and the second is polystyrene. Both work in two ways, the first is by cushioning your wrists while you are not typing, and the second is to remind you to keep your wrists straight - you shouldn't have to rest on any surface as you type, because that angle can compress the carpal tunnel.

The chair is probably your most important piece of ergonomic furniture. It determines your sitting position and thus the angle your body is at while reading the screen and typing. It's important to set your seat so that your thighs are slightly higher than your knees to support your head and arms and stretch your spine.

Check that the seat pad is in contact with your thighs but not touching the inside of your knees, you run the risk of cutting off circulation in your legs. Your thighs should touch the seat pad, but not the back or inside of your knees. If they do, you may cut off the circulation to your thighs.

It is vital that your chair can be tilted so that the chair takes more of your weight. This reduces pressure on the back and thighs. If you can't place your feet flat on the floor and your hands in the right place in relation to the desk or keyboard, you need to invest in a footrest. If you chose to use armrests on your chair, make sure that they allow optimum wrist positioning rather than causing dead straight arms that don't allow your wrists to move.

To avoid RSI you should avoid more than two hours of computer use or other repetitive hand movement per day - this means planning your work more effectively. If you injure your wrists every month struggling to hit reporting deadlines, you are likely to damage yourself. If you have to work in a high stress situation at a computer, take regular breaks, you will be more productive afterwards and regular breaks ensure that you maintain good posture while working.

Work creatively to prevent repetitive movement. If you can phone someone instead of emailing them, do so. Using an organiser or personal information management suite to manage your time more effectively means that you don't have regular gluts of work that cause time, and consequently, muscle pressure. Ask your colleagues for information rather than searching the web - you never know, it might improve your relationships as well.

Ensure all the equipment you need is within a reachable position and never use your shoulder to hold the phone so you can continue typing. Use headsets or do one thing at a time. This sort of position so familiar to workers is particularly hazardous to neck muscles that can easily cramp and be damaged by lack of blood flow.

Designers, in particular, need to ensure they do not sit in one position for a long time, holding the mouse in front of a computer - this is called static loading and can severely injure wrists, hands and neck muscles.

As an employer, you are responsible for protecting the welfare of your employees. You can help fulfil this obligation by supplying the correct equipment and ensuring they take regular breaks. Remember that computers distort employees' sense of time, they may not be aware that they have been working without a break for several hours until it is pointed out to them. For this reason, there have been several RSI prevention software packages created. These use pop up boxes to remind workers to take a break. This doesn't necessarily mean stopping work, perhaps a walk to the fax machine, filing cabinet or simply to the kettle to make a drink will be enough to make your workers more alert and productive, AND prevent RSI.

Rachel Hodgkins


Email Alerts

Register now to receive ComputerWeekly.com IT-related news, guides and more, delivered to your inbox.
By submitting you agree to receive email from TechTarget and its partners. If you reside outside of the United States, you consent to having your personal data transferred to and processed in the United States. Privacy

This was first published in September 1999

 

COMMENTS powered by Disqus  //  Commenting policy