Repetitive Strain Injuries

In simple medical terms, repetitive strain injury (RSI) is defined as a cumulative trauma disorder (CTD) stemming from prolonged repetitive, forceful, or awkward hand movements. The result is damage to muscles, tendons, and nerves of the neck, shoulder, forearm, and hand, which can cause pain, weakness, numbness, or impairment of motor control.

You may wonder how seemingly innocuous activities such as typing and clicking a mouse button could possibly be harmful. Fine hand movements, repeated hour after hour, day after day, thousands upon thousands of times, eventually strain the muscles and tendons of the forearms, wrists, and fingers, causing microscopic tears. Injured muscles tend to contract, decreasing the range of motion necessary for stress free work. The sheaths that cover delicate tendons run out of lubrication because they aren't given time to rest, so tendon and sheath chafe, resulting in pain. Due to this abrasion, tendons become inflamed, and begin to pinch neighboring nerves. This can result in numbness, tingling, or hypersensitivity to touch. Unless this cycle is interrupted, it repeats itself over and over, and a long-term, chronic problem results.

Repetitive strain injury can affect more than just your hands and wrists. Poor posture can lead to severe neck and back injuries. Staring at a computer screen can lead to eye strain. Repetitive reaching for a mouse can lead to arm and neck strain as well as spinal asymmetry.

RSI is not a specific medical diagnosis, but rather a family of disorders. Many people mistakenly equate RSI with carpal tunnel syndrome, even though CTS is only one particular form of RSI. One recent study even reported that frequent computer users are no more likely to develop CTS than non-computer users. Don't let this mislead you, though. Many other forms of RSI do come on as a result of frequent computer use.

Who is at risk?

The three primary risk factors are poor posture, poor technique, and overuse. These topics are discussed in depth in the section on prevention. In addition to these, there are several other risk factors to be aware of. While they may not cause RSI on their own, they can increase your risk if you already possess one of the three primary risk factors. The following lists several risk factors. You may be at risk for developing an RSI if you:

• Have poor posture
• Have poor technique
• Use a computer more than two to four hours a day
• Have a job that requires constant computer use, especially heavy input
• Don't take frequent breaks
• Are loose-jointed
• Don't exercise regularly
• Work in a high-pressure environment
• Have arthritis, diabetes, or another serious medical condition
• Keep your fingernails long
• Have an unhealthy, stressful, or sedentary lifestyle
• Weigh more than you should
• Don't sleep well

The primary warning sign of RSI is pain in the upper extremities (fingers, palms, wrists, forearms, shoulders). The pain may be burning, aching, or shooting. It could be local (e.g., fingertips) or diffuse (e.g., the entire forearm). The pain will typically be increased after a long session of computer use. Keep in mind, however, you can have severe RSI without experiencing pain. The following checklist, can help you determine whether you have RSI:

Do you experience:

• Fatigue or lack of endurance?
• Weakness in the hands or forearms?
• Tingling, numbness, or loss of sensation?
• Heaviness: Do your hands feel like dead weight?
• Clumsiness: Do you keep dropping things?
• Lack of strength in your hands? Is it harder to open jars? Cut vegetables?
• Lack of control or coordination?
• Chronically cold hands?
• Heightened awareness? Just being slightly more aware of a body part can be a clue that something is wrong.
• Hypersensitivity?
• Frequent self-massage (subconsciously)?
• Sympathy pains? Do your hands hurt when someone else talks about their hand pain?

When to seek help

If you believe that you may have developed RSI, the first thing you should do is to implement all of the prevention strategies outlined above. If you find that your situation continues to worsen, you should consider seeking professional medical advice. A general rule of thumb is that if your hands still hurt a couple of days after you last typed, you need to see a doctor.