There are three main things that lead to RSI:

• Poor posture
• Stress
• Repetitive motion

When all three of these are present, you run the risk of developing RSI. And even though these are the three main causes, there are other things that can factor in to the equation.

Posture
You probably don’t think much about this when you’re sitting at your computer, but most of your day is spent sitting in the same position for hours on end. It’s not that you can’t be "comfortable" sitting at your desk, but you have to change positions frequently. This helps to shift stress to different parts of your body and to increase blood circulation. The best way to avoid stiffness and stress is to take breaks. Yes, we’re all driven by the need to produce and to just "get it done," but RSI can lead to extreme pain when typing, so why not take a couple of precautions now?

Stress
Stress is often thought of as a psychological problem, but it often pans out into physical effects. Your muscles tend to tighten up when you are stressed. This may cut down on circulation, and can also cause muscle cramping.

Repetitive Motion
You may think that only strenuous repetitive motions put you at risk, but case studies prove that easy movements, like typing or playing the piano, can lead to RSI. In other words, you may be injuring yourself when you do a motion continuously, even though it doesn't hurt -- at first -- when you do it.

Typing Technique
The "correct" way to type is to have the monitor at eye level, so that there is no strain on your neck. Your wrists should be straight and level, not bent back, when you type. Also, it is better to type in a warm environment, to keep your muscles warm and relaxed. Air-conditioned and poorly heated rooms increase the risk of RSI.

Drugs
Caffeine, alcohol, prescription drugs and nicotine are all considered drugs, and they can all help bring about RSI. Caffeine is particularly dangerous -- and remarkably prevalent at a university. It stimulates the brain and reduces fatigue during prolonged activity. As a result, it can hide how tired you really are, and enable you to put more strain on yourself than you would normally allow.

Alcohol
When you drink alcohol, your sleep is not as deep as it should be. If you don’t get enough "good" sleep, you won’t be able to work safely.

Smoking
Nicotine hinders blood circulation. It is important to keep up your circulation to remove waste products from the blood stream before they can build up.

Double-jointedness
If you are double-jointed, when you type your finger joints tend to collapse instead of holding firm. This makes your wrists bounce up and down more than they should.

Previous Injury
Injuries to your hands, wrists, back, shoulders and upper arms can all make you more susceptible to RSI.

Weight
Weight is a risk factor. The muscles of overweight people must support a greater load. Overweight people have to work harder to hold their forearms up to the keyboard. They are also more likely to be out of shape, which is itself a risk factor for RSI.

Physical Fitness
If you are out of shape, your muscles do not work at an optimum level, so some muscles have to work harder than others. Typing should work your back, shoulders, arms and hands, not just the forearms and fingers.

Women
Women are more at risk than men. Females tend to work at jobs that put repetitive strain on their wrists. They also tend to have weaker muscles. In addition, some doctors say that pregnancy, menopause, and taking oral contraceptives or post-hysterectomy hormone supplements may increase susceptibility. Also, most workstations are designed to fit the needs of the average male, and women may be unable to adjust these arrangements.

Age
The older you are, the more likely you are to develop RSI. The longer a person has been at his or her job, the more stress may have built up, and the more bad posture may have been reinforced.