Specific movements repeated over an extensive period of time cause the muscles to strain. When the muscle becomes worn out it becomes stiff and the blood flow to the area becomes limited. The lack of blood flow prevents the muscle from being able to naturally repair itself because there is a lack of oxygen.

This then creates a situation where the muscles and tendons are unable to replace the damaged cells with healthy new ones. The build-up of dead cells, also known as scar tissue, is what leads to the development of RSI.

The excess scar tissue weakens the muscle and then the surrounding muscles and tendons have to overcompensate for the now weakened muscle. This then puts excess strain on the surrounding muscles and tendons, which can cause the same thing to happen to them that happened in the original muscles.

Other symptoms besides pain and discomfort in the muscles and tendons include sensations of stiffness, numbness, and muscle weakness. People with RSI have also experience burning and sharp jolts of pain in the affected area. Along with these symptoms, it is also likely that someone with RSI may experience more difficulty and fatigue when performing everyday tasks. This condition can occur to anyone who overuses a muscle over a period of time, but it is commonly found in people who heavily use their hands and wrists, like dentists, hair stylists, musicians, golfers, and people who use the computer often.