Repetitive strain injury (RSI) is a condition where pain and other symptoms occur in an area of the body which has done repetitive tasks (often the arms or hands). Repetitive strain means strain related to actions which are frequently repeated. Symptoms of Repetitive Motion Injury can be seen as follows:
Throbbing
Numbness
Tingling
Pain
Tightness
Dull ache

The symptoms tend to develop gradually. At first the symptoms may only occur whilst you do the repetitive task and ease off when you rest. In time the symptoms can be present all the time but tend to be made worse by doing the repetitive task. Symptoms can range from mild to severe.

Type 1 RSI
Carpal tunnel syndrome (pain and squashing (compression) of a nerve in the wrist).
Tendonitis (inflammation of a tendon).
Tenosynovitis (inflammation of a tendon sheath).

These conditions may be due to, or be made worse by, repetitive tasks. However, these syndromes are also common in people who have not done repetitive tasks. These syndromes may have other symptoms such as swelling, inflammation, nerve compression problems, etc.

Type 2 RSI
This is where symptoms do not fit into a well-defined syndrome. Also, there are no objective or measurable signs such as inflammation, swelling or problems with nerve function. It is sometimes called diffuse RSI or nonspecific pain syndrome.