This Web site, hosted and supported by Carnegie Mellon University, is all about putting concerns for your health first and not taking chances with bad typing habits. Your hands might not hurt today, but they may tomorrow. And then it might be too late to do something about it.

"RSI" actually stands for Repetitive Strain Injury. Sounds easy enough, but unfortunately, it's not that easy to define. There are several different types of RSI and there are different symptoms for each one. We will do our best, using this Web site and other resources, to let you know how to avoid injury.

Types of Injuries

The following types of injuries are often associated with Repetitive Strain Injury.

Adverse Mechanical Tension (AMT):
Muscle spasms in your shoulders cause the nerves that run down your arm to contrast and compress. This injury is also known as "neural tension," and can be misdiagnosed as another RSI disorder. AMT can be treated and reversed with physiotherapy.

Carpal Tunnel Syndrome (CTS):
The nerves that run through your wrist into your fingers get trapped by the inflamed muscles around them. Symptoms include feeling "pins and needles," tingling, numbness and even loss of sensation.

Tendons can become inflamed through repeated tensing. Eventually, the fibers of the tendon start separating, and can even break, leaving behind debris that induces more friction, more swelling, and more pain. "Sub-acute" tendonitis is more common, and is a dull ache over the wrist and forearm that gets worse with repetitive activity.

The tendon sheath thickens and becomes inflamed when repetitive activity exceeds the sheath’s ability to lubricate the tendon. As a result, the area around the sheath becomes tender and painful.

DeQuervain’s Disease:
A special case of tenosynovitis that occurs in the abductor and extensor tendons of the thumb where they share a common sheath. This condition often results from combined forceful gripping and hand twisting.

Thoracic Outlet Syndrome (TOS):
The nerves and vessels between the neck and shoulders compress from long periods of hunching or raising your shoulders. Symptoms include pain in wrist/hand and lack of pulse in the affected arm. The last two fingers of the affected hand may be numb, tingle or turn blue due to a lack of blood.


The symptoms or RSI include:

  • Stiffness or pain in your neck, shoulders or back
  • Tiredness, numbness, tingling or pain in your arms, wrists, hands or fingers
  • Clumsiness or loss of strength and coordination in your hands
  • Pain that wakes you up at night
  • Feeling a need to massage your hands, wrists and arms

These symptoms do not simply "happen." There are many factors that add up and lead to RSI. Those factors are covered in the section of this Web site titled "Am I at Risk."

Ergonomic Terms and Definitions

Creating a good ergonomic work environment can help you avoid RSI. The following are some terms and definitions related to ergonomics.

The science that seeks to adapt work or working conditions to suit you, the worker.

Repetitive Strain Injury:
Excessive wear and tear on tendons, muscles, and sensitive nerve tissue caused by continuous use over an extended period of time.

Neutral Position:
Keeping your body in its natural alignment.

Movement that decreases or increases the angle between two bones.

Radial/Ulnar Deviation:
Bending your hand at the wrist in either the direction of or away from the thumb.

Neck Tension:
An irritation of muscles in your neck, commonly occurring after repeated or sustained work.