Definition of Repetitive Motion Injury or Disorder

There are several different types of repetitive motion or musculoskeletal disorders and there are different symptoms for each one. An excellent Web site, hosted and supported by Carnegie Mellon University, is a great place to start learning about these matters.

Types of Injuries

The following types of injuries are often associated with repetitive motion injuries:.

  • Adverse Mechanical Tension (AMT):
    Muscle spasms in your shoulders cause the nerves that run down your arm to contract 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.
  • Tendonitis:
    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.
  • Tenosynovitis:
    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.

What kinds of injuries occur in the office?

Most problems that occur in the office are caused by physical stress, such as prolonged awkward positions, repetitive motions, and overuse. These injuries can cause stress and strain on muscles, nerves, tendons, joints, blood vessels, or spinal discs. Symptoms include fatigue and hand, wrist, arm, shoulder, neck, or back pain. Employees may also be at risk for conditions such as tendinopathy and bursitis, which are caused by overuse and repetitive motions. Ultimately, physical stress decreases overall well-being and may cause chronic health problems.

The U. S. Department of Labor defines a musculoskeletal disorder (MSD) as an injury or disorder of the muscles, nerves, tendons, joints, cartilage, and spinal discs. MSDs do not include disorders caused by slips, trips, falls, motor vehicle accidents, or similar accidents

The National Institute for Occupational Safety and Health (NIOSH) has seen an increase in calls about work-related musculoskeletal disorders. Such calls are now second only to questions about chemical hazards, and most callers are associated with small and medium sized businesses. Because musculoskeletal disorders have been associated with non-work activities (e.g. sports) and medical conditions (e.g. renal disease, rheumatoid arthritis), it is difficult to determine the proportion due solely to occupation.

For example, in the general population, non-occupational causes of low back pain are probably more common than work place causes. However, even in these cases, the musculoskeletal disorders may be aggravated by work-place factors. The statistics from are very interesting:

Injuries Musculoskeletal Disorders
Number Rate Number Rate
Total: 1,183,500 127.8 357,160 38.6
Gender: Male 775,900 142.8 222,880 41.0
Female 403,740 106.4 133,710 35.2





Injuries Musculoskeletal Disorders
Number Rate Number Rate
Office and administrative support
83,320 54.3 26,960 17.6

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