A repetitive motion disorder (RMD) is a physical condition that results from repeated motions made in the course of normal work, athletic activity, and just going about the business of everyday life.
As such, RMD is an umbrella term for many types of disorders, injuries and conditions that result from repetitive motion.
Taken together, the terms apply to a wide range of injuries and symptoms. Taken individually, they can describe specific causes or effects on the body.
What are RMDs?
RMDs can be caused by too many uninterrupted repetitions of an activity or a motion. From unnatural or awkward motions such as twisting the arm or wrist, from overexertion, incorrect posture or muscular fatigue.
RMDs occur most commonly in the joints of the hands, wrists, elbows and shoulders. They can also happen in the neck, back, hips, knees, feet, legs and ankles. RMDs are characterized by pain, tingling, numbness, visible swelling or redness of the affected area, as wells as the loss of flexibility and strength.
In some people, there may be no visible sign of injury, although they may find it difficult to perform what would otherwise be described as easy tasks. Over time, RMDs can cause temporary or permanent damage to the soft tissues in the body — including the muscles, nerves, tendons and ligaments — as well as compression of nerves and tissue.
Some estimates have placed repetitive motion as the root cause of 50 percent of all athletic-related injuries seen by physicians in the United States. However, it’s more often more everyday actions, such as typing or mopping the floor, that can lead to this condition. Many jobs come with their own associated repetitive motions, from sign language interpreters to mechanics and from musicians to janitors, and perhaps more obviously, factory and farm workers. RMDs represent sizeable healthcare costs, a diminished quality of life and losses to productivity.
What’s in a Name?
The most common types of repetitive motion injuries are tendonitis and bursitis, which as the names suggest, affects the tendons and the bursae, respectively. These disorders are difficult to distinguish and they can be present at the same time. However other anatomical features and areas can be stressed and their response can lead to an injury.
As common as they are, it is perhaps no surprise that the list of names associated with them is substantial. Some terms used interchangeably with RMD are:
Repetitive stress injury (RSI)
Repetitive stress disorder (RSD)
Repetitive strain injury (RSI)
Repetitive strain disorder (RSD)
Repetitive motion injury (RMI)
Repetitive motion disorder (RMD)
Cumulative trauma disorder (CTD)
Musculoskeletal disorder (MSD)
Many of these terms are used interchangeably, even though there are in some cases nuanced semantic differences between some of them. For example, the term Repetitive Strain Injury describes injury caused by strain instead of stress. Repetitive Strain Disorder is a repetitive strain injury using the disorder classification rather than “injury”. Most (but not all) repetitive stress injuries are some type of irritation or injury to the musculoskeletal system. However, RMDs are not restricted to musculoskeletal disorders in that they do not necessarily affect the muscles or bones, but rather some other part of the anatomy.
In general, there is a preferred use for a given purpose, such as a medical diagnosis or in a field such as physical therapy. In interdisciplinary discussions, it is worth clarifying terminology to avoid confusion.
Outlook for RMDs
Left untreated, RMDs can result in permanent injury and loss of function in an affected area. Most people with RMDs recover completely and can avoid re-injury simply by changing the pattern(s) that resulted in the condition, such as the manner and frequency in which they perform repetitive and the amount of rest time taken between movements. Not surprisingly, much of the current research into RMDs focuses on rehabilitation and prevention.
1. Higgs, MD, Philip E., and Susan E. Mackinnon, MD. “Repetitive motion injuries.” Annual review of medicine 46.1 (1995): 1-16.
2. Mitchell, James W. “Repetitive-Motion Injuries.” Journal of Occupational and Environmental Medicine 28.2 (1986): 75-78.