Ergonomic Tips (01/01)
General ergonomic definitions
by John R. Chait D.C., drchait@home.com
Member of the Sarasota Personal Computer Users Group, Inc.
Ergonomics - The
study of the design and 
arrangement
of equipment so that people will interact with the equipment in healthy,
comfortable, and efficient manner. As related to computer equipment,
ergonomics is concerned with such factors as the physical design of the
keyboard, screens, and related hardware, and the manner in which people
interact with these hardware devices.
Duration - Duration is the span of exposure to a risk aspect. It can be measured as the minutes or hours per day the person is exposed to a risk. Duration can also be viewed as the years of exposure to a risk factor. In general, the greater the duration of exposure to a risk factor, the greater the degree of risk. However, specific duration guidelines have not been recognized for risk factors such as force, posture and repetition.
Force - The amount of muscular exertion required to perform a chore. Generally speaking, the greater the force, the greater the degree of hazard. High force has been associated with occupation related musculoskeletal disorders at the shoulder, forearm, wrist, hand, neck and the low back.
Motion: Velocity/Acceleration - Velocity/ acceleration is the speed of body part movement and the rate of change of momentum of body part motion, respectively. It is generally regarded that increased acceleration leads to increased risk of tissue damage. Recovery Time - Recovery time is the span of rest between exertions. Short work pauses can reduce discomfort. Inadequate rest periods between exertions can decrease performance. As the duration of the nonstop work increases, so does the amount of recovery time needed.
Repetition - Repetition is the number of a similar exertions performed
during 
a
motion. An electrician uses a screwdriver repetitively, which can cause
joint stress. An office worker user the computer mouse with the same
motion continuously or incorrectly. Repetitive motion has been
associated with injury and worker discomfort.
Awkward Posture -Posture is the position of the body while performing work activities. Awkward posture is associated with an increased risk for injury. It is generally considered that the more a joint deviates from the neutral (natural) position, the greater the risk of injury.
Cumulative Trauma Disorders - Term used for injuries that occur over a
period
because of repeated trauma or exposure to a specific body part, such as
the back, hand, wrist and forearm. Muscles and joints are stressed,
tendons are inflamed, nerves pinched or the flow of blood is restricted.
Common occupational induced disorders in this class include,
epicondylitis (tennis elbow), tendinitis, carpal tunnel syndrome, low
back pain and neck pain. (Many of these syndromes can be helped through
Chiropractic care). :
_______________________________________________________________ Copyright 2001. This article is from the January 2001 issue of the Sarasota PC Monitor, the official monthly publication of the Sarasota Personal Computer Users Group, Inc., P.O. Box 15889, Sarasota, FL 34277-1889. Permission to reprint is granted only to other non-profit computer user groups, provided proper credit is given to the author and our publication. We would appreciate receiving a copy of the publication the reprint appears in, please send to above address, Attn: Editor. For further information about our group, email: admin@spcug.org/ Web: http://www.spcug.org/
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