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VDT ergonomics: The effects of selected trunk and cervical angles upon subjective reports of discomfort and upon eledromyographic readings in the upper trapezius

1 May 1988


In order to provide physical therapists with more functional methods of postural correction in persons with neck pain associated with video display terminal (VDT) use, the effects of varying low back angles and head/neck angles on 1) muscular contraction levels in the upper trapezius as measured by EMG biofeedback 2) the amount of EMG level increase after five minutes of work at a VDT, and 3) subjective reports of comfort after five minutes of work in each of the positions were studied. Seventeen health volunteers were tested in a prospective experimental design. Each subject was tested in five different seating positions at a VDT for five minutes, with eight minutes of rest in between each test.

Results of the study showed three positions with initial and end EMG readings that were either lower or not significantly greater than those taken in a neutral position. Position four, a position in which the low back is reclined posteriorly and the head is inclined anteriorly, showed the lowest number of subjective reports of discomfort.

Further research is needed to discover how frequent shifting or changing of one's position over long periods of work at VDT's will affect one's EMG levels and/or subjective complaints.


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