Document Detail

The effect of a tilting seat on back, lower back and legs during sitting work.
MedLine Citation:
PMID:  10547952     Owner:  NLM     Status:  MEDLINE    
The purpose of this study was to examine the possible effects of a tilting seat on the back, lower back and legs. Ten healthy male subjects aged 22-28 performed word-processing operations while sitting on a chair for one hour under two different seating conditions: the rocking condition and the fixed condition. While the subjects were performing the task, measurements of lower leg swelling were taken using bioelectrical impedance plethysmography, and pain scores were recorded every five min for the neck, shoulders, back, lower back, hips and legs. Electromyograms (EMGs) of the back and lower back (at Th5-6, Th8-9, L1-2 and L3-4) were recorded every sec. In addition, the subjects were videotaped while using the rocking seat, in order to analyze the angle and frequency of seat tilting. At the end of the experiment, the subjects were asked to evaluate the two conditions with respect to localized fatigue and operational efficiency. There was no significant difference in lower leg swelling between the two conditions. EMGs were significantly different at Th5-6, Th8-9 and L1-2 between the two conditions. The rocking condition generated greater EMGs at Th5-6 and L1-2, whereas the fixed condition produced greater EMGs at Th8-9. The pain scores for the neck, shoulders, back and lower back were higher under the fixed condition, while those for the buttocks were higher under the rocking condition. The average tilting frequency was as low as 25.2 times per hour, with 15.6 times per hour for tilting angles ranging from 1 to 2 degrees, and 9.6 times per hour for tilting angles exceeding 2 degrees. As for the subjective evaluations of localized fatigue, seven of the ten subjects preferred the rocking condition, while two preferred the fixed condition and one subject had no preference. Thus, there was a significant difference in the subjective evaluations of the two chairs. These findings suggest that the rocking condition, in contrast to the fixed seating condition, reduced back and lower back pain as a result of its tilting capability. The results of EMGs suggest that the rocking condition reduced back and lower back pain by increasing the overall muscle activity of the back and lower back. The leg impedance measurements showed no effect of the rocking condition on the leg swelling, as compared with the fixed condition.
H Udo; M Fujimura; F Yoshinaga
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Industrial health     Volume:  37     ISSN:  0019-8366     ISO Abbreviation:  Ind Health     Publication Date:  1999 Oct 
Date Detail:
Created Date:  1999-11-18     Completed Date:  1999-11-18     Revised Date:  2004-11-17    
Medline Journal Info:
Nlm Unique ID:  2985065R     Medline TA:  Ind Health     Country:  JAPAN    
Other Details:
Languages:  eng     Pagination:  369-81     Citation Subset:  IM    
Department of Public Health, Hiroshima University School of Medicine, Japan.
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MeSH Terms
Edema / etiology,  prevention & control
Electric Impedance
Human Engineering
Low Back Pain / etiology*,  prevention & control
Occupational Health*
Word Processing

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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