Effect of different sitting postures on lung capacity, expiratory flow, and lumbar lordosis.
OBJECTIVE
To investigate the effect of sitting posture on lung capacity and expiratory flow (LC-EF) and lumbar lordosis.


METHODS
Repeated measures on 1 group of subjects in 4 postures.


METHODS
Laboratory.


METHODS
Seventy able-bodied volunteers.


METHODS
Postures were assumed randomly: normal, with full ischial support and flat lumbar support; slumped, with the pelvis positioned in the middle of seat while leaning against the backrest; against the back part of the seat without ischial support (WO-BPS), with partially removed ischial support and an enhanced lumbar support; and standing.


METHODS
For LC-EF, forced vital capacity, maximum forced expiratory flow, forced expiratory volume in 1 second, and peak expiratory flow; and lumbar lordosis.


RESULTS
All LC-EF measures in standing were significantly superior to those in slumped and normal sitting, and 4 measures were significantly higher than in WO-BPS. In slumped sitting, LC-EF significantly decreased from that in normal sitting. WO-BPS sitting significantly increased 4 of the LC-EF measures from those in the normal sitting. Lumbar lordosis was the highest in standing and progressively decreased in WO-BPS, normal, and slumped sitting.


CONCLUSIONS
Slumped sitting significantly decreased LC-EF and lumbar lordosis. Because it increases the lumbar lordosis and promotes LC-EF, the WO-BPS posture may be a better seating option for people sitting for a prolonged time.
Lin
Fang
F
Department of Physical Therapy and Human Movement Sciences, Northwestern University, Chicago, IL, USA.
Parthasarathy
Sriranjani
S
Taylor
Susan J
SJ
Pucci
Deborah
D
Hendrix
Ronald W
RW
Makhsous
Mohsen
M
D000328:Adult; D000704:Analysis of Variance; D005260:Female; D006801:Humans; D008141:Lordosis / Q000503:physiopathology*; D008159:Lumbar Vertebrae / Q000502:physiology*; D008176:Lung Volume Measurements; D008297:Male; D008875:Middle Aged; D010366:Peak Expiratory Flow Rate / Q000502:physiology*; D011187:Posture / Q000502:physiology*; D014910:Wheelchairs