Abstract

The purpose of this study was to investigate changes that occur in pulmonary function when postural changes in the sagittal plane are made in a seated position in students. This cross sectional analytical study was done randomly on 20 boys from Iran, and the results of a forced expiratory manouvre in these young healthy subjects were compared according to body posture. Twenty able-bodied studentsboys (age 13.5±1.09 yr, height 158.25±5.65 cm and weight, 50.45±7.02 kg), participated in this study. Standard spirometric measurements forced vital capacity (FVC), forced expiratory volume in 1 s (FEV₁) and peak expiratory flow(PEF) were taken for each subject in each of 3 sitting postures: (normal, slumped and kyphotic) and standing posture. A repeated measure ANOVA and a paired t test indicated that FVC and FEV₁ value in standing posture was significantly higher than other sitting postures. In slumped sitting, FVC, FEV₁ and PEF significantly decreased from other sitting posture. But there was no significant difference for FVC, PEF and FEV₁ between the normal and kyphotic sitting postures. The results showed that FVC, FEV₁ and PEF as importance index in health of pulmonary system function, was affected by sitting posture, particularly in slumped sitting posture. Also student should prevent slumped sitting posture.

Key words: Pulmonary function, sitting, forced vital capacity, forced expiratory volume in 1 s, peak expiratory flow.