Abstract
Objective. The present study compared the effects of upright and slouched sitting postures on the respiratory muscle strength in healthy young males. Methods. A total of 35 adult male subjects aged 18-35 years participated in this study. Respiratory muscle strength was determined by measurement of sniff nasal inspiratory pressure (SNIP) using a MicroRPM device in the upright and slouched sitting positions. The subjects were asked to perform the pulmonary function test including peak expiratory flow (PEF), forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and FEV1/FVC ratio at baseline. Body composition was also determined. Results. There was a significant difference of SNIP score between upright sitting and slouched sitting positions (P = 0.04). The mean difference of SNIP score between upright sitting and slouched sitting positions was 8.7 cm H2O. Significant correlations were found between SNIP in upright sitting and FEV1% predicted values [R = .651], SNIP in slouched sitting and FEV1% predicted values [R = .579], and SNIP in upright sitting and SNIP in slouched sitting positions [R = .926] (P < 0.05 for all). There were no significant correlations between SNIP scores, demographic variables, and other baseline clinical data (P > 0.05). Conclusions. The slouched sitting position had a lower SNIP score compared to upright sitting position suggesting a reduced diaphragm tension and movement as a result of altered body posture.