Change in biomechanics of sitting posture affects the pulmonary function

ABSTRACT The objective of this study was to characterize the postures induced by two different chair-desk systems and analyze their effects on lung function. This was a cross-sectional, descriptive study of single subject with intra-series type analysis (A-B, B-A) during consecutive days of data collection. Fifteen volunteers participated using two chair-desk systems: conventional (A) and experimental (B). Postural evaluation was performed in both systems using photogrammetry. These images were analyzed using AutoCAD® 2010, estimating the average position of the joint angles of individuals in each system. These values were analyzed verifying the averages in each posture. Postural and respiratory data were compared by checking whether the different positions adopted by the participants resulted in changes in the spirometry values. Conventional chair-desk system promoted two different postural patterns, considering that one presented joint angles similar to experimental system, with similar spirometry results and the other presented body angles according to the reference of standards and spirometry results significantly lower in FEV1, FEV1/FVC and FEFmax. Experimental system differed from values of literature in standing posture only in FEFmax, suggesting similarity of postural situation. It was concluded that the experimental furniture proved a tool capable of benefiting respiratory function in sitting posture and may be an option to benefit people in special conditions such as pregnant women, obese individuals and people with chronic pulmonary diseases.