Effects of increased functional residual capacity on finger-floor distance in healthy young adults

[Purpose] To investigate the effect of increased functional residual capacity on the finger-floor distance and to assess spinal curvature in the sagittal plane using the Spinal Mouse in healthy young participants. [Participants and Methods] Thirty-nine healthy volunteers (age=21.2 ± 0.8 years) participated in this study. The finger-floor distance was used to measure trunk flexion and was recorded at the resting expiration level and at 2 different functional residual capacity levels: 1,000 and 2,000 ml air inhaled at the resting expiration level. Spinal curvature morphology was evaluated using the Spinal Mouse in the sagittal plane when flexion was completed under the 2 increased functional residual capacity and resting expiration level conditions during finger-floor distance measurement. Finger-floor distance and spinal curvature were assessed according to functional residual capacity using one-way repeated measures analysis of variance and post-hoc analysis. [Results] Significant effects and differences were found for the finger-floor distance under all conditions. No significant effect was found for spinal curvature. [Conclusion] An increase in functional residual capacity may decrease trunk flexion. This correlation might also be observed in patients with chronic obstructive pulmonary disease.