Postural-ventilatory coordination changes related to changes in base of support in upright position in healthy individuals

Abstract

Objective: In this study, we investigated the effects of modified postural demand through changes in subjects’ base of support (BOS) on the ventilatory control and postural-ventilatory coordination. Methods: Ten healthy subjects (6 females) were
asked to sustain an upright stance with the feet apart (FA) or in semi-tandem (ST) BOS. Center of pressure (CP) coordinates was acquired through a force platform, along with the thoracic horizontal expansion, measured through a strain gauge coupled
in an elastic belt positioned over the mid-portion of subjects’ sternal bone. Directional stability index in anterior-posterior direction (DSIAP, summed variance of CP position and velocity), thoracic expansion coefficient of variation (CV), and measures of cross correlation coefficient between CPAP displacement and thoracic expansion [peak cross-correlation (CCPEAK) and time relation (TR)] were computed. Paired t-test was used for BOS comparison, along with Cohen’s d as effect size measure. Results: Significant differences between were found for DSIAP (P<0.001, d=-3.804), but not for CV (P=0.887, d=0.049), suggesting increases in postural sway from FA to ST stance, without changes in thoracic expansion. Additionally, significant differences were found for CCPEAK (P=0.014, d=-1.042), but not for TR (P=0.754, d=-0.108), with a higher postural-ventilatory coupling in ST stance, without temporal relation changes. Conclusion: In summary, changes in postural sway were followed by modification in ventilatory patterns, suggesting a bidirectional pathway for regulation of postural and ventilatory control.