Effects of breathing movement on the reduction of postural sway during postural-cognitive dual tasking

An execution of cognitive processing interferes with postural sway during quiet standing. It reduces sway variability in young adults, but the mechanism is not clear. To elucidate the mechanisms, we focused on breathing in the present study. The purpose of this study was to clarify whether a decrease in postural sway amplitude during a postural-cognitive task is related to the change in breathing movement. The center of pressure (COP) was recorded via a force plate and the motion of leg joints (ankle, knee, and hip), and breathing movements were measured with a 3D motion capture system in quiet standing and standing with cognitive (mental arithmetic) task conditions. The change ratios of each variable from the quiet standing condition to the cognitive task were also calculated. In the results, the breathing rate was faster and the amplitude of breathing movement smaller when subjects performed the cognitive task. A significant positive correlation (r = 0.75, p < 0.01) was found betwe...