A Study on Gender and Vision Differences in Terms of the Center of Gravity Sway in Adults’ Standing

Abstract

In a standing posture, the human center of gravity shaking (CGS) changes constantly; its variation increases depending on the disturbance stimulus. When eyes are closed, the standing posture becomes unstable because of restricted information feedback from visual cues. In this investigation, we assumed that gender differences in the CGS variables and their relationships differed when the eyes were open and when they were closed. We examined the gender differences in the CGS variables and the relationships among them when the subjects' eyes were open and then closed while standing. Do the gender and vision differences exists in terms of gravity sway with 81 healthy participants aged 21-32 years when their eyes were open and shut? The participants maintained a Romberg posture (standing posture with feet closed) for 1 min on the measuring equipment in two different conditions: with eyes opened as well as closed. The x-axis, y-axis, total trajectory lengths, and outer peripheral area (general sway variable: GS variable) were input to a computer with a sampling rate of 20 Hz. A peak power frequency (peak) and peak power spectrum value (power) appeared in three directions (X, Y, and R) and were computed as power spectrum variables (PS variable). The measurement order was randomized in both conditions. We performed three trials for both conditions with a 1min rest between each trial. The mean of the last two trials became the evaluation variables. A two-way analysis of variance and multiple comparison tests resulted in the following: 1) the y-axis trajectory length had a higher value for men with eyes closed and in both genders with eyes closed; 2) the total trajectory length had a higher value for men under both conditions and in both genders with eyes closed; 3) the outer peripheral area had a higher value only for men with closed eyes; 4) the x-axis trajectory length and x-direction power had higher values for men and those with closed eyes; 5) the peak and power of x-direction and the peak of r-direction also had higher values for eyes closed than for open conditions; and 6) the power of x-, y-, and r-directions had higher values in men than in women. The results from the correlation analysis showed that the GS variables exhibited mutually significant correlations during and between both conditions in both genders. The PS variables showed significant correlations between y-and r-direction powers in both genders with eyes open and closed, only in the x-direction power between eyes open and closed in men, and in only the y-direction peak between eyes

Effects of Intensive Up-to-Exhaustion Walking Exercise on the Center of Gravity Sway

“…A favorable ICC greater than 0.79 was obtained for all variables. Thus, the mean values obtained from the last two measurements after the initial 3-min sitting rest were used as the represented values for both groups [24].…”