Fig. 1
Distributions of the baseline one-leg standing time with eyes closed across 249 air and spacecraft manufacturing workers of different ages. (a) Scatter plots with a fitted quadratic spline curve illustrating individual data points and a linear declining trend across ages. The number of participants achieving 30 s of one-leg standing test was 51 (20–29 years), 47 (30–39 years), 59 (40–49 years), 12 (50–59 years), and 1 (60–66 years). (b) Bar charts representing the mean one-leg standing times for each 10-year age category, highlighting a declining trend in static physical balance by age (P for trend < 0.001). The mean (standard deviation) of one-leg standing time with eyes closed was 28.5 (4.5) s, 26.9 (7.2) s, 24.1 (9.1) s, 19.4 (10.9) s, and 16.8 (14.2) s at 20–29 years (n = 62), 30–39 years (n = 61), 40–49 years (n = 92), 50–59 years (n = 30), and 60–66 years (n = 4), respectively. The error bars in the graph represent the 95% confidence intervals.
