In April 2020, the Japanese government declared a state of emergency due to the novel coronavirus disease (COVID-19). Schools were closed and a stay-at-home order was issued in April and May 2020. This before-and-after study aimed to measure the effects of these COVID-19-related restrictions on physical function among Japanese children. The study included children aged 6-7 years, enrolled before and after the emergency declaration. Their body fat percentage, single-leg standing time, Gait Deviation Index score, and history of falls were compared. There were 56 and 54 children in the before and after groups, respectively. Children in the after group had a higher body fat percentage (p = 0.037), shorter single-leg standing time (p = 0.003), and a larger number of falls per month (p < 0.001) than those in the before group. In the logistic regression analysis, children in the after group had a significantly shorter single-leg standing time (odds ratio (OR): 0.985, 95% confidence interval (CI): 0.972-0.997, p = 0.013), a greater number of falls per month (OR: 1.899, 95% CI: 1.123-3.210, p = 0.017), and a higher body fat percentage (OR: 1.111, 95% CI: 1.016-1.215, p = 0.020) than those in the before group. The COVID-19 emergency restrictions had a negative effect on children's physical function, especially on balance.
Keywords: COVID-19; Gait Deviation Index; Japan; balance; body fat; pandemic response; physical health; restrictions; single-leg standing time.