The COVID-19-related closing of schools and sport facilities resulted in major changes to daily routines worldwide. It was the aim of this study to investigate the impact of COVID-19-related mitigation measures on the health and fitness status of primary school children in Austria. Seven hundred and eight primary school children (7-10 years old) participated in the longitudinal study. Data on height, weight, waist circumference, and fitness were collected before (September 2019) and during the course of the COVID-19 pandemic (June 20, September 20, March 21, June 21). A significant increase in EQUI BMIAUT (ηp2 = 0.087) and significant changes (ηp2 = 0.355) in waist circumference were found. Cardiorespiratory endurance (ηp2 = 0.440) and action speed (ηp2 = 0.221) decreased dramatically following lockdowns/school closures. In contrast, muscle strength showed no significant changes. The COVID-19-related mitigation measures intended to contain a communicable disease resulted in an acceleration of the pre-existing pandemic of overweight and obesity. The adverse combination of increasing BMI and the loss of physical fitness is likely to result in long-term negative effects on the health status of growing and developing individuals. Health professionals should therefore not only support further longitudinal observations of this "non-communicable disease" but also support intervention programs to reverse this worrying side-effect of COVID-19-associated containment policies.
Keywords: COVID-19; body mass index; cardiorespiratory endurance; children; health-related fitness; physical fitness; school; waist-to-height ratio; weight classification.