Association of School Social Status with COVID-19 Pandemic-Related Changes and Post-Pandemic Rebounds of Children's Physical Fitness.

Background: In a recent study, we examined Covid-19 pandemic effects on the physical fitness of German third-graders tested between 2016 and 2022. The present report includes new data from 2023 to examine whether there were post-pandemic rebounds in the negatively affected fitness components, and whether pandemic and potential rebound effects differed by school social status.

Methods: The EMOTIKON project annually tests the fitness of all third-graders in the Federal State of Brandenburg, Germany. Tests assess cardiorespiratory endurance (6-min-run), coordination (star-run), speed (20-m linear sprint), lower (powerLOW, standing long jump), and upper (powerUP, ball-push test) limbs muscle power, and static balance (one-legged-stance test). A total of 108,308 third-graders aged between 8 and 9.2 years from 444 schools were tested in the falls from 2016 to 2023. Linear mixed models, specified for a regression discontinuity design with random factors for child and school, estimated pandemic effects on the first day of school in the school year 2020/21 (i.e., the critical date), as well as cohort trends before and after the pandemic onset.

Results: Higher school social status was associated with better cardiorespiratory endurance, coordination, speed, and powerLOW. At the critical date, there were small negative pandemic effects in cardiorespiratory endurance, coordination, speed, and powerUP. Pandemic effects in speed and coordination were larger in schools with higher social status. Coordination and powerUP were characterized by a post-pandemic rebound, with slightly larger coordination rebounds for schools with higher social status. There was no evidence for rebounds of cardiorespiratory endurance and speed.

Conclusions: Absence of evidence for task-specific rebounds may indicate long-term consequences of pandemic-related movement restrictions. Lower cardiorespiratory endurance, coordination, speed, and powerLOW in schools with low social status may indicate the need for improved access to sports opportunities in these schools.