The Covid Pandemic Affected the Physical Fitness of Primary School Children

Abstract Background: In spring 2020, the Sars-CoV-2 incidence rate increased rapidly in Germany and around the world. Throughout the next two years, schools were temporarily closed and social distancing measures were put in place to slow the spread of Covid-19. Did these restrictions affect children’s physical fitness? The EMOTIKON project annually tests the physical fitness of all third-graders in the Federal State of Brandenburg, Germany. The tests assess cardiorespiratory endurance (6-minute-run test), coordination (star-run test), speed (20-m sprint test), lower (powerLOW; standing long jump test) and upper (powerUP; ball-push test) limbs muscle power, and static balance (one-legged stance test with eyes closed). Children were tested in the falls from 2016 to 2021. Primary analyses included 83,476 keyage third-graders (i.e., school enrollment according to the legal key date, aged between eight and nine years) from 512 schools. Secondary analyses focused on two other groups of children, namely 22,761 older-than-keyage third-graders (i.e., OTK, delayed school enrollment or repetition of a grade, aged between nine and ten years), and 1,321 younger-than-keyage third-graders (i.e., YTK, early school enrollment or skipping of a grade, aged between seven and eight years). Linear mixed models took into account cubic secular trends, and differences between children and schools. Results: In keyage children, the Covid pandemic negatively affected a composite fitness score as well as cardiorespiratory endurance, coordination, and speed. We found a positive pandemic effect on powerLOW, but no evidence for pandemic effects on powerUP and balance. Cohen’s |ds| for the effects of each pandemic year ranged from 0.05 for cardiorespiratory endurance and powerLOW to 0.15 for coordination. In each pandemic year, keyage children exhibited developmental delays of 3.5 months for cardiorespiratory endurance and coordination, 2.1 months for speed, and a developmental gain of 1.6 months for powerLOW. The pandemic further increased developmental delays of OTK children, who already exhibited physical fitness impairments prior to the pandemic, in cardiorespiratory endurance, coordination, powerUP and balance. We found no evidence for differential pandemic effects for YTK children. Conclusions: The Covid pandemic negatively affected several physical fitness components in primary school children. Health-related interventions should prioritize the negatively affected physical fitness components.