*4.1. Summary and Evaluation of the Results*

For the test item 20 m dash, the statistically significant differences had no practical relevance. Speed levels remained stable in the COVID-19 cohorts. Comparing the results for balancing backwards, we see that the previously constant performance increased in the measurement for COVID2, but remained the same in COVID1. In addition, representing the dimension coordination, jumping sideways also had a peak in COVID1, but the same stable level before and after. Thus, no evidence for an effect was found. Pombo et al. [31] also reported no inferior results for jumping sideways in 6–9-year-old Portuguese children tested before and after the COVID-19 lockdown. However, from December 2019 to September 2020, there was an overall general trend of shifting to a lower quartile [31]. An increase in children's performance categorized as "very low" in the 20 m shuttle run was also observed by Basterfield et al. for participants in a primary school in England [25]. Flexibility performance in the stand-and-reach test did not differ significantly between the three cohorts. The rising trend of recent years was not stopped by the pandemic. In contrast, there was a negative effect in the study in England, which measured a decrease of 1.8 cm between October 2019 and November 2020 for 8–10-year-old children [25].

The number of performed push-ups was significantly higher in both COVID cohorts compared to the overall 2012–2019 pre-pandemic cohort, which was also reflected in the results of the sit-ups test. There was no evidence that upper body strength levels were influenced negatively by COVID-19 restrictions and consequences. While Wahl-Alexander and Camic [27] found a decrease of 35.6% for push-ups and 19.4% for situps in children with a mean age of 9.6 years between summer 2019 and 2020, other results are consistent with our findings. The same was found for leg strength, which was measured using the standing long jump test. Performance levels increased significantly in the COVID1 cohort, but then remained stable again compared to the PreCOVID cohort, and showed no evidence of negative effects. Basterfield et al. [25] and Wessely et al. [32] also reported a performance increase for standing long jump. This suggests that strength is

more resilient to negative effects of COVID-19 than other dimensions of physical fitness [25]. However, Chambonnière et al. [24] measured the standing long jump performance of 3rd and 4th graders in France for the period between 2020 and 2021 and found a decrease of 34.7 cm. This is consistent with another study examining the same age between 2019 and 2020 [31].

The analysis for endurance revealed no significant difference between the cohorts and no effect of the COVID-19 pandemic. The performance levels for the 6 min run were stable across the measured cohorts. Other studies that analyzed endurance found different effects [23,25,27,31]. Jarnig et al. [23], who also implemented the 6 min run, reported a decrease of 102 m in children aged 7-to-10 years old between September 2019 and September 2020 [23]. Two other studies performed the 20 m shuttle run to measure effects for endurance and reported 2.39 [24] and 3 [25] fewer shuttles in their second measurement point.
