Physical fitness (PF) of children and adolescents is an important resource for their future health. Population-based studies, however, rarely report secular changes of PF, although monitoring of these is crucial to deriving information for adequate interventions. This review aims to report trends in PF of children and adolescents. A literature search was conducted in PubMed in July 2019. Cohort studies published in English allowing statements to be made on trends in PF by comparing youth between the ages of four and 18 years were included. The review identified 24 studies from 16 countries meeting the inclusion criteria, with an overall sample size of more than 860,000 children and adolescents. Through a standardized quality assessment tool, we classified two studies as strong, 21 as moderate, and only one as weak. We analyzed specific secular trends separately for the five different dimensions: endurance, strength, speed, flexibility, and coordination. The majority of studies report a decline of PF over time; however, a few studies report conflicting results. Performance in endurance, strength, and flexibility decreased over time, whereas there was no consistent trend reported for speed and coordination. Overall, there is no international standard on examining and reporting changes or secular trends in PF of children and adolescents, and comparability of studies is limited due to heterogeneous conditions of conducting and analyzing PF tests. Consequently, standardized and consistent international monitoring should be implemented.

Interventions to promote physical activity (PA) in children, adolescents and young adults based on social-cognitive theories often fail to increase PA. In recent years, affect-based approaches have gained interest, but the current state of research is not sufficiently reported. Therefore, a systematic review about the influence of interventions to promote positive affect and PA enjoyment and PA in children, adolescents and young adults was conducted. Literature searches were carried out including studies published between September 2009 and April 2019. Intervention studies targeting healthy children, adolescents or young adults and measuring enjoyment and PA were included. Thirteen studies met the inclusion criteria, including five group-based PA interventions, three multi-component school interventions, two internet-based interventions and three exergaming interventions. Most studies use multiple components in their intervention. Group-based PA programs incorporating task-oriented teaching styles and opportunities for voluntary PA are most consistently associated with positive findings. This review shows moderate evidence of interventions for children, adolescents and young adults being effective in increasing enjoyment and PA. Besides physical education and comprehensive school interventions, heterogenous intervention designs limit the comparability of studies. Future research should focus on theory-based, multi-component interventions with mediator analyses.

With the beginning of the COVID-19 pandemic in December 2019, each country has developed strategies to try to control the virus. The restrictions and subsequent consequences also limited the possibilities and structures for being physically active. Therefore, the aim of this study was to examine changes in physical fitness in a cohort that was investigated over an extended period. Physical fitness testing was conducted with the IPPTP-R in a primary school from a small rural community annually since 2012. Mean values of test items were calculated for each cohort. We conducted an ANCOVA to examine the differences between cohorts PreCOVID and 2020 as the first year of the COVID-19 pandemic, and between PreCOVID and 2021 as the second year of the COVID-19 pandemic. Overall, no evidence for a negative effect of the COVID-19 pandemic on physical fitness in children between the ages of 7 and 9 years was found. In strength tests, performances increased when comparing the PreCOVID cohort and COVID-19 cohorts (Push-Ups: p < 0.001, ηp2 = 0.032; p = 0.017, ηp2 = 0.006). No evidence for a change was found for endurance (6-min Run: p = 0.341, ηp2 = 0.001; p = 0.267, ηp2 = 0.001. The rural community maintained physical fitness despite restrictions and limitations through the environmental circumstances. Considering this, it is a positive example of how adequate long-term efforts promoting physical fitness make an impact and an active friendly environment helps to overcome COVID-19 pandemics limiting the structures for being physically active.

Introduction: Motor Performance (MP) in children is an important resource for their future active lifestyle and health. Monitoring of MP is crucial to derive information of trends and to implement specific programs on the base of current MP levels. A variety of MP assessment tools exist, making it difficult to determine a “gold-standard” for assessment and to compare the findings. In Germany, the German Motor Test 6–18 (GMT 6–18) and Kinderturntest Plus 3–10 (KITT+ 3–10) are widely used MP assessment tools. The aim of this paper is to show which key questions can be answered within the context of a best practice example of a MP assessment tool and what can be derived from this for a practical application (the Fitness Barometer).Methods: The raw data of the Fitness Barometer was collected with the MP assessment tools GMT 6–18 and KITT+ 3–10 from 2012 through 2020. Data was pooled anonymously with the e-Research infrastructure MO|REdata and categorized into percentiles for MP and BMI. Overall, we included data of 23,864 children for the statistical analyses. T-tests for independent samples, percentage frequency analysis, descriptive statistics (chi- square-test) and single analysis of variance were conducted.Results and Discussion: Children tested reached a mean value of 57.03 (SD = 18.85). Of the sample, 12.7% children were overweight or obese and there is a significant difference between age groups [χ(4)2 = 178.62, p &lt; 0.001, Cramer V = 0.09; n = 23.656]. The relationship between BMI category and mean value of MP was significant [F(4,19,523) = 224.81, p &lt; 0.001]. During 2020, the year of the COVID-19 pandemic, mean value of endurance and speed decreased [Welch's F(1,573) = 8.08, p = 0.005; Welch's F(1,610) = 35.92, p &lt; 0.001]. The GMT 6–18 and KITT+ 3–10 are valid, objective, reliable, and economic MP assessment tools for monitoring MP levels and derive added practical value. Specific programs and interventions should focus on the findings of these. The Fitness Barometer is a best practice example how a standardized assessment tool of monitoring MP point to trends on which practical evidence-based suggestions can be derived with many various partners and expertise.