Start Early – Healthy Through Life: Exercise and Prevention in Childhood and Adolescence

Physical activity is medicine – but only if it becomes part of everyday life. What sounds simple is in reality a challenge for many children and adolescents. Epidemiological evidence is clear: in Germany, only a fraction of children meet the WHO’s recommendations for daily physical activity. According to recent data from the MoMo Studygroup (8), only 22% of boys and 21% of girls aged 4 to 17 years reach the recommended 60 minutes of moderate to vigorous physical activity per day by the WHO in 2020. At the same time, physical inactivity, screen time, and obesity are rising sharply even in early childhood (3,4). However, emerging evidence suggests a simultaneous rise in physical inactivity, excessive screen time, and obesity rates, raising alarms about the long-term health implications for future 
generations (1, 10).

Physical activity not only supports motor development, but also contributes positively to cognitive performance, emotional well-being, and social behavior (2). It plays a key role in bone health, immune function, and metabolic regulation.

Particularly noteworthy is the link between physical fitness and perceived health, as shown by recent longitudinal findings (5).

In short: physical activity is a key resource for healthy development – yet for many children, it is not an inherent part of their daily routine.

To advance prevention efforts in childhood, we need reliable, high-quality data that identify key areas for action (7)—and research that goes beyond problem descriptions to support practical, real-world solutions. Germany already has a strong foundation in this regard, supported by a range of national and regional studies. These include, for example, the MoMo (Motorik-Modul) Study , the KOMPASS Study, the Fitness Barometer, the COMO Study, the EMOTIKON Study, “Berlin hat Talent”, the genEffects Study, and the Report Card of Physical Activity to name just a few. These projects provide essential insights into physical fitness, physical activity, psychosocial determinants, and social inequalities in youth.

However, to ensure long-term impact, these studies must receive stronger institutional support, interconnectivity, and sustained funding. At the same time, we must enhance the potential of existing data sources. New technological developments – including artificial intelligence (AI), advanced data mining, pattern recognition, and harmonized metadata structures – offer novel opportunities to reinterpret and repurpose existing datasets across disciplines. Data pooling beyond individual studies, standardization of variable definitions, and open-access strategies can elevate movement research to a new methodological level (6). These tools hold enormous promise for both fundamental and applied public health research.
This issue of the German Journal of Sports Medicine presents current contributions from the field of epidemiological research in pediatric physical activity – illustrating what we know so far, and where we need to act.

Active School Travel: More Than Just Infrastructure
The study by Estorff et al. within this special issue applies a socio-ecological model to examine individual, familial, and environmental factors influencing Active School Travel among primary school children. With a particular focus on parental perceptions and behaviors, the findings emphasize that promoting active mobility should not rely solely on infrastructure improvements. Parents and families represent critical resources for fostering independent mobility and daily physical activity, and should therefore be more actively involved across various levels of social influence than has previously been the case.

Social Inequalities and Physical Activity Behavior
Another contribution, based on data from the KOMPASS study, highlights the significant role social inequalities play in children’s physical activity behavior, as well as in parental and environmental support factors. It is overly simplistic to base interventions solely on the individual socioeconomic status of parents. In light of social disparities, the article by Ebert et al. within this special issue shifts the focus toward the neighborhood’s socio-spatial environment and analyzes both children’s movement behavior and relevant support structures. In the future, a socio-spatial neighborhood indicator could help to more precisely target movement promotion efforts where children and their families face multi-level social disadvantages, thereby fostering more equitable opportunities for healthy development.

Muscular Fitness and Self-Rated Health
The article by Klein et al. within this special issue explores the link between muscular fitness and self-rated health among children and adolescents. If children with below-average muscle strength are at significantly higher risk of perceiving their health as poor, this underscores the importance of strength training and muscle-enhancing activities for the current and future well-being of young people. Consequently, physical activity guidelines should explicitly include such forms of training. However, to formulate specific and differentiated recommendations, robust longitudinal data are needed—data that also integrate psychological, behavioral, and environmental factors to better understand the complex interrelations with child health. This represents a considerable challenge.

Selection Bias in Population-Based Studies
The COMO study by Niessner et al. (4) addresses the issue of selective sampling and attrition in panel surveys. Especially in the context of the COVID-19 pandemic, developing strategies to enhance representativeness is crucial. The study outlines innovative recruitment methods, the use of reminders, and the calculation of design and adjustment weights to minimize bias. These methodological approaches are essential for ensuring the validity and comparability of population-based studies, and for enabling fair and targeted prevention efforts

In-silico Approaches in Sports Epidemiology
A rapid review by Niessner et al. within this special issue explores the potential of computer-based modeling and simulations (in-silico methods) for physical activity prevention in childhood. While these approaches are already well established in other scientific disciplines, their application in sports epidemiology remains in its infancy.

The current contributions demonstrate: we have data, methods, and scientific expertise – but we need to translate this into societal change. This requires long-term support for surveillance and intervention research, close collaboration between science, education, and policy, and the political will to improve structural conditions. Moreover, we must leverage digital innovations and promote their widespread application in prevention research. Start early, work across disciplines, and act within real-life settings – this remains the guiding principle. The data is there. The challenges are known. What we lack is the decisive action to anchor physical activity as a basic pillar of healthy development. If we succeed in making movement a natural part of daily life from early childhood onward, we not only improve public health outcomes – we also strengthen well-being, equity, and the future potential of entire generations.