Documented impact of a school-based physical activity programme
The Fit First programme improves schoolchildren’s fitness, body composition and health profile – also among 10–15-year-old girls and boys.
Most Danish schoolchildren are not as physically active as recommended. According to the Danish Health Authorities and the World Health Organization (WHO), children and youth should engage in at least 60 minutes of moderate-to-vigorous physical activity per day – yet Danish studies show that only one in three 11–15-year-olds meet the guidelines.
This can negatively impact their health, learning, and overall wellbeing. However, a series of new studies from the University of Southern Denmark (SDU) now demonstrate that schools can contribute significantly to the fitness and health profile of their pupils and enhance physical activity enjoyment.
Fit First works – even for older pupils
Researchers at SDU have previously shown that the school-based physical activity programme Fit First, with three 40-minute lessons per week, is effective for younger children. Now, after testing more than 4,000 pupils in secondary school, they can document that Fit First also has a strong impact among 10–15-year-old girls and boys.
Three questions for Peter Krustrup about the studies:
What did you investigate? The effects of the Fit First programme on physical fitness, body composition, health and wellbeing among 5,500 children in Denmark and 400 children in the Faroe Islands aged 7–15 years.
What are the key findings? Fit First promotes enjoyment of physical activity and improves fitness, body composition and health in all age groups. Wellbeing was maintained.
What can the results be used for? In my opinion the programme is ready for nationwide implementation and can serve as a bridge to leisure-time sport clubs – especially for children who might not otherwise find their way into sports communities.
– Our new research shows that Fit First improves cardiovascular fitness, body composition and overall health profile for pupils in secondary school. This means we can now confidently state that Fit First is a robust, evidence-based physical activity concept that works across all grades in elementary school, says Professor Peter Krustrup, research leader at the Sport and Health Sciences Research Unit, Department of Sports Science and Clinical Biomechanics.
The programme has been developed by SDU, the Danish Sports Confederation (DIF) and Team Denmark, and includes 390 teaching lessons based on 26 different sports, evenly distributed across primary school and secondary school. Fit First gives children and adolescents a motivating introduction to a diverse range of sports they may not otherwise encounter.
– Fit First builds a bridge between school and leisure-time sport clubs. Children are introduced to many different sports, increasing the likelihood they want to be active in leisure-time, says Karin Ingemann, Head of Development at the Danish Sports Confederation.
Physical activity in schools – but wellbeing needs more
While Fit First increases enjoyment of movement and improves physical fitness and health profile, the studies show that wellbeing – especially among teenage girls – appears to be more closely linked to participation in community sport during leisure time.
– We see that Fit First creates a strong framework for physical activity during the school day, but our data also show that girls who are active in sports clubs – particularly in team sports – report higher physical and mental wellbeing. Together our findings emphasize the combined effects of school and leisure time physical activity, explains Peter Krustrup.
How the studies were conducted
The Fit First studies were carried out as controlled cluster-randomised intervention trials and cross-sectional analyses involving over 5,500 children aged 7–15 across more than 100 schools. In the intervention trials, pupils were allocated to either Fit First groups or control groups receiving standard physical education.
The programme typically consisted of three 40-minute lessons per week of intense, varied school-based physical activity, drawing on 26 different sports. Physical fitness was assessed using standardised tests including the Yo-Yo IR1C (intermittent running), standing long jump, handgrip strength, blood pressure and resting heart rate. Body composition was measured using bioelectrical impedance (InBody270), including fat percentage, muscle mass, weight and BMI.
Wellbeing and quality of life were assessed using the internationally validated KIDSCREEN-27 and KIDSCREEN-52 questionnaires for children and adolescents. All data was gathered both before and after the interventions. In the cross-sectional studies, results were combined with pupils’ leisure-time sport participation.
Furthermore, the studies reveal that girls in this age group are more prone than boys to dropping out of community sport and tend to experience lower wellbeing, when not engaged in leisure-time sports club activities.
– Fit First can help open the door to community sport – and that’s crucial, especially for girls, who we know are more likely to drop out. School can offer them a first encounter with sport that is both safe and motivating, adds Karin Ingemann.
The research behind the results
The Fit First studies were conducted as controlled cluster-randomized intervention trials with pre- and post-intervention assessments. Researchers measured children’s physical performance, resting heart rate, blood pressure, fat percentage, muscle mass, muscle strength and motor function – as well as their wellbeing – using validated international questionnaires (KIDSCREEN-27 and KIDSCREEN-52).
– After 13 years of development and research, we now have a well-documented and practically applicable Fit First concept for all grades in elementary school. The next step is implementation – in close collaboration with municipalities, schools and sports organisations, says Peter Krustrup.
Ready for nationwide rollout
The research project Fit First For All combines physiological research, behavioural science and implementation research at SDU and is supported by the Novo Nordisk Foundation According to Peter Krustrup, the results are now sufficiently strong for nationwide implementation.
This week, researchers held three Fit First For All seminars, featuring the launch of research findings, practical demonstrations and a panel debate on implementation. The seminars were supported by the Ole Kirk’s Foundation.
How Fit First can be used in practice
Fit First is designed for easy integration into the school day, without requiring special equipment or facilities beyond those typically used in PE. The programme consists of three weekly 40-minute sessions delivered as part of regular teaching – usually during PE lessons, activity breaks or supporting teaching time.
Lessons follow a didactic concept based on 26 different sports, including pairbased or small-sided team game activities. They are designed to be intense, engaging and motivating, with high exercise intensity and active participation from all pupils.
Programmes are delivered by the school’s own teachers or educators, who receive an training course and teaching materials developed by the research team. The material includes detailed lesson plans, pedagogical guidance and ideas for differentiation so activities can be adapted for different age groups and ability levels.
The studies show that implementation works best when school leadership supports the initiative and when teachers have the opportunity to plan and test the activities together. Experiences from previous participating schools suggest that the programme can be successfully delivered without external support – provided that staff are well trained and familiar with the principles of the concept.
Studies behind Fit First For All
Fit First in the Faroe Islands – primary and secondary school (ages 7–16)
Duration: 10 weeks
Participants: Grades 1–9, 360 pupils
Effects: Marked improvements in fitness and body composition, and a slight improvement in wellbeing.
Published in: Frontiers in Public Health Link: https://www.frontiersin.org/journals/public-health/articles/10.3389/fpubh.2024.1419824/full og Frontiers in Psychology – Health Psychology Section Link: https://www.frontiersin.org/journals/sports-and-active-living/articles/10.3389/fspor.2025.1533723/full
Duration: 10 weeks
Participants: 1,417 pupils in Grades 6–9
Effects: Lower resting heart rate in the Fit First group, indicating improved cardiovascular fitness.
Published in: Journal of Sports Sciences: https://www.tandfonline.com/doi/full/10.1080/02640414.2025.2505380#abstract
Design: Cross-sectional study of 1,333 pupils, Grades 6-9, age 12-15
Results: Pupils active in leisure-time sports had superior physical fitness, health profile and better physical and mental wellbeing. Girls in team sports and multisport had the highest scores. However, many girls dropped out of organised leisure-time sport in their teenage years.
Published in: PLOS ONE
: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0330950
Duration: 20 weeks
Participants: 1,357 pupils in Grades 2–3 and their teachers, across 68 classes in 27 schools
Results: Fit First proved suitable for implementation and received medium to high scores for acceptability, relevance and feasibility.
Published in: Frontiers in Sports and Active Living: https://www.frontiersin.org/journals/sports-and-active-living/articles/10.3389/fspor.2025.1504494/full
Another five peer-reviewed articles are in the pipeline, covering the effects of Fit First over a full school year (40 weeks) among 10–12-year-olds (Fit First 20) and 12–15-year-olds (Fit First Teen). These findings include that 69% of pupils reported high enjoyment of movement through Fit First, and 31% reported moderate enjoyment. The articles are published as a part of two PhD theses at SDU, scheduled for public defence in the first quarter of 2026, and have been accepted for presentation at scientific conferences.
Mød forskeren
Peter Krustrup is a Professor and Head of Research at the Department of Sports Science and Clinical Biomechanics. His field of research is sport and health. He is also affiliated with the Danish Institute for Advanced Study (DIAS).