Active Schools in Chile: Impact on Fitness, Physical Activity, and Sports Participation

Impact of a School-based Intervention on Physical Activity, Fitness, and Sports Participation in Chilean Children: a Single-arm Cluster Study

Study Rationale:

Currently, a significant proportion of children in Chile do not meet recommended physical activity levels, which may adversely affect their health and development. The school environment provides an ideal setting to promote healthy habits. This study was designed to evaluate whether a school-based program incorporating physical activity, sports, and health education can improve physical fitness and increase the time children dedicate to physical activity practice.

Objective:

The primary objective of this study is to evaluate the impact of a two-year school-based intervention on physical activity levels, muscular fitness (measured by upper body, lower body, and abdominal muscular strength), and sports participation among Chilean schoolchildren.

How the study works:

This is a single-arm cluster intervention study incorporating a pre-post design. Participating schools were allocated in a specialized program focused on physical activity and the promotion of sports practice throughout two school years.

What was measured:

At baseline and after the two-year intervention, the following outcomes were assessed:

Physical Activity Levels: Measured via accelerometry; Muscular Fitness: Assessed through muscular strength tests, including upper limb strength (handgrip strength using a dynamometer), lower limb strength (standing long jump test), and abdominal strength (60-second curl-up test).

Sports Participation: Evaluated through self-reports of involvement in organized sports.

Researchers compared pre- and post-intervention data between the intervention to determine if children in the special program showed significantly greater improvements compared to those in the standard routine.

This is a a single-arm school-based intervention study designed to address the growing concern about low levels of physical activity among schoolchildren. Currently, a significant proportion of children in Chile do not meet global physical activity recommendations, which can lead to long-term health problems. Since children spend a large part of their day at school, this environment offers a unique opportunity to promote healthier lifestyles and sustainable physical habits.

The main objective of this intervention is to evaluate whether a comprehensive, two-year, multi-component program can effectively increase physical activity levels, improve physical fitness, and encourage sports participation. Unlike traditional programs that focus solely on physical education classes, this study uses a holistic approach based on three main pillars:

Active Recess: Transforming school breaks into opportunities for movement through structured and supervised activities, thus reducing sedentary time during the school day.

Enhanced Physical Education: Implementing high-engagement strategies within the existing curriculum to maximize benefits for students.

Health Education: Involving the entire school community-including students, teachers, and families-through workshops that highlight the importance of an active life and the practice of organized sports.

To ensure rigorous results, schools were randomly assigned to either an Intervention Group, which implemented the program over two school years (2024-2025). Children who did not participate in specific intervention activities continued their usual school routine and regular physical education classes; however, they were not considered a control group for analytical purposes.

The program's effectiveness was evaluated through a pre-post analysis. Using high-precision tools such as ActiGraph accelerometers for objective movement tracking and standardized muscle strength tests, researchers monitored changes in children's physical health. Additionally, the study investigates the frequency of sports participation to verify whether a more active school environment leads to greater interest in organized sports.

Ultimately, this study aims to provide evidence-based strategies that can be replicated in other schools in Chile and in similar contexts, contributing to the formation of a healthier and more active future generation.

Inclusion Criteria:

• Students enrolled in the third grade of elementary school at the selected schools.
• Minimum enrollment period of at least one year at the current school.
• Residing in the same municipality where the school is located.
• Open to all students regardless of migration status.

Exclusion Criteria:

• Students following any type of restrictive diet related to previously diagnosed chronic diseases.
• Diagnosis of chronic conditions that require dietary or physical limitations (e.g., diabetes, celiac disease, renal disease, among others).