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

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

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, physical fitness (measured by upper body, lower body, and abdominal muscular strength), and sports participation among Chilean schoolchildren.

How the study works:

This study is a cluster-randomized clinical trial incorporating a control group and a pre-post design. Participating schools were allocated into two groups:

Intervention Group: Participated in a specialized program focused on physical activity and the promotion of sports practice throughout two school years.

Control Group: Continued with the standard school curriculum and regular physical education classes for the same period.

What was measured:

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

Physical Activity Levels: Measured via accelerometry; Physical 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 and control groups to determine if children in the special program showed significantly greater improvements compared to those in the standard routine.

Study Overview

• Status: Completed
• Conditions: Physical Activity; Health Promotion; Child Health; Sports; Physical Fitness; Sedentary Behaviors
• Intervention / Treatment: Other: Regular Physical Education; Behavioral: Active Schools Program

Detailed Description

This study is a cluster-randomized clinical trial 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), or a Control Group, which followed the standard national curriculum.

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.

• Study Type: Interventional
• Enrollment (Actual): 209
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Chile
  • Santiago, Chile
    • Universidad de Santiago de Chile

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child
• Accepts Healthy Volunteers: Yes

Description

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).

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Other: Control Group; Students followed the standard Chilean school curriculum, including mandated physical education classes (twice weekly) and unstructured recess. This group did not receive any additional intervention, specialized equipment, or health workshops provided by the research team throughout the two-year study period. All school activities for this group remained consistent with the national educational guidelines.	Other: Regular Physical Education; Participants in the control group followed the standard Chilean school curriculum, as mandated by the Ministry of Education. This included the regular Physical Education program (typically two sessions per week) and standard school recess periods, without any additional structured physical activity, specialized equipment, or health education workshops provided by the research team. No specific intervention was implemented to modify physical activity levels, muscular strength, or sports participation patterns during the study period.
Active Comparator: School-based Intervention Program; Students participated in a two-year, multicomponent school-based program designed to promote physical activity and sports participation. The intervention consisted of three core elements: (1) Active Recesses, involving structured and supervised physical activities during school breaks; (2) Enhanced Physical Education, utilizing high-engagement pedagogical strategies; and (3) Health Education workshops for students and the school community focused on active lifestyles. All activities were integrated into the regular school calendar.	Behavioral: Active Schools Program; The intervention was conducted two to three times per week, depending on the specific schedule of each school. In addition to enhanced physical education classes, educational content related to the benefits of healthy behaviors was integrated across various academic subjects to increase students' awareness. During physical education classes, activities designed to maximize PA levels and improve muscular strength were implemented. Additionally, strategies to foster active recess were established, including the provision of equipment such as jump ropes, medicine balls, and resistance bands for recreational and playful activities. Specific areas were also organized for PA during breaks, featuring floor and wall markings for game and exercise stations, accompanied by instructional posters suggesting activities. These actions aimed to encourage movement and increase students' engagement in PA throughout the school day.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change from Baseline in the levels of physical activity.	Average daily minutes spent at different levels of physical activity, objectively measured using ActiGraph accelerometers worn over 7 consecutive days.	Baseline (Month 2-3) and End of Intervention (Month 27-30)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change from Baseline in Upper Limb Strength	Handgrip strength (absolute strength) will be assessed using a Smedley-type handheld dynamometer, with results recorded in kilograms (kg). The participants will perform the test in a standing position with their arms extended alongside the body. Following a demonstration and a familiarization trial, two measurements will be taken for each hand, alternating between the right and left sides to allow for adequate recovery. The final score for each participant will be calculated as the mean of the two trials for each hand.	Baseline (Month 2-3) and End of Intervention (Month 27-30)
Change from Baseline in Sports Participation Frequency	Measured by the Physical Activity Questionnaire for Children (PAQ-C), a self-reported instrument designed to assess general levels of physical activity, with a particular focus on participation in sports and organized activities. The full title of the instrument is the Physical Activity Questionnaire for Children (PAQ-C). It consists of nine items scored on a 5-point Likert scale. The final score is the mean of these items, ranging from 1 to 5, where higher scores represent greater involvement in physical activity and sports.	Baseline (Month 2-3) and End of Intervention (Month 27-30)
Change from Baseline in Sedentary Behavior	Average daily minutes of sedentary behavior, measured objectively via ActiGraph accelerometry.	Baseline (Month 2-3) and End of Intervention (Month 27-30).
Change from Baseline in Lower Limb Strength	Evaluated using the standing long jump test, with results recorded in centimeters (cm). Participants will stand behind a starting line and perform a jump as far as possible, landing with both feet simultaneously. The distance is measured from the starting line to the heel of the foot that lands closest to the line. After a familiarization trial, two official attempts will be performed, and the final score will be recorded as the mean of the two trials.	Baseline (Month 2-3) and End of Intervention (Month 27-30)
Change from Baseline in Abdominal Muscle Strength	Measured using the 60-second curl-up test, recording the maximum number of correct repetitions performed within the time limit. Participants lie in a supine position with knees bent at 90 degrees and feet flat on the floor. On the signal 'Go', they perform as many controlled curl-ups as possible. The final result is recorded as the total number of successfully completed repetitions in one minute.	Baseline (Month 2-3) and End of Intervention (Month 27-30)

Collaborators and Investigators

• Sponsor: Universidad de Santiago de Chile

Study record dates

Study Major Dates

• Study Start (Actual): December 11, 2023
• Primary Completion (Actual): December 15, 2025
• Study Completion (Actual): March 2, 2026

Study Registration Dates

• First Submitted: May 11, 2026
• First Submitted That Met QC Criteria: May 15, 2026
• First Posted (Actual): May 19, 2026

Study Record Updates

• Last Update Posted (Actual): May 19, 2026
• Last Update Submitted That Met QC Criteria: May 15, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Children; School-based intervention; Physical activity; Accelerometry; Sedentary behavior; Sports participation
• Additional Relevant MeSH Terms: Behavior; Motor Activity; Sedentary Behavior
• Other Study ID Numbers: 256/2023

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No