Calisthenics-Based Intervention in Adolescents: Effects on Strength, Body Composition, Eating Habits, and Self-Concept (CALI-TEENS)

School-Based Calisthenics Intervention for Promoting Physical Activity in Adolescents

This study evaluates the effectiveness of a school-based calisthenics intervention in promoting physical activity and improving health-related outcomes in adolescents. Physical inactivity during adolescence is a growing public health concern associated with increased risks of obesity, poor physical fitness, and reduced psychological well-being. Schools provide an optimal environment to implement structured interventions that encourage lifelong healthy habits.

Calisthenics is a form of exercise that uses bodyweight movements to improve strength, flexibility, and coordination. It is cost-effective, accessible, and does not require specialized equipment, making it particularly suitable for school settings. The present study integrates a structured calisthenics program into regular physical education classes.

A total of 100 students aged 13 to 16 years will be randomly assigned to either an experimental group, which will participate in the calisthenics program, or a control group, which will follow the standard physical education curriculum. The intervention will last 12 weeks, with three sessions per week.

Primary and secondary outcomes will be assessed at baseline and after the intervention. These include physical fitness (muscle strength), body composition, dietary habits, and self-concept. Strength will be measured using a handgrip dynamometer, body composition through anthropometric assessment, dietary habits through a validated questionnaire, and self-concept using the Self-Concept Form-5 (AF5).

Findings from this study will provide evidence regarding the feasibility and effectiveness of implementing calisthenics in school settings as a strategy to improve both physical and psychological health in adolescents.

Study Overview

• Status: Completed
• Conditions: Physical Activity; Body Composition; Self Concept; Strength
• Intervention / Treatment: Other: Calisthenics; Other: Physical Activity School Education Program

Detailed Description

Study Design This is a randomized, parallel-group, controlled trial designed to assess the effects of a school-based calisthenics intervention on physical fitness, body composition, dietary habits, and self-concept in adolescents. Participants will be randomly assigned in a 1:1 ratio to an experimental group or a control group.

Study Setting The study will be conducted at a public secondary school in Turmequé, Boyacá, Colombia, involving ninth-grade students.

Participants A total of 120 adolescents aged between 13 and 16 years will be recruited. Eligibility will be determined based on predefined inclusion and exclusion criteria. Written informed consent from parents or legal guardians and assent from participants will be obtained prior to enrollment.

Randomization and Allocation Participants will be assigned to study groups using a computer-generated randomization sequence. Allocation will be conducted by an independent individual not directly involved in the study procedures to minimize selection bias. Due to the nature of the intervention, participant blinding is not feasible.

Intervention The experimental group will participate in a structured calisthenics program integrated into physical education classes over a 12-week period. The program consists of three weekly sessions of approximately 60 minutes each.

Each session will include the following components:

• Warm-up phase (mobility and dynamic stretching)
• Main exercise phase, including six bodyweight exercises targeting upper body, lower body, or full-body strength
• Cool-down phase with static stretching and relaxation exercises

The intervention follows a progressive overload model:

Exercise duration will increase over time (from 60 to 90 seconds per exercise) Rest intervals between sets will decrease progressively (from 40 to 15 seconds) Effort intensity will be monitored using the Borg Rating of Perceived Exertion scale

Sessions will be conducted in school facilities, including outdoor spaces and sports courts, under the supervision of a qualified instructor to ensure safety and proper execution.

Control Group Participants in the control group will continue with their standard physical education curriculum, which includes activities such as volleyball and handball, according to the institutional academic plan.

Outcome Measures Assessments will be conducted at baseline (week 0) and post-intervention (week 13).

Primary Outcomes

- Muscle strength: measured using a digital handgrip dynamometer

Secondary Outcomes

• Body composition: assessed through anthropometric measurements and skinfold thickness to estimate body fat percentage and body mass index
• Dietary habits: evaluated using a validated food frequency questionnaire
• Self-concept: assessed using the Self-Concept Form-5 (AF5), which measures multiple dimensions including physical self-perception

Sample Size Calculation The sample size was calculated to detect a meaningful difference in strength outcomes between groups, assuming a standard deviation of 15 units, with 90% power and a 5% significance level. A minimum of 60 participants per group is required.

Statistical Analysis Descriptive statistics will be calculated for all variables. Normality will be assessed using the Kolmogorov-Smirnov test. A two-way analysis of variance (ANOVA) will be performed to examine the effects of time, group, and their interaction. Bonferroni post hoc tests will be applied where appropriate. Statistical significance will be set at p < 0.05.

Data Management Participant data will be coded to ensure confidentiality. Only authorized research personnel will have access to the dataset. Data will be stored securely and managed in accordance with data protection regulations.

Ethical Considerations The study will be conducted in accordance with the principles of the Declaration of Helsinki and applicable national and international regulations. The study involves minimal risk, as it consists of supervised physical activity within a school setting. Participants will be informed that their participation is voluntary and that they may withdraw at any time without consequences.

Expected Impact This study aims to provide evidence on the effectiveness of calisthenics as a low-cost, accessible intervention to promote physical activity and improve health outcomes in adolescents. The results may contribute to the development of innovative physical education strategies and inform public health policies targeting youth populations.

• Study Type: Interventional
• Enrollment (Actual): 100
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Colombia
  • Departamento de Boyacá
    • Turmequé, Departamento de Boyacá, Colombia, 153060
      • Institución Educativa Técnica Industrial de Turmequé-Boyacá

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Enrollment in the ninth grade at the Institución Educativa Técnica Industrial de Turmequé, Boyacá.
• Age between 13 and 16 years.
• Agreement to random group assignment.

Exclusion Criteria:

• Presence of medical conditions or disorders that could contraindicate physical exercise, including but not limited to cardiac arrhythmias, heart murmurs, coronary artery disease, or hypertension, as diagnosed by a physician at the start of the calisthenics program.
• Presence of psychiatric disorders, such as severe anxiety attacks or depression, diagnosed by a qualified healthcare professional at the beginning of the calisthenics program.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Calisthenics; Calisthenics 12 week, 3 times per week, exercise program	Other: Calisthenics; 12 week exercise program, with a frequency of 3 times per week and a duration of 1 hour per session
Active Comparator: Control; School exercise programm	Other: Physical Activity School Education Program; Physical activity following School Education Program

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Hand grip strenght	Handgrip strength is assessed using a handheld dynamometer to evaluate muscular strength. Participants are instructed to squeeze the device with maximal effort, usually with the dominant hand, for a few seconds. The highest value from repeated trials is recorded in kilograms or newtons	From enrollment to the end of the intervention at 12 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Percentage of body fat	Skinfold anthropometric measurements will be determined to estimate body fat. The thickness of subcutaneous fat at the biceps, triceps, subscapular and suprailiac sites using standarized calipers will be performed. These values will be applied to equations to calculate body density and, from it, body fat percentage.	From enrollment to the end of treatment at 12 weeks
Dietary habits	Self-report of habitual food frequency consumption using a standardized and validated questionnaire. Briefly, it consists of a 33-item questionnaire including foods commonly consumed by the selected study group.	From enrollment to the end of treatment at 12 weeks
Self-concept	Reported by each volunteer using the AF5 Self-Concept Questionnaire, a validated instrument that assesses self-concept across five dimensions (academic/work, social, emotional, family, and physical) using a Likert-type scale, where higher scores indicate a more positive self-perception in each domain.	From enrollment to the end to the treatment at 12 weeks

Collaborators and Investigators

• Sponsor: Universitat de Lleida
• Investigators: Study Director: Jose CE Serrano, PhD, Universitat de Lleida

Study record dates

Study Major Dates

• Study Start (Actual): January 15, 2024
• Primary Completion (Actual): September 15, 2025
• Study Completion (Actual): December 15, 2025

Study Registration Dates

• First Submitted: April 29, 2026
• First Submitted That Met QC Criteria: May 7, 2026
• First Posted (Actual): May 13, 2026

Study Record Updates

• Last Update Posted (Actual): May 13, 2026
• Last Update Submitted That Met QC Criteria: May 7, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Adolescents; School-based intervention; Calisthenics
• Additional Relevant MeSH Terms: Behavior; Motor Activity; Motor Activity; Movement; Musculoskeletal Physiological Phenomena; Musculoskeletal and Neural Physiological Phenomena; Exercise; Gymnastics
• Other Study ID Numbers: CALI-TEENS; Universitat de Lleida (Registry Identifier: Escola de Doctorat)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Individual participant data are not publicly available due to ethical and privacy restrictions. However, de-identified data may be made available from the corresponding author upon reasonable request and with approval from the institutional ethics committee.
• IPD Sharing Time Frame: January 2026 util January 2036
• IPD Sharing Access Criteria: Upon request by e-mail
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; CSR

Drug and device information, study documents

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