Effects of 8-Week CrossFit-Based Concurrent Training on Fitness, Body Composition, and Psychological Outcomes in Schoolchildren

NCT07552844 | Not Yet Recruiting

• 1 other identifier: SICEIA-2025-000408
• Study Type: interventional
• Target: 30
• Locations: 1 country
• Sites: 1

Brief Summary

This study examines the effects of an 8-week CrossFit-based concurrent training program in boys and girls aged 7 to 11 years, comparing an experimental group (n=15) with a control group (n=15). The aim is to assess changes in strength, cardiorespiratory fitness, body composition, and psychological variables such as anxiety, stress, and self-esteem, using field-based physical tests (CMJ, Course Navette, handgrip strength, etc.) and validated questionnaires. The study follows a randomized controlled trial design with pre- and post-intervention assessments. The experimental group will complete two weekly CrossFit sessions adapted for children, while the control group will maintain their usual routine without structured physical training. The hypothesis states that the intervention will significantly improve both physical performance and psychological well-being in the experimental group compared to the control group.

Conditions

Children; Crossfit; Psychology, Child; Physical Fitness; Body Composition

Keywords

children; stress; anxiety; exercise training; crossfit; self-esteem; Physical Fitness; body composition

Outcome Measures

Primary Outcomes (10)

• Countermovement Jump Test (CMJ) - Explosive Strength Test

  The countermovement jump (CMJ), is used to assess explosive strength of the lower limbs. In this test, participants begin in an upright standing position with their hands placed on their hips to avoid arm swing contribution. They are instructed to perform a maximal vertical jump following a rapid downward countermovement, descending to approximately 90° of knee flexion, and then immediately jumping as high as possible.

  Week 1 (Day 1), Week 8 (Day 16)

• Standing Long Jump

  This test consists of performing a horizontal jump using both feet simultaneously, starting from the same level. A preliminary jump is not allowed. The maximum horizontal distance achieved is recorded, measuring from the starting line to the rearmost point of the shoe closest to that line. Upon landing, the participant must maintain balance and remain stationary.

  Week 1 (Day 1), Week 8 (Day 16)

• Medicine Ball Throw Test

  The medicine ball throw test (2 kg) is performed from an upright standing position, holding the ball with both hands above the head. Participants are required to throw the ball as far as possible by performing a flexion-extension movement of the legs, with or without trunk extension.

  Week 1 (Day 1), Week 8 (Day 16)

• 20 m Shuttle Run Test (Course-Navette)

  In the 20 m shuttle run test, participants run back and forth between two lines set 20 m apart, with progressively increasing speed. The initial running speed is 8.5 km/h and increases by 0.5 km/h every minute. Each increase in speed corresponds to a new level.

  Week 1 (Day 1), Week 8 (Day 16)

• Plank Hold Time

  The plank protocol requires participants to maintain a static prone position, with only the forearms and toes in contact with the ground. Proper form requires feet together with toes pointing downward, elbows positioned under the shoulders at forearm width, and hands clasped together on the floor.

  Week 1 (Day 1), Week 8 (Day 16)

• Burpess

  To perform a burpee, participants begin with feet shoulder-width apart and lower into a squat by bending the knees. They then place their palms on the floor and jump back into a plank position with arms extended, ensuring hands face forward, feet rest on the toes, and the back remains straight. Next, they perform a push-up by bending the elbows and returning to the plank position. Then, they jump forward into a squat position, keeping hands on the ground, hips lowered, thighs parallel to the floor, and knees positioned between the elbows. Finally, they jump vertically from the squat position, extending the arms overhead during the jump.

  Week 1 (Day 1), Week 8 (Day 16)

• Step Test

  This test consists of stepping up and down on a platform approximately 30 cm in height, maintaining a constant speed and rhythm.

  Week 1 (Day 1), Week 8 (Day 16)

• State-Trait Anxiety Inventory for Children

  State-Trait Anxiety Inventory for Children is a psychological instrument designed to measure two dimensions of anxiety in children: state anxiety, referring to temporary or situational anxiety, and trait anxiety, which assesses the general tendency to experience anxiety.

  Week 1 (Day 1), Week 8 (Day 16)

• Children's Daily Stress Inventory

  This test aims to assess daily stress in children by evaluating how common experiences, such as school, family, and social issues, contribute to stress levels.

  Week 1 (Day 1), Week 8 (Day 16)

• Rosenberg Self-Esteem Scale

  The Rosenberg Self-Esteem Scale assesses an individual's self-worth through a series of statements reflecting overall self-evaluation.

  Week 1 (Day 1), Week 8 (Day 16)

Secondary Outcomes (2)

• Body composition

  Week 1 (Day 1), Week 8 (Day 16)

• Perceived Exertion

  Week 1 (Day 1), Week 8 (Day 16)

Study Arms (2)

Crossfit training

EXPERIMENTAL

Other: CrossFit training

Control

NO INTERVENTION

The control arm will not receive any structured exercise intervention during the study period and will continue with their usual daily school routine. This will allow comparison of changes in physical and psychological outcomes between both groups.

Interventions

CrossFit training OTHER

The experimental arm will receive an 8-week concurrent training intervention based on a CrossFit program adapted for children, with a frequency of two 50-minute sessions per week. Each session will be structured into a warm-up (mobility exercises and games), strength training (technical and functional exercises), metabolic conditioning (METCON), and a cool-down phase. The program will be supervised by qualified professionals to ensure safety and proper execution of the exercises.

Also known as: Body composition, Psychological Outcomes

Crossfit training

Eligibility Criteria

• Age: 7 Years - 11 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Child (0-17)

You may qualify if:

• Age: 7-11 years.
• Students enrolled at CEIP Pablo García Baena (Córdoba).
• For the experimental group:
• Availability to attend the Triple XXX Box (Polígono Pedroches, C. los Alfareros, Parcel 119, 14014 Córdoba), where both assessments and training sessions will be conducted.
• Availability to attend training sessions twice per week for the 8-week intervention period.
• No participation in extracurricular physical activity prior to the start of the CrossFit program.
• For the control group:
• No participation in extracurricular physical activity. Informed consent signed by parents or legal guardians. No medical, psychological, or behavioral contraindications that would prevent participation in physical activity.

You may not qualify if:

• Children with musculoskeletal injuries, diseases, or medical, psychological, or behavioral conditions that limit physical activity or interfere with the assessment of outcomes.
• Inability or anticipated difficulty in regularly attending training sessions.
• Refusal of parents or legal guardians to provide informed consent.

Sponsors & Collaborators

• Maimónides Biomedical Research Institute of Córdoba: lead
• Universidad de Córdoba: collaborator
• Escuela Universitaria de Osuna: collaborator

Study Sites (1)

IMIBIC

Córdoba, Córdoba, 14004, Spain

Location

MeSH Terms

Conditions

Anxiety Disorders

Interventions

Body Composition

Condition Hierarchy (Ancestors)

Mental Disorders

Intervention Hierarchy (Ancestors)

Biochemical Phenomena; Chemical Phenomena; Metabolism; Body Constitution; Physiological Phenomena

Central Study Contacts

José Manuel Jurado Castro

CONTACT

+34 957 21 37 00; jose.jurado@imibic.org

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NON RANDOMIZED
• Masking: NONE
• Purpose: OTHER
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal Investigator

Model Details: Randomized clinical trial

Study Record Dates

• First Submitted: April 20, 2026
• First Posted: April 27, 2026
• Study Start (Estimated): June 1, 2026
• Primary Completion (Estimated): June 1, 2026
• Study Completion (Estimated): July 1, 2026
• Last Updated: April 30, 2026

Record last verified: 2026-04

Data Sharing

• IPD Sharing: Will not share

Locations

ES (1)