Feasibility and Preliminary Effects of a Structured Resistance Training Program in Children Aged 10-14 Years

Feasibility and Preliminary Effects of a Structured Resistance Training Programme in Children Aged 10-14 Years: A Randomised Controlled Pilot Study

This study is a randomised controlled pilot trial designed to evaluate the feasibility, safety, and preliminary efficacy of a 12-week resistance training intervention in children aged 10-14 years. The study adheres to the CONSORT extension for randomised pilot and feasibility trials and incorporates key elements of the SPIRIT guidelines for clinical trial protocols.

The primary purpose of the study is to assess feasibility-related outcomes and to generate effect size estimates to inform the design of a subsequent fully powered randomised controlled trial (RCT).

Study Overview

• Status: Not yet recruiting
• Conditions: Ultrasonic Diagnosis; Muscle Architecture
• Intervention / Treatment: Behavioral: Progressive Resistance Training Program

• Study Type: Interventional
• Enrollment (Estimated): 31
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Michal Steffl, PhD; Phone Number: +420778701882; Email: michal.steffl@ftvs.cuni.cz

Study Locations

• Czechia
  • Czech Republic
    • Prague, Czech Republic, Czechia, 16200
      • Faculty of Physical Education and Sport Charles University

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Children aged 10-14 years
• Ability to safely participate in supervised resistance training
• Written informed consent from a parent or legal guardian
• Assent provided by the child participant
• Willingness to comply with all study procedures and attend training sessions

Exclusion Criteria:

• Acute illness at the time of enrolment
• Recent musculoskeletal injury or immobilisation
• Chronic cardiovascular, metabolic, or endocrine disorders
• Use of medications that may affect muscle composition or function
• Any medical or psychological condition that may compromise safety or adherence

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Structured Progressive Resistance Training Program; Participants will complete an 8-week supervised progressive resistance training (PRT) program performed twice weekly. Each ~45-minute session includes a warm-up, whole-body resistance exercises (with emphasis on lower limbs), and a cool-down. Exercises include squat variations, hip hinge movements, unilateral lower-limb exercises, upper-body pushing/pulling, and core stabilization. Training intensity is guided by a youth-specific RPE scale (5-8), with progressive overload based on individual technique. Sessions are delivered in small groups under qualified supervision to ensure safety and adherence. The program consists of three phases: familiarisation (weeks 1-2), progressive overload (weeks 3-5), and strength-oriented training (weeks 6-8). Outcomes are assessed pre- and post-intervention.

Behavioral: Progressive Resistance Training Program; An 8-week supervised progressive resistance training (PRT) program performed twice weekly in children aged 10-14 years. Each ~45-minute session includes a warm-up, whole-body resistance exercises (with emphasis on lower-limb musculature), and a cool-down. Exercises include squat variations, hip hinge movements, unilateral lower-limb exercises, upper-body pushing and pulling, and core stabilization. Training intensity is prescribed using a youth-specific rating of perceived exertion (RPE 5-8), with progressive overload applied individually based on proper technique. The program is divided into three phases: familiarisation (weeks 1-2), progressive overload (weeks 3-5), and strength-oriented training (weeks 6-8). Sessions are delivered in small groups under qualified supervision to ensure safety and adherence.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Muscle Quality (Echo Intensity)	Ultrasound-derived echo intensity (EI) of the quadriceps femoris (QF) muscle assessed as an indicator of skeletal muscle quality. EI will be derived from longitudinal scans of each QF head and the cross-sectional area (CSAQF) from panoramic mid-thigh images	Time Frame: Pre-intervention (baseline) and post-intervention (8 weeks)
Muscle Strength (Knee Extensor Strength)	Maximum voluntary contraction (MVC) of knee extensors measured using an isokinetic dynamometer.	Time Frame: Pre-intervention and post-intervention (8 weeks)
Feasibility of the Intervention	Feasibility assessed by recruitment rate, retention rate, and adherence to the training program (percentage of sessions attended and proportion of participants attending ≥80% of sessions).	Throughout the 8-week intervention
Safety of the Intervention	Safety evaluated by the number, type, and severity of adverse events recorded during training sessions, and the proportion of participants experiencing at least one adverse event.	Throughout the 8-week intervention

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Functional Performance	Functional lower-body performance assessed using the 30-second sit-to-stand test (30STS).	Pre-intervention and post-intervention (8 weeks)
Body Composition	Body composition assessed using dual-energy X-ray absorptiometry (DXA), including lean mass and fat mass parameters.	Pre-intervention and post-intervention (8 weeks)

Collaborators and Investigators

• Sponsor: Charles University, Czech Republic

Study record dates

Study Major Dates

• Study Start (Estimated): September 1, 2026
• Primary Completion (Estimated): December 31, 2027
• Study Completion (Estimated): September 30, 2028

Study Registration Dates

• First Submitted: March 26, 2026
• First Submitted That Met QC Criteria: April 1, 2026
• First Posted (Actual): April 6, 2026

Study Record Updates

• Last Update Posted (Actual): April 6, 2026
• Last Update Submitted That Met QC Criteria: April 1, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: Children; Resistance Training; Feasibility Study
• Other Study ID Numbers: EK 007/2026

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

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