Effects of Deloading Periods in Resistance Training on Muscular Strength and Hypertrophy (DPRT)

Effects of Deloading Periods in Resistance Training on Muscular Strength and Hypertrophy in Untrained Young Individuals: a Randomized Controlled Trial

This study investigates the effects of deloading periods (short breaks or reductions in training volume) in a 8-week resistance training program on muscle strength and hypertrophy in young, untrained individuals.

Participants were randomly assigned to two training conditions:

Deload Training Group: Reduced training volume for one week every four weeks. Continuous Training Group: Regular training without reductions. Muscle thickness was measured using ultrasound, and muscle strength was evaluated through a 10-repetition maximum (10RM) test before and after the intervention.

The findings showed that both training strategies led to significant increases in muscle strength and size, with no major differences between groups. This suggests that incorporating deloading periods does not negatively impact muscle development and may serve as an effective alternative for individuals with time constraints or minor injuries.

This study was conducted at Gaziantep University, Faculty of Sports Sciences, with approval from the university's ethics committee.

Study Overview

• Status: Completed
• Conditions: Muscle Hypertrophy in Healthy Young Men
• Intervention / Treatment: Behavioral: Resistance Training with Deloading Periods; Behavioral: Continuous Resistance Training

Detailed Description

This study examines the effects of deloading periods (planned reductions in training volume and frequency) within an 8-week resistance training program on muscle hypertrophy and strength in untrained young individuals.

The study utilized a randomized within-subject design, where each participant's limbs were assigned to one of two conditions:

Deload Training Condition: Training volume and frequency were reduced during Weeks 4 and 8 to allow for recovery.

Continuous Training Condition: No reductions in training volume were applied. The resistance training program included unilateral leg extension and unilateral dumbbell biceps curl exercises performed twice per week. The training intensity was adjusted to ensure participants reached voluntary muscular failure within the 8-12 repetition range.

Assessments & Measurements:

Muscle Hypertrophy: Measured using B-mode ultrasound at different quadriceps and biceps locations.

Muscle Strength: Evaluated through 10-repetition maximum (10RM) testing before and after the intervention.

Statistical Analysis: A 2-way repeated-measures ANOVA was used to compare training conditions, with effect sizes analyzed to determine the significance of adaptations.

The study was approved by the Gaziantep University Health and Sports Sciences Ethics Committee and conducted in accordance with the Declaration of Helsinki guidelines.

• Study Type: Interventional
• Enrollment (Actual): 19
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Turkey
  • Şehitkamil
    • Gaziantep, Şehitkamil, Turkey, 27350
      • Gaziantep University, Faculty of Sport Sciences

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Healthy, untrained individuals (no prior structured resistance training experience for at least 6 months).
• Aged between 18-25 years old.
• No current or recent musculoskeletal injuries affecting exercise performance.
• No diagnosed medical conditions that could interfere with resistance training.
• Willing to participate in an 8-week structured resistance training program.
• No use of performance-enhancing drugs, anabolic steroids, or other muscle-growth supplements.

Exclusion Criteria:

• Individuals with prior resistance training experience within the last 6 months.
• Any current or past musculoskeletal injuries or conditions affecting the lower or upper limbs.
• Any diagnosed metabolic, cardiovascular, or neurological disorders that could affect physical performance.
• Individuals currently taking medications that affect muscle function or recovery.
• Pregnant or breastfeeding individuals.
• Failure to comply with the study protocol (e.g., missing more than 2 training sessions).

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Deload Training; Participants in this group followed an 8-week resistance training program with deloading periods every four weeks. During these deload weeks, training volume and intensity were reduced to facilitate recovery while maintaining training adaptations.	Behavioral: Resistance Training with Deloading Periods; Participants performed an 8-week unilateral resistance training program in which training volume and intensity were reduced during weeks 4 and 8 to facilitate recovery and adaptation.
Active Comparator: Continuous Training; Participants in this group followed an 8-week continuous resistance training program with no reductions in training volume or intensity. This group served as a comparison to assess the effects of deloading periods on muscle hypertrophy and strength.	Behavioral: Continuous Resistance Training; Participants followed an 8-week unilateral resistance training program without any deloading periods. Training volume and intensity remained consistent throughout the study.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Muscular Strength	Changes in muscle strength will be assessed using 10-repetition maximum (10RM) testing before and after the intervention. Strength assessments will be conducted for both the quadriceps (leg extension) and biceps brachii (dumbbell curl).	Baseline and after 8 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Muscle Hypertrophy	Changes in muscle thickness will be measured using B-mode ultrasound imaging. Measurements will be taken at multiple anatomical points on the quadriceps and biceps brachii muscles before and after the intervention.	Baseline and after 8 weeks

Collaborators and Investigators

• Sponsor: University of Gaziantep
• Investigators: Principal Investigator: Zarife Pancar Assistant Professor,, PhD, University of Gaziantep

Study record dates

Study Major Dates

• Study Start (Actual): May 1, 2024
• Primary Completion (Actual): June 25, 2024
• Study Completion (Actual): August 20, 2024

Study Registration Dates

• First Submitted: February 4, 2025
• First Submitted That Met QC Criteria: February 7, 2025
• First Posted (Actual): March 25, 2025

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: February 7, 2025
• Last Verified: February 1, 2025

More Information

Terms related to this study

• Keywords: muscle strength; resistance training; Muscle hypertrophy
• Additional Relevant MeSH Terms: Pathological Conditions, Anatomical; Hypertrophy
• Other Study ID Numbers: GAUN-SBF-PANCAR-02; OFS (Registry Identifier: 7a55420f9c0843838b7da349ba26195f)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: De-identified individual participant data (IPD) will be shared with other researchers upon reasonable request. Data will be available after study completion and publication, following ethical approval and data-sharing agreements. Researchers interested in accessing the data may contact the corresponding author.
• IPD Sharing Time Frame: De-identified individual participant data (IPD), along with the study protocol and statistical analysis plan, will be made available upon request after study completion and publication. Researchers interested in accessing the data should contact the corresponding author. Data will be shared under a data-sharing agreement to ensure compliance with ethical and privacy guidelines.
• IPD Sharing Access Criteria: De-identified individual participant data (IPD) and supporting documents, including the study protocol and statistical analysis plan, will be available upon reasonable request for research purposes. Access will be granted to qualified researchers affiliated with academic or research institutions. Researchers must submit a data-sharing request, including a brief study proposal outlining their intended use of the data. All data-sharing requests will be reviewed by the study team, and approved researchers must sign a data-sharing agreement to ensure compliance with ethical and privacy guidelines. Data will be shared in a secure format via institutional data-sharing platforms or encrypted file transfer.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; 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
• product manufactured in and exported from the U.S.: No