Cluster Training in Female Volleyball Players

NCT07785778 | Completed

• 1 other identifier: IR.BIRJAND.REC.1401.004
• Study Type: interventional
• Target: 30
• Locations: 1 country
• Sites: 1

Brief Summary

This study compares the effects of three different resistance training methods-traditional training, standard cluster training, and undulating cluster training-on strength, hormonal responses, and inflammation in female volleyball players aged 18-30 years. Thirty participants with at least two years of volleyball and resistance training experience were randomly assigned to one of three groups. All participants performed resistance training three times per week and volleyball-specific training two times per week for eight weeks. Blood samples were taken before and after the first session (acute response) and after eight weeks (chronic adaptation) to measure testosterone, cortisol, IGF-1, progesterone, and C-reactive protein (CRP). Performance tests included upper-body and lower-body strength (bench press and squat), speed, agility, and vertical jump. The main finding was that undulating cluster training produced significantly greater improvements in upper-body strength compared to standard cluster training, while all three methods were equally effective for lower-body strength and other performance measures. No significant differences were found between groups for hormonal or inflammatory changes. The study provides practical guidance for coaches seeking to optimize upper-body strength gains in female volleyball players.

Conditions

Athletic Performance; Volleyball Players; Resistance Training

Keywords

Cluster; Configuration

Outcome Measures

Primary Outcomes (1)

• Change in Relative Peak Power

  Relative peak power derived from the CMJ height and body mass, calculated using the Sayers equation: Peak power (W) = 60.7 × jump height (cm) + 45.3 × body mass (kg) - 2055.

  baseline and after 8- week

Secondary Outcomes (10)

• Change in Lower-Body Strength (Squat 1-RM)

  Baseline and 8 weeks

• Change in Speed (20-m Sprint)

  baseline and after 8- week

• Change in Agility

  baseline and after 8- week

• Change in Countermovement Jump (CMJ) Height

  baseline and after 8- week

• Change in Relative Peak Power

  baseline and after 8- week

Study Arms (3)

Traditional Resistance Training (TRT)

ACTIVE COMPARATOR

Eight weeks of traditional resistance training, 3 sessions per week. Linear progression with 240s inter-set rest (weeks 1-3), 200s (weeks 4-5), 180s (weeks 6-8). Exercises: dumbbell thruster, power clean, back squat, deadlift, knee flexion curl, bench press, military press, lat pulldown

Behavioral: Traditional Resistance Training

Standard Cluster Resistance Training (SCRT)

EXPERIMENTAL

Eight weeks of standard cluster resistance training, 3 sessions per week. Similar to TRT but with intra-set rest intervals (10-30s between clusters) to maintain movement quality and power output.

Behavioral: Standard Cluster Resistance Training

Undulating Cluster Resistance Training (UCRT)

EXPERIMENTAL

Eight weeks of undulating cluster resistance training, 3 sessions per week. Combines intra-set rest with systematic weekly variations in load and repetition schemes, balancing neural drive and load tolerance

Behavioral: Undulating Cluster Resistance Training

Interventions

Traditional Resistance Training BEHAVIORAL

Eight weeks of traditional resistance training, 3 sessions per week. Each session includes 8 exercises: dumbbell thruster, power clean, back squat, deadlift, knee flexion curl, bench press, military p

Traditional Resistance Training (TRT)

Standard Cluster Resistance Training BEHAVIORAL

Eight weeks of standard cluster resistance training, 3 sessions per week. Same exercises and intensity progression as TRT, but with intra-set rest intervals (10-30 seconds between clusters) to maintain movement quality, repetition velocity, and power output across multiple sets.

Standard Cluster Resistance Training (SCRT)

Undulating Cluster Resistance Training BEHAVIORAL

Eight weeks of undulating cluster resistance training, 3 sessions per week. Combines intra-set rest intervals (10-30 seconds between clusters) with systematic weekly variations in load and repetition schemes. Intensity and volume undulate across weeks to balance neural drive and load tolerance while preserving high-quality repetitions.

Undulating Cluster Resistance Training (UCRT)

Eligibility Criteria

• Age: 18 Years - 30 Years
• Sex: female
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Female volleyball players aged 18 to 30 years
• At least 2 years of continuous training in volleyball and resistance training
• Complete health status (based on health and wellness questionnaire results)
• No anterior cruciate ligament injury or other upper-/lower-extremity injuries in the past 6 months
• Familiarity with basic resistance training techniques
• Non-pregnant, with regular menstrual cycles
• No regular use of medications (including oral contraceptives)
• No use of ergogenic supplements affecting muscle mass (e.g., anabolic steroids, growth hormone, or insulin-like substances) in the 6 months prior to the study

You may not qualify if:

• Absence from more than three consecutive training sessions
• Any musculoskeletal injury that prevented continuation of the training program

Sponsors & Collaborators

• Birjand University of Medical Sciences: lead

Study Sites (1)

Faculty of Sport Sciences, University of Birjand

Birjand, South Khorasan Province, 9717434765, Iran

Location

Study Officials

• Mohsen Mohammadnia Ahmadi, PhD

  university of birjand

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Masking Details: Due to the nature of the exercise interventions, blinding of participants and trainers is not feasible. However, outcome assessors performing the performance tests and blood sample analysis were blinded to group allocation where possible.
• Purpose: BASIC SCIENCE
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Assistant professor

Study Record Dates

• First Submitted: August 17, 2026
• First Posted: August 25, 2026
• Study Start: November 20, 2022
• Primary Completion: December 20, 2022
• Study Completion: December 30, 2022
• Last Updated: August 25, 2026

Record last verified: 2026-08

Locations

IR (1)