An interventional study of Traditional Resistance Training and Standard Cluster Resistance Training in Athletic Performance, Volleyball Players and Resistance Training, sponsored by Birjand University of Medical Sciences. Completed at 1 site in Iran. Open to female participants aged 18 Years to 30 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-08-25.
Sponsored by Birjand University of Medical Sciences · Not applicable, Interventional, and Basic science
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.
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.
Birjand University of Medical Sciences is the lead sponsor of 7 studies on the registry; 1 is open to participants now.
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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 )
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
Exclusion Criteria:
Any musculoskeletal injury that prevented continuation of the training program
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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
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
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
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
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.
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.
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.
Time frame: baseline and after 8- week
Change in Lower-Body Strength (Squat 1-RM)
Maximum dynamic strength of the lower body, measured using the estimated 1-repetition maximum (1-RM) test for the squat exercise. The 1-RM was estimated using the Brzycki formula based on the maximum weight participants could lift for 1-9 repetitions.
Time frame: Baseline and 8 weeks
Change in Speed (20-m Sprint)
Sprint performance measured over a distance of 20 meters. Participants performed a maximal sprint, and the time was recorded in seconds.
Time frame: baseline and after 8- week
Change in Agility
Agility performance measured using a standard agility test (e.g., T-test or similar). Participants performed the test, and the completion time was recorded in seconds.
Time frame: baseline and after 8- week
Change in Countermovement Jump (CMJ) Height
Vertical jump height measured using a countermovement jump (CMJ) test. Participants performed 3 maximal jumps with 30-second rest intervals. The highest jump height (in centimeters) was recorded using a wall-mounted graduated tape. Peak power was then calculated using the Sayers equation.
Time frame: baseline and after 8- week
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.
Time frame: baseline and after 8- week
Change in Serum Testosterone
Serum levels of testosterone measured using commercial chemiluminescence immunoassay kits. Samples were collected before and after the first session (acute) and after eight weeks (chronic).
Time frame: Baseline, immediately after the first session, and 48 hours after the last session (week 8)
Change in Serum Cortisol
Serum levels of cortisol measured using commercial chemiluminescence immunoassay kits. Samples were collected before and after the first session (acute) and after eight weeks (chronic).
Time frame: Baseline, immediately after the first session, and 48 hours after the last session (week 8)
Change in Serum IGF-1
Serum levels of insulin-like growth factor-1 (IGF-1) measured using commercial chemiluminescence immunoassay kits. Samples were collected before and after the first session (acute) and after eight weeks (chronic).
Time frame: Baseline, immediately after the first session, and 48 hours after the last session (week 8)
Change in Serum Progesterone
Serum levels of progesterone measured using commercial chemiluminescence immunoassay kits. Samples were collected before and after the first session (acute) and after eight weeks (chronic) to verify menstrual cycle phase.
Time frame: Baseline, immediately after the first session, and 48 hours after the last session (week 8)
Change in Serum C-Reactive Protein (CRP)
Serum levels of C-reactive protein (CRP), an inflammatory marker, measured using an enhanced turbidimetric assay. Samples were collected before and after the first session (acute) and after eight weeks (chronic).
Time frame: Baseline, immediately after the first session, and 48 hours after the last session (week 8)
This study is completed, as verified in Aug 2026. You cannot join it, but the record below documents what was studied.
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Birjand University of Medical Sciences