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IRCT20250905067129N2 IRCT 2026-04-21 National Defense University (Center for Elites and Top Talents of the Armed Forces) Unstable Loaded Plyometric Training ULPT=Unstable Loaded Plyometric Training Comparison of the Effects of Unstable and Stable Loaded Plyometric Training on Some Physical Fitness Factors in Pas Gorgan Volleyball Team Players 2026-05-05 anticipated 21 Recruiting https://irct.ir/trial/89035 interventional Randomization: Randomized, Blinding: Single blinded, Placebo: Not used, Assignment: Parallel, Purpose: Supportive, Randomization description: In this study, the process of assigning participants to groups will be carried out with a combined approach of initial pairing (pair-matching) and simple randomization to reduce initial heterogeneity between groups on the one hand and ensure true randomization on the other. First, all participants will be grouped into pairs of equal jumping ability based on the results of the vertical jump test (Jump-and-Reach) at the beginning of the study. This pairing method will be used to initially balance the jumping ability in the groups. Then, in each pair, assignment to study groups will be done randomly. Microsoft Excel software and the (RAND) function will be used to generate the random sequence. A random number will be generated for each individual and based on the ascending sorting of these numbers, participants will be divided into three study groups including: 1. Unstable Loaded Plyometric Training (ULPT) group, 2. Stable Loaded Plyometric Training (SLPT) group, and 3. The active control group (CON) will be allocated. The randomization unit in this study will be individual-based. The randomization sequence will be generated and maintained by one of the researchers who is not involved in data collection and analysis. To maintain confidentiality and prevent any possible bias in the allocation process, the randomization sequence will be placed in opaque, sealed, and numbered envelopes and will only be returned at the time of allocation of each participant. Thus, the randomization process in this study will both reduce the initial heterogeneity between groups and fully respect the random nature of the allocation of participants, Blinding description: In this study, blinding will be performed in a single-blind manner. Participants will be unaware of their group assignment and the exact purpose of the intervention. In addition, data analysis will be performed by a consulting statistician who is unaware of the group assignment. However, the intervention and functional test administrator will be aware of the group assignment due to the nature of the research and the need to monitor the correct implementation of the exercises. Thus, in this study, blinding will be observed at the level of participants and data analyst, but there will be no possibility of blinding the test administrator. N/A Volleyball players' performance. Intervention 1: Intervention group 1: Participants in this group performed unstable loaded plyometric exercises equivalent to 10% of body weight over a 12-week period (three sessions per week, a total of 36 sessions). The unstable load was provided by a barbell and two water-filled gimbal balls. The exercises were performed on the gym floor and included countermovement jumps. The intensity and volume of the exercise gradually increased, such that the number of jumps increased from 72 repetitions in the first session to 140 repetitions in the final sessions. Each session lasted 15 to 25 minutes, with a work-to-rest ratio of 1:7 and a two-minute rest interval between exercises. All sessions began with a RAMP warm-up protocol (light jogging, dynamic stretching, and submaximal jumps). Intervention 2: Intervention Group 2: Participants in this group performed 10% of their body weight of sustained loading plyometric exercises over a 12-week period (three sessions per week, a total of 36 sessions). The unstable load was provided by a barbell and weights. The exercises were performed on the gym floor and included countermovement jumps. The intensity and volume of the exercise gradually increased, such that the number of jumps increased from 72 repetitions in the first session to 140 repetitions in the final sessions. Each session lasted 15 to 25 minutes, with a work-to-rest ratio of 1:7 and a two-minute rest interval between exercises. All sessions began with a RAMP warm-up protocol (light jogging, dynamic stretching, and submaximal jumps). Intervention 3: Control group: Participants in the control group continued their normal volleyball training during the 12-week period. Their training consisted of typical team technical and tactical activities and did not receive any additional plyometric training or specific intervention. This group served as a comparison to determine the net effect of the plyometric interventions on the other two groups. No - There is not a plan to make this available Justification or reason for not sharing IPD is To adhere to ethical principles and protect participants' personal and confidential information, the raw data (individual participant data) from this study will not be shared for public use or secondary research. However, if required, and solely to assure journal reviewers or editors of the accuracy of statistical analyses, the data will be provided confidentially.
public Parsa Soltani
No. 182, Shahid Beheshti Governance School, Corner of Shohada St. (Opposite Indonesian Embassy), Qaem Maqam Farahani St., Shahid Beheshti St.
Tehran Iran (Islamic Republic of) ۱۵۸۶۷۵۵۴۱۴ +98 21 8872 8937 par.soltani@mail.sbu.ac.ir National Elite Foundation scientific Amir Falahnezhad Mojarad
Amin University of Law Enforcement Sciences - Shahid Kharrazi Highway - End of Shahid Hemmat Gharb Highway - Tehran
Tehran Iran (Islamic Republic of) ۱۴۳۹۹۱۴۱۵۳ +98 21 4893 1289 amirfalh.sport@gmail.com Amin University of Police Sciences Iran (Islamic Republic of) Age range: 18-28 years sports history of participating in league competitions for at least 2 years, ability to jump vertically at least 45 cm be completely medically healthy and have no problems performing sports related to the research have no cardiovascular problems Avoid using stimulants and certain medications (steroids). Player of the Gorgan Pas volleyball team 18 years 28 years Male History of acute or chronic musculoskeletal injuries/disorders of the ankles, knees, or back History of cardiovascular disease and problems in the participant. Taking steroid medications. Tobacco and alcohol consumption Other Other Other Intervention group 1: Participants in this group performed unstable loaded plyometric exercises equivalent to 10% of body weight over a 12-week period (three sessions per week, a total of 36 sessions). The unstable load was provided by a barbell and two water-filled gimbal balls. The exercises were performed on the gym floor and included countermovement jumps. The intensity and volume of the exercise gradually increased, such that the number of jumps increased from 72 repetitions in the first session to 140 repetitions in the final sessions. Each session lasted 15 to 25 minutes, with a work-to-rest ratio of 1:7 and a two-minute rest interval between exercises. All sessions began with a RAMP warm-up protocol (light jogging, dynamic stretching, and submaximal jumps). Intervention Group 2: Participants in this group performed 10% of their body weight of sustained loading plyometric exercises over a 12-week period (three sessions per week, a total of 36 sessions). The unstable load was provided by a barbell and weights. The exercises were performed on the gym floor and included countermovement jumps. The intensity and volume of the exercise gradually increased, such that the number of jumps increased from 72 repetitions in the first session to 140 repetitions in the final sessions. Each session lasted 15 to 25 minutes, with a work-to-rest ratio of 1:7 and a two-minute rest interval between exercises. All sessions began with a RAMP warm-up protocol (light jogging, dynamic stretching, and submaximal jumps). Control group: Participants in the control group continued their normal volleyball training during the 12-week period. Their training consisted of typical team technical and tactical activities and did not receive any additional plyometric training or specific intervention. This group served as a comparison to determine the net effect of the plyometric interventions on the other two groups. Sargent's jump height. Timepoint: 1. Initial measurement (pre-test) of Sargent jump height in week 0, before the start of training 2; Intermediate measurement at the end of week 4, 48 hours after the last training session, 3. Intermediate measurement at the end of week 8, 48 hours after the last training session, 4. Final measurement (post-test) at the end of week 12, 48 hours after the last training session. Method of measurement: For the Sargent jump height, hand height is initially assessed in a straight standing position with both feet in a lateral position close to the wall, the arm of the dominant hand fully extended in a vertical direction, and the fingers touching a wall-mounted tactile sensor connected to a digital display (Sargent Jumping Device, Danesh Salar Iranian, Iran). After that, participants perform a reverse movement (i.e., knee and hip flexion) with an arm swing immediately after a rapid and powerful vertical jump. The participants’ task is to touch the scale mounted on the wall with their middle finger while flying at the highest position. Depth jump. Timepoint: 1. Initial measurement (pre-test) of Sargent jump height in week 0, before the start of training 2; Intermediate measurement at the end of week 4, 48 hours after the last training session, 3. Intermediate measurement at the end of week 8, 48 hours after the last training session, 4. Final measurement (post-test) at the end of week 12, 48 hours after the last training session. Method of measurement: The depth jump is performed by landing from a 40 cm box on firm ground and immediately jumping as high as possible. Participants are instructed to touch a scale mounted on the wall during the flight at the highest point. The jump height is defined as the difference between the height of the hand in the standing position and the height of the hand in the jumping position. Standing long jump. Timepoint: 1. Initial measurement (pre-test) of standing long jump in week 0, before the start of training; 2. Intermediate measurement at the end of week 4, 48 hours after the last training session; 3. Intermediate measurement at the end of week 8, 48 hours after the last training session; 4. Final measurement (post-test) at the end of week 12, 48 hours after the last training session. Method of measurement: To measure horizontal explosive power of the lower limbs, the subject will stand on the ground behind a designated starting line with both feet together. After a warm-up movement involving bending the knees and swinging the arms, the subject will jump forward with maximum force and attempt to cover as much distance as possible. The landing must be done with both feet simultaneously within the landing area. The distance from the front edge of the starting line to the heel of the foot closest to the landing area will be measured in centimeters using an accurate tape measure. Each subject will make three valid attempts and the best record will be recorded as the final result. A 2-minute rest period will be given between each attempt. Attempts in which the subject stands further than the permitted distance on the starting line or loses balance during landing will be considered invalid and will be repeated. Linear speed 10 meters. Timepoint: 1. Initial measurement (pre-test) of 10-meter linear speed in week 0, before the start of training; 2. Intermediate measurement at the end of week 4, 48 hours after the last training session; 3. Intermediate measurement at the end of week 8, 48 hours after the last training session; 4. Final measurement (post-test) at the end of week 12, 48 hours after the last training session. Method of measurement: To assess short-term linear acceleration and speed, subjects will perform a 10-meter sprint test. The subject will stand in a ready position behind the designated starting line and, upon the examiner's command, will begin an explosive run. The running time will be recorded using an accurate hand-held stopwatch from the moment of crossing the starting line to reaching the finish line at a distance of 10 meters. Each subject will make two valid attempts and the best record (the shortest time in seconds) will be recorded as the final result. A 3-minute rest period will be considered between attempts to prevent fatigue. Subjects will be required to run at maximum power in each attempt and not deviate from a straight line along the way. Agility T. Timepoint: 1. Initial measurement (pre-test) of T agility in week 0, before the start of training; 2. Intermediate measurement at the end of the fourth week, 48 hours after the last training session; 3. Intermediate measurement at the end of the eighth week, 48 hours after the last training session; 4. Final measurement (post-test) at the end of the twelfth week, 48 hours after the last training session. Method of measurement: The test route consists of four cones arranged in the shape of the letter T: one cone at the starting line, one 9.14 m in front of it, and two other cones each 4.57 m apart on either side of the middle cone. The subject will stand behind the starting line in a ready position and, at the command of the examiner, will begin an explosive run. First, he will run forward to the middle cone, then quickly shuffle to the right and touch the side cone, immediately move sideways to the left and touch the other cone, then move sideways again to the center, and finally run backwards to the starting line. The test time from the moment of departure until the complete crossing of the finish line will be recorded with a hand stopwatch. Each subject will have two valid attempts and the best time (the shortest time in seconds) will be recorded as the final record. A minimum of 3 minutes of rest will be given between each attempt. Dynamic balance Y. Timepoint: 1. Initial measurement (pre-test) of dynamic balance Y in week 0, before the start of training 2; Intermediate measurement at the end of the fourth week, 48 hours after the last training session, 3. Intermediate measurement at the end of the eighth week, 48 hours after the last training session, 4. Final measurement (post-test) at the end of the twelfth week, 48 hours after the last training session. Method of measurement: In this test, after a standard warm-up (light jogging and dynamic stretching), subjects will stand on the supporting (dominant) leg and touch the opposite leg as far as possible in three directions: anterior, posterior-medial, and posterolateral. The order of execution will consist of three attempts in each direction, and the best valid record will be recorded. During the execution, the supporting leg must remain completely fixed on the ground and the hands must be placed on the pelvis. Attempts in which the subject loses balance, the standing leg is moved, or the hands are used for assistance will be considered invalid and will be repeated. To prevent fatigue, a minimum of 30 seconds of rest will be given between each attempt. The test will be performed for the dominant leg. Police Command of the Islamic Republic of Iran Approved 2026-02-09 Deputy of Health, Relief and Treatment, Police Command of the Islamic Republic of Iran - Shahid Behe Tehran, Valiasr St., above Vanak Square, opposite Zafar, Hazrat Valiasr Hospital, Applied Research Center of the Deputy of Health Services of NAJA Tehran Tehran Iran (Islamic Republic of)