Plyometric-jump training with unstable load

Plyometric-jump training with versus without unstable load to improve physical fitness in trained young volleyball players: a randomized controlled trial

Status

Active, not recruiting

Phases

Unknown

Study type

Interventional

Source

IRCT

Registry ID

IRCT20250905067129N1

Enrollment

Registered

2025-09-15

Start date

2025-04-21

Completion date

Unknown

Last updated

2025-10-13

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

None listed

Interventions

Intervention 1: Intervention group1: Participants in this group performed plyometric jump training with an unstable load equivalent to 10% of their body weight over a 4-week period (three sessions pe

Eligibility

Sex/Gender

Male

Age

14 Years to 18 Years

Inclusion criteria

Inclusion criteria: At least 2 years of experience competing in Tehran volleyball school competitions or Tehran league competitions. Their specific sports training volume is =6 hours per week. Boys age range 14 to 18 years. No cardiovascular problems. Avoiding the use of stimulants and certain medications (steroids) No smoking or drinking alcohol.

Exclusion criteria

Exclusion criteria: A history of acute or chronic musculoskeletal injury/disorders of the ankle, knees, or lower back. Training volume less than 6 hours per week. Age above 18 and below 14. History of cardiovascular disease and problems in the participant. Taking steroid medications. Tobacco and alcohol consumption. Experience of participating in competitions for more or less than 2 years.

Design outcomes

Primary

Measure	Time frame
Jump-and-reach height. Timepoint: 1. Initial measurement (pre-test) of jump and reach height in week zero, before the start of training.2. Final measurement (post-test) at the end of week four, 48 hours after the last training session. Method of measurement: For J&R, standing reach height was initially assessed during upright erect standing with both feet in lateral position close to a wall, the dominant arm fully extended in upright direction and the fingers touch-ing a wall-mounted touch-sensitive sensor connected to a digital display (Sargent jump device, Danesh Salar Iranian, Iran). Subsequently, participants performed a countermovement (i.e., knee and hip flexion) with arm swing immediately followed by a rapid and powerful vertical jump. The participants’ task was to touch the wall-mounted scale during flight time at the highest position with their middle finger.;Drop jump. Timepoint: 1. Initial measurement (pre-test) of drop jump in week zero, before the start of training.2. Final measurement (post-test) at the end of week four, 48 hours after the last training session. Method of measurement: Drop jumps were performed with the participants stepping off a 40 cm box, landing on firm floor, and immediately jumping as high as possible. Participants were instructed to touch the wall-mounted scale during the flight at the highest position. Jump height was defined as the difference between standing reach height and jumping reach height.;Knee flexion/extension peak isokinetic torque. Timepoint: 1. Initial measurement (pre-test) of Knee flexion/extension peak isokinetic torque in week zero, before the start of training.2. Final measurement (post-test) at the end of week four, 48 hours after the last training session. Method of measurement: The Knee flexion/extension peak isokinetic torque in the dominant leg was measured using the Biodex Multi-Joint System 4 Pro (Biodex Medical System Inc., USA). Leg dominance was determined based on the lateral preference questionnair	—

Measure

Time frame

Jump-and-reach height. Timepoint: 1. Initial measurement (pre-test) of jump and reach height in week zero, before the start of training.2. Final measurement (post-test) at the end of week four, 48 hours after the last training session. Method of measurement: For J&R, standing reach height was initially assessed during upright erect standing with both feet in lateral position close to a wall, the dominant arm fully extended in upright direction and the fingers touch-ing a wall-mounted touch-sensitive sensor connected to a digital display (Sargent jump device, Danesh Salar Iranian, Iran). Subsequently, participants performed a countermovement (i.e., knee and hip flexion) with arm swing immediately followed by a rapid and powerful vertical jump. The participants’ task was to touch the wall-mounted scale during flight time at the highest position with their middle finger.;Drop jump. Timepoint: 1. Initial measurement (pre-test) of drop jump in week zero, before the start of training.2. Final measurement (post-test) at the end of week four, 48 hours after the last training session. Method of measurement: Drop jumps were performed with the participants stepping off a 40 cm box, landing on firm floor, and immediately jumping as high as possible. Participants were instructed to touch the wall-mounted scale during the flight at the highest position. Jump height was defined as the difference between standing reach height and jumping reach height.;Knee flexion/extension peak isokinetic torque. Timepoint: 1. Initial measurement (pre-test) of Knee flexion/extension peak isokinetic torque in week zero, before the start of training.2. Final measurement (post-test) at the end of week four, 48 hours after the last training session. Method of measurement: The Knee flexion/extension peak isokinetic torque in the dominant leg was measured using the Biodex Multi-Joint System 4 Pro (Biodex Medical System Inc., USA). Leg dominance was determined based on the lateral preference questionnair

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Countries

Iran (Islamic Republic of)

Contacts

Public ContactMohammad Fashi

Shahid Beheshti University

fashi84.u@gmail.com+98 21 2990 5858

Outcome results