Acute Effects of Bilateral Versus Unilateral Isometric Conditioning Activity on Jump Performance … (NCT07709104) | Clinical Trial Compass
By InvitationNot Applicable
Acute Effects of Bilateral Versus Unilateral Isometric Conditioning Activity on Jump Performance in Volleyball Players
Poland14 participantsStarted 2026-07-23
Plain-language summary
This randomized crossover trial investigates the acute effects of bilateral and unilateral isometric conditioning activity on bilateral and unilateral jump performance in highly trained male volleyball players. Fourteen athletes will complete three experimental conditions in randomized order: bilateral isometric squat conditioning activity (BI), unilateral isometric squat conditioning activity (UNI), and a control condition consisting of low-intensity treadmill walking (CTRL). In both isometric conditions, participants will perform three sets of three maximal 3-second contractions, with 3-minute recovery intervals between sets. Jump performance will be assessed before each experimental condition and at 4, 8, and 12 minutes afterward using bilateral countermovement jumps and single-leg jumps performed separately with each lower limb. The primary aim of the study is to determine whether the mode of isometric conditioning activity, unilateral versus bilateral, influences the magnitude and time course of acute changes in jump performance. An additional objective is to assess whether the effects of the conditioning activity differ between bilateral and unilateral jumping tasks.
Who can participate
Sex
MALE
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Inclusion Criteria:
* minimum of 7 years of systematic volleyball training,
* at least 3 resistance training sessions per week during the preceding 5 years,
* no musculoskeletal injury requiring training cessation longer than 4 weeks within 6 months prior to enrollment,
* absence of tattoos over the rectus femoris muscle that could interfere with thermographic assessment.
Exclusion Criteria:
* less than 7 years of systematic volleyball training,
* less than 3 resistance training sessions per week during the previous 5 years,
* any musculoskeletal injury within the 6 months prior to enrollment that required cessation of training for longer than 4 weeks,
* current musculoskeletal pain or injury that could affect jumping performance or participation in maximal isometric exercise,
* tattoos, scars, or skin conditions over the rectus femoris muscle that could interfere with thermographic measurements,
* use of medications or substances that may affect neuromuscular performance or muscle function,
* failure to comply with study procedures or testing requirements.
Questions worth asking your doctor
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
Questions for the trial coordinator
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.
What they're measuring
1
Changes in Bilateral Countermovement Jump Height
Timeframe: Baseline and 4, 8, and 12 minutes after each experimental condition
2
Changes in Single-Leg Jump Height
Timeframe: Baseline and 4, 8, and 12 minutes after each experimental condition
Trial details
NCT IDNCT07709104
SponsorThe Jerzy Kukuczka Academy of Physical Education in Katowice