By InvitationNot Applicable

Acute Effects of Isometric Conditioning on Sprint, Jump and Change of Direction Performance in Youth Soccer Players

Poland12 participantsStarted 2026-03-10

Plain-language summary

This study aims to examine the acute effects of an isometric conditioning activity on sprinting, jumping, and change-of-direction performance in elite youth soccer players. Twelve male soccer players aged 15-19 years from a professional academy will participate in a randomized crossover study. Each participant will complete two experimental sessions separated by one week. During each session, participants will perform a standardized warm-up followed by baseline performance tests including countermovement jumps, drop jumps, a 30-m sprint test, and a 505 change-of-direction test. After baseline testing, participants will complete one of two conditions in randomized order: (1) an isometric conditioning activity consisting of unilateral standing isometric calf raises, or (2) a control condition consisting of low-intensity treadmill walking. Performance tests will be repeated seven minutes after the intervention to assess acute changes in neuromuscular performance. Jump performance will be assessed using a dual force plate system sampling at 1000 Hz, and sprint performance will be measured using electronic timing gates. The study will be conducted on an indoor athletics runway located in a gymnasium. The results will help determine whether isometric conditioning activities can acutely enhance explosive performance in youth soccer players.

Who can participate

Age range

14 Years – 19 Years

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: * Male soccer players aged 14-19 years * Currently participating in organized soccer training within a competitive soccer academy * Minimum of one year of experience in resistance training * Regular participation in both soccer training and resistance training for at least one year prior to the study * Free from neuromuscular and musculoskeletal disorders that could affect performance Exclusion Criteria: * Presence of any current musculoskeletal injury affecting the lower limbs. * History of neuromuscular disorders or medical conditions that could influence physical performance * Any injury or health condition preventing maximal sprinting or jumping efforts during testing.

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

Sprint time at 5 m and 30 m

Timeframe: Baseline and 7 minutes post-intervention

505 Change of Direction Test Time

Timeframe: Baseline and 7 minutes post-intervention

Trial details

NCT IDNCT07482254

SponsorThe Jerzy Kukuczka Academy of Physical Education in Katowice

Sponsor typeOTHER

Study typeINTERVENTIONAL

Primary completion2026-03-17

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