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Acute Effects of Bilateral Versus Unilateral Isometric Conditioning Activity on Jump Performance in Volleyball Players (BI-UNI ICA)

13 juli 2026 bijgewerkt door: The Jerzy Kukuczka Academy of Physical Education in Katowice

Acute Effects of Bilateral Versus Unilateral Isometric Conditioning Activity on Bilateral and Unilateral Jump Performance in Highly Trained Male Volleyball Players: A Randomized Crossover Trial

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.

Studie Overzicht

Toestand

Aanmelden op uitnodiging

Conditie

Interventie / Behandeling

Gedetailleerde beschrijving

This study is a randomized, counterbalanced crossover trial designed to examine the acute effects of unilateral and bilateral isometric conditioning activity on jump performance in highly trained male volleyball players. Fourteen participants will complete three experimental conditions on separate occasions in randomized order: bilateral isometric conditioning activity (BI), unilateral isometric conditioning activity (UNI), and a control condition (CTRL). Because each participant will complete all three conditions, every athlete will serve as his own control.

Each experimental session will begin with a standardized warm-up consisting of 5 minutes of cycling followed by bodyweight squats, walking lunges, thoracic spine rotations, and submaximal countermovement jumps. Baseline jump performance will then be assessed using two bilateral countermovement jumps and two single-leg jumps performed separately with each lower limb. The single-leg jump will involve take-off from one limb and landing on both limbs.

In the BI condition, participants will perform three sets of three maximal 3-second bilateral isometric squat contractions against an immovable resistance, with 3-minute recovery intervals between sets. In the UNI condition, participants will perform three sets of three maximal 3-second unilateral isometric squat contractions with each lower limb. The limbs will be alternated to reduce systematic differences in recovery time between sides. In the CTRL condition, participants will complete 9 minutes of low-intensity treadmill walking at 6 km/h.

Following each experimental condition, bilateral countermovement jump and single-leg jump performance will be reassessed at 4, 8, and 12 minutes. All jumps will be performed on force platforms. The primary outcome will be bilateral countermovement jump height. Secondary outcomes will include single-leg jump height and selected force-time variables derived from the bilateral and unilateral jump tests.

The primary objective of the study is to compare the acute effects of unilateral and bilateral isometric conditioning activity on bilateral countermovement jump performance. A secondary objective is to determine whether the type of conditioning activity produces task-specific effects on unilateral jump performance and whether the time course of post-activation performance enhancement differs between the BI and UNI conditions.

Studietype

Ingrijpend

Inschrijving (Geschat)

14

Fase

  • Niet toepasbaar

Contacten en locaties

In dit gedeelte vindt u de contactgegevens van degenen die het onderzoek uitvoeren en informatie over waar dit onderzoek wordt uitgevoerd.

Studie Locaties

  • Polen
    • Silesian Voivodeship
      • Katowice, Silesian Voivodeship, Polen, 40-065
        • Academy of Physical Education in Katowice

Deelname Criteria

Onderzoekers zoeken naar mensen die aan een bepaalde beschrijving voldoen, de zogenaamde geschiktheidscriteria. Enkele voorbeelden van deze criteria zijn iemands algemene gezondheidstoestand of eerdere behandelingen.

Geschiktheidscriteria

Leeftijden die in aanmerking komen voor studie

  • Kind
  • Volwassen
  • Oudere volwassene

Accepteert gezonde vrijwilligers

Ja

Beschrijving

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.

Studie plan

Dit gedeelte bevat details van het studieplan, inclusief hoe de studie is opgezet en wat de studie meet.

Hoe is de studie opgezet?

Ontwerpdetails

  • Primair doel: Fundamentele wetenschap
  • Toewijzing: Gerandomiseerd
  • Interventioneel model: Crossover-opdracht
  • Masker: Geen (open label)

Wapens en interventies

Deelnemersgroep / Arm
Interventie / Behandeling
Experimenteel: Bilateral Isometric Conditioning Activity
Participants will perform a bilateral isometric conditioning activity consisting of three sets of three maximal 3-second isometric squat contractions against an immovable resistance. Each set will be separated by 3 minutes of recovery.
Gedragsmatig: Bilateral Isometric Conditioning Activity
Three sets of three maximal 3-second bilateral isometric squat contractions performed against an immovable resistance, with 3-minute recovery intervals between sets. Participants will be instructed to push as hard and as fast as possible during each contraction.
Andere namen:
  • BI
Experimenteel: Unilateral Isometric Conditioning Activity
Participants will perform a unilateral isometric conditioning activity consisting of three sets of three maximal 3-second isometric squat contractions with each lower limb against an immovable resistance. The lower limbs will be alternated, and each set will be separated by 3 minutes of recovery.
Gedragsmatig: Unilateral Isometric Conditioning Activity
Three sets of three maximal 3-second unilateral isometric squat contractions performed with each lower limb against an immovable resistance. The lower limbs will be alternated, and 3-minute recovery intervals will be provided between sets. Participants will be instructed to push as hard and as fast as possible during each contraction.
Andere namen:
  • UNI
Experimenteel: Control Condition
Participants will complete 9 minutes of low-intensity treadmill walking at a speed of 6 km/h. This condition will serve as the control condition for comparison with the bilateral and unilateral isometric conditioning activities.
Gedragsmatig: Low-Intensity Treadmill Walking
All participants will complete all three experimental conditions in a randomized and counterbalanced order, with a standardized recovery interval between sessions. Each participant will therefore serve as his own control.

Wat meet het onderzoek?

Primaire uitkomstmaten

Uitkomstmaat
Maatregel Beschrijving
Tijdsspanne
Changes in Bilateral Countermovement Jump Height
Tijdsspanne: Baseline and 4, 8, and 12 minutes after each experimental condition
Bilateral countermovement jump height will be assessed using dual force platforms operating at a sampling frequency of 1000 Hz. Jump height will be calculated from center-of-mass take-off velocity using the impulse-momentum method and expressed in centimeters. Participants will perform two valid trials at each time point, and the mean value will be used for analysis. Changes from the condition-specific baseline will be compared between the bilateral isometric, unilateral isometric, and control conditions.
Baseline and 4, 8, and 12 minutes after each experimental condition
Changes in Single-Leg Jump Height
Tijdsspanne: Baseline and 4, 8, and 12 minutes after each experimental condition
Single-leg jump height will be assessed separately for the right and left lower limbs using force platforms. Each jump will be performed with take-off from one limb and landing on both limbs. Jump height will be calculated from center-of-mass take-off velocity using the impulse-momentum method and expressed in centimeters. Two valid trials will be performed with each limb at each time point, and the mean value for each limb will be used for analysis.
Baseline and 4, 8, and 12 minutes after each experimental condition

Secundaire uitkomstmaten

Uitkomstmaat
Maatregel Beschrijving
Tijdsspanne
Changes in Bilateral Countermovement Jump Modified Reactive Strength Index
Tijdsspanne: Baseline and 4, 8, and 12 minutes after each experimental condition
The modified reactive strength index during the bilateral countermovement jump will be calculated as jump height in meters divided by time to take-off in seconds and expressed in meters per second. Participants will perform two valid trials at each time point, and the mean value will be used for analysis.
Baseline and 4, 8, and 12 minutes after each experimental condition
Changes in Inter-Limb Concentric Impulse Asymmetry During the Bilateral Countermovement Jump
Tijdsspanne: Baseline and 4, 8, and 12 minutes after each experimental condition
Concentric impulse will be calculated separately for the right and left lower limbs from force-time data recorded using dual force platforms. Inter-limb asymmetry will be expressed as a percentage and calculated using the following formula: absolute difference between limbs divided by the higher limb value, multiplied by 100. A value of 0% represents perfect symmetry, while higher values indicate greater inter-limb asymmetry. The mean of two valid trials will be used for analysis.
Baseline and 4, 8, and 12 minutes after each experimental condition
Changes in Inter-Limb Single-Leg Jump Height Asymmetry
Tijdsspanne: Baseline and 4, 8, and 12 minutes after each experimental condition
Inter-limb asymmetry in single-leg jump height will be calculated from the mean jump height obtained separately for the right and left lower limbs. Asymmetry will be expressed as a percentage and calculated as the absolute difference between limbs divided by the higher limb value, multiplied by 100. A value of 0% represents perfect symmetry, while higher values indicate greater inter-limb asymmetry.
Baseline and 4, 8, and 12 minutes after each experimental condition

Medewerkers en onderzoekers

Hier vindt u mensen en organisaties die betrokken zijn bij dit onderzoek.

Sponsor

The Jerzy Kukuczka Academy of Physical Education in Katowice

Publicaties en nuttige links

De persoon die verantwoordelijk is voor het invoeren van informatie over het onderzoek stelt deze publicaties vrijwillig ter beschikking. Dit kan gaan over alles wat met het onderzoek te maken heeft.

Algemene publicaties

Studie record data

Deze datums volgen de voortgang van het onderzoeksdossier en de samenvatting van de ingediende resultaten bij ClinicalTrials.gov. Studieverslagen en gerapporteerde resultaten worden beoordeeld door de National Library of Medicine (NLM) om er zeker van te zijn dat ze voldoen aan specifieke kwaliteitscontrolenormen voordat ze op de openbare website worden geplaatst.

Bestudeer belangrijke data

Studie start (Geschat)

23 juli 2026

Primaire voltooiing (Geschat)

3 augustus 2026

Studie voltooiing (Geschat)

3 augustus 2026

Studieregistratiedata

Eerst ingediend

13 juli 2026

Eerst ingediend dat voldeed aan de QC-criteria

13 juli 2026

Eerst geplaatst (Werkelijk)

16 juli 2026

Updates van studierecords

Laatste update geplaatst (Werkelijk)

16 juli 2026

Laatste update ingediend die voldeed aan QC-criteria

13 juli 2026

Laatst geverifieerd

1 juli 2026

Meer informatie

Termen gerelateerd aan deze studie

Trefwoorden

Andere studie-ID-nummers

  • 2-X/2025/002

Plan Individuele Deelnemersgegevens (IPD)

Bent u van plan om gegevens van individuele deelnemers (IPD) te delen?

JA

Beschrijving IPD-plan

De-identified individual participant data will be shared upon reasonable request after publication of the study results. Requests should be directed to the corresponding author.

IPD-tijdsbestek voor delen

De-identified individual participant data and supporting documents will be available beginning 3 months after publication of the primary study results and will remain available for 5 years.

IPD-toegangscriteria voor delen

De-identified individual participant data and supporting documents will be made available to qualified researchers who submit a methodologically sound research proposal. Requests should be directed to the corresponding author and will be reviewed by the study investigators. Access will be granted for analyses consistent with the approved proposal and may require a data-use agreement.

IPD delen Ondersteunend informatietype

  • LEERPROTOCOOL
  • SAP

Informatie over medicijnen en apparaten, studiedocumenten

Bestudeert een door de Amerikaanse FDA gereguleerd geneesmiddel

Nee

Bestudeert een door de Amerikaanse FDA gereguleerd apparaatproduct

Nee

Deze informatie is zonder wijzigingen rechtstreeks van de website clinicaltrials.gov gehaald. Als u verzoeken heeft om uw onderzoeksgegevens te wijzigen, te verwijderen of bij te werken, neem dan contact op met register@clinicaltrials.gov. Zodra er een wijziging wordt doorgevoerd op clinicaltrials.gov, wordt deze ook automatisch bijgewerkt op onze website .

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