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Acute Effects of Bilateral Versus Unilateral Isometric Conditioning Activity on Jump Performance in Volleyball Players

NCT07709104 · Status: ENROLLING_BY_INVITATION · Phase: NA · Type: INTERVENTIONAL · Enrollment: 14

Last updated 2026-07-16

No results posted yet for this study

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.

Conditions

  • Athletic Performance
  • Volleyball
  • Isometric Strength Training
  • Post Activation Potentiation

Interventions

BEHAVIORAL

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.

BEHAVIORAL

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.

BEHAVIORAL

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.

Sponsors & Collaborators

  • The Jerzy Kukuczka Academy of Physical Education in Katowice

    lead OTHER

Study Design

Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
NONE
Model
CROSSOVER

Eligibility

Sex
MALE
Healthy Volunteers
Yes

Timeline & Regulatory

Start
2026-07-23
Primary Completion
2026-08-03
Completion
2026-08-03

Countries

  • Poland

Study Locations

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Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT07709104 on ClinicalTrials.gov