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

Enrolling by invitation · Not applicable

Conditions studied: Athletic Performance, Volleyball, Isometric Strength Training, Post Activation Potentiation

In brief

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.

Key facts

Study ID

NCT07709104

Run by

The Jerzy Kukuczka Academy of Physical Education in Katowice

People needed

14

Starts

2026-07-23

Expected to finish

2026-08-03

Last updated by the study team

2026-07-16

Who can join

Age: any. Sex: male. Healthy volunteers: accepted.

You may qualify if…

• 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.

You may not qualify if…

• 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.

Where it is running

• Academy of Physical Education in Katowice — Katowice, Silesian Voivodeship, Poland

Full record on ClinicalTrials.gov

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