Priming Magnitude and Retention in Highly Trained Male Volleyball Players

NCT07483931 | Completed

• 1 other identifier: ID 2-X/2025
• Study Type: interventional
• Target: 14
• Locations: 1 country
• Sites: 1

Brief Summary

This study examined whether a short, high-intensity isometric exercise can influence physical performance and muscle characteristics several hours after it is performed. Specifically, the study compared the effects of a maximal isometric conditioning activity with a typical volleyball-specific warm-up routine. Highly trained male volleyball players participated in the study. Each participant completed two experimental conditions in a randomized crossover design: (1) a maximal isometric conditioning activity and (2) a volleyball-specific warm-up used as a control condition. The researchers evaluated changes in countermovement jump performance, muscle viscoelastic properties of the rectus femoris, and skin surface temperature over the quadriceps muscle. Measurements were taken before the intervention and again 6 hours and 30 hours later to determine whether the conditioning activity produced delayed improvements in neuromuscular performance. Understanding these delayed effects may help coaches and athletes optimize training and competition preparation strategies. The results of this study may provide insights into whether specific conditioning exercises can enhance or maintain explosive performance in volleyball players several hours after they are performed.

Conditions

Athletic Performance

Keywords

volleyball; priming; viscoelastic properties; skin surface temperature

Outcome Measures

Primary Outcomes (1)

• Countermovement Jump Height (cm)

  Vertical jump height measured during a countermovement jump using a dual force plate system (ForceDecks, VALD Performance) sampling at 1000 Hz. Participants perform maximal countermovement jumps with hands on hips. Jump height is calculated from center-of-mass velocity at take-off using the impulse-momentum method. Jump height will be reported in centimeters (cm).

  Baseline, 6 and 30 hours post-intervention

Secondary Outcomes (2)

• Quadriceps Skin Surface Temperature (°C)

  Baseline, 6 and 30 hours post-intervention

• Rectus Femoris Muscle Stiffness (N/m)

  Baseline, 6 hours post-intervention, 30 hours post-intervention

Study Arms (2)

Isometric Conditioning Activity (ICA)

EXPERIMENTAL

Participants performed a maximal isometric conditioning activity designed to provide a high-intensity neuromuscular stimulus to the knee extensors. The protocol consisted of repeated maximal isometric back-squat contractions performed at a fixed knee joint angle. Neuromuscular performance, muscle viscoelastic properties, and quadriceps skin surface temperature were measured before the intervention and again 6 hours and 30 hours after the session.

Behavioral: Isometric Conditioning Activity (ICA)

Volleyball-Specific Warm-Up (Control Condition)

ACTIVE COMPARATOR

Participants performed a volleyball-specific warm-up routine commonly used before training sessions. This condition served as the control condition to compare the effects of the isometric conditioning activity.

Behavioral: Volleyball-Specific Warm-Up (Control Condition)

Interventions

Isometric Conditioning Activity (ICA) BEHAVIORAL

Participants performed a maximal voluntary isometric back-squat protocol consisting of 3 sets of 5 repetitions of 3-second maximal contractions at a knee joint angle of 120°. Each set was separated by 3 minutes of rest. The protocol was performed on a fixed barbell setup designed to allow maximal isometric force production.

Isometric Conditioning Activity (ICA)

Volleyball-Specific Warm-Up (Control Condition) BEHAVIORAL

Participants performed a 9-minute volleyball-specific warm-up consisting of mobility exercises and plyometric drills designed to prepare athletes for explosive movements typical for volleyball.

Volleyball-Specific Warm-Up (Control Condition)

Eligibility Criteria

• Sex: male
• Healthy Volunteers: Yes
• Age Groups: Child (0-17), Adult (18-64), Older Adult (65+)

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.

Sponsors & Collaborators

• The Jerzy Kukuczka Academy of Physical Education in Katowice: lead

Study Sites (1)

Academy of Physical Education in Katowice

Katowice, Silesian Voivodeship, 40-065, Poland

Location

Related Publications (3)

• Jarosz J,Drozd M,Gawel D,Wilk M,Helbin J,Krzysztofik M

  BACKGROUND

• Helbin J, Gawel D, Terbalyan A, Wilk M, Krzysztofik M, Lum D, Jarosz J. Acute Effects of Isometric Contraction Distribution on Jump Performance in Volleyball Players. J Funct Morphol Kinesiol. 2025 Sep 9;10(3):343. doi: 10.3390/jfmk10030343.

  PMID: 40981042 BACKGROUND

• Pereira LA, Zmijewski P, Golas A, Kotula K, McGuigan MR, Loturco I. Priming Exercises and Their Potential Impact on Speed and Power Performance: A Narrative Review. J Hum Kinet. 2025 Jun 25;98:153-168. doi: 10.5114/jhk/204371. eCollection 2025 Jul.

  PMID: 40837515 BACKGROUND

Study Officials

• Jakub Jarosz, PhD

  Academy of Physical Education in Katowice

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: OUTCOMES ASSESSOR
• Masking Details: Complete blinding of participants and intervention providers was not feasible due to the visibly distinct nature of the isometric conditioning activity (ICA) and control activation (CON) protocols. However, investigators responsible for outcome assessments (spike-specific test, spike velocity, and countermovement jump performance) were blinded to the intervention allocation. In addition, researchers performing the statistical analyses remained blinded to the intervention condition to minimize potential assessment and analytical bias. Participants were not informed about the sequence of experimental conditions until completion of the study.
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: This study used a randomized, counterbalanced crossover design in which all participants completed two experimental conditions: an isometric conditioning activity (ICA) and a volleyball-specific activation control condition (CON). The order of conditions was randomly assigned, and each condition was separated by a 7-day washout period. In each experimental microcycle, participants performed the assigned intervention during a morning session. Performance and physiological outcomes were assessed at baseline and again approximately 6 hours and 30 hours after the intervention. This within-subject crossover design allowed each participant to serve as their own control, reducing inter-individual variability.

Study Record Dates

• First Submitted: March 12, 2026
• First Posted: March 19, 2026
• Study Start: January 5, 2026
• Primary Completion: January 17, 2026
• Study Completion: January 17, 2026
• Last Updated: March 19, 2026

Record last verified: 2026-03

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP
• Time Frame: Individual participant data and supporting documents will be available beginning 3 months after publication of the study results and ending 5 years following publication.
• Access Criteria: Researchers may request access to de-identified individual participant data by contacting the corresponding author. Data will be shared upon reasonable request for scientific research purposes.

Locations

PL (1)