Priming Magnitude and Retention in Highly Trained Male Volleyball Players

Priming Magnitude and Retention in Highly Trained Male Volleyball Players Are Unaffected by Exercise Type, Muscle Temperature, or Viscoelasticity

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.

Study Overview

• Status: Completed
• Conditions: Athletic Performance
• Intervention / Treatment: Behavioral: Isometric Conditioning Activity (ICA); Behavioral: Volleyball-Specific Warm-Up (Control Condition)

Detailed Description

This study investigated the delayed effects of a maximal isometric conditioning activity on neuromuscular performance and muscle mechanical properties in highly trained male volleyball players. Conditioning activities are often used in sport to induce post-activation performance enhancement (PAPE), which may improve explosive performance such as jumping. While most studies have examined the acute effects occurring within minutes after the conditioning activity, less is known about possible delayed responses occurring several hours later.

The aim of this study was to determine whether a maximal isometric conditioning protocol could influence countermovement jump performance, muscle viscoelastic properties, and skin surface temperature several hours after its application. The study also compared these effects with those produced by a volleyball-specific warm-up routine commonly used in training and competition settings.

A randomized crossover design was used. Participants completed two experimental conditions on separate occasions: (1) a maximal isometric conditioning activity and (2) a volleyball-specific warm-up serving as a control condition. All participants were highly trained male volleyball players with experience in resistance and plyometric training.

Neuromuscular performance was assessed using countermovement jump tests. In addition, muscle mechanical properties of the rectus femoris were evaluated using a myotonometric device to determine muscle stiffness and other viscoelastic characteristics. Skin surface temperature over the quadriceps muscle group was also measured to monitor potential physiological responses to the conditioning activity.

Measurements were collected at baseline before the intervention and repeated 6 hours and 30 hours after the conditioning protocol or the control warm-up. This design allowed the researchers to examine whether a single high-intensity isometric stimulus could induce delayed changes in neuromuscular performance or muscle properties.

Understanding delayed performance responses to conditioning activities may help coaches and athletes better plan training sessions and competition preparation. If such activities can produce beneficial effects several hours later, they could be strategically implemented earlier in the day to optimize performance during later training sessions or competitions.

• Study Type: Interventional
• Enrollment (Actual): 14
• Phase: Not Applicable

Contacts and Locations

Study Locations

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

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

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.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Isometric Conditioning Activity (ICA); 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); 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.
Active Comparator: Volleyball-Specific Warm-Up (Control Condition); 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); 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.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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 Outcome Measures

Outcome Measure	Measure Description	Time Frame
Quadriceps Skin Surface Temperature (°C)	Skin surface temperature of the quadriceps measured using infrared thermography (FLIR E54, FLIR Systems, USA). Thermal images are collected under standardized environmental conditions, and the region of interest is defined over the rectus femoris muscle. Temperature values will be reported in degrees Celsius (°C).	Baseline, 6 and 30 hours post-intervention
Rectus Femoris Muscle Stiffness (N/m)	Muscle stiffness of the rectus femoris measured using a handheld digital myotonometer (MyotonPRO, Myoton AS, Tallinn, Estonia). The device applies a brief mechanical impulse (0.4 N for 15 ms) to the muscle and records the resulting oscillations of the tissue. Stiffness values are calculated from the oscillation response as an indicator of the muscle's resistance to external deformation. Measurements are performed at the midpoint of the rectus femoris with the participant in a relaxed supine position. For each measurement site, the mean value of five consecutive impulses is used for analysis. Muscle stiffness will be reported in Newtons per meter (N/m).	Baseline, 6 hours post-intervention, 30 hours post-intervention

Collaborators and Investigators

• Sponsor: The Jerzy Kukuczka Academy of Physical Education in Katowice
• Investigators: Principal Investigator: Jakub Jarosz, PhD, Academy of Physical Education in Katowice

Publications and helpful links

General Publications

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

Study record dates

Study Major Dates

• Study Start (Actual): January 5, 2026
• Primary Completion (Actual): January 17, 2026
• Study Completion (Actual): January 17, 2026

Study Registration Dates

• First Submitted: March 12, 2026
• First Submitted That Met QC Criteria: March 16, 2026
• First Posted (Actual): March 19, 2026

Study Record Updates

• Last Update Posted (Actual): March 19, 2026
• Last Update Submitted That Met QC Criteria: March 16, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: priming; volleyball; viscoelastic properties; skin surface temperature
• Other Study ID Numbers: ID 2-X/2025

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: 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 Sharing 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.
• IPD Sharing 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.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No