Athletic PerformanceNCT07483931
Priming Magnitude and Retention in Highly Trained Male Volleyball Players
A study testing Isometric Conditioning Activity (ICA) in people with Athletic Performance, run by The Jerzy Kukuczka Academy of Physical Education in Katowice at 1 site in Poland.
Trial 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. Read more about this study
- Who is it for?
- Any age, men onlyHealthy volunteers can take part
- Conditions the study is for
- Athletic Performance
- What is being tested?
- Isometric Conditioning Activity (ICA)
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 14 participants
- Where
- 1 sitePoland
- Study dates
- 5 Jan 2026to 17 Jan 2026
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages Any age
- Men only
- Healthy volunteers accepted
- Child, Adult, Older adult
Who may be able to join
- 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.
Who cannot join
- 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.
Trial locations and contacts
1 site in 1 country.
Poland1 site
Academy of Physical Education in Katowice
Katowice, Silesian Voivodeship, 40-065
About this study
Official title: 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.
Read more
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.
Read the 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.
- Conditions
- Athletic Performance
- Being tested
- Isometric Conditioning Activity (ICA), Volleyball-Specific Warm-Up (Control Condition)
- Keywords
- volleyball, priming, viscoelastic properties, skin surface temperature
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Isometric Conditioning Activity (ICA)Behavioural
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.
Volleyball-Specific Warm-Up (Control Condition)Behavioural
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.
| Study group | Role | What they receive |
|---|---|---|
| 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. Receives: 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. Receives: Behavioral: Volleyball-Specific Warm-Up (Control Condition) |
What is being measured
The primary outcome is the main question the study is designed to answer.
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).
Measured: Baseline, 6 and 30 hours post-intervention
Secondary outcomes (2)
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).
Measured: 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).
Measured: Baseline, 6 hours post-intervention, 30 hours post-intervention
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted19 Mar 2026
- Study start5 Jan 2026
- Primary completion17 Jan 2026
- Study completion17 Jan 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (4)Papers the sponsor has linked to this study.
- Other trials for Athletic PerformanceStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- 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.
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 14 participants (actual)
Sponsor and investigators
- Lead sponsor
- The Jerzy Kukuczka Academy of Physical Education in Katowice
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Jakub Jarosz, PhD, Principal investigator, Academy of Physical Education in Katowice
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07483931
- Sponsor's protocol ID
- ID 2-X/2025
- Status last verified
- Mar 2026
- First submitted
- 12 Mar 2026
- Last updated
- 19 Mar 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: 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.
Publications
Jarosz J, Drozd M, Gawel D, Wilk M, Helbin J, Krzysztofik M. Acute effects of isometric conditioning activity with different distribution contraction on countermovement jump performance in resistance trained participants. Sci Rep. 2025 May 15;15(1):16960. doi: 10.1038/s41598-025-02126-4.
PubMed 40374844Helbin 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.
PubMed 40981042Pereira 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.
PubMed 40837515Gepfert M, Terbalyan A, Helbin J, Thapa RK, Stastny P, Krzysztofik M, Jarosz J. Priming magnitude and retention in highly trained male volleyball players are unaffected by exercise type, muscle temperature, or viscoelasticity. BMC Sports Sci Med Rehabil. 2026 Apr 25;18(1):270. doi: 10.1186/s13102-026-01705-w.
PubMed 42035131
Study at a glance
From the registry record, last updated by the sponsor on 19 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Priming Magnitude and Retention in Highly Trained Male Volleyball Players Are Unaffected by Exercise Type, Muscle Temperature, or Viscoelasticity
- ClinicalTrials.gov ID
- NCT07483931
- Acronym / sponsor ID
- ID 2-X/2025
- Conditions
- Athletic Performance
- Keywords
- volleyball, priming, viscoelastic properties, skin surface temperature
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 14 participants (actual)
- Lead sponsor
- The Jerzy Kukuczka Academy of Physical Education in KatowiceUniversity, hospital or other
- Study start
- 5 Jan 2026 (actual)
- Primary completion
- 17 Jan 2026 (actual)
- Study completion
- 17 Jan 2026 (actual)
- First posted
- 19 Mar 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
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 design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind (outcomes assessor)
- Number of arms
- 2
- Model description
- 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.
| Arm | Type | Receives |
|---|---|---|
| Isometric Conditioning Activity (ICA) | Experimental | Behavioral: 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. |
| Volleyball-Specific Warm-Up (Control Condition) | Active comparator | Behavioral: 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. |
Who may qualify
- Sex
- Male only
- Healthy volunteers
- Accepted
- Age groups
- Child, Adult, Older adult
Key inclusion criteria (4 listed)
- 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.
Key exclusion criteria (7 listed)
- 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,
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| 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. | Behavioural | Isometric Conditioning Activity (ICA) |
| 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. | Behavioural | Volleyball-Specific Warm-Up (Control Condition) |
Primary outcome
Countermovement Jump Height (cm)
Time frame: Baseline, 6 and 30 hours post-intervention
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).
2 secondary outcomes
Quadriceps Skin Surface Temperature (°C)
Time frame: Baseline, 6 and 30 hours post-intervention
Rectus Femoris Muscle Stiffness (N/m)
Time frame: Baseline, 6 hours post-intervention, 30 hours post-intervention
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 19 Mar 2026.
- Background: PubMed 40374844Jarosz J, Drozd M, Gawel D, Wilk M, Helbin J, Krzysztofik M. Acute effects of isometric conditioning activity with different distribution contraction on countermovement jump performance in resistance trained participants. Sci Rep. 2025 May 15;15(1):16960. doi: 10.1038/s41598-025-02126-4.
- Background: PubMed 40981042Helbin 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.
- Background: PubMed 40837515Pereira 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.
- Derived from this study: PubMed 42035131Gepfert M, Terbalyan A, Helbin J, Thapa RK, Stastny P, Krzysztofik M, Jarosz J. Priming magnitude and retention in highly trained male volleyball players are unaffected by exercise type, muscle temperature, or viscoelasticity. BMC Sports Sci Med Rehabil. 2026 Apr 25;18(1):270. doi: 10.1186/s13102-026-01705-w.
- Individual participant dataSharing planned: Yes. 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.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Jakub Jarosz, PhD principal investigator
Academy of Physical Education in Katowice
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Isometric Conditioning Activity (ICA) in people with Athletic Performance, run by The Jerzy Kukuczka Academy of Physical Education in Katowice at 1 site in Poland.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 7 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 19 Mar 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Poland. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Countermovement Jump Height (cm) (time frame: Baseline, 6 and 30 hours post-intervention). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07483931, which also lists 4 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 19 Mar 2026.