Neuromuscular FunctionNCT06982937
Mechanistic Drivers of Acute PAPE Responsiveness: Muscle Architecture, Contractile Kinetics, and Excitability in a Randomized Controlled Trial
A study testing High-Intensity Half-Squat and Treadmill running in people with Neuromuscular Function and Muscle Activation, run by The Jerzy Kukuczka Academy of Physical Education in Katowice at 1 site in Poland.
Trial summary
The goal of this study is to find out if one short set of heavy half-squats can help football players jump higher right away-and to understand what happens inside their muscles and nerves to make that boost happen. Read more about this study
- Who is it for?
- Ages 18 to 23 years, men onlyHealthy volunteers can take part
- Conditions the study is for
- Neuromuscular Function, Muscle Activation, Postactivation Potentiation
- What is being tested?
- High-Intensity Half-Squat and Treadmill running
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 44 participants
- Where
- 1 sitePoland
- Study dates
- 2 Feb 2025to 25 Jul 2025
- Phase
- Interventional
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
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 18 to 23 years
- Men only
- Healthy volunteers accepted
- Adult
Who may be able to join
- Male football players aged 18-23 years
- Minimum of 3 structured training sessions per week for the past 6 months
- No history of lower-limb musculoskeletal injuries (e.g., ligament sprain, muscle tear) within the past 2 months
- No diagnosed dermatological conditions affecting electrode placement (e.g., psoriasis, eczema)
- No cardiovascular disease (e.g., hypertension, arrhythmia)
- No neuromuscular disorders (e.g., neuropathy, myopathy) on clinical examination
- Able to complete a 1RM half-squat protocol and countermovement jump without pain
Who cannot join
- Use of performance-enhancing supplements/medications within 2 weeks prior to enrollment
- Missed more than 4 scheduled training sessions per month over the past 2 months
- Blood pressure >140/90 mmHg at rest or resting heart rate >90 bpm
- Any contraindication to electrical stimulation (e.g., pacemaker, implanted metal device)
- Failure to provide written informed consent or withdrawal of consent at any time
Trial locations and contacts
1 site in 1 country.
Poland1 site
The Jerzy Kukuczka Academy of Physical Education in Katowice
Katowice, Silesian Voivodeship, 40-065
About this study
Official title: A Mechanistic Perspective on Post-Activation Performance Enhancement Responsiveness: A Randomized Controlled Study of Acute Changes in Muscle Architecture, Contractile Property Kinetics, and Muscle Excitability
The goal of this study is to find out if one short set of heavy half-squats can help football players jump higher right away-and to understand what happens inside their muscles and nerves to make that boost happen.
Key questions
Read more
- Will performing 2-3 half-squats at 90% of one-rep max give a bigger jump boost than jogging on a treadmill for five minutes?
- After each warm-up, how do muscle speed and stiffness, muscle size and fiber angle, and nerve signals change over the next 12 minutes?
- Does each player's contribution of fast and slow muscle fibers affect how much and how long their jump improves?
Study Plan Researches will invite 44 healthy football players, ages 18-21, who train regularly and meet our health rules. No one will know which warm-up each player does until the end.
Participants will:
- Get baseline tests of jump height, muscle speed and stiffness (using a harmless electrical sensor), muscle size and fiber angle (using ultrasound), and nerve signals (using sticky pads on the skin).
- Be randomly assigned to either:
- Heavy-squat group: 2-3 half-squats at 90% of their one-rep max
- Jogging group: easy jog or walk on a treadmill for five minutes
- Repeat all tests right after the warm-up and again at 4, 6, 8, 10, and 12 minutes to see how jump height and all muscle and nerve measures change over time.
- Have their muscle fiber mix estimated from the first muscle-speed test to see if fiber type explains who gets the biggest jump boost.
All tests are safe, painless, and approved by an ethics board. Players can stop at any time without giving a reason. This study will help athletes and coaches choose the best warm-up to get stronger, faster jumps right before a game or practice.
Read the detailed description
Design and setting. The study will be a randomized, assessor-blinded, parallel-group trial conducted in university sport-science laboratories. Two arms will be used: a heavy half-squat conditioning activity and an active warm-up control. All procedures will follow written standard operating protocols.
Participants. Healthy, 44 resistance-trained male football/soccer players will be screened and will provide written informed consent. Eligibility will require regular training and the absence of musculoskeletal, neurological, dermatological, or cardiovascular contraindications to high-intensity exercise or peripheral electrical stimulation. Testing will be scheduled on a consistent team microcycle day to control for prior load.
Visit schedule. Visit 1 - Familiarization and strength assessment. Medical screening, anthropometrics, and a progressive half-squat session will determine individual one-repetition maximum (1RM). Squat depth will be standardized at approximately 90° knee flexion with rack pins and spotters.
Visit 2 - Experimental session. After compliance checks (sleep, diet, caffeine), participants will complete a structured general warm-up. Baseline tensiomyography (TMG) of the dominant vastus lateralis (VL), surface electromyography (EMG) normalization to maximal voluntary contraction (MVC), and baseline countermovement-jump (CMJ) testing will be completed. The allocated intervention will be delivered, followed by repeated CMJ testing with concurrent EMG at one-minute intervals. Ultrasound imaging will be obtained at baseline and after the final CMJ series.
Arms and interventions. Experimental arm (conditioning activity). One set of 2-3 free-weight half-squats at ~90% 1RM will be performed from a rack with spotter supervision.
Control arm (active warm-up). Approximately five minutes of treadmill running at light-moderate intensity (0% incline) will be completed.
Outcome measures and timing. Primary outcome. Change in CMJ height at each minute from 4 to 12 minutes after the intervention, relative to baseline (5 prespecified post-intervention time points at 2-min resolution).
CMJ-derived flight time, take-off velocity (device-derived where available), and individualized responder categorization at each minute using a predefined smallest-detectable-change threshold anchored to familiarization reliability.
Exploratory relationships between neuromuscular phenotype (TMG) and the magnitude/timing of CMJ responses.
Exploratory changes in VL architecture (ultrasound thickness, pennation, derived fascicle length) across the session.
Electromyography outcome (recorded for every jump). For every CMJ, surface EMG amplitude will be recorded and expressed as a percentage of the participant's maximal voluntary contraction (%MVC). The primary EMG variables will be RMS EMG (%MVC) across the propulsive phase and peak RMS (%MVC) within the final 200-250 ms before take-off.
Following the intervention, one CMJ will be performed at minute 1 and subsequently at each exact minute through minute 12. If a jump is technically invalid, a single replacement attempt will be permitted within that minute. Standardized instructions and hand placement will be maintained for all trials.
Instrumentation and standardization. CMJ. Jumps will be measured with a validated optical timing system on a non-slip surface. Foot placement and countermovement depth will be self-selected but replicated across trials.
Electromyography. Wireless surface EMG will be recorded from VL (with optional rectus femoris and biceps femoris for context). Skin will be shaved, lightly abraded, and cleaned with alcohol; disposable Ag/AgCl electrodes with ~20-mm inter-electrode distance will be placed along the fiber direction following SENIAM guidance and skin-marked for repeatability. Signals will be sampled at ≥2,000 Hz, band-pass filtered 20-450 Hz, notch-filtered at mains frequency, full-wave rectified, and converted to RMS with a 50-ms window. EMG and CMJ timing will be synchronized via hardware trigger; take-off will be identified from the optical system to define the propulsive phase. Prior to experimental jumps, three 3-5 s isometric knee-extension MVCs at ~60° knee flexion will be performed against a fixed dynamometer or rigid strap with strong verbal encouragement and 2-3 min rests. The highest stable 500-ms RMS epoch will define 100% MVC for normalization.
Tensiomyography. VL contractile properties (Td, Tc, Tr, Ts, Dm, and displacement-rate metrics) will be obtained with a displacement sensor at constant pre-tension. Participants will be supine with the knee supported at ~120°. Electrode positions will be standardized and skin-marked; single twitches will be delivered with inter-stimulus intervals ≥10 s. A validated multivariable model will estimate %MHC-I as a non-invasive phenotype proxy.
Ultrasound. B-mode imaging with a linear-array transducer will quantify VL thickness and pennation at mid-thigh; probe alignment will follow fascicle direction with minimal gel and consistent pressure. Fascicle length will be estimated from thickness and pennation. Three longitudinal images per site will be acquired and averaged.
Randomization and masking. Participants will be randomized using concealed, sequentially numbered envelopes prepared by personnel independent of data collection. CMJ/EMG assessors will be blinded to allocation and will operate in a separate space from the intervention station. Data files will contain coded identifiers only.
Participant flow during Visit 2. Participants will arrive for compliance checks. A standardized warm-up will be performed. MVC procedures for EMG normalization will be completed. Baseline TMG and baseline CMJ with EMG will be recorded. The allocated intervention will be administered. CMJ with EMG will be recorded at minutes 1-12. Ultrasound imaging will be performed at the end of the series, followed by cool-down and debrief.
Responder framework. At each minute, CMJ change will be classified for individual interpretation as positive, no-change, or negative using a priori smallest-detectable-change thresholds derived from familiarization reliability.
Safety and risk mitigation. Heavy squats will be performed in racks with pins and spotters; participants will have been familiarized with high loads during Visit 1. TMG will use brief single twitches with conservative current progression and long inter-stimulus intervals. Surface EMG and ultrasound are non-invasive; electrode preparation and probe handling will follow hygienic and standardized procedures. Adverse events and discomfort will be documented, and testing will cease if safety concerns arise.
Data capture and quality assurance. All devices will be calibrated before each session. Electrode and probe sites will be marked to ensure within-session consistency. Operators will complete training and inter-rater checks before data collection. Raw data will be stored on encrypted, access-controlled servers with audit trails. Predefined rules will govern artifact handling, trial acceptance, and protocol deviations.
Confidentiality and data handling. Participant identities will be coded. Source documents and electronic records will be stored on encrypted drives with restricted access limited to authorized personnel.
Discontinuation and withdrawal. Participants may withdraw at any time. Investigators will discontinue participation in the case of adverse signs, illness, or non-compliance. Data collected to the point of withdrawal will be retained unless the participant requests removal under the approved ethics framework.
- Conditions
- Neuromuscular Function, Muscle Activation, Postactivation Potentiation, Ultrasonography, Tensiomyography, Contraction
- Being tested
- High-Intensity Half-Squat, Treadmill running
- Keywords
- MHC-I, Tensiomyography, Ulstrasonography, Electromyogpraphy, Postactivation potentiation, PAPE
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
High-Intensity Half-SquatOther
Participants in the conditioning arm perform a single set of two to three half-squats with a free-weight barbell set at 90% of their one-rep max (1RM). Each squat is taken down until the thigh is parallel to the floor (knee at ~90°) and then driven upward as explosively as possible.
Treadmill runningOther
Participants engaged in a standardized 5-minute treadmill warm-up. Participants were instructed to walk at a moderate, self-selected pace of approximately 7-9 km/h, maintaining an incline of 0%. Heart rate and perceived exertion were monitored to ensure that the activity remained within a light-intensity range (Borg scale: 6-11).
| Study group | Role | What they receive |
|---|---|---|
| High-Intensity Half-Squat | Experimental | Participants perform one set half-squats using a free-weight barbell in a squat rack to elicit PAPE Receives: Other: High-Intensity Half-Squat |
| Treadmill running | Active comparator | Participants jogged on a level treadmill for five minutes at a comfortable pace to provide general muscle warm-up without significant neuromuscular priming. Receives: Other: Treadmill running |
What is being measured
The primary outcome is the main question the study is designed to answer.
Jump Height 4 Minute
Measured: 4 minutes post-intervention
Jump Height 6 Minute
Measured: 6 minutes post-intervention
Jump Height 8 Minute
Measured: 8 minutes post-intervention
Jump Height 10 Minute
Measured: 10 minutes post-intervention
Jump Height 12 Minute
Measured: 12 minute post-intervention
Muscle Thickness Post
Measured: Immediate post-intervention
Muscle Thickness 4 Minute
Measured: 4 minute post-intervention (single session)
Muscle Thickness 6 Minute
Measured: 6 minutes post-intervention
Muscle Thickness 8 Minute
Measured: 8 minutes post-intervention
Muscle Thickness 10 Minute
Measured: 10 minutes post-intervention
Muscle Thickness 12 Minute
Measured: 12 minutes post-intervention
Pennation Angle Post
Measured: Immediate post-intervention
Pennation Angle 4 Minute
Measured: 4 minutes post-intervention
Pennation Angle 6 Minute
Measured: 6 minutes post-intervention
Pennation Angle 8 Minute
Measured: 8 minutes post-intervention
Pennation Angle 10 Minute
Measured: 10 minutes post-intervention
Pennation Angle 12 Minute
Measured: 12 minutes post-intervention
Fascicle Length Post
Measured: Immediate post-intervention
Fascicle Length 4 Minute
Measured: 4 minutes post-intervention
Fascicle Length 6 Minute
Measured: 6 minutes post-intervention
Fascicle Length 8 Minute
Measured: 8 minutes post-intervention
Fascicle Length 10 Minute
Measured: 10' minutes post-intervention
Fascicle Length 12 Minute
Measured: 12 minutes post-intervention
Muscle Activation During Countermovement Jump in 4 Minute
Surface electromyographic activity (voluntary activation level) of the vastus lateralis muscle recorded during a standardized countermovement jump. Higher values indicate greater muscle activation of the vastus lateralis during the jump, whereas lower values indicate reduced activation.
Results presented as % from maximal voluntary contraction (MVC) during the procedure of normalization (locked at 90 degrees knee extension)
Measured: 4 minutes post-intervention
Muscle Activation During Countermovement Jump in 6 Minute
Surface electromyographic activity (voluntary activation level) of the vastus lateralis muscle recorded during a standardized countermovement jump. Higher values indicate greater muscle activation of the vastus lateralis during the jump, whereas lower values indicate reduced activation.
Results presented as % from maximal voluntary contraction (MVC) during the procedure of normalization (locked at 90 degrees knee extension)
Measured: 6 minutes post-intervention
Muscle Activation During Countermovement Jump in 8 Minute
Surface electromyographic activity (voluntary activation level) of the vastus lateralis muscle recorded during a standardized countermovement jump. Higher values indicate greater muscle activation of the vastus lateralis during the jump, whereas lower values indicate reduced activation.
Results presented as % from maximal voluntary contraction (MVC) during the procedure of normalization (locked at 90 degrees knee extension)
Measured: 8 minutes post-intervention
Muscle Activation During Countermovement Jump in 10 Minute
Surface electromyographic activity (voluntary activation level) of the vastus lateralis muscle recorded during a standardized countermovement jump. Higher values indicate greater muscle activation of the vastus lateralis during the jump, whereas lower values indicate reduced activation.
Results presented as % from maximal voluntary contraction (MVC) during the procedure of normalization (locked at 90 degrees knee extension)
Measured: 10 minutes post-intervention
Muscle Activation During Countermovement Jump in 12 Minute
Surface electromyographic activity (voluntary activation level) of the vastus lateralis muscle recorded during a standardized countermovement jump. Higher values indicate greater muscle activation of the vastus lateralis during the jump, whereas lower values indicate reduced activation.
Results presented as % from maximal voluntary contraction (MVC) during the procedure of normalization (locked at 90 degrees knee extension)
Measured: 12 minutes post-intervention
Contraction Time Post
Measured: Immediate post-intervention
Contraction Time 4 Minute
Measured: 4 minutes post-intervention
Contraction Time 6 Minute
Measured: 6 minutes post-intervention
Contraction Time 8 Minute
Measured: 8 minutes post-intervention
Contraction Time 10 Minute
Measured: 10 minutes post-intervention
Contraction Time 12 Minutes
Measured: 12 post-intervention
Delay Time Post
Measured: Immediate post-intervention
Delay Time 4 Minute
Measured: 4 minutes post-intervention
Delay Time 6 Minute
Measured: 6 minutes post-intervention
Delay Time 8 Minute
Measured: 8 minutes post-intervention
Delay Time 10 Minute
Measured: 10 minutes post-intervention
Delay Time 12 Minute
Measured: 12 minutes post-intervention
Relaxation Time Post
Measured: Immediate post-intervention
Relaxation Time 4 Minute
Measured: 4 minutes post-intervention
Relaxation Time 6 Minute
Measured: 6 minutes post-intervention
Relaxation Time 8 Minute
Measured: 8 minutes post-intervention
Relaxation Time 10 Minute
Measured: 10 minutes post-intervention
Relaxation Time 12 Minute
Measured: 12 minutes post-intervention
Muscle Displacement Post
Measured: Immediate post-intervention
Muscle Displacement 4 Minute
Measured: 4 minutes post-intervention
Muscle Displacement 6 Minute
6' post intervention measure
Measured: 6 minutes post-intervention
Muscle Displacement 8 Minute
Measured: 8 minutes post-intervention
Muscle Displacement 10 Minute
Measured: 12 minutes post-intervention
Muscle Displacement 12 Minute
Measured: 12 minutes post-intervention
Sustain Time Post
Measured: Immediate post-intervention
Sustain Time 4 Minute
Measured: 4 minutes post-intervention
Sustain Time 6 Minute
Measured: 6 minutes post-intervention
Sustain Time 8 Minute
Measured: 8 minutes post-intervention
Sustain Time 10 Minutes
Measured: 10 minutes post-intervention
Sustain Time 12 Minute
Measured: 12 minutes post-intervention
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 May 2025
- Study start2 Feb 2025
- Primary completion25 Jun 2025
- Study completion25 Jul 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Publications (2)Papers the sponsor has linked to this study.
- Other trials for Neuromuscular FunctionStudies 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
- Parallel groups
- Masking
- Triple blind
- Who is masked
- Participant, Care provider, Outcomes assessor
- Enrolment
- 44 participants (actual)
Sponsor and investigators
- Lead sponsor
- The Jerzy Kukuczka Academy of Physical Education in Katowice
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Artur Terbalyan, The Jerzy Kukuczka Academy of Physical Education in Katowice
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06982937
- Sponsor's protocol ID
- 01/2023
- Status last verified
- Nov 2025
- First submitted
- 5 May 2025
- Last updated
- 16 Dec 2025
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Data collected during this study will be available upon reasonable request. Individual participant data sharing will be considered on a case-by-case basis, subject to ethical approval, participant consent, and data protection regulations. Data requests must clearly outline the purpose, intended analyses, and measures taken to ensure confidentiality and data security.
Publications
Simunic B, Degens H, Rittweger J, Narici M, Mekjavic IB, Pisot R. Noninvasive estimation of myosin heavy chain composition in human skeletal muscle. Med Sci Sports Exerc. 2011 Sep;43(9):1619-25. doi: 10.1249/MSS.0b013e31821522d0.
PubMed 21552151Terbalyan A, Skotniczny K, Matuszczyk F, Roczniok R, Zak M. Triangulating lower-extremity neuromuscular function in soccer players: The incremental value of twitch kinetics and neural activation over muscle architecture in performance testing. J Sports Sci. 2026 Oct 25:1-15. doi: 10.1080/02640414.2026.2750650. Online ahead of print.
PubMed 42927465
Study at a glance
From the registry record, last updated by the sponsor on 16 Dec 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Mechanistic Perspective on Post-Activation Performance Enhancement Responsiveness: A Randomized Controlled Study of Acute Changes in Muscle Architecture, Contractile Property Kinetics, and Muscle Excitability
- ClinicalTrials.gov ID
- NCT06982937
- Acronym / sponsor ID
- 01/2023
- Conditions
- Neuromuscular Function, Muscle Activation, Postactivation Potentiation, Ultrasonography, Tensiomyography, Contraction
- Keywords
- MHC-I, Tensiomyography, Ulstrasonography, Electromyogpraphy, Postactivation potentiation, PAPE
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 44 participants (actual)
- Lead sponsor
- The Jerzy Kukuczka Academy of Physical Education in KatowiceUniversity, hospital or other
- Study start
- 2 Feb 2025 (actual)
- Primary completion
- 25 Jun 2025 (actual)
- Study completion
- 25 Jul 2025 (actual)
- First posted
- 21 May 2025 (actual)
- Results
- Posted 16 Dec 2025
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The goal of this study is to find out if one short set of heavy half-squats can help football players jump higher right away-and to understand what happens inside their muscles and nerves to make that boost happen.
Key questions
- Will performing 2-3 half-squats at 90% of one-rep max give a bigger jump boost than jogging on a treadmill for five minutes?
- After each warm-up, how do muscle speed and stiffness, muscle size and fiber angle, and nerve signals change over the next 12 minutes?
- Does each player's contribution of fast and slow muscle fibers affect how much and how long their jump improves?
Study Plan Researches will invite 44 healthy football players, ages 18-21, who train regularly and meet our health rules. No one will know which warm-up each player does until the end.
Participants will:
- Get baseline tests of jump height, muscle speed and stiffness (using a harmless electrical sensor), muscle size and fiber angle (using ultrasound), and nerve signals (using sticky pads on the skin).
- Be randomly assigned to either:
- Heavy-squat group: 2-3 half-squats at 90% of their one-rep max
- Jogging group: easy jog or walk on a treadmill for five minutes
- Repeat all tests right after the warm-up and again at 4, 6, 8, 10, and 12 minutes to see how jump height and all muscle and nerve measures change over time.
- Have their muscle fiber mix estimated from the first muscle-speed test to see if fiber type explains who gets the biggest jump boost.
All tests are safe, painless, and approved by an ethics board. Players can stop at any time without giving a reason. This study will help athletes and coaches choose the best warm-up to get stronger, faster jumps right before a game or practice.
Detailed description
Design and setting. The study will be a randomized, assessor-blinded, parallel-group trial conducted in university sport-science laboratories. Two arms will be used: a heavy half-squat conditioning activity and an active warm-up control. All procedures will follow written standard operating protocols.
Participants. Healthy, 44 resistance-trained male football/soccer players will be screened and will provide written informed consent. Eligibility will require regular training and the absence of musculoskeletal, neurological, dermatological, or cardiovascular contraindications to high-intensity exercise or peripheral electrical stimulation. Testing will be scheduled on a consistent team microcycle day to control for prior load.
Visit schedule. Visit 1 - Familiarization and strength assessment. Medical screening, anthropometrics, and a progressive half-squat session will determine individual one-repetition maximum (1RM). Squat depth will be standardized at approximately 90° knee flexion with rack pins and spotters.
Visit 2 - Experimental session. After compliance checks (sleep, diet, caffeine), participants will complete a structured general warm-up. Baseline tensiomyography (TMG) of the dominant vastus lateralis (VL), surface electromyography (EMG) normalization to maximal voluntary contraction (MVC), and baseline countermovement-jump (CMJ) testing will be completed. The allocated intervention will be delivered, followed by repeated CMJ testing with concurrent EMG at one-minute intervals. Ultrasound imaging will be obtained at baseline and after the final CMJ series.
Arms and interventions. Experimental arm (conditioning activity). One set of 2-3 free-weight half-squats at ~90% 1RM will be performed from a rack with spotter supervision.
Control arm (active warm-up). Approximately five minutes of treadmill running at light-moderate intensity (0% incline) will be completed.
Outcome measures and timing. Primary outcome. Change in CMJ height at each minute from 4 to 12 minutes after the intervention, relative to baseline (5 prespecified post-intervention time points at 2-min resolution).
CMJ-derived flight time, take-off velocity (device-derived where available), and individualized responder categorization at each minute using a predefined smallest-detectable-change threshold anchored to familiarization reliability.
Exploratory relationships between neuromuscular phenotype (TMG) and the magnitude/timing of CMJ responses.
Exploratory changes in VL architecture (ultrasound thickness, pennation, derived fascicle length) across the session.
Electromyography outcome (recorded for every jump). For every CMJ, surface EMG amplitude will be recorded and expressed as a percentage of the participant's maximal voluntary contraction (%MVC). The primary EMG variables will be RMS EMG (%MVC) across the propulsive phase and peak RMS (%MVC) within the final 200-250 ms before take-off.
Following the intervention, one CMJ will be performed at minute 1 and subsequently at each exact minute through minute 12. If a jump is technically invalid, a single replacement attempt will be permitted within that minute. Standardized instructions and hand placement will be maintained for all trials.
Instrumentation and standardization. CMJ. Jumps will be measured with a validated optical timing system on a non-slip surface. Foot placement and countermovement depth will be self-selected but replicated across trials.
Electromyography. Wireless surface EMG will be recorded from VL (with optional rectus femoris and biceps femoris for context). Skin will be shaved, lightly abraded, and cleaned with alcohol; disposable Ag/AgCl electrodes with ~20-mm inter-electrode distance will be placed along the fiber direction following SENIAM guidance and skin-marked for repeatability. Signals will be sampled at ≥2,000 Hz, band-pass filtered 20-450 Hz, notch-filtered at mains frequency, full-wave rectified, and converted to RMS with a 50-ms window. EMG and CMJ timing will be synchronized via hardware trigger; take-off will be identified from the optical system to define the propulsive phase. Prior to experimental jumps, three 3-5 s isometric knee-extension MVCs at ~60° knee flexion will be performed against a fixed dynamometer or rigid strap with strong verbal encouragement and 2-3 min rests. The highest stable 500-ms RMS epoch will define 100% MVC for normalization.
Tensiomyography. VL contractile properties (Td, Tc, Tr, Ts, Dm, and displacement-rate metrics) will be obtained with a displacement sensor at constant pre-tension. Participants will be supine with the knee supported at ~120°. Electrode positions will be standardized and skin-marked; single twitches will be delivered with inter-stimulus intervals ≥10 s. A validated multivariable model will estimate %MHC-I as a non-invasive phenotype proxy.
Ultrasound. B-mode imaging with a linear-array transducer will quantify VL thickness and pennation at mid-thigh; probe alignment will follow fascicle direction with minimal gel and consistent pressure. Fascicle length will be estimated from thickness and pennation. Three longitudinal images per site will be acquired and averaged.
Randomization and masking. Participants will be randomized using concealed, sequentially numbered envelopes prepared by personnel independent of data collection. CMJ/EMG assessors will be blinded to allocation and will operate in a separate space from the intervention station. Data files will contain coded identifiers only.
Participant flow during Visit 2. Participants will arrive for compliance checks. A standardized warm-up will be performed. MVC procedures for EMG normalization will be completed. Baseline TMG and baseline CMJ with EMG will be recorded. The allocated intervention will be administered. CMJ with EMG will be recorded at minutes 1-12. Ultrasound imaging will be performed at the end of the series, followed by cool-down and debrief.
Responder framework. At each minute, CMJ change will be classified for individual interpretation as positive, no-change, or negative using a priori smallest-detectable-change thresholds derived from familiarization reliability.
Safety and risk mitigation. Heavy squats will be performed in racks with pins and spotters; participants will have been familiarized with high loads during Visit 1. TMG will use brief single twitches with conservative current progression and long inter-stimulus intervals. Surface EMG and ultrasound are non-invasive; electrode preparation and probe handling will follow hygienic and standardized procedures. Adverse events and discomfort will be documented, and testing will cease if safety concerns arise.
Data capture and quality assurance. All devices will be calibrated before each session. Electrode and probe sites will be marked to ensure within-session consistency. Operators will complete training and inter-rater checks before data collection. Raw data will be stored on encrypted, access-controlled servers with audit trails. Predefined rules will govern artifact handling, trial acceptance, and protocol deviations.
Confidentiality and data handling. Participant identities will be coded. Source documents and electronic records will be stored on encrypted drives with restricted access limited to authorized personnel.
Discontinuation and withdrawal. Participants may withdraw at any time. Investigators will discontinue participation in the case of adverse signs, illness, or non-compliance. Data collected to the point of withdrawal will be retained unless the participant requests removal under the approved ethics framework.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, care provider, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| High-Intensity Half-Squat | Experimental | Other: High-Intensity Half-SquatParticipants perform one set half-squats using a free-weight barbell in a squat rack to elicit PAPE |
| Treadmill running | Active comparator | Other: Treadmill runningParticipants jogged on a level treadmill for five minutes at a comfortable pace to provide general muscle warm-up without significant neuromuscular priming. |
Who may qualify
- Ages
- 18 to 23 years
- Sex
- Male only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (7 listed)
- Male football players aged 18-23 years
- Minimum of 3 structured training sessions per week for the past 6 months
- No history of lower-limb musculoskeletal injuries (e.g., ligament sprain, muscle tear) within the past 2 months
- No diagnosed dermatological conditions affecting electrode placement (e.g., psoriasis, eczema)
- No cardiovascular disease (e.g., hypertension, arrhythmia)
Key exclusion criteria (5 listed)
- Use of performance-enhancing supplements/medications within 2 weeks prior to enrollment
- Missed more than 4 scheduled training sessions per month over the past 2 months
- Blood pressure >140/90 mmHg at rest or resting heart rate >90 bpm
- Any contraindication to electrical stimulation (e.g., pacemaker, implanted metal device)
- Failure to provide written informed consent or withdrawal of consent at any time
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 |
|---|---|---|
| High-Intensity Half-SquatParticipants in the conditioning arm perform a single set of two to three half-squats with a free-weight barbell set at 90% of their one-rep max (1RM). Each squat is taken down until the thigh is parallel to the floor (knee at ~90°) and then driven upward as explosively as possible. | Other | High-Intensity Half-Squat |
| Treadmill runningParticipants engaged in a standardized 5-minute treadmill warm-up. Participants were instructed to walk at a moderate, self-selected pace of approximately 7-9 km/h, maintaining an incline of 0%. Heart rate and perceived exertion were monitored to ensure that the activity remained within a light-intensity range (Borg scale: 6-11). | Other | Treadmill running |
Primary outcome
Jump Height 4 Minute
Time frame: 4 minutes post-intervention
Jump Height 6 Minute
Time frame: 6 minutes post-intervention
Jump Height 8 Minute
Time frame: 8 minutes post-intervention
Jump Height 10 Minute
Time frame: 10 minutes post-intervention
Jump Height 12 Minute
Time frame: 12 minute post-intervention
Muscle Thickness Post
Time frame: Immediate post-intervention
Muscle Thickness 4 Minute
Time frame: 4 minute post-intervention (single session)
Muscle Thickness 6 Minute
Time frame: 6 minutes post-intervention
Muscle Thickness 8 Minute
Time frame: 8 minutes post-intervention
Muscle Thickness 10 Minute
Time frame: 10 minutes post-intervention
Muscle Thickness 12 Minute
Time frame: 12 minutes post-intervention
Pennation Angle Post
Time frame: Immediate post-intervention
Pennation Angle 4 Minute
Time frame: 4 minutes post-intervention
Pennation Angle 6 Minute
Time frame: 6 minutes post-intervention
Pennation Angle 8 Minute
Time frame: 8 minutes post-intervention
Pennation Angle 10 Minute
Time frame: 10 minutes post-intervention
Pennation Angle 12 Minute
Time frame: 12 minutes post-intervention
Fascicle Length Post
Time frame: Immediate post-intervention
Fascicle Length 4 Minute
Time frame: 4 minutes post-intervention
Fascicle Length 6 Minute
Time frame: 6 minutes post-intervention
Fascicle Length 8 Minute
Time frame: 8 minutes post-intervention
Fascicle Length 10 Minute
Time frame: 10' minutes post-intervention
Fascicle Length 12 Minute
Time frame: 12 minutes post-intervention
Muscle Activation During Countermovement Jump in 4 Minute
Time frame: 4 minutes post-intervention
Surface electromyographic activity (voluntary activation level) of the vastus lateralis muscle recorded during a standardized countermovement jump. Higher values indicate greater muscle activation of the vastus lateralis during the jump, whereas lower values indicate reduced activation. Results presented as % from maximal voluntary contraction (MVC) during the procedure of normalization (locked at 90 degrees knee extension)
Muscle Activation During Countermovement Jump in 6 Minute
Time frame: 6 minutes post-intervention
Surface electromyographic activity (voluntary activation level) of the vastus lateralis muscle recorded during a standardized countermovement jump. Higher values indicate greater muscle activation of the vastus lateralis during the jump, whereas lower values indicate reduced activation. Results presented as % from maximal voluntary contraction (MVC) during the procedure of normalization (locked at 90 degrees knee extension)
Muscle Activation During Countermovement Jump in 8 Minute
Time frame: 8 minutes post-intervention
Surface electromyographic activity (voluntary activation level) of the vastus lateralis muscle recorded during a standardized countermovement jump. Higher values indicate greater muscle activation of the vastus lateralis during the jump, whereas lower values indicate reduced activation. Results presented as % from maximal voluntary contraction (MVC) during the procedure of normalization (locked at 90 degrees knee extension)
Muscle Activation During Countermovement Jump in 10 Minute
Time frame: 10 minutes post-intervention
Surface electromyographic activity (voluntary activation level) of the vastus lateralis muscle recorded during a standardized countermovement jump. Higher values indicate greater muscle activation of the vastus lateralis during the jump, whereas lower values indicate reduced activation. Results presented as % from maximal voluntary contraction (MVC) during the procedure of normalization (locked at 90 degrees knee extension)
Muscle Activation During Countermovement Jump in 12 Minute
Time frame: 12 minutes post-intervention
Surface electromyographic activity (voluntary activation level) of the vastus lateralis muscle recorded during a standardized countermovement jump. Higher values indicate greater muscle activation of the vastus lateralis during the jump, whereas lower values indicate reduced activation. Results presented as % from maximal voluntary contraction (MVC) during the procedure of normalization (locked at 90 degrees knee extension)
Contraction Time Post
Time frame: Immediate post-intervention
Contraction Time 4 Minute
Time frame: 4 minutes post-intervention
Contraction Time 6 Minute
Time frame: 6 minutes post-intervention
Contraction Time 8 Minute
Time frame: 8 minutes post-intervention
Contraction Time 10 Minute
Time frame: 10 minutes post-intervention
Contraction Time 12 Minutes
Time frame: 12 post-intervention
Delay Time Post
Time frame: Immediate post-intervention
Delay Time 4 Minute
Time frame: 4 minutes post-intervention
Delay Time 6 Minute
Time frame: 6 minutes post-intervention
Delay Time 8 Minute
Time frame: 8 minutes post-intervention
Delay Time 10 Minute
Time frame: 10 minutes post-intervention
Delay Time 12 Minute
Time frame: 12 minutes post-intervention
Relaxation Time Post
Time frame: Immediate post-intervention
Relaxation Time 4 Minute
Time frame: 4 minutes post-intervention
Relaxation Time 6 Minute
Time frame: 6 minutes post-intervention
Relaxation Time 8 Minute
Time frame: 8 minutes post-intervention
Relaxation Time 10 Minute
Time frame: 10 minutes post-intervention
Relaxation Time 12 Minute
Time frame: 12 minutes post-intervention
Muscle Displacement Post
Time frame: Immediate post-intervention
Muscle Displacement 4 Minute
Time frame: 4 minutes post-intervention
Muscle Displacement 6 Minute
Time frame: 6 minutes post-intervention
6' post intervention measure
Muscle Displacement 8 Minute
Time frame: 8 minutes post-intervention
Muscle Displacement 10 Minute
Time frame: 12 minutes post-intervention
Muscle Displacement 12 Minute
Time frame: 12 minutes post-intervention
Sustain Time Post
Time frame: Immediate post-intervention
Sustain Time 4 Minute
Time frame: 4 minutes post-intervention
Sustain Time 6 Minute
Time frame: 6 minutes post-intervention
Sustain Time 8 Minute
Time frame: 8 minutes post-intervention
Sustain Time 10 Minutes
Time frame: 10 minutes post-intervention
Sustain Time 12 Minute
Time frame: 12 minutes post-intervention
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 16 Dec 2025.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Background: PubMed 21552151Simunic B, Degens H, Rittweger J, Narici M, Mekjavic IB, Pisot R. Noninvasive estimation of myosin heavy chain composition in human skeletal muscle. Med Sci Sports Exerc. 2011 Sep;43(9):1619-25. doi: 10.1249/MSS.0b013e31821522d0.
- Derived from this study: PubMed 42927465Terbalyan A, Skotniczny K, Matuszczyk F, Roczniok R, Zak M. Triangulating lower-extremity neuromuscular function in soccer players: The incremental value of twitch kinetics and neural activation over muscle architecture in performance testing. J Sports Sci. 2026 Oct 25:1-15. doi: 10.1080/02640414.2026.2750650. Online ahead of print.
- Individual participant dataSharing planned: No. Data collected during this study will be available upon reasonable request. Individual participant data sharing will be considered on a case-by-case basis, subject to ethical approval, participant consent, and data protection regulations. Data requests must clearly outline the purpose, intended analyses, and measures taken to ensure confidentiality and data security.
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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.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing High-Intensity Half-Squat and Treadmill running in people with Neuromuscular Function and Muscle Activation, 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 7 inclusion and 5 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 16 Dec 2025. 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?
Yes. Results are posted in the registry (first posted 16 Dec 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
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?
Jump Height 4 Minute (time frame: 4 minutes post-intervention). The study lists 58 primary outcomes in all. 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 NCT06982937, which also lists 2 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 16 Dec 2025.