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CompletedNCT06982937Updated Dec 16, 2025Results posted

Mechanistic Drivers of Acute PAPE Responsiveness: Muscle Architecture, Contractile Kinetics, and Excitability in a Randomized Controlled Trial

An interventional study of High-Intensity Half-Squat and Treadmill running in Neuromuscular Function, Muscle Activation and Postactivation Potentiation, sponsored by The Jerzy Kukuczka Academy of Physical Education in Katowice. Completed at 1 site in Poland. Open to male participants aged 18 Years to 23 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2025-12-16.

Sponsored by The Jerzy Kukuczka Academy of Physical Education in Katowice · Not applicable, Interventional, and Basic science

From the registry’s dates

  • Registered 3 months after the study started (first participant enrolled Feb 2025, registered May 2025).
Phase
Not applicable
Study type
Interventional
Enrollment
44
Allocation
Randomized
Ages
18 Years to 23 Years
Sex
Male
01

Study 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.

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:

    1. Heavy-squat group: 2-3 half-squats at 90% of their one-rep max
    2. 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.

02

Conditions studied

  • Neuromuscular Function
  • Muscle Activation
  • Postactivation Potentiation
  • Ultrasonography
  • Tensiomyography
  • Contraction
  • MHC-I

Keywords

  • MHC-I
  • Tensiomyography
  • Ulstrasonography
  • Electromyogpraphy
  • Postactivation potentiation
  • PAPE
03

In context

Lead sponsor

The Jerzy Kukuczka Academy of Physical Education in Katowice is the lead sponsor of 30 studies on the registry; 14 are open to participants now.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
18 Years to 23 Years
Sexes eligible
Male
Accepts healthy volunteers
Yes

Inclusion criteria

  • 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

Exclusion criteria

Exclusion Criteria:

  • 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
05

Study design

Phase
Not applicable
Primary purpose
Basic science
Allocation
Randomized
Intervention model
Parallel assignment
Masking
Triple (Participant, Care provider, Outcomes assessor)
Enrollment
44 participants (actual)

Study arms

  • Experimental
    High-Intensity Half-Squat

    Participants perform one set half-squats using a free-weight barbell in a squat rack to elicit PAPE

    Other: High-Intensity Half-Squat

  • Active comparator
    Treadmill running

    Participants jogged on a level treadmill for five minutes at a comfortable pace to provide general muscle warm-up without significant neuromuscular priming.

    Other: Treadmill running

Interventions

  • OtherHigh-Intensity Half-Squat

    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.

  • OtherTreadmill running

    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).

06

What researchers measure

Primary outcomes

  1. Jump Height 4 Minute

    Time frame: 4 minutes post-intervention

  2. Jump Height 6 Minute

    Time frame: 6 minutes post-intervention

  3. Jump Height 8 Minute

    Time frame: 8 minutes post-intervention

  4. Jump Height 10 Minute

    Time frame: 10 minutes post-intervention

  5. Jump Height 12 Minute

    Time frame: 12 minute post-intervention

  6. Muscle Thickness Post

    Time frame: Immediate post-intervention

  7. Muscle Thickness 4 Minute

    Time frame: 4 minute post-intervention (single session)

  8. Muscle Thickness 6 Minute

    Time frame: 6 minutes post-intervention

  9. Muscle Thickness 8 Minute

    Time frame: 8 minutes post-intervention

  10. Muscle Thickness 10 Minute

    Time frame: 10 minutes post-intervention

  11. Muscle Thickness 12 Minute

    Time frame: 12 minutes post-intervention

  12. Pennation Angle Post

    Time frame: Immediate post-intervention

  13. Pennation Angle 4 Minute

    Time frame: 4 minutes post-intervention

  14. Pennation Angle 6 Minute

    Time frame: 6 minutes post-intervention

  15. Pennation Angle 8 Minute

    Time frame: 8 minutes post-intervention

  16. Pennation Angle 10 Minute

    Time frame: 10 minutes post-intervention

  17. Pennation Angle 12 Minute

    Time frame: 12 minutes post-intervention

  18. Fascicle Length Post

    Time frame: Immediate post-intervention

  19. Fascicle Length 4 Minute

    Time frame: 4 minutes post-intervention

  20. Fascicle Length 6 Minute

    Time frame: 6 minutes post-intervention

  21. Fascicle Length 8 Minute

    Time frame: 8 minutes post-intervention

  22. Fascicle Length 10 Minute

    Time frame: 10' minutes post-intervention

  23. Fascicle Length 12 Minute

    Time frame: 12 minutes post-intervention

  24. 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)

    Time frame: 4 minutes post-intervention

  25. 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)

    Time frame: 6 minutes post-intervention

  26. 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)

    Time frame: 8 minutes post-intervention

  27. 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)

    Time frame: 10 minutes post-intervention

  28. 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)

    Time frame: 12 minutes post-intervention

  29. Contraction Time Post

    Time frame: Immediate post-intervention

  30. Contraction Time 4 Minute

    Time frame: 4 minutes post-intervention

  31. Contraction Time 6 Minute

    Time frame: 6 minutes post-intervention

  32. Contraction Time 8 Minute

    Time frame: 8 minutes post-intervention

  33. Contraction Time 10 Minute

    Time frame: 10 minutes post-intervention

  34. Contraction Time 12 Minutes

    Time frame: 12 post-intervention

  35. Delay Time Post

    Time frame: Immediate post-intervention

  36. Delay Time 4 Minute

    Time frame: 4 minutes post-intervention

  37. Delay Time 6 Minute

    Time frame: 6 minutes post-intervention

  38. Delay Time 8 Minute

    Time frame: 8 minutes post-intervention

  39. Delay Time 10 Minute

    Time frame: 10 minutes post-intervention

  40. Delay Time 12 Minute

    Time frame: 12 minutes post-intervention

  41. Relaxation Time Post

    Time frame: Immediate post-intervention

  42. Relaxation Time 4 Minute

    Time frame: 4 minutes post-intervention

  43. Relaxation Time 6 Minute

    Time frame: 6 minutes post-intervention

  44. Relaxation Time 8 Minute

    Time frame: 8 minutes post-intervention

  45. Relaxation Time 10 Minute

    Time frame: 10 minutes post-intervention

  46. Relaxation Time 12 Minute

    Time frame: 12 minutes post-intervention

  47. Muscle Displacement Post

    Time frame: Immediate post-intervention

  48. Muscle Displacement 4 Minute

    Time frame: 4 minutes post-intervention

  49. Muscle Displacement 6 Minute

    6' post intervention measure

    Time frame: 6 minutes post-intervention

  50. Muscle Displacement 8 Minute

    Time frame: 8 minutes post-intervention

  51. Muscle Displacement 10 Minute

    Time frame: 12 minutes post-intervention

  52. Muscle Displacement 12 Minute

    Time frame: 12 minutes post-intervention

  53. Sustain Time Post

    Time frame: Immediate post-intervention

  54. Sustain Time 4 Minute

    Time frame: 4 minutes post-intervention

  55. Sustain Time 6 Minute

    Time frame: 6 minutes post-intervention

  56. Sustain Time 8 Minute

    Time frame: 8 minutes post-intervention

  57. Sustain Time 10 Minutes

    Time frame: 10 minutes post-intervention

  58. Sustain Time 12 Minute

    Time frame: 12 minutes post-intervention

07

Results

Posted Dec 16, 2025
Limitations and caveats
First, although outcome assessment was blinded, full double-blinding is pragmatically challenging in strength interventions and expectancy effects cannot be entirely excluded. Second, the fiber-type estimate pertains to a single muscle (VL), whereas CMJ performance reflects coordinated output from multiple muscle groups; generalizing VL composition to the whole task effector has inherent constraints. Finally, the MHC-I content of 26.14 ± 9.19% in the VL appears somewhat underestimated

Participant flow

Participant flow — Overall Study
MilestoneHigh-Intensity Half-SquatTreadmill Running
Started2222
Completed2222
Not completed00

Outcome measures

PrimaryJump Height 4 Minute
Time frame:
4 minutes post-intervention
Reported as:
Mean · cm
Jump Height 4 Minute
cmHigh-Intensity Half-SquatTreadmill Running
Jump Height 4 Minute45.34 ± 5.2847.41 ± 5.13
PrimaryJump Height 6 Minute
Time frame:
6 minutes post-intervention
Reported as:
Mean · cm
Jump Height 6 Minute
cmHigh-Intensity Half-SquatTreadmill Running
Jump Height 6 Minute48.01 ± 5.1347.41 ± 3.92
PrimaryJump Height 8 Minute
Time frame:
8 minutes post-intervention
Reported as:
Mean · cm
Jump Height 8 Minute
cmHigh-Intensity Half-SquatTreadmill Running
Jump Height 8 Minute47.08 ± 5.3148.10 ± 4.60
PrimaryJump Height 10 Minute
Time frame:
10 minutes post-intervention
Reported as:
Mean · cm
Jump Height 10 Minute
cmHigh-Intensity Half-SquatTreadmill Running
Jump Height 10 Minute46.17 ± 5.1747.59 ± 3.90
PrimaryJump Height 12 Minute
Time frame:
12 minute post-intervention
Reported as:
Mean · cm
Jump Height 12 Minute
cmHigh-Intensity Half-SquatTreadmill Running
Jump Height 12 Minute45.27 ± 5.1447.91 ± 4.27
PrimaryMuscle Thickness Post
Time frame:
Immediate post-intervention
Reported as:
Mean · cm
Muscle Thickness Post
cmHigh-Intensity Half-SquatTreadmill Running
Muscle Thickness Post2.95 ± 0.372.63 ± 0.33
PrimaryMuscle Thickness 4 Minute
Time frame:
4 minute post-intervention (single session)
Reported as:
Mean · cm
Muscle Thickness 4 Minute
cmHigh-Intensity Half-SquatTreadmill Running
Muscle Thickness 4 Minute2.92 ± 0.352.58 ± 0.33
PrimaryMuscle Thickness 6 Minute
Time frame:
6 minutes post-intervention
Reported as:
Mean · cm
Muscle Thickness 6 Minute
cmHigh-Intensity Half-SquatTreadmill Running
Muscle Thickness 6 Minute2.83 ± 0.372.58 ± 0.30
PrimaryMuscle Thickness 8 Minute
Time frame:
8 minutes post-intervention
Reported as:
Mean · cm
Muscle Thickness 8 Minute
cmHigh-Intensity Half-SquatTreadmill Running
Muscle Thickness 8 Minute2.70 ± 0.362.53 ± 0.32
PrimaryMuscle Thickness 10 Minute
Time frame:
10 minutes post-intervention
Reported as:
Mean · cm
Muscle Thickness 10 Minute
cmHigh-Intensity Half-SquatTreadmill Running
Muscle Thickness 10 Minute2.66 ± 0.352.60 ± 0.39
PrimaryMuscle Thickness 12 Minute
Time frame:
12 minutes post-intervention
Reported as:
Mean · cm
Muscle Thickness 12 Minute
cmHigh-Intensity Half-SquatTreadmill Running
Muscle Thickness 12 Minute2.57 ± 0.442.55 ± 0.38
PrimaryPennation Angle Post
Time frame:
Immediate post-intervention
Reported as:
Mean · degrees
Pennation Angle Post
degreesHigh-Intensity Half-SquatTreadmill Running
Pennation Angle Post17.83 ± 2.4913.84 ± 1.98
PrimaryPennation Angle 4 Minute
Time frame:
4 minutes post-intervention
Reported as:
Mean · degress
Pennation Angle 4 Minute
degressHigh-Intensity Half-SquatTreadmill Running
Pennation Angle 4 Minute16.95 ± 2.6313.37 ± 2.07
PrimaryPennation Angle 6 Minute
Time frame:
6 minutes post-intervention
Reported as:
Mean · degrees
Pennation Angle 6 Minute
degreesHigh-Intensity Half-SquatTreadmill Running
Pennation Angle 6 Minute17.09 ± 2.7014.06 ± 2.39
PrimaryPennation Angle 8 Minute
Time frame:
8 minutes post-intervention
Reported as:
Mean · degrees
Pennation Angle 8 Minute
degreesHigh-Intensity Half-SquatTreadmill Running
Pennation Angle 8 Minute16.84 ± 2.8814.09 ± 2.45
PrimaryPennation Angle 10 Minute
Time frame:
10 minutes post-intervention
Reported as:
Mean · degrees
Pennation Angle 10 Minute
degreesHigh-Intensity Half-SquatTreadmill Running
Pennation Angle 10 Minute16.52 ± 2.7013.96 ± 2.42
PrimaryPennation Angle 12 Minute
Time frame:
12 minutes post-intervention
Reported as:
Mean · degrees
Pennation Angle 12 Minute
degreesHigh-Intensity Half-SquatTreadmill Running
Pennation Angle 12 Minute14.61 ± 3.1613.55 ± 2.62
PrimaryFascicle Length Post
Time frame:
Immediate post-intervention
Reported as:
Mean · cm
Fascicle Length Post
cmHigh-Intensity Half-SquatTreadmill Running
Fascicle Length Post9.82 ± 1.8811.26 ± 2.49
PrimaryFascicle Length 4 Minute
Time frame:
4 minutes post-intervention
Reported as:
Mean · cm
Fascicle Length 4 Minute
cmHigh-Intensity Half-SquatTreadmill Running
Fascicle Length 4 Minute10.27 ± 2.1811.54 ± 3.17
PrimaryFascicle Length 6 Minute
Time frame:
6 minutes post-intervention
Reported as:
Mean · cm
Fascicle Length 6 Minute
cmHigh-Intensity Half-SquatTreadmill Running
Fascicle Length 6 Minute9.80 ± 1.6410.86 ± 1.90
PrimaryFascicle Length 8 Minute
Time frame:
8 minutes post-intervention
Reported as:
Mean · cm
Fascicle Length 8 Minute
cmHigh-Intensity Half-SquatTreadmill Running
Fascicle Length 8 Minute9.59 ± 2.6110.57 ± 1.60
PrimaryFascicle Length 10 Minute
Time frame:
10' minutes post-intervention
Reported as:
Mean · cm
Fascicle Length 10 Minute
cmHigh-Intensity Half-SquatTreadmill Running
Fascicle Length 10 Minute9.69 ± 2.4610.97 ± 1.76
PrimaryFascicle Length 12 Minute
Time frame:
12 minutes post-intervention
Reported as:
Mean · cm
Fascicle Length 12 Minute
cmHigh-Intensity Half-SquatTreadmill Running
Fascicle Length 12 Minute10.69 ± 3.1111.14 ± 1.98
PrimaryMuscle 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)

Time frame:
4 minutes post-intervention
Reported as:
Mean · percentage of MVC
Muscle Activation During Countermovement Jump in 4 Minute
percentage of MVCHigh-Intensity Half-SquatTreadmill Running
Muscle Activation During Countermovement Jump in 4 Minute50.63 ± 14.1843.96 ± 11.31
PrimaryMuscle 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)

Time frame:
6 minutes post-intervention
Reported as:
Mean · percentage of MVC
Muscle Activation During Countermovement Jump in 6 Minute
percentage of MVCHigh-Intensity Half-SquatTreadmill Running
Muscle Activation During Countermovement Jump in 6 Minute45.29 ± 13.8543.96 ± 11.31
PrimaryMuscle 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)

Time frame:
8 minutes post-intervention
Reported as:
Mean · percentage of MVC
Muscle Activation During Countermovement Jump in 8 Minute
percentage of MVCHigh-Intensity Half-SquatTreadmill Running
Muscle Activation During Countermovement Jump in 8 Minute46.38 ± 13.6149.43 ± 12.44
PrimaryMuscle 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)

Time frame:
10 minutes post-intervention
Reported as:
Mean · percentage of MVC
Muscle Activation During Countermovement Jump in 10 Minute
percentage of MVCHigh-Intensity Half-SquatTreadmill Running
Muscle Activation During Countermovement Jump in 10 Minute48.76 ± 21.9051.71 ± 14.85
PrimaryMuscle 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)

Time frame:
12 minutes post-intervention
Reported as:
Mean · percentage of MVC
Muscle Activation During Countermovement Jump in 12 Minute
percentage of MVCHigh-Intensity Half-SquatTreadmill Running
Muscle Activation During Countermovement Jump in 12 Minute43.19 ± 9.4934.39 ± 8.23
PrimaryContraction Time Post
Time frame:
Immediate post-intervention
Reported as:
Mean · ms
Contraction Time Post
msHigh-Intensity Half-SquatTreadmill Running
Contraction Time Post31.34 ± 2.9429.04 ± 2.45
PrimaryContraction Time 4 Minute
Time frame:
4 minutes post-intervention
Reported as:
Mean · ms
Contraction Time 4 Minute
msHigh-Intensity Half-SquatTreadmill Running
Contraction Time 4 Minute29.94 ± 2.6127.91 ± 2.55
PrimaryContraction Time 6 Minute
Time frame:
6 minutes post-intervention
Reported as:
Mean · ms
Contraction Time 6 Minute
msHigh-Intensity Half-SquatTreadmill Running
Contraction Time 6 Minute26.87 ± 2.3227.98 ± 2.24
PrimaryContraction Time 8 Minute
Time frame:
8 minutes post-intervention
Reported as:
Mean · ms
Contraction Time 8 Minute
msHigh-Intensity Half-SquatTreadmill Running
Contraction Time 8 Minute26.54 ± 2.3326.43 ± 2.05
PrimaryContraction Time 10 Minute
Time frame:
10 minutes post-intervention
Reported as:
Mean · ms
Contraction Time 10 Minute
msHigh-Intensity Half-SquatTreadmill Running
Contraction Time 10 Minute26.24 ± 2.3526.83 ± 2.58
PrimaryContraction Time 12 Minutes
Time frame:
12 post-intervention
Reported as:
Mean · ms
Contraction Time 12 Minutes
msHigh-Intensity Half-SquatTreadmill Running
Contraction Time 12 Minutes26.01 ± 2.0926.29 ± 1.77
PrimaryDelay Time Post
Time frame:
Immediate post-intervention
Reported as:
Mean · ms
Delay Time Post
msHigh-Intensity Half-SquatTreadmill Running
Delay Time Post21.49 ± 1.1622.54 ± 1.33
PrimaryDelay Time 4 Minute
Time frame:
4 minutes post-intervention
Reported as:
Mean · ms
Delay Time 4 Minute
msHigh-Intensity Half-SquatTreadmill Running
Delay Time 4 Minute21.06 ± 1.1422.41 ± 1.35
PrimaryDelay Time 6 Minute
Time frame:
6 minutes post-intervention
Reported as:
Mean · ms
Delay Time 6 Minute
msHigh-Intensity Half-SquatTreadmill Running
Delay Time 6 Minute21.04 ± 1.1822.52 ± 1.38
PrimaryDelay Time 8 Minute
Time frame:
8 minutes post-intervention
Reported as:
Mean · ms
Delay Time 8 Minute
msHigh-Intensity Half-SquatTreadmill Running
Delay Time 8 Minute20.77 ± 1.1622.07 ± 1.36
PrimaryDelay Time 10 Minute
Time frame:
10 minutes post-intervention
Reported as:
Mean · ms
Delay Time 10 Minute
msHigh-Intensity Half-SquatTreadmill Running
Delay Time 10 Minute22.05 ± 2.3922.84 ± 1.86
PrimaryDelay Time 12 Minute
Time frame:
12 minutes post-intervention
Reported as:
Mean · ms
Delay Time 12 Minute
msHigh-Intensity Half-SquatTreadmill Running
Delay Time 12 Minute21.70 ± 2.5422.88 ± 1.91
PrimaryRelaxation Time Post
Time frame:
Immediate post-intervention
Reported as:
Mean · ms
Relaxation Time Post
msHigh-Intensity Half-SquatTreadmill Running
Relaxation Time Post20.97 ± 7.4616.35 ± 5.71
PrimaryRelaxation Time 4 Minute
Time frame:
4 minutes post-intervention
Reported as:
Mean · ms
Relaxation Time 4 Minute
msHigh-Intensity Half-SquatTreadmill Running
Relaxation Time 4 Minute19.08 ± 7.9016.35 ± 5.71
PrimaryRelaxation Time 6 Minute
Time frame:
6 minutes post-intervention
Reported as:
Mean · ms
Relaxation Time 6 Minute
msHigh-Intensity Half-SquatTreadmill Running
Relaxation Time 6 Minute18.16 ± 7.5217.57 ± 6.20
PrimaryRelaxation Time 8 Minute
Time frame:
8 minutes post-intervention
Reported as:
Mean · ms
Relaxation Time 8 Minute
msHigh-Intensity Half-SquatTreadmill Running
Relaxation Time 8 Minute19.28 ± 8.0219.94 ± 8.53
PrimaryRelaxation Time 10 Minute
Time frame:
10 minutes post-intervention
Reported as:
Mean · ms
Relaxation Time 10 Minute
msHigh-Intensity Half-SquatTreadmill Running
Relaxation Time 10 Minute17.71 ± 7.1416.63 ± 4.88
PrimaryRelaxation Time 12 Minute
Time frame:
12 minutes post-intervention
Reported as:
Mean · ms
Relaxation Time 12 Minute
msHigh-Intensity Half-SquatTreadmill Running
Relaxation Time 12 Minute17.20 ± 6.6417.30 ± 5.48
PrimaryMuscle Displacement Post
Time frame:
Immediate post-intervention
Reported as:
Mean · mm
Muscle Displacement Post
mmHigh-Intensity Half-SquatTreadmill Running
Muscle Displacement Post5.70 ± 1.546.37 ± 1.35
PrimaryMuscle Displacement 4 Minute
Time frame:
4 minutes post-intervention
Reported as:
Mean · mm
Muscle Displacement 4 Minute
mmHigh-Intensity Half-SquatTreadmill Running
Muscle Displacement 4 Minute5.98 ± 1.786.36 ± 1.46
PrimaryMuscle Displacement 6 Minute

6' post intervention measure

Time frame:
6 minutes post-intervention
Reported as:
Mean · mm
Muscle Displacement 6 Minute
mmHigh-Intensity Half-SquatTreadmill Running
Muscle Displacement 6 Minute5.80 ± 1.196.83 ± 0.90
PrimaryMuscle Displacement 8 Minute
Time frame:
8 minutes post-intervention
Reported as:
Mean · mm
Muscle Displacement 8 Minute
mmHigh-Intensity Half-SquatTreadmill Running
Muscle Displacement 8 Minute5.97 ± 1.346.59 ± 1.04
PrimaryMuscle Displacement 10 Minute
Time frame:
12 minutes post-intervention
Reported as:
Mean · mm
Muscle Displacement 10 Minute
mmHigh-Intensity Half-SquatTreadmill Running
Muscle Displacement 10 Minute6.21 ± 1.436.22 ± 1.11
PrimaryMuscle Displacement 12 Minute
Time frame:
12 minutes post-intervention
Reported as:
Mean · mm
Muscle Displacement 12 Minute
mmHigh-Intensity Half-SquatTreadmill Running
Muscle Displacement 12 Minute6.50 ± 1.556.23 ± 1.21
PrimarySustain Time Post
Time frame:
Immediate post-intervention
Reported as:
Mean · ms
Sustain Time Post
msHigh-Intensity Half-SquatTreadmill Running
Sustain Time Post48.86 ± 3.8638.83 ± 2.77
PrimarySustain Time 4 Minute
Time frame:
4 minutes post-intervention
Reported as:
Mean · ms
Sustain Time 4 Minute
msHigh-Intensity Half-SquatTreadmill Running
Sustain Time 4 Minute46.23 ± 3.7439.52 ± 2.70
PrimarySustain Time 6 Minute
Time frame:
6 minutes post-intervention
Reported as:
Mean · ms
Sustain Time 6 Minute
msHigh-Intensity Half-SquatTreadmill Running
Sustain Time 6 Minute43.27 ± 6.5238.82 ± 4.52
PrimarySustain Time 8 Minute
Time frame:
8 minutes post-intervention
Reported as:
Mean · ms
Sustain Time 8 Minute
msHigh-Intensity Half-SquatTreadmill Running
Sustain Time 8 Minute42.36 ± 4.3339.03 ± 3.50
PrimarySustain Time 10 Minutes
Time frame:
10 minutes post-intervention
Reported as:
Mean · ms
Sustain Time 10 Minutes
msHigh-Intensity Half-SquatTreadmill Running
Sustain Time 10 Minutes42.91 ± 5.4739.11 ± 4.31
PrimarySustain Time 12 Minute
Time frame:
12 minutes post-intervention
Reported as:
Mean · ms
Sustain Time 12 Minute
msHigh-Intensity Half-SquatTreadmill Running
Sustain Time 12 Minute43.47 ± 4.9740.77 ± 3.72

Adverse events

Collected over 2 months. Non-serious events are listed at a 0% frequency threshold.

Adverse event summary by group
GroupDeathsSeriousOther
High-Intensity Half-Squat0/22 (0%)0/22 (0%)0/22 (0%)
Treadmill Running0/22 (0%)0/22 (0%)0/22 (0%)

Baseline characteristics

Age, Categorical
Age, Categorical(Participants)High-Intensity Half-SquatTreadmill RunningTotal
<=18 years000
Between 18 and 65 years222244
>=65 years000
Sex: Female, Male
Sex: Female, Male(Participants)High-Intensity Half-SquatTreadmill RunningTotal
Female000
Male222244
Race (NIH/OMB)
Race (NIH/OMB)(Participants)High-Intensity Half-SquatTreadmill RunningTotal
American Indian or Alaska Native000
Asian000
Native Hawaiian or Other Pacific Islander000
Black or African American000
White222244
More than one race000
Unknown or Not Reported000
Region of Enrollment
Region of Enrollment(participants)High-Intensity Half-SquatTreadmill RunningTotal
Poland222244
%MHC-1
%MHC-1(%)High-Intensity Half-SquatTreadmill RunningTotal
Mean26.14 ± 9.1927.28 ± 10.0126.71 ± 9.6
Contraction time
Contraction time(ms)High-Intensity Half-SquatTreadmill RunningTotal
Mean26.34 ± 2.1523.01 ± 1.0824.68 ± 0.76
Delay time
Delay time(ms)High-Intensity Half-SquatTreadmill RunningTotal
Mean23.47 ± 1.1621.91 ± 1.1422.69 ± 0.02
Muscle displacement
Muscle displacement(mm)High-Intensity Half-SquatTreadmill RunningTotal
Mean6.78 ± 1.936.61 ± 1.596.70 ± 1.75

8 further baseline measures are reported on the registry.

08

Study locations

1 site
  • The Jerzy Kukuczka Academy of Physical Education in Katowice
    Katowice, Silesian Voivodeship 40-065, Poland
09

References and documents

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 21552151 ↗

Study documents

  • Protocol and statistical analysis plan · May 18, 2025
  • Informed consent form · Mar 15, 2023

Documents are hosted by the registry — open the source record to download them.

Individual participant data

Plan to share: 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.

10

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Dec 16, 2025, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
11

Registry details

Key details

Study ID
NCT06982937
Lead sponsor
The Jerzy Kukuczka Academy of Physical Education in Katowice
Responsible party
Artur Terbalyan (PhD student, lecturer, The Jerzy Kukuczka Academy of Physical Education in Katowice) — Principal investigator
First posted
May 21, 2025
Start date
Feb 2, 2025
Primary completion
Jun 25, 2025
Completion
Jul 25, 2025
Results posted
Dec 16, 2025
Last update
Dec 16, 2025

Oversight

Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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