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Isometric vs. Dynamic Squat Pre-Loading: Acute PAPE Responses (IPP vs DPP)

6 juli 2026 bijgewerkt door: Neslihan AKÇAY, Karabuk University

Acute Post-Activation Performance Responses to Isometric and Dynamic Squat Pre-Loading Protocols: A Randomized Crossover Trial

This randomized crossover study compared the acute post-activation performance responses to isometric and dynamic squat-based preconditioning protocols performed with and without electromyostimulation (EMS). Participants completed five randomized experimental conditions: maximal voluntary isometric contraction (MVIC), dynamic contraction (DC), MVIC+EMS, DC+EMS, and EMS only (O-EMS). Baseline and post-intervention assessments included countermovement jump (CMJ), countermovement jump with arm swing (CMJWH), zig-zag agility, and shooting speed, with post-tests conducted after a 4-minute recovery period. Perceptual responses, including ratings of perceived exertion (RPE), perceived discomfort (RPD), and fatigue (VAS), were recorded immediately after each protocol. All sessions were conducted between 14:00 and 16:00 under standardized conditions, with protocol order randomized and participants instructed to avoid strenuous exercise and food intake before testing.

Studie Overzicht

Toestand

Nog niet aan het werven

Conditie

Interventie / Behandeling

Gedetailleerde beschrijving

This study aimed to compare the acute post-activation performance responses to isometric and dynamic squat-based preconditioning protocols, with and without EMS. All testing sessions were conducted between 14:00 and 16:00 to minimize the potential effects of circadian rhythms and fatigue on performance. The study was conducted using a randomized, crossover design. On the remaining five experimental days, the order of the protocols was randomized for each participant using a computer-generated randomization sequence (randomizer.org) to reduce order effects. During the first session, participants' anthropometric measurements were recorded, their one-repetition maximum (1RM) back squat loads were determined, and they were familiarized with the equipment and testing procedures. Participants completed five separate experimental sessions consisting of the following conditions: [A] Isometric Contraction + EMS (MVIC-EMS), [B] Dynamic Contraction + EMS (DC-EMS), [C] Dynamic Contraction (DC), [D] Isometric Contraction (MVIC), and [E] Only EMS (O-EMS). Before each experimental protocol, baseline measurements were obtained using countermovement jump (CMJ), CMJ with hands (CMJWH), zig-zag agility test, and shooting speed assessments. After each protocol, all tests were repeated after a 4-minute rest period (Chen et al., 2023). Under all conditions, the electrodes were placed identically by the same experienced researcher. Subsequently, players' shooting speeds were measured using a radar gun, with two trials performed and the highest value recorded. Immediately after each experimental protocol, ratings of perceived exertion (RPE), perceived discomfort (RPD), and perceived fatigue level were assessed using a visual analog scale (VAS) and recorded. Participants were instructed to refrain from food intake for 1.5 hours before testing, to avoid resistance training throughout the study period, and were verbally encouraged during all testing sessions.

Studietype

Ingrijpend

Inschrijving (Geschat)

22

Fase

  • Niet toepasbaar

Contacten en locaties

In dit gedeelte vindt u de contactgegevens van degenen die het onderzoek uitvoeren en informatie over waar dit onderzoek wordt uitgevoerd.

Studiecontact

Studie Contact Back-up

  • Naam: Neslihan Akçay, Doctorate

Studie Locaties

  • Turkije (Türkiye)
    • Turkey
      • Karabük, Turkey, Turkije (Türkiye), 78200
        • Karabuk University
        • Contact:
        • Hoofdonderzoeker:
          • Neslihan Akçay, Doctorate
        • Onderonderzoeker:
          • Cem Sofuoğlu
        • Onderonderzoeker:
          • Wolfgang Kemmler, Prof.Dr.
        • Onderonderzoeker:
          • Andre Filipovic, Prof.Dr.
        • Onderonderzoeker:
          • Metehan Yana, Doctorate
        • Onderonderzoeker:
          • Erşan Arslan, Prof.Dr.

Deelname Criteria

Onderzoekers zoeken naar mensen die aan een bepaalde beschrijving voldoen, de zogenaamde geschiktheidscriteria. Enkele voorbeelden van deze criteria zijn iemands algemene gezondheidstoestand of eerdere behandelingen.

Geschiktheidscriteria

Leeftijden die in aanmerking komen voor studie

  • Volwassen

Accepteert gezonde vrijwilligers

Ja

Beschrijving

Inclusion Criteria:

  • Being healthy
  • Male volleyball athletes
  • Willing to maintain the intervention for all sessions

Exclusion Criteria:

  • Being under 18 years old
  • Having a chronic disease
  • Contraindications for exercise

Studie plan

Dit gedeelte bevat details van het studieplan, inclusief hoe de studie is opgezet en wat de studie meet.

Hoe is de studie opgezet?

Ontwerpdetails

  • Primair doel: Behandeling
  • Toewijzing: Gerandomiseerd
  • Interventioneel model: Crossover-opdracht
  • Masker: Enkel

Wapens en interventies

Deelnemersgroep / Arm
Interventie / Behandeling
Experimenteel: Condition 1
Dynamic contraction
Ander: dynamic conraction
Participants performed a dynamic back squat conditioning protocol on a Smith machine consisting of five sets of one repetition at 90% of one-repetition maximum (1RM), with 1 min of passive recovery between sets. Each repetition included a controlled descent to approximately 90° of knee flexion, an explosive concentric phase, a 2-s isometric hold at full knee extension, and a slow, controlled eccentric phase (Pincivero et al.). All repetitions were supervised to ensure proper technique. The protocol was selected based on previous evidence supporting high-intensity resistance exercise as an effective conditioning activity for inducing PAPE responses (Dobbs et al.).
Experimenteel: Condition 2
isometric contraction
Ander: isometric contraction
The isometric contraction protocol was conducted as described by Koźlenia and Domaradzki (2023) and Lim and Kong (2013). Participants assumed a squat position in a squat rack with the barbell fixed in place and the knee joint positioned at approximately 90° of flexion (Profitness 1030, Türkiye). The barbell was secured to the rack using safety pins, and participants were instructed to exert maximal force against the immovable bar to produce a MVIC. Each contraction lasted 3 seconds, and a total of 3 repetitions were performed with 2 min of rest between repetitions (Koźlenia & Domaradzki, 2023; Lim & Kong, 2013).
Experimenteel: Condition 3
Dynamic + EMS contraction
Ander: dynamic and EMS contraction
Participants performed a dynamic back squat conditioning protocol on a Smith machine consisting of five sets of one repetition at 90% of one-repetition maximum (1RM), with 1 min of passive recovery between sets. In the DC-EMS condition, electromyostimulation (EMS) was applied simultaneously throughout the conditioning protocol. Each repetition included a controlled descent to approximately 90° of knee flexion, an explosive concentric phase, a 2-s isometric hold at full knee extension, and a slow, controlled eccentric phase (Pincivero et al.). All repetitions were supervised to ensure proper technique. The protocol was selected based on previous evidence supporting high-intensity resistance exercise as an effective conditioning activity for inducing PAPE responses (Dobbs et al.).
Experimenteel: Condition 4
Isometric + EMS Contraction
Ander: isometric and EMS conraction
The isometric contraction protocol was conducted as described by Koźlenia and Domaradzki (2023) and Lim and Kong (2013). Participants assumed a squat position in a squat rack with the barbell fixed in place and the knee joint positioned at approximately 90° of flexion (Profitness 1030, Türkiye). The barbell was secured to the rack using safety pins, and participants were instructed to exert maximal force against the immovable bar to produce an MVIC. Each contraction lasted 3 seconds, and a total of three repetitions were performed with 2 min of rest between repetitions (Koźlenia & Domaradzki, 2023; Lim & Kong, 2013). In the MVIC-EMS condition, electromyostimulation (EMS) was applied simultaneously during each maximal voluntary isometric contraction.
Experimenteel: Condition 5
EMS contraction
Ander: ems contraction
EMS was delivered bilaterally to the quadriceps using a portable stimulator (Compex Rehab 400, Compex Medical SA, Switzerland) with a biphasic symmetrical rectangular waveform (75 Hz, 450 μs). Four self-adhesive electrodes were placed over the vastus medialis and vastus lateralis muscles of both legs. Participants remained seated for 10 min with the knees flexed at approximately 90° and the hips flexed at approximately 110°, while receiving EMS without performing any voluntary contractions. Stimulation intensity was gradually increased to the highest level tolerated by each participant and maintained throughout the intervention (Paillard et al., 2008; Sofuoğlu et al., 2025).

Wat meet het onderzoek?

Primaire uitkomstmaten

Uitkomstmaat
Maatregel Beschrijving
Tijdsspanne
Countermovement Jump (CMJ) Height
Tijdsspanne: aseline and 4 minutes after each experimental condition
Change in countermovement jump (CMJ) height (cm) from baseline to 4 minutes after each conditioning protocol, measured using a jump assessment system.
aseline and 4 minutes after each experimental condition
Countermovement Jump with Arm Swing (CMJWH) Height
Tijdsspanne: Baseline and 4 minutes after each experimental condition
Change in countermovement jump with arm swing (CMJWH) height (cm) from baseline to 4 minutes after each conditioning protocol.
Baseline and 4 minutes after each experimental condition
Zig-Zag Agility Performance
Tijdsspanne: Baseline and 4 minutes after each experimental condition
Change in zig-zag agility performance time (s) from baseline to 4 minutes after each conditioning protocol.
Baseline and 4 minutes after each experimental condition
Shooting Speed
Tijdsspanne: Baseline and 4 minutes after each experimental condition
Change in maximal shooting speed (km/h) from baseline to 4 minutes after each conditioning protocol, measured using a radar gun.
Baseline and 4 minutes after each experimental condition

Secundaire uitkomstmaten

Uitkomstmaat
Maatregel Beschrijving
Tijdsspanne
Rating of Perceived Exertion (RPE)
Tijdsspanne: Immediately after each experimental condition
Rating of perceived exertion assessed immediately after each conditioning protocol using the Borg CR-10 scale.
Immediately after each experimental condition
Rating of Perceived Discomfort (RPD)
Tijdsspanne: Immediately after each experimental condition
Rating of perceived discomfort assessed immediately after each conditioning protocol using the Borg CR-10 scale.
Immediately after each experimental condition
Perceived Fatigue
Tijdsspanne: Immediately after each experimental condition
Perceived fatigue assessed immediately after each conditioning protocol using a visual analog scale (VAS).
Immediately after each experimental condition

Medewerkers en onderzoekers

Hier vindt u mensen en organisaties die betrokken zijn bij dit onderzoek.

Sponsor

Karabuk University

Onderzoekers

  • Studie stoel: Neslihan Akçay, Doctorate, Karabuk University

Publicaties en nuttige links

De persoon die verantwoordelijk is voor het invoeren van informatie over het onderzoek stelt deze publicaties vrijwillig ter beschikking. Dit kan gaan over alles wat met het onderzoek te maken heeft.

Algemene publicaties

Studie record data

Deze datums volgen de voortgang van het onderzoeksdossier en de samenvatting van de ingediende resultaten bij ClinicalTrials.gov. Studieverslagen en gerapporteerde resultaten worden beoordeeld door de National Library of Medicine (NLM) om er zeker van te zijn dat ze voldoen aan specifieke kwaliteitscontrolenormen voordat ze op de openbare website worden geplaatst.

Bestudeer belangrijke data

Studie start (Geschat)

1 augustus 2026

Primaire voltooiing (Geschat)

30 augustus 2026

Studie voltooiing (Geschat)

5 september 2026

Studieregistratiedata

Eerst ingediend

6 juli 2026

Eerst ingediend dat voldeed aan de QC-criteria

6 juli 2026

Eerst geplaatst (Werkelijk)

10 juli 2026

Updates van studierecords

Laatste update geplaatst (Werkelijk)

10 juli 2026

Laatste update ingediend die voldeed aan QC-criteria

6 juli 2026

Laatst geverifieerd

1 juli 2026

Meer informatie

Termen gerelateerd aan deze studie

Trefwoorden

Aanvullende relevante MeSH-voorwaarden

Andere studie-ID-nummers

  • UKarabuk-6

Plan Individuele Deelnemersgegevens (IPD)

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ONBESLIST

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Bestudeert een door de Amerikaanse FDA gereguleerd geneesmiddel

Nee

Bestudeert een door de Amerikaanse FDA gereguleerd apparaatproduct

Nee

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