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

6 juli 2026 uppdaterad av: 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.

Studieöversikt

Status

Har inte rekryterat ännu

Betingelser

Intervention / Behandling

Detaljerad beskrivning

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.

Studietyp

Interventionell

Inskrivning (Beräknad)

22

Fas

  • Inte tillämpbar

Kontakter och platser

Det här avsnittet innehåller kontaktuppgifter för dem som genomför studien och information om var denna studie genomförs.

Studiekontakt

Studera Kontakt Backup

  • Namn: Neslihan Akçay, Doctorate

Studieorter

  • Turkiet (Türkiye)
    • Turkey
      • Karabük, Turkey, Turkiet (Türkiye), 78200
        • Karabuk University
        • Kontakt:
        • Huvudutredare:
          • Neslihan Akçay, Doctorate
        • Underutredare:
          • Cem Sofuoğlu
        • Underutredare:
          • Wolfgang Kemmler, Prof.Dr.
        • Underutredare:
          • Andre Filipovic, Prof.Dr.
        • Underutredare:
          • Metehan Yana, Doctorate
        • Underutredare:
          • Erşan Arslan, Prof.Dr.

Deltagandekriterier

Forskare letar efter personer som passar en viss beskrivning, så kallade behörighetskriterier. Några exempel på dessa kriterier är en persons allmänna hälsotillstånd eller tidigare behandlingar.

Urvalskriterier

Åldrar som är berättigade till studier

  • Vuxen

Tar emot friska volontärer

Ja

Beskrivning

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

Studieplan

Det här avsnittet ger detaljer om studieplanen, inklusive hur studien är utformad och vad studien mäter.

Hur är studien utformad?

Designdetaljer

  • Primärt syfte: Behandling
  • Tilldelning: Randomiserad
  • Interventionsmodell: Crossover tilldelning
  • Maskning: Enda

Vapen och interventioner

Deltagargrupp / Arm
Intervention / Behandling
Experimentell: Condition 1
Dynamic contraction
Övrig: 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.).
Experimentell: Condition 2
isometric contraction
Övrig: 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).
Experimentell: Condition 3
Dynamic + EMS contraction
Övrig: 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.).
Experimentell: Condition 4
Isometric + EMS Contraction
Övrig: 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.
Experimentell: Condition 5
EMS contraction
Övrig: 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).

Vad mäter studien?

Primära resultatmått

Resultatmått
Åtgärdsbeskrivning
Tidsram
Countermovement Jump (CMJ) Height
Tidsram: 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
Tidsram: 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
Tidsram: 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
Tidsram: 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

Sekundära resultatmått

Resultatmått
Åtgärdsbeskrivning
Tidsram
Rating of Perceived Exertion (RPE)
Tidsram: 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)
Tidsram: 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
Tidsram: Immediately after each experimental condition
Perceived fatigue assessed immediately after each conditioning protocol using a visual analog scale (VAS).
Immediately after each experimental condition

Samarbetspartners och utredare

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Sponsor

Karabuk University

Utredare

  • Studiestol: Neslihan Akçay, Doctorate, Karabuk University

Publikationer och användbara länkar

Den som ansvarar för att lägga in information om studien tillhandahåller frivilligt dessa publikationer. Dessa kan handla om allt som har med studien att göra.

Allmänna publikationer

Studieavstämningsdatum

Dessa datum spårar framstegen för inlämningar av studieposter och sammanfattande resultat till ClinicalTrials.gov. Studieposter och rapporterade resultat granskas av National Library of Medicine (NLM) för att säkerställa att de uppfyller specifika kvalitetskontrollstandarder innan de publiceras på den offentliga webbplatsen.

Studera stora datum

Studiestart (Beräknad)

1 augusti 2026

Primärt slutförande (Beräknad)

30 augusti 2026

Avslutad studie (Beräknad)

5 september 2026

Studieregistreringsdatum

Först inskickad

6 juli 2026

Först inskickad som uppfyllde QC-kriterierna

6 juli 2026

Första postat (Faktisk)

10 juli 2026

Uppdateringar av studier

Senaste uppdatering publicerad (Faktisk)

10 juli 2026

Senaste inskickade uppdateringen som uppfyllde QC-kriterierna

6 juli 2026

Senast verifierad

1 juli 2026

Mer information

Termer relaterade till denna studie

Nyckelord

Ytterligare relevanta MeSH-villkor

Andra studie-ID-nummer

  • UKarabuk-6

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