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

6 de julho de 2026 atualizado por: 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.

Visão geral do estudo

Status

Ainda não está recrutando

Condições

Intervenção / Tratamento

Descrição detalhada

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.

Tipo de estudo

Intervencional

Inscrição (Estimado)

22

Estágio

  • Não aplicável

Contactos e Locais

Esta seção fornece os detalhes de contato para aqueles que conduzem o estudo e informações sobre onde este estudo está sendo realizado.

Contato de estudo

Estude backup de contato

  • Nome: Neslihan Akçay, Doctorate

Locais de estudo

  • Turquia (Türkiye)
    • Turkey
      • Karabük, Turkey, Turquia (Türkiye), 78200
        • Karabuk University
        • Contato:
        • Investigador principal:
          • Neslihan Akçay, Doctorate
        • Subinvestigador:
          • Cem Sofuoğlu
        • Subinvestigador:
          • Wolfgang Kemmler, Prof.Dr.
        • Subinvestigador:
          • Andre Filipovic, Prof.Dr.
        • Subinvestigador:
          • Metehan Yana, Doctorate
        • Subinvestigador:
          • Erşan Arslan, Prof.Dr.

Critérios de participação

Os pesquisadores procuram pessoas que se encaixem em uma determinada descrição, chamada de critérios de elegibilidade. Alguns exemplos desses critérios são a condição geral de saúde de uma pessoa ou tratamentos anteriores.

Critérios de elegibilidade

Idades elegíveis para estudo

  • Adulto

Aceita Voluntários Saudáveis

Sim

Descrição

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

Plano de estudo

Esta seção fornece detalhes do plano de estudo, incluindo como o estudo é projetado e o que o estudo está medindo.

Como o estudo é projetado?

Detalhes do projeto

  • Finalidade Principal: Tratamento
  • Alocação: Randomizado
  • Modelo Intervencional: Atribuição cruzada
  • Mascaramento: Solteiro

Armas e Intervenções

Grupo de Participantes / Braço
Intervenção / Tratamento
Experimental: Condition 1
Dynamic contraction
Outro: 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.).
Experimental: Condition 2
isometric contraction
Outro: 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).
Experimental: Condition 3
Dynamic + EMS contraction
Outro: 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.).
Experimental: Condition 4
Isometric + EMS Contraction
Outro: 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.
Experimental: Condition 5
EMS contraction
Outro: 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).

O que o estudo está medindo?

Medidas de resultados primários

Medida de resultado
Descrição da medida
Prazo
Countermovement Jump (CMJ) Height
Prazo: 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
Prazo: 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
Prazo: 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
Prazo: 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

Medidas de resultados secundários

Medida de resultado
Descrição da medida
Prazo
Rating of Perceived Exertion (RPE)
Prazo: 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)
Prazo: 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
Prazo: Immediately after each experimental condition
Perceived fatigue assessed immediately after each conditioning protocol using a visual analog scale (VAS).
Immediately after each experimental condition

Colaboradores e Investigadores

É aqui que você encontrará pessoas e organizações envolvidas com este estudo.

Patrocinador

Karabuk University

Investigadores

  • Cadeira de estudo: Neslihan Akçay, Doctorate, Karabuk University

Publicações e links úteis

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Publicações Gerais

Datas de registro do estudo

Essas datas acompanham o progresso do registro do estudo e os envios de resumo dos resultados para ClinicalTrials.gov. Os registros do estudo e os resultados relatados são revisados ​​pela National Library of Medicine (NLM) para garantir que atendam aos padrões específicos de controle de qualidade antes de serem publicados no site público.

Datas Principais do Estudo

Início do estudo (Estimado)

1 de agosto de 2026

Conclusão Primária (Estimado)

30 de agosto de 2026

Conclusão do estudo (Estimado)

5 de setembro de 2026

Datas de inscrição no estudo

Enviado pela primeira vez

6 de julho de 2026

Enviado pela primeira vez que atendeu aos critérios de CQ

6 de julho de 2026

Primeira postagem (Real)

10 de julho de 2026

Atualizações de registro de estudo

Última Atualização Postada (Real)

10 de julho de 2026

Última atualização enviada que atendeu aos critérios de controle de qualidade

6 de julho de 2026

Última verificação

1 de julho de 2026

Mais Informações

Termos relacionados a este estudo

Palavras-chave

Termos MeSH relevantes adicionais

Outros números de identificação do estudo

  • UKarabuk-6

Plano para dados de participantes individuais (IPD)

Planeja compartilhar dados de participantes individuais (IPD)?

INDECISO

Informações sobre medicamentos e dispositivos, documentos de estudo

Estuda um medicamento regulamentado pela FDA dos EUA

Não

Estuda um produto de dispositivo regulamentado pela FDA dos EUA

Não

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