Isometric vs. Dynamic Squat Pre-Loading: Acute PAPE Responses (IPP vs DPP)
6 de julio de 2026 actualizado 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.
Descripción general del estudio
Estado
Aún no reclutando
Condiciones
Descripción detallada
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 estudio
Intervencionista
Inscripción (Estimado)
22
Fase
- No aplica
Contactos y Ubicaciones
Esta sección proporciona los datos de contacto de quienes realizan el estudio e información sobre dónde se lleva a cabo este estudio.
Estudio Contacto
- Nombre: Neslihan Akçay, Doctorate
- Número de teléfono: +905468426671
- Correo electrónico: neslihanozcan@karabuk.edu.tr
Copia de seguridad de contactos de estudio
- Nombre: Neslihan Akçay, Doctorate
Ubicaciones de estudio
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Turkey
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Karabük, Turkey, Turquía (Türkiye), 78200
- Karabuk University
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Contacto:
- Neslihan Akçay, Doctorate
- Número de teléfono: +905468426671
- Correo electrónico: neslihanozcan@karabuk.edu.tr
-
Investigador principal:
- Neslihan Akçay, Doctorate
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Sub-Investigador:
- Cem Sofuoğlu
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Sub-Investigador:
- Wolfgang Kemmler, Prof.Dr.
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Sub-Investigador:
- Andre Filipovic, Prof.Dr.
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Sub-Investigador:
- Metehan Yana, Doctorate
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Sub-Investigador:
- Erşan Arslan, Prof.Dr.
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Criterios de participación
Los investigadores buscan personas que se ajusten a una determinada descripción, denominada criterio de elegibilidad. Algunos ejemplos de estos criterios son el estado de salud general de una persona o tratamientos previos.
Criterio de elegibilidad
Edades elegibles para estudiar
- Adulto
Acepta Voluntarios Saludables
Sí
Descripción
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
Plan de estudios
Esta sección proporciona detalles del plan de estudio, incluido cómo está diseñado el estudio y qué mide el estudio.
¿Cómo está diseñado el estudio?
Detalles de diseño
- Propósito principal: Tratamiento
- Asignación: Aleatorizado
- Modelo Intervencionista: Asignación cruzada
- Enmascaramiento: Único
Armas e Intervenciones
Grupo de participantes/brazo |
Intervención / Tratamiento |
|---|---|
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Experimental: Condition 1
Dynamic contraction
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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.).
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Experimental: Condition 2
isometric contraction
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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).
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Experimental: Condition 3
Dynamic + EMS contraction
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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
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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.
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Experimental: Condition 5
EMS contraction
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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).
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¿Qué mide el estudio?
Medidas de resultado primarias
Medida de resultado |
Medida Descripción |
Periodo de tiempo |
|---|---|---|
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Countermovement Jump (CMJ) Height
Periodo de tiempo: aseline and 4 minutes after each experimental condition
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Change in countermovement jump (CMJ) height (cm) from baseline to 4 minutes after each conditioning protocol, measured using a jump assessment system.
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aseline and 4 minutes after each experimental condition
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Countermovement Jump with Arm Swing (CMJWH) Height
Periodo de tiempo: Baseline and 4 minutes after each experimental condition
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Change in countermovement jump with arm swing (CMJWH) height (cm) from baseline to 4 minutes after each conditioning protocol.
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Baseline and 4 minutes after each experimental condition
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Zig-Zag Agility Performance
Periodo de tiempo: Baseline and 4 minutes after each experimental condition
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Change in zig-zag agility performance time (s) from baseline to 4 minutes after each conditioning protocol.
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Baseline and 4 minutes after each experimental condition
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Shooting Speed
Periodo de tiempo: Baseline and 4 minutes after each experimental condition
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Change in maximal shooting speed (km/h) from baseline to 4 minutes after each conditioning protocol, measured using a radar gun.
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Baseline and 4 minutes after each experimental condition
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Medidas de resultado secundarias
Medida de resultado |
Medida Descripción |
Periodo de tiempo |
|---|---|---|
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Rating of Perceived Exertion (RPE)
Periodo de tiempo: Immediately after each experimental condition
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Rating of perceived exertion assessed immediately after each conditioning protocol using the Borg CR-10 scale.
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Immediately after each experimental condition
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Rating of Perceived Discomfort (RPD)
Periodo de tiempo: Immediately after each experimental condition
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Rating of perceived discomfort assessed immediately after each conditioning protocol using the Borg CR-10 scale.
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Immediately after each experimental condition
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Perceived Fatigue
Periodo de tiempo: Immediately after each experimental condition
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Perceived fatigue assessed immediately after each conditioning protocol using a visual analog scale (VAS).
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Immediately after each experimental condition
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Colaboradores e Investigadores
Aquí es donde encontrará personas y organizaciones involucradas en este estudio.
Patrocinador
Investigadores
- Silla de estudio: Neslihan Akçay, Doctorate, Karabuk University
Publicaciones y enlaces útiles
La persona responsable de ingresar información sobre el estudio proporciona voluntariamente estas publicaciones. Estos pueden ser sobre cualquier cosa relacionada con el estudio.
Publicaciones Generales
- Keskin K, Akcay N, Ozmen T, Contarli N, Yildiz KC, Sofuoglu C, Kamis O, Rolnick N, de Queiros VS, Montoye A. Effects of different pre-exercise strategies on jumping performance in female volleyball players. J Sports Med Phys Fitness. 2025 Jan;65(1):59-68. doi: 10.23736/S0022-4707.24.16196-8. Epub 2024 Oct 3.
- Sofuoglu C, Fujita RA, Keskin K, Kamis O, Akcay N. Acute electrical muscle stimulation effects on strength and anaerobic power in soccer players. Int J Sports Med. 2025 Jun;46(7):501-509. doi: 10.1055/a-2563-9289. Epub 2025 Mar 20.
Fechas de registro del estudio
Estas fechas rastrean el progreso del registro del estudio y los envíos de resultados resumidos a ClinicalTrials.gov. Los registros del estudio y los resultados informados son revisados por la Biblioteca Nacional de Medicina (NLM) para asegurarse de que cumplan con los estándares de control de calidad específicos antes de publicarlos en el sitio web público.
Fechas importantes del estudio
Inicio del estudio (Estimado)
1 de agosto de 2026
Finalización primaria (Estimado)
30 de agosto de 2026
Finalización del estudio (Estimado)
5 de septiembre de 2026
Fechas de registro del estudio
Enviado por primera vez
6 de julio de 2026
Primero enviado que cumplió con los criterios de control de calidad
6 de julio de 2026
Publicado por primera vez (Actual)
10 de julio de 2026
Actualizaciones de registros de estudio
Última actualización publicada (Actual)
10 de julio de 2026
Última actualización enviada que cumplió con los criterios de control de calidad
6 de julio de 2026
Última verificación
1 de julio de 2026
Más información
Términos relacionados con este estudio
Palabras clave
Términos MeSH relevantes adicionales
Otros números de identificación del estudio
- UKarabuk-6
Plan de datos de participantes individuales (IPD)
¿Planea compartir datos de participantes individuales (IPD)?
INDECISO
Información sobre medicamentos y dispositivos, documentos del estudio
Estudia un producto farmacéutico regulado por la FDA de EE. UU.
No
Estudia un producto de dispositivo regulado por la FDA de EE. UU.
No
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