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Photobiomodulation Effects on Fatigue and Muscle Damage Induced by NMES

24 de agosto de 2026 actualizado por: Marco Aurélio Vaz, PhD, Federal University of Rio Grande do Sul

Effects of Photobiomodulation on Fatigue and Muscle Damage Induced by Neuromuscular Electrical Stimulation in Healthy Individuals: a Randomized Clinical Trial

Neuromuscular electrical stimulation (NMES) is widely used to improve muscle strength and mitigate atrophy. However, its clinical efficacy is often limited by early neuromuscular fatigue, muscle damage, and discomfort, which reduce patient tolerance and contraction time. Photobiomodulation (PBM) has emerged as a potential therapy to enhance muscle performance and accelerate recovery by minimizing fatigue and damage. Despite its potential, few studies have investigated the effects of PBM applied specifically before an NMES-evoked fatigue protocol. This randomized, double-blind, placebo-controlled trial aims to evaluate the acute effects of PBM on neuromuscular fatigue, muscle damage, and functional outcomes in healthy young subjects. Participants will receive either active PBM (cluster probe: 5 lasers 810nm/200mW; 4 LEDs 660nm/10mW; Total Energy: 249.6 J per limb) or sham treatment 5 minutes before a fatiguing NMES protocol (80 contractions at 20% MVIC, 80 Hz, 1ms pulse width) applied to the quadriceps muscle. Assessments will be performed at baseline, immediately post-intervention, and at 24h, 48h, and 72h post-intervention. Primary outcomes include maximum and evoked isometric strength, mechanical work, and electrical muscle activity. Secondary outcomes include muscle damage (ultrasound echo-intensity), delayed onset muscle soreness (DOMS), functional performance (unilateral vertical jump), and clinical discomfort. The study seeks to determine if PBM can effectively modulate NMES-induced fatigue and muscle damage, potentially optimizing its clinical application.

Descripción general del estudio

Estado

Reclutamiento

Condiciones

Intervención / Tratamiento

Tipo de estudio

Intervencionista

Inscripción (Estimado)

36

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: Marco A Vaz, PhD
  • Número de teléfono: +555133085853
  • Correo electrónico: marco.vaz@ufrgs.br

Ubicaciones de estudio

    • Rio Grande do Sul
      • Porto Alegre, Rio Grande do Sul, Brasil, 90690200
        • Reclutamiento
        • Laboratório de Pesquisa do Exercício
        • Contacto:
        • Investigador principal:
          • Marco A Vaz, PhD
        • Sub-Investigador:
          • Gustavo N Petter, MSc

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:

  • Healthy male and female volunteers.
  • Age between 18 and 45 years.
  • Practice physical activity regularly
  • No history of musculoskeletal injuries in the lower limbs in the last 6 months
  • Ability to tolerate NMES

Exclusion Criteria:

  • Have sensory intolerable changes due to NMES
  • Consumed coffee or another stimulant in the last 12 hours
  • Have a body mass index (BMI) greater than 30 kg/m2 (grade I obesity)
  • Present any contraindication for the performance of maximum effort
  • Abnormal increase in blood pressure after maximal exertion

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 paralela
  • Enmascaramiento: Triple

Armas e Intervenciones

Grupo de participantes/brazo
Intervención / Tratamiento
Experimental: Photobiomodulation (PBM)
Participants in this arm will receive active photobiomodulation therapy.
Application of PBMT using a cluster probe (Thor-DD2; 5 laser diodes: 810nm, 200mW; 4 LEDs: 660nm, 10mW). The treatment involves 8 points on the quadriceps (2 on vastus medialis, 3 on vastus lateralis, and 3 on rectus femoris). Each point is irradiated for 30 seconds in continuous mode with direct contact and slight pressure. Total energy: 31.2 J per point and 249.6 J per limb. Both therapist and participant will wear protective goggles.
Neuromuscular Electrical Stimulation (Myomed 932) applied to the quadriceps. Parameters: 80 Hz frequency, 1 ms pulse width (biphasic rectangular pulse), 5s:10s ON:OFF ratio with 1s ramp-up/down. The protocol lasts 20 minutes, totaling 80 evoked isometric contractions. Current intensity is adjusted to generate an initial torque of 20% of the baseline Maximum Voluntary Isometric Contraction (MVIC).
Comparador falso: Sham PBM
Participants in this arm will receive an inactive (placebo) photobiomodulation treatment.
Neuromuscular Electrical Stimulation (Myomed 932) applied to the quadriceps. Parameters: 80 Hz frequency, 1 ms pulse width (biphasic rectangular pulse), 5s:10s ON:OFF ratio with 1s ramp-up/down. The protocol lasts 20 minutes, totaling 80 evoked isometric contractions. Current intensity is adjusted to generate an initial torque of 20% of the baseline Maximum Voluntary Isometric Contraction (MVIC).
The procedure is identical to the active PBMT (8 points, 30 seconds per point, same pressure and positioning), but the device will be turned off. To ensure blinding, participants will wear protective goggles and a blindfold to prevent visual perception of the light.

¿Qué mide el estudio?

Medidas de resultado primarias

Medida de resultado
Medida Descripción
Periodo de tiempo
Maximal voluntary isometric contraction (MVIC)
Periodo de tiempo: Baseline (pre-intervention) on Day 1; immediately after the fatigue protocol on Day 1; and at 24, 48, and 72 hours after the fatigue protocol (on Days 2, 3, and 4, respectively).

Largest knee extensor torque generated isometrically and voluntarily on an isokinetic dynamometer.

Unit of Measure: Newton-meters (N.m)

Baseline (pre-intervention) on Day 1; immediately after the fatigue protocol on Day 1; and at 24, 48, and 72 hours after the fatigue protocol (on Days 2, 3, and 4, respectively).
Evoked fatigue
Periodo de tiempo: Continuously during the 20-minute fatigue protocol.
Fall in the evoked torque during the fatigue protocol. Unit of Measure: Newton-meters (N.m)
Continuously during the 20-minute fatigue protocol.

Medidas de resultado secundarias

Medida de resultado
Medida Descripción
Periodo de tiempo
Muscle Echo Intensity
Periodo de tiempo: Baseline (pre-intervention) on Day 1; immediately after the fatigue protocol on Day 1; and at 24, 48, and 72 hours after the fatigue protocol (on Days 2, 3, and 4, respectively).

Quantitative analysis of muscle ultrasound images to assess changes in echo intensity, reflecting acute edema and changes in muscle quality. Analysis will be performed specifically on the Rectus Femoris (RF), Vastus Medialis (VM), and Vastus Lateralis (VL).

Unit of Measure: Arbitrary Units (au) on a 0-255 grayscale

Baseline (pre-intervention) on Day 1; immediately after the fatigue protocol on Day 1; and at 24, 48, and 72 hours after the fatigue protocol (on Days 2, 3, and 4, respectively).
Pressure Pain Threshold
Periodo de tiempo: Baseline (pre-intervention) on Day 1; immediately after the fatigue protocol on Day 1; and at 24, 48, and 72 hours after the fatigue protocol (on Days 2, 3, and 4, respectively).
The minimum pressure at which a subject perceives a stimulus as painful, measured via pressure algometry on the quadriceps muscle bellies to quantify delayed onset muscle soreness (DOMS). Unit of Measure: Newtons (N)
Baseline (pre-intervention) on Day 1; immediately after the fatigue protocol on Day 1; and at 24, 48, and 72 hours after the fatigue protocol (on Days 2, 3, and 4, respectively).
Quadriceps Muscle Thickness
Periodo de tiempo: Baseline (pre-intervention) on Day 1; immediately after the fatigue protocol on Day 1; and at 24, 48, and 72 hours after the fatigue protocol (on Days 2, 3, and 4, respectively).

Ultrasound assessment of structural changes in the quadriceps muscle group, for the Rectus Femoris (RF), Vastus Medialis (VM), and Vastus Lateralis (VL). This variable evaluates acute morphological changes or edema-induced swelling following the NMES protocol.

Unit of Measure: Millimeters (mm)

Baseline (pre-intervention) on Day 1; immediately after the fatigue protocol on Day 1; and at 24, 48, and 72 hours after the fatigue protocol (on Days 2, 3, and 4, respectively).
Countermovement Jump (CMJ) Height
Periodo de tiempo: Baseline (pre-intervention) on Day 1; immediately after the fatigue protocol on Day 1; and at 24, 48, and 72 hours after the fatigue protocol (on Days 2, 3, and 4, respectively).

Measure Description: Maximum jump height achieved during a vertical countermovement jump on a force platform to assess dynamic muscle power.

Unit of Measure: Centimeters (cm)

Baseline (pre-intervention) on Day 1; immediately after the fatigue protocol on Day 1; and at 24, 48, and 72 hours after the fatigue protocol (on Days 2, 3, and 4, respectively).
Lower Limb Joint Kinematics During Jump
Periodo de tiempo: Baseline (pre-intervention) on Day 1; immediately after the fatigue protocol on Day 1; and at 24, 48, and 72 hours after the fatigue protocol (on Days 2, 3, and 4, respectively).

Measure Description: Sagittal plane kinematic analysis for the ankle, knee, hip, and trunk joints to evaluate movement strategies and joint range of motion during the countermovement jump.

Unit of Measure: Degrees (°)

Baseline (pre-intervention) on Day 1; immediately after the fatigue protocol on Day 1; and at 24, 48, and 72 hours after the fatigue protocol (on Days 2, 3, and 4, respectively).
Force-Time Curve Dynamics During Jump
Periodo de tiempo: Baseline (pre-intervention) on Day 1; immediately after the fatigue protocol on Day 1; and at 24, 48, and 72 hours after the fatigue protocol (on Days 2, 3, and 4, respectively).
Analysis of the vertical ground reaction force-time curve during the propulsion phase of the countermovement jump. The primary parameter will be the Vertical Impulse, calculated as the integral of force over time. Unit of Measure: Newton-seconds (N.s)
Baseline (pre-intervention) on Day 1; immediately after the fatigue protocol on Day 1; and at 24, 48, and 72 hours after the fatigue protocol (on Days 2, 3, and 4, respectively).
Muscle Activation
Periodo de tiempo: Baseline (pre-intervention) on Day 1; immediately after the fatigue protocol on Day 1; and at 24, 48, and 72 hours after the fatigue protocol (on Days 2, 3, and 4, respectively).
Surface electromyography (sEMG) to assess muscle activation amplitude during MVIC. Unit of Measure: Microvolts (uV)
Baseline (pre-intervention) on Day 1; immediately after the fatigue protocol on Day 1; and at 24, 48, and 72 hours after the fatigue protocol (on Days 2, 3, and 4, respectively).
Vastus Lateralis Fascicle Length
Periodo de tiempo: Continuously during the 20-minute fatigue protocol on Day 1.

Measure Description: Assessment of real-time changes in the fascicle length of the Vastus Lateralis muscle during the fatigue protocol using continuous ultrasound imaging.

Unit of Measure: Millimeters (mm)

Continuously during the 20-minute fatigue protocol on Day 1.

Otras medidas de resultado

Medida de resultado
Medida Descripción
Periodo de tiempo
Vastus Lateralis Pennation Angle
Periodo de tiempo: Continuously during the 20-minute fatigue protocol on Day 1.

Measure Description: Assessment of real-time changes in the pennation angle of the Vastus Lateralis muscle during the fatigue protocol using continuous ultrasound imaging.

Unit of Measure: Degrees (°)

Continuously during the 20-minute fatigue protocol on Day 1.
Adipose Tissue Thickness
Periodo de tiempo: Baseline
Measurement of the fat layer thickness overlying the Rectus Femoris, Vastus Medialis, and Vastus Lateralis using ultrasound imaging. This measure is used to characterize the sample's morphology and will serve as a covariate to adjust the delivered PBM dose and NMES current penetration analysis. Unit of Measure: Millimeters (mm)
Baseline

Colaboradores e Investigadores

Aquí es donde encontrará personas y organizaciones involucradas en este estudio.

Patrocinador

Colaboradores

Investigadores

  • Silla de estudio: Marco A Vaz, PhD, Federal University of Rio Grande do Sul
  • Director de estudio: Marco A Vaz, PhD, Federal University of Rio Grande do Sul
  • Investigador principal: Marco A Vaz, PhD, Federal University of Rio Grande do Sul

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 (Actual)

1 de junio de 2026

Finalización primaria (Estimado)

30 de agosto de 2026

Finalización del estudio (Estimado)

30 de septiembre de 2026

Fechas de registro del estudio

Enviado por primera vez

27 de abril de 2026

Primero enviado que cumplió con los criterios de control de calidad

15 de mayo de 2026

Publicado por primera vez (Actual)

22 de mayo de 2026

Actualizaciones de registros de estudio

Última actualización publicada (Actual)

25 de agosto de 2026

Última actualización enviada que cumplió con los criterios de control de calidad

24 de agosto de 2026

Última verificación

1 de agosto de 2026

Más información

Términos relacionados con este estudio

Otros números de identificación del estudio

  • 5.309.992(1)

Plan de datos de participantes individuales (IPD)

¿Planea compartir datos de participantes individuales (IPD)?

NO

Descripción del plan IPD

A final decision regarding the sharing of individual participant data has not yet been made. The study team intends to evaluate this possibility following the primary data analysis, in accordance with institutional guidelines and ethical committee requirements.

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

Esta información se obtuvo directamente del sitio web clinicaltrials.gov sin cambios. Si tiene alguna solicitud para cambiar, eliminar o actualizar los detalles de su estudio, comuníquese con register@clinicaltrials.gov. Tan pronto como se implemente un cambio en clinicaltrials.gov, también se actualizará automáticamente en nuestro sitio web. .