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Photobiomodulation Effects on Fatigue and Muscle Damage Induced by NMES

24 de agosto de 2026 atualizado 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.

Visão geral do estudo

Status

Recrutamento

Condições

Intervenção / Tratamento

Tipo de estudo

Intervencional

Inscrição (Estimado)

36

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

Locais de estudo

    • Rio Grande do Sul
      • Porto Alegre, Rio Grande do Sul, Brasil, 90690200
        • Recrutamento
        • Laboratório de Pesquisa do Exercício
        • Contato:
        • Investigador principal:
          • Marco A Vaz, PhD
        • Subinvestigador:
          • Gustavo N Petter, MSc

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:

  • 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

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 Paralela
  • Mascaramento: Triplo

Armas e Intervenções

Grupo de Participantes / Braço
Intervenção / Tratamento
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.

O que o estudo está medindo?

Medidas de resultados primários

Medida de resultado
Descrição da medida
Prazo
Maximal voluntary isometric contraction (MVIC)
Prazo: 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
Prazo: 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 resultados secundários

Medida de resultado
Descrição da medida
Prazo
Muscle Echo Intensity
Prazo: 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
Prazo: 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
Prazo: 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
Prazo: 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
Prazo: 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
Prazo: 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
Prazo: 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
Prazo: 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.

Outras medidas de resultado

Medida de resultado
Descrição da medida
Prazo
Vastus Lateralis Pennation Angle
Prazo: 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
Prazo: 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

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

Patrocinador

Colaboradores

Investigadores

  • Cadeira de estudo: Marco A Vaz, PhD, Federal University of Rio Grande do Sul
  • Diretor de estudo: Marco A Vaz, PhD, Federal University of Rio Grande do Sul
  • Investigador principal: Marco A Vaz, PhD, Federal University of Rio Grande do Sul

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 (Real)

1 de junho de 2026

Conclusão Primária (Estimado)

30 de agosto de 2026

Conclusão do estudo (Estimado)

30 de setembro de 2026

Datas de inscrição no estudo

Enviado pela primeira vez

27 de abril de 2026

Enviado pela primeira vez que atendeu aos critérios de CQ

15 de maio de 2026

Primeira postagem (Real)

22 de maio de 2026

Atualizações de registro de estudo

Última Atualização Postada (Real)

25 de agosto de 2026

Última atualização enviada que atendeu aos critérios de controle de qualidade

24 de agosto de 2026

Última verificação

1 de agosto de 2026

Mais Informações

Termos relacionados a este estudo

Outros números de identificação do estudo

  • 5.309.992(1)

Plano para dados de participantes individuais (IPD)

Planeja compartilhar dados de participantes individuais (IPD)?

NÃO

Descrição do plano 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.

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

Essas informações foram obtidas diretamente do site clinicaltrials.gov sem nenhuma alteração. Se você tiver alguma solicitação para alterar, remover ou atualizar os detalhes do seu estudo, entre em contato com register@clinicaltrials.gov. Assim que uma alteração for implementada em clinicaltrials.gov, ela também será atualizada automaticamente em nosso site .