Photobiomodulation on NMES-Induced Muscle Fatigue and Damage: A Pilot Study

NCT07790016 | Completed DMC

• 1 other identifier: 56181622.4.0000.5347
• Study Type: interventional
• Target: 12
• Locations: 1 country
• Sites: 1

Brief Summary

Neuromuscular electrical stimulation (NMES) is an effective tool for muscle strengthening and rehabilitation, but its clinical application is often limited by rapid neuromuscular fatigue, muscle discomfort, and potential muscle damage. Photobiomodulation therapy (PBMT) using low-level lasers or LEDs has been proposed as an ergogenic and protective modality capable of attenuating exercise-induced muscle fatigue and damage. However, evidence regarding the acute preventive effects of PBMT on NMES-induced fatigue and muscle damage in humans remains limited and conflicting. The purpose of this randomized, sham-controlled, crossover pilot trial was to evaluate the acute effects of PBMT applied prior to an NMES-induced fatigue protocol on knee extensor neuromuscular fatigability, muscle damage, discomfort, and functional performance in healthy young individuals. Healthy participants had both lower limbs randomized to receive either active PBMT (810 nm, 240 J total per limb across 8 points) or sham PBMT 5 minutes prior to an NMES fatigue protocol (20 minutes of evoked isometric contractions at 20% of maximal voluntary contraction). Primary and secondary outcomes-including maximal voluntary isometric contraction (MVIC) torque, supramaximal twitch torque, muscle damage via ultrasound echointensity (rectus femoris and vastus lateralis), pain pressure thresholds (algometry), visual analog scale (VAS) for discomfort, and functional tests (Single Hop Test and stair ascent/descent)-were assessed at baseline, immediately post-fatigue, and at 24, 48, and 72 hours post-intervention.

Conditions

Muscle Fatigue (C23.888.592.612.612); Delayed Onset Muscle Soreness (DOMS); Muscle Damage; Photobiomodulation (PBM); Neuromuscular Electrical Stimulation (NMES)

Keywords

Photobiomodulation; Low-Level Laser Therapy; Neuromuscular Electrical Stimulation; Muscle Fatigue; Pilot Study

Outcome Measures

Primary Outcomes (1)

• Maximal Voluntary Isometric Contraction (MVIC) Torque

  Knee extensor peak isometric torque measured on an isokinetic dynamometer (Biodex System 3 Pro) during 5-second maximal isometric contractions with the knee fixed at 90° flexion, expressed in Newton-meters (N.m).

  Baseline, Immediately post-fatigue protocol, 24 hours, 48 hours, and 72 hours post-fatigue.

Secondary Outcomes (9)

• Muscle Damage via Ultrasound Echointensity

  Baseline, Immediately post-fatigue protocol, 24 hours, 48 hours, and 72 hours post-fatigue.

• Supramaximal Evoked Twitch Torque

  Baseline, Immediately post-fatigue protocol, 24 hours, 48 hours, and 72 hours post-fatigue.

• Evoked Neuromuscular Efficiency

  Baseline, Immediately post-fatigue protocol, 24 hours, 48 hours, and 72 hours post-fatigue.

• Sitting Muscle Discomfort

  Baseline, Immediately post-fatigue protocol, 24 hours, 48 hours, and 72 hours post-fatigue.

• Pain Pressure Threshold (PPT)

  Baseline, Immediately post-fatigue protocol, 24 hours, 48 hours, and 72 hours post-fatigue.

Study Arms (2)

Active PBMT + NMES

EXPERIMENTAL

Participants receive active Photobiomodulation Therapy (PBMT) applied to the knee extensor muscles 5 minutes prior to undergoing a 20-minute neuromuscular electrical stimulation (NMES) fatigue protocol on the randomized lower limb.

Device: Photobiomodulation Therapy (PBMT)

Sham PBMT + NMES

SHAM COMPARATOR

Participants receive sham Photobiomodulation Therapy (device turned off, identical positioning and acoustic blinding) applied to the knee extensor muscles 5 minutes prior to undergoing a 20-minute neuromuscular electrical stimulation (NMES) fatigue protocol on the contralateral lower limb.

Device: Sham Photobiomodulation

Interventions

Photobiomodulation Therapy (PBMT) DEVICE

Multi-diode cluster probe (GaAlAs laser; 5 diodes; wavelength: 810 nm; power output: 200 mW per diode; continuous mode) applied across 8 points over the quadriceps femoris (3 on rectus femoris, 3 on vastus lateralis, and 2 on vastus medialis) for 30 seconds per point (30 J/point), delivering a total energy dose of 240 J per limb.

Active PBMT + NMES

Sham Photobiomodulation DEVICE

Identical probe positioning over the 8 quadriceps locations for 30 seconds per point with the laser device completely turned off. Auditory headphones are used to blind participants against sound cues.

Sham PBMT + NMES

Eligibility Criteria

• Age: 18 Years - 40 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Healthy male and female adults aged between 18 and 40 years.
• Engaging in regular physical activity (minimum of twice a week).
• No history of hospitalization for COVID-19 in the past 12 months.
• Demonstrated ability to tolerate neuromuscular electrical stimulation (NMES).
• Capable of fully understanding and complying with the experimental protocol and procedures.

You may not qualify if:

• Presence of any sensory impairments or neurological alterations.
• Ingestion of caffeine, coffee, energy drinks, or other stimulants in the 12 hours preceding the testing sessions.
• Body Mass Index (BMI) greater than 30 kg/m².
• Any medical contraindication to performing maximal physical exertion or presenting an abnormal cardiovascular/blood pressure response after maximal effort.

Sponsors & Collaborators

• Federal University of Rio Grande do Sul: lead
• Conselho Nacional de Desenvolvimento Científico e Tecnológico: collaborator

Study Sites (1)

Laboratório de Pesquisa do Exercício

Porto Alegre, Rio Grande do Sul, 90690200, Brazil

Location

MeSH Terms

Interventions

Low-Level Light Therapy

Intervention Hierarchy (Ancestors)

Laser Therapy; Therapeutics; Phototherapy

Study Officials

• Marco A Vaz, PhD

  Federal University of Rio Grande do Sul

  STUDY CHAIR

• Marco A Vaz, PhD

  Federal University of Rio Grande do Sul

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: PARTICIPANT
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Full Professor

Study Record Dates

• First Submitted: August 24, 2026
• First Posted: August 27, 2026
• Study Start: November 1, 2022
• Primary Completion: August 1, 2023
• Study Completion: December 1, 2023
• Last Updated: August 27, 2026

Record last verified: 2026-08

Locations

BR (1)