PhotobiomodulationNCT07602933
Photobiomodulation Effects on Fatigue and Muscle Damage Induced by NMES
A study testing Active Photobiomodulation and NMES-evoked fatigue protocol in people with Photobiomodulation and Fatigue, run by Federal University of Rio Grande do Sul at 1 site in Brazil.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 18 to 45 yearsHealthy volunteers can take part
- Conditions the study is for
- Photobiomodulation, Fatigue, Discomfort
- What is being tested?
- Active Photobiomodulation and NMES-evoked fatigue protocol
- Type of treatment
- Medical device
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 36 participants
- Where
- 1 siteBrazil
- Study dates
- 1 Jun 2026to 30 Sep 2026
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 45 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- 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
Who cannot join
- 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
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Brazil1 site, 1 recruiting
- Recruiting
Laboratório de Pesquisa do Exercício
Porto Alegre, Rio Grande do Sul, 90690200
Jeam M Geremia, PhD, 5133085853, jeam.geremia@ufrgs.br
Marco A Vaz, PhD
About this study
Official title: 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.
- Conditions
- Photobiomodulation, Fatigue, Discomfort, Electrical Stimulation, Muscle Damage
- Being tested
- Active Photobiomodulation, Placebo Photobiomodulation, NMES-evoked fatigue protocol
- Keywords
- Photobiomodulation, Fatigue, Discomfort, Muscle Damage, Electrical stimulation
- Medical subject headings
- Fatigue
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Active PhotobiomodulationDevice
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.
Placebo PhotobiomodulationDevice
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.
NMES-evoked fatigue protocolOther
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).
| Study group | Role | What they receive |
|---|---|---|
| Photobiomodulation (PBM) | Experimental | Participants in this arm will receive active photobiomodulation therapy. Receives: Device: Active Photobiomodulation; Other: NMES-evoked fatigue protocol |
| Sham PBM | Sham comparator | Participants in this arm will receive an inactive (placebo) photobiomodulation treatment. Receives: Device: Placebo Photobiomodulation; Other: NMES-evoked fatigue protocol |
What is being measured
The primary outcome is the main question the study is designed to answer.
Maximal voluntary isometric contraction (MVIC)
Largest knee extensor torque generated isometrically and voluntarily on an isokinetic dynamometer.
Unit of Measure: Newton-meters (N.m)
Measured: 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
Fall in the evoked torque during the fatigue protocol. Unit of Measure: Newton-meters (N.m)
Measured: Continuously during the 20-minute fatigue protocol.
Secondary outcomes (8)
Muscle Echo Intensity
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
Measured: 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
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)
Measured: 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
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)
Measured: 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
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)
Measured: 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
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 (°)
Measured: 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
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)
Measured: 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
Surface electromyography (sEMG) to assess muscle activation amplitude during MVIC. Unit of Measure: Microvolts (uV)
Measured: 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
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)
Measured: Continuously during the 20-minute fatigue protocol on Day 1.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted22 May 2026
- Study start1 Jun 2026
- Primary completion30 Aug 2026 (estimated)
- Study completion30 Sep 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for PhotobiomodulationStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Design Model: Parallel Assignment. Number of Arms: 2 (Arm 1: PBM; Arm 2: Sham). Timeline: Assessments will be performed at baseline, followed by the NMES-evoked fatigue protocol. Subsequent evaluations will be conducted post-intervention immediately, and at 24, 48, and 72 hours post-intervention.
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 36 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Federal University of Rio Grande do Sul
- Sponsor type
- University, hospital or other
- Collaborators
- Conselho Nacional de Desenvolvimento Científico e Tecnológico
- Responsible party
- Principal investigator, Marco Aurélio Vaz, PhD, Federal University of Rio Grande do Sul
- Investigators
- Marco A Vaz, PhD, Study chair, Federal University of Rio Grande do SulMarco A Vaz, PhD, Study director, Federal University of Rio Grande do SulMarco A Vaz, PhD, Principal investigator, Federal University of Rio Grande do Sul
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07602933
- Sponsor's protocol ID
- 5.309.992(1)
- Status last verified
- Aug 2026
- First submitted
- 27 Apr 2026
- Last updated
- 25 Aug 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: 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.
Study at a glance
From the registry record, last updated by the sponsor on 25 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effects of Photobiomodulation on Fatigue and Muscle Damage Induced by Neuromuscular Electrical Stimulation in Healthy Individuals: a Randomized Clinical Trial
- ClinicalTrials.gov ID
- NCT07602933
- Acronym / sponsor ID
- 5.309.992(1)
- Conditions
- Photobiomodulation, Fatigue, Discomfort, Electrical Stimulation, Muscle Damage
- Keywords
- Photobiomodulation, Fatigue, Discomfort, Muscle Damage, Electrical stimulation
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 36 participants (estimated)
- Lead sponsor
- Federal University of Rio Grande do SulUniversity, hospital or other
- Collaborators
- Conselho Nacional de Desenvolvimento Científico e Tecnológico
- Study start
- 1 Jun 2026 (actual)
- Primary completion
- 30 Aug 2026 (estimated)
- Study completion
- 30 Sep 2026 (estimated)
- First posted
- 22 May 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 2
- Model description
- Design Model: Parallel Assignment. Number of Arms: 2 (Arm 1: PBM; Arm 2: Sham). Timeline: Assessments will be performed at baseline, followed by the NMES-evoked fatigue protocol. Subsequent evaluations will be conducted post-intervention immediately, and at 24, 48, and 72 hours post-intervention.
| Arm | Type | Receives |
|---|---|---|
| Photobiomodulation (PBM) | Experimental | Device: Active Photobiomodulation, Other: NMES-evoked fatigue protocolParticipants in this arm will receive active photobiomodulation therapy. |
| Sham PBM | Sham comparator | Device: Placebo Photobiomodulation, Other: NMES-evoked fatigue protocolParticipants in this arm will receive an inactive (placebo) photobiomodulation treatment. |
Who may qualify
- Ages
- 18 to 45 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (5 listed)
- 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
Key exclusion criteria (5 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Active PhotobiomodulationApplication 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. | Device | Photobiomodulation (PBM) |
| Placebo PhotobiomodulationThe 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. | Device | Sham PBM |
| NMES-evoked fatigue protocolNeuromuscular 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). | Other | Photobiomodulation (PBM), Sham PBM |
Primary outcome
Maximal voluntary isometric contraction (MVIC)
Time frame: 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)
Evoked fatigue
Time frame: Continuously during the 20-minute fatigue protocol.
Fall in the evoked torque during the fatigue protocol. Unit of Measure: Newton-meters (N.m)
8 secondary outcomes
Muscle Echo Intensity
Time frame: 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
Time frame: 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
Time frame: 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
Time frame: 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
Time frame: 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
Time frame: 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
Time frame: 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
Time frame: Continuously during the 20-minute fatigue protocol on Day 1.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 25 Aug 2026.
- Individual participant dataSharing planned: No. 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.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Marco A Vaz, PhD study chair
Federal University of Rio Grande do Sul
Marco A Vaz, PhD study director
Federal University of Rio Grande do Sul
Marco A Vaz, PhD principal investigator
Federal University of Rio Grande do Sul
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Active Photobiomodulation and NMES-evoked fatigue protocol in people with Photobiomodulation and Fatigue, run by Federal University of Rio Grande do Sul at 1 site in Brazil.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 25 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Brazil. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Marco A Vaz, PhD (+555133085853, marco.vaz@ufrgs.br), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Maximal voluntary isometric contraction (MVIC) (time frame: 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 study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 25 Aug 2026.