Exercise-Induced Muscle FatigueHILTNCT07895862
Acute Effects of High-Intensity Laser Therapy on Pain, Muscle Stiffness, and Grip Strength in Healthy Adults
A study of Exercise-Induced Muscle Fatigue and Fatigue Recovery, run by University of Primorska.
Trial summary
The goal of this clinical trial is to learn whether high-intensity laser therapy applied before exercise reduces the loss of handgrip strength, muscle stiffness, and pain after a tiring forearm exercise in healthy adults. This therapy delivers laser light through the skin to the underlying tissues. Read more about this study
- Who is it for?
- Ages 18 to 40 yearsHealthy volunteers can take part
- Conditions the study is for
- Exercise-Induced Muscle Fatigue, Fatigue Recovery, Health Adult Subjects
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 30 participants
- Where
- No sites listed yet
- Study dates
- 1 Dec 2026to 1 Mar 2027
- 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 40 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Healthy adults aged 18 to 40 years.
- Willingness to participate and provide written informed consent.
Who cannot join
- Acute or chronic injuries of the upper limbs.
- Neurological, musculoskeletal, or systemic diseases that could affect muscle function.
- Contraindications to high-intensity laser therapy.
Trial locations and contacts
No sites are listed yet. Contact the study team or a site near you to ask about taking part.
About this study
The goal of this clinical trial is to learn whether high-intensity laser therapy applied before exercise reduces the loss of handgrip strength, muscle stiffness, and pain after a tiring forearm exercise in healthy adults. This therapy delivers laser light through the skin to the underlying tissues.
The main questions this study aims to answer are:
Read more
Does laser therapy reduce the loss of handgrip strength after exercise compared with placebo treatment?
Does laser therapy reduce the increase in forearm muscle stiffness after exercise?
Does laser therapy reduce pain after exercise?
Researchers will compare active laser therapy with placebo laser treatment to assess whether the active treatment affects the muscles' response to exercise. Each participant will receive both treatments on separate visits. The order of treatments will be assigned by chance.
Participants will attend two laboratory visits at the Faculty of Health Sciences, University of Primorska, Slovenia. At one visit, they will receive active laser therapy over the muscles that bend the wrist in their dominant forearm. At the other visit, they will receive placebo treatment over the same area.
At each visit, participants will:
Rest before the initial measurements.
Have their handgrip strength, forearm muscle stiffness, and pain measured before treatment.
Receive active laser therapy or placebo treatment.
Wait five minutes before starting the exercise procedure.
Complete a wrist-strength test, then hold a muscle contraction at half of their maximum wrist-bending strength until they can no longer maintain the required force.
Have their handgrip strength, muscle stiffness, and pain measured again immediately after exercise and five and fifteen minutes later.
Handgrip strength will be measured by squeezing a handheld device. Muscle stiffness will be measured using a device that applies a brief, gentle mechanical tap to the skin over the muscle. Participants will rate their pain using a visual scale.
Participants will be asked to avoid strenuous physical activity for at least 24 hours before each visit and to keep their diet and regular supplement use similar before both visits.
The main outcome is the change in handgrip strength from before treatment to after exercise. Changes in muscle stiffness and pain will also be compared between the two treatments. Researchers expect active laser therapy to result in a smaller decrease in handgrip strength and smaller increases in muscle stiffness and pain than placebo treatment.
- Being tested
- High-Intensity Laser Therapy (HILT) and sham HILT
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
High-Intensity Laser Therapy (HILT) and sham HILTDevice
High-intensity laser therapy will be administered using the Platinum 4 device (Summus Medical Laser) over the wrist flexor muscles of the dominant forearm, from the medial epicondyle of the humerus toward the wrist. All four wavelengths available on the device will be used. Each participant will receive one active treatment session, followed by a five-minute interval before the muscle-fatiguing exercise procedure. Both the participant and the therapist will wear appropriate protective eyewear.
Placebo high-intensity laser therapy will be administered over the wrist flexor muscles of the dominant forearm before the same muscle-fatiguing exercise procedure used in the active treatment condition. Each participant will receive one placebo treatment session, followed by a five-minute interval before the exercise procedure.
| Study group | Role | What they receive |
|---|---|---|
| Active HILT Followed by Placebo HILT | Experimental | High-intensity laser therapy will be administered using the Platinum 4 device (Summus Medical Laser) over the wrist flexor muscles of the dominant forearm, from the medial epicondyle of the humerus toward the wrist. All four wavelengths available on the device will be used. Each participant will receive one active treatment session, followed by a five-minute interval before the muscle-fatiguing exercise procedure. Both the participant and the therapist will wear appropriate protective eyewear. Receives: Device: High-Intensity Laser Therapy (HILT) and sham HILT |
| Sham HILT Followed by Placebo HILT | Sham comparator | Sham high-intensity laser therapy will be administered over the wrist flexor muscles of the dominant forearm before the same muscle-fatiguing exercise procedure used in the active treatment condition. Each participant will receive one placebo treatment session, followed by a five-minute interval before the exercise procedure. Receives: Device: High-Intensity Laser Therapy (HILT) and sham HILT |
What is being measured
The primary outcome is the main question the study is designed to answer.
Handgrip Strength
Handgrip strength will be measured using a Baseline Lite handheld dynamometer on the dominant hand. Participants will be seated with the upper arm alongside the trunk, the elbow flexed to 90 degrees, the forearm in a neutral position, and the wrist in slight extension and ulnar deviation. Three maximal grip attempts will be performed at each assessment, and the highest value will be used for analysis. Changes from the pre-intervention baseline will be compared between active and placebo high-intensity laser therapy.
Measured: At each of the two study visits: before the intervention (baseline), immediately after the fatiguing exercise, and 5 and 15 minutes after the fatiguing exercise. Visits will be separated by at least one week.
Secondary outcomes (1)
Wrist Flexor Muscle Stiffness
Muscle stiffness will be assessed using the MyotonPRO device at a predefined and marked anatomical measurement site over the wrist flexor muscles of the dominant forearm. The device applies a brief mechanical impulse to the skin and measures the tissue response to calculate muscle stiffness in newtons per meter (N/m). Higher values indicate greater stiffness. Changes from the pre-intervention baseline will be compared between active and placebo high-intensity laser therapy.
Measured: At each of the two study visits: before the intervention (baseline), immediately after the fatiguing exercise, and 5 and 15 minutes after the fatiguing exercise. Visits will be separated by at least one week.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted26 Oct 2026
- Study start1 Dec 2026 (estimated)
- Primary completion1 Feb 2027 (estimated)
- Study completion1 Mar 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Exercise-Induced Muscle FatigueStudies 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
- Prevention
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Enrolment
- 30 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Primorska
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Matej Voglar, University of Primorska
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07895862
- Sponsor's protocol ID
- HILT effects_forearm
- Acronym
- HILT
- Status last verified
- Aug 2026
- First submitted
- 19 Oct 2026
- Last updated
- 5 Nov 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 5 Nov 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Acute Effects of High-Intensity Laser Therapy on Pain, Muscle Stiffness, and Grip Strength in Healthy Adults
- ClinicalTrials.gov ID
- NCT07895862
- Acronym / sponsor ID
- HILT / HILT effects_forearm
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 30 participants (estimated)
- Lead sponsor
- University of PrimorskaUniversity, hospital or other
- Study start
- 1 Dec 2026 (estimated)
- Primary completion
- 1 Feb 2027 (estimated)
- Study completion
- 1 Mar 2027 (estimated)
- First posted
- 26 Oct 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.
The goal of this clinical trial is to learn whether high-intensity laser therapy applied before exercise reduces the loss of handgrip strength, muscle stiffness, and pain after a tiring forearm exercise in healthy adults. This therapy delivers laser light through the skin to the underlying tissues.
The main questions this study aims to answer are:
Does laser therapy reduce the loss of handgrip strength after exercise compared with placebo treatment?
Does laser therapy reduce the increase in forearm muscle stiffness after exercise?
Does laser therapy reduce pain after exercise?
Researchers will compare active laser therapy with placebo laser treatment to assess whether the active treatment affects the muscles' response to exercise. Each participant will receive both treatments on separate visits. The order of treatments will be assigned by chance.
Participants will attend two laboratory visits at the Faculty of Health Sciences, University of Primorska, Slovenia. At one visit, they will receive active laser therapy over the muscles that bend the wrist in their dominant forearm. At the other visit, they will receive placebo treatment over the same area.
At each visit, participants will:
Rest before the initial measurements.
Have their handgrip strength, forearm muscle stiffness, and pain measured before treatment.
Receive active laser therapy or placebo treatment.
Wait five minutes before starting the exercise procedure.
Complete a wrist-strength test, then hold a muscle contraction at half of their maximum wrist-bending strength until they can no longer maintain the required force.
Have their handgrip strength, muscle stiffness, and pain measured again immediately after exercise and five and fifteen minutes later.
Handgrip strength will be measured by squeezing a handheld device. Muscle stiffness will be measured using a device that applies a brief, gentle mechanical tap to the skin over the muscle. Participants will rate their pain using a visual scale.
Participants will be asked to avoid strenuous physical activity for at least 24 hours before each visit and to keep their diet and regular supplement use similar before both visits.
The main outcome is the change in handgrip strength from before treatment to after exercise. Changes in muscle stiffness and pain will also be compared between the two treatments. Researchers expect active laser therapy to result in a smaller decrease in handgrip strength and smaller increases in muscle stiffness and pain than placebo treatment.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Active HILT Followed by Placebo HILT | Experimental | Device: High-Intensity Laser Therapy (HILT) and sham HILTHigh-intensity laser therapy will be administered using the Platinum 4 device (Summus Medical Laser) over the wrist flexor muscles of the dominant forearm, from the medial epicondyle of the humerus toward the wrist. All four wavelengths available on the device will be used. Each participant will receive one active treatment session, followed by a five-minute interval before the muscle-fatiguing exercise procedure. Both the participant and the therapist will wear appropriate protective eyewear. |
| Sham HILT Followed by Placebo HILT | Sham comparator | Device: High-Intensity Laser Therapy (HILT) and sham HILTSham high-intensity laser therapy will be administered over the wrist flexor muscles of the dominant forearm before the same muscle-fatiguing exercise procedure used in the active treatment condition. Each participant will receive one placebo treatment session, followed by a five-minute interval before the exercise procedure. |
Who may qualify
- Ages
- 18 to 40 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (2 listed)
- Healthy adults aged 18 to 40 years.
- Willingness to participate and provide written informed consent.
Key exclusion criteria (3 listed)
- Acute or chronic injuries of the upper limbs.
- Neurological, musculoskeletal, or systemic diseases that could affect muscle function.
- Contraindications to high-intensity laser therapy.
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 |
|---|---|---|
| High-Intensity Laser Therapy (HILT) and sham HILTHigh-intensity laser therapy will be administered using the Platinum 4 device (Summus Medical Laser) over the wrist flexor muscles of the dominant forearm, from the medial epicondyle of the humerus toward the wrist. All four wavelengths available on the device will be used. Each participant will receive one active treatment session, followed by a five-minute interval before the muscle-fatiguing exercise procedure. Both the participant and the therapist will wear appropriate protective eyewear. Placebo high-intensity laser therapy will be administered over the wrist flexor muscles of the dominant forearm before the same muscle-fatiguing exercise procedure used in the active treatment condition. Each participant will receive one placebo treatment session, followed by a five-minute interval before the exercise procedure. | Device | Active HILT Followed by Placebo HILT, Sham HILT Followed by Placebo HILT |
Primary outcome
Handgrip Strength
Time frame: At each of the two study visits: before the intervention (baseline), immediately after the fatiguing exercise, and 5 and 15 minutes after the fatiguing exercise. Visits will be separated by at least one week.
Handgrip strength will be measured using a Baseline Lite handheld dynamometer on the dominant hand. Participants will be seated with the upper arm alongside the trunk, the elbow flexed to 90 degrees, the forearm in a neutral position, and the wrist in slight extension and ulnar deviation. Three maximal grip attempts will be performed at each assessment, and the highest value will be used for analysis. Changes from the pre-intervention baseline will be compared between active and placebo high-intensity laser therapy.
1 secondary outcome
Wrist Flexor Muscle Stiffness
Time frame: At each of the two study visits: before the intervention (baseline), immediately after the fatiguing exercise, and 5 and 15 minutes after the fatiguing exercise. Visits will be separated by at least one week.
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 5 Nov 2026.
- Individual participant dataSharing planned: Undecided
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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.
Questions about this trial
What is this clinical trial studying?
A study of Exercise-Induced Muscle Fatigue and Fatigue Recovery, run by University of Primorska.
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 2 inclusion and 3 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: opening soon, as of the sponsor's last update on 5 Nov 2026. Status can change between updates, so confirm with the study contact before making plans.
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 Denisa Manojlović Ivezić, PhD (+385989394672, denisa.manojlovic@fvz.upr.si), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Handgrip Strength (time frame: At each of the two study visits: before the intervention (baseline), immediately after the fatiguing exercise, and 5 and 15 minutes after the fatiguing exercise. Visits will be separated by at least one week.). 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 5 Nov 2026.