Effect of Low-level Laser Therapy on Exercise-induced Muscle Damage

Study Overview
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Brief Summary
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Introduction: The effects of Low Level Laser Therapy (LLLT) on exercise-induced muscular damage have been studied over the last years. Studies have been conducted on animals and humans in order to try to show the benefits of the intervention, but there is still conflicting evidence about its protective and therapeutic effects. Objectives: To describe the effects of LLLT on pain, strength and muscular inflammation after plyometric exercise. Methods: A randomized, double-blinded, placebo-controlled trial with participation of 20 male healthy volunteers will be performed. Healthy and physically active individuals, aged between 18 and 35 years, with no history of injury on the lower limbs or contra-indications to maximal exercise performance will be included. A protocol of 10 series with 10 repetitions of the countermovement jump will be used to induce muscle damage at the lower limbs. Immediately before or after the exercise protocol, LLLT will be applied on one lower limb, while the other will receive placebo treatment. Phototherapy will be applied with an equipment of 810nm and a cluster with 5 diodes on 8 different points of the knee extensor muscle, totalizing a dosage of 240J. The placebo treatment will be held on the same way, but the equipment will be turned off. The volunteers will be evaluated at baseline (before the exercise protocol) and at follow-up of 24, 48 and 72 hours. The following outcomes will be evaluated: knee extensors isometric peak torque by Isokinetic Dynamometer, pain by Visual Analogue Scale and muscular tissue echo intensity by Ultrasonography.

Official Title
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Effect of Low-level Laser Therapy on Exercise-induced Muscle Damage: a Randomized Clinical Trial

Conditions
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Muscle Damage

Intervention / Treatment
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* Device: LLLT before muscle damage
* Device: Placebo LLLT before muscle damage
* Device: LLLT after muscle damage
* Device: Placebo LLLT after muscle damage


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy males aged between 18 and 35 years; Sedentary or physically active individuals who exercise up to 3 times per week. Exclusion Criteria: Individuals who participate in systematic exercise training; Individuals who participate in strength training for the lower limbs; Individuals with lower or upper limb injuries; Individuals with contra-indications to maximal exercise performance (due to neurological, cardiovascular or respiratory conditions); Individuals who show difficulties to understand the study protocol.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 35 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: LLLT before muscle damage<br>Low Level Laser Therapy (LLLT) will be applied before the exercise protocol on one lower limb, while the other will receive placebo treatment. Phototherapy will be applied with an equipment of 810nm and a cluster with five diodes on eight different points of quadriceps muscle, totalizing a dosage of 240J. | Device: LLLT before muscle damage<br> <br> |
| Placebo Comparator: Placebo LLLT before muscle damage<br>Placebo LLLT will be applied before the exercise protocol on one lower limb, while the other will receive real treatment. Placebo treatment will also be applied on eight different points of quadriceps muscle, but the equipment will be turned off. | Device: Placebo LLLT before muscle damage<br> <br> |
| Active Comparator: LLLT after muscle damage<br>Low Level Laser Therapy (LLLT) will be applied after the exercise protocol on one lower limb, while the other will receive placebo treatment. Phototherapy will be applied with an equipment of 810nm and a cluster with five diodes on eight different points of quadriceps muscle, totalizing a dosage of 240J. | Device: LLLT after muscle damage<br> <br> |
| Placebo Comparator: Placebo LLLT after muscle damage<br>Placebo LLLT will be applied after the exercise protocol on one lower limb, while the other will receive real treatment. Placebo treatment will also be applied on eight different points of quadriceps muscle, but the equipment will be turned off. | Device: Placebo LLLT after muscle damage<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Knee extensors isometric peak torque (Nm) | Isokinetic Dynamometer | Baseline and 24, 48 and 72 hours follow-up | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Knee extensors soreness (Visual Analogue scale) |  | Baseline and 24, 48 and 72 hours follow-up | 
| Knee extensors echo intensity (number of white and black pixels) |  | Baseline and 24, 48 and 72 hours follow-up | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Phototherapy, Plyometric exercise, Muscle recovery