Photobiomodulation Therapy in a Field Test With High-level Rugby Players

Study Overview
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Brief Summary
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Background/Aim: While growing evidence supports the use of photobiomodulation therapy (PBMT) for performance and recovery enhancement, there have only been laboratory-controlled studies. Therefore, the aim of this study was to analyze the effects of PBMT in performance and recovery of high-level rugby players during an anaerobic field test. Methods: It is a randomized, crossover, double-blinded, placebo-controlled trial. Twelve male high-level rugby athletes were recruited in this study. No intervention was performed before the Bangsbo Sprint Test (BST) at familiarization phase (week 1). At weeks 2 and 3, pre-exercise PBMT or placebo were randomly applied to each athlete. PBMT/placebo irradiation was performed at 17 sites of each lower limb, employing a cluster with 12 diodes (4 laser diodes of 905nm, 4 LED diodes of 875nm, and 4 LED diodes of 640nm, 30J per site - manufactured by Multi Radiance Medical™). Average time of sprints, best time of sprints, and fatigue index were obtained from BST. Blood lactate levels were assessed at baseline, and at 3, 10, 30 and 60 minutes after BST. Athletes' perceived fatigue was also assessed through a questionnaire.

Detailed Description
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All exercise tests were conducted in an enclosed soccer/rugby field. The three test phases, administered one week apart, were performed on the same day of the week (Tuesday) and time (1-5pm). The average temperature inside the building during the trials ranged from 26°C to 28°C. At first stage (exercise test 1) all athletes performed the Bangsbo Sprint Test (BST) to familiarization with the procedure. No interventions or comparators were applied before this test. However, at the second and third stages (exercise tests 2 and 3, respectively) either a placebo or active PBMT was applied according to randomization. Blood samples were collected from the athlete's fingertips prior to stretching and warming-up (baseline), and at 3, 10, 30 and 60 minutes after BST at each of the three study stages/phase (exercise tests). After blood sample collection (to establish baseline), a warm-up comprised of low-intensity activities such as dynamic stretches and low-intensity short running were performed by each athlete. Following the warm-up and cool down period, either the active or placebo comparator was applied to the athlete according to the randomization procedure for the second test. For the third test, the other comparator was utilized to complete the cross over design. A quick perception of fatigue survey was administered following each test.

Official Title
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Phototherapy (With a Combination of Super-pulsed Laser and LEDs) in a Field Test With High-level Rugby Players

Conditions
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High-level Rugby Athletes, Performance, Recovery

Intervention / Treatment
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* Device: Photobiomodulation therapy (Phototherapy)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: high-level athletes from São José Rugby Club (Brazil) Exclusion Criteria: Athlete would be excluded if the participant presented any skeletal muscle injury if athlete took any nutritional supplement or pharmacological agent if the athlete presented signs and symptoms of any disease (i.e., neurological, inflammatory, pulmonary, metabolic, oncologic), and if the athlete had history of cardiac arrest that could limit performance of high-intensity exercises

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: Health Services Research
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Active PBMT<br>Active PBMT was applied employing MR4 Laser Therapy Systems outfitted with LaserShower 50 4D emitters (both manufactured by Multi Radiance Medical, Solon - OH, USA). The cluster style emitter contains 12 diodes comprising of four super-pulsed laser diodes (905 nm, 0.3125 mW average power, and 12.5 W peak power for each diode), four red LED diodes (640 nm, 15 mW average power for each diode), and four infrared LEDs diodes (875 nm, 17.5 mW average power for each diode). | Device: Photobiomodulation therapy (Phototherapy)<br>* PBMT was applied employing MR4 Laser Therapy Systems manufactured by Multi Radiance Medical, Solon - OH, USA. The cluster emitter contains 12 diodes with four super-pulsed laser diodes (905 nm, 0.3125 mW average power, and 12.5 W peak power for each diode), four red LED diodes (640 nm, 15 mW average power for each diode), and four infrared LEDs diodes (875 nm, 17.5 mW average power for each diode). It was applied in direct contact with the skin to 9 sites on extensor muscles of the knee, 6 sites on knee flexors of the knee, and 2 sites on the calf of both lower limbs. To ensure blinding, the device emitted the same sounds and regardless of the programmed mode (active or placebo).<br>* Other names: Photobiomodulation therapy (PBMT);|
| Placebo Comparator: Placebo PBMT<br>Placebo PBMT was applied using the same device that emitted the same sounds and light, but with no effective irradiation. | Device: Photobiomodulation therapy (Phototherapy)<br>* PBMT was applied employing MR4 Laser Therapy Systems manufactured by Multi Radiance Medical, Solon - OH, USA. The cluster emitter contains 12 diodes with four super-pulsed laser diodes (905 nm, 0.3125 mW average power, and 12.5 W peak power for each diode), four red LED diodes (640 nm, 15 mW average power for each diode), and four infrared LEDs diodes (875 nm, 17.5 mW average power for each diode). It was applied in direct contact with the skin to 9 sites on extensor muscles of the knee, 6 sites on knee flexors of the knee, and 2 sites on the calf of both lower limbs. To ensure blinding, the device emitted the same sounds and regardless of the programmed mode (active or placebo).<br>* Other names: Photobiomodulation therapy (PBMT);|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Bangsbo Sprint Test (BST) - Average Time (sec) | The Average Time of sprints performed during entire test (ST mean). This is the one of the variables from BST to evaluate performance. | The test was performed for three weeks, once a week, on the same day and time of the week. | 
| Bangsbo Sprint Test (BST) - Best Time (sec) | The fastest (best) time (ST best) among the seven sprints performed at each test. One of the variables from BST to evaluate performance. | The test was performed for three weeks, once a week, on the same day and time of the week. | 
| Bangsbo Sprint Test (BST) - Fatigue Index (%) | Fatigue index was calculated by the following equation: FI(%)= (STmean / STbest x 100) ˗ 100 to measure the percentage of decrease in performance between all sprints. One of the variables from BST to evaluate performance. | The test was performed for three weeks, once a week, on the same day and time of the week. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Questionnaire of fatigue | A quick perception of fatigue survey. The questionnaire consisted of eight questions pertaining to perception of training, sleep, leg pain, concentration, effectiveness, anxiety, irritability and stress. Each question was evaluated according to a score scale where 1-2 points corresponds to not at all, 3-4 points to normal, and 5-7 to very much. The scores was calculated according to the relative importance of each question and a lower score indicates better general well-being perception, and a higher score demonstrates greater fatigue perception. | This questionnaire was answered for the participants in the last day of the tests, so, at the end of the third week of the tests. | 
| Blood Lactate analysis | Blood samples were collected from the athlete's fingertips prior to stretching and warming-up (baseline), and at 3, 10, 30 and 60 minutes after BST at each of the three study stages/phase (exercise tests). | Blood sample was collected in the three phases of the study (three weeks, once a week) at 3, 10, 30 and 60 minutes after BST. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Low-level laser therapy, Light emitting diodes, Rugby, Field test, Photobiomodulation