Effects of Light Emitting Diodes (LED) Therapy in Rugby Athletes

Randomized crossover clinical trial, composed of three groups that will receive LED treatment at three different times. Sample made up of rugby athletes of both sexes, aged between 18 and 35 years. On the first day of the study, there will be an anamnesis, in which the participants will answer questions about personal data, history of injuries and training time, right after receiving weight, height, heart rate and blood pressure, in addition to collecting a blood sample. standardize the baseline values of the individual. After the initial assessment, participants will be randomized to not receive the LED (CO) or receive LED therapy at three different times: before (Lpré), in the interval (Lin) and after (Lpós) of the performance tests. Then, the modified Star Trek Balance Test (SEBTm), the Single Jump Test (SGHT) and the Triple Jump Test (THT) will be performed. Soon after, the familiarization protocol with the Bangsbo Sprint test (BST) will begin, with the participants positioned close to the initial marker (photocell) and the signal, they must execute a maximum of 34.2 meters, performing seven repetitions, with twenty-five seconds duration for active recovery between sprints. At the end of the sprints, the participant will rest for 10 minutes and then perform the intermittent Yo-Yo level 1 recovery test (Yo-Yo IR1). At the end of this test, participants remain at rest for 10 minutes and then perform the same tests (BST and Yo-Yo IR1) again. At the end of the second battery of tests, heart rate, blood pressure, perceived exertion, blood sample and functional tests will be measured again. After 48 hours of performance tests, blood samples will be collected and functional tests will be carried out, in addition to all participants answering the Stress Recovery Questionnaire for Athletes (RESTQ-Sport-76), to quantify the recovery and psychophysiological stress during the test and recovery days. At 7, 14 and 21 days after the initial tests, the same test and evaluation protocol will be performed, but the participants will receive LED therapy before, during or after the performance tests, according to their randomization. All participants will receive LED therapy at the three times, only the application sequence will be randomized. LED therapy will be performed at two points on the quadriceps, two on the hamstrings and two on the gastrocnemius bilaterally. At each point, irradiation will be applied for 60 seconds, with a wavelength of 850nm (± 20nm) and an energy density of 8 joules per square centimeter (J/cm2).