Influence of Power and Wavelength on Photobiomodulation Therapy for Muscle Performance in Healthy Subjects

It is a blinded randomized clinical trial. The volunteers will undergo pre-evaluation, 5 weeks of training associated with the LED application, being distributed in two applications per week, and a re-evaluation 24 hours after the last application, totaling a total of approximately 7 weeks. Thus, on the first day (Pre-test) volunteers will be submitted to anthropometric evaluation and evaluation by bioimpedance for analysis of detailed body composition. Then, the maximum voluntary contraction test (CVM) will be performed on the isokinetic dynamometer, together with the electromyographic evaluation. Before and after the evaluation with the isokinetic dynamometer, thermography will be collected. Still, will be evaluated the vertical jump test after 15 minutes of passive rest.

After the initial evaluations, the researcher will go apply the respective interventions, which consist of applying LEDs all over the quadriceps and hamstring bilaterally, while the sham group (GS) will receive the LED application off, without the emission of light. The application will occur for five weeks and will occur twice weekly, on days spaced for at least 48 hours. The same will be done in conjunction with the lower limb strength training protocol. It is noteworthy that although the therapy follows the same energy values, two different pieces of equipment will be used, thus changing the wavelength, total power and power density, and the consequent coverage time and area.

The tests performed at the time of pre-application of the LED (Pre-test) will be reapplied in the same order 24 hours after the last application of the interventions. After seven days of the last application, the isokinetic evaluation, electromyography, and vertical jump evaluation will be performed. In addition, at the end of the second and fourth weeks, the volunteer will carry out an evaluation with the isokinetic dynamometer, electromyography, plethysmography, and thermography.

Inclusion criteria

• healthy individuals;

Exclusion criteria

• musculoskeletal injury in the last three months;
• cardiovascular diseases;
• use of anabolic, anti-inflammatory and analgesic drugs 72 hours before the evaluations;
• use of alcohol and illicit drugs during the collection period;