Influence of Power and Wavelength on Photobiomodulation Therapy for Muscle Performance in Healthy Subjects
Condition: Low Level Laser Therapy; Photobiomodulation; Performance; Sport
Study type: Interventional

Summary: 
      In recent years, photobiomodulation has been studied as a means of increasing muscle
      performance in athletes and healthy individuals. This is possible due to the physiological
      changes that photobiomodulation therapy can promote. Moreover, given a large number of
      existing studies on the subject, some directions for future research have been established.
      For example, future research was established, the relationship between power and time because
      with high power, it will achieve the same energy with shorter application times. However,
      irradiation may not be offered for the minimum recommended time. Therefore, this study aims
      to compare different powers and, consequently, different application times for muscle
      performance in healthy individuals. For this, 42 participants will be recruited, males
      between 18 to 40 years old, without recent musculoskeletal injury or cardiorespiratory
      problems. The participants will participate in 3 evaluations containing functional and
      physiological variables and ten training sessions of lower limbs with previous
      photobiomodulation therapy application, comparing devices with a power of 0.864W and 1.864W.
      0.864W and 1.2W. Lower limbs training will be composed of stiff and squat exercises twice a
      week, for five weeks. In the pre- and post-intervention evaluations, the following parameters
      will be evaluated isokinetic apparatus, body composition, and functionality of the vertical
      jump. For data analysis, we will use a normality test to verify the distribution and
      statistical tests will be used for intra and intra and intergroup comparisons, considering
      two factors in the comparisons time and group. A significance level of 5% will be adopted.
    

Detailed description: 
      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.
    

Intervention name(s): Photobiomodulation; Sham
Intervention type(s): Other; Other
Intervention description(s): Photobiomodulation consists of irradiation by light in order to achieve photochemical and photophysical outcomes.; Simulation of the application of photobiomodulation therapy.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Primary purpose: Other
Keywords: Physical Therapy; Photobiomodulation; Muscle Strength; Power; Athletic Performance