Effect of Light-Emitting Diode on the Strenght and Resistence Capacities of Cycling Athletes
Condition: Athletes
Study type: Interventional

Summary: 
      Phototherapy is a therapeutic resource of increasing use in the last decade. The
      photobiomodulatory effects are commonly produced by means of low intensity lasers or LED
      emitting diodes, and can be used at different wavelengths. These light sources are divergent
      as to coherence, but produce equivalent tissue effects. The application of laser or LED light
      is able to induce biochemical changes in tissues, allowing for inhibitory or stimulating
      effects. These responses are associated to a cascade of cellular reactions, which favor the
      absorption of enzymes by cytochrome c oxidase, generating physiological responses that lead
      to decreased production of reactive oxygen species and increased synthesis of adenosine
      triphosphate (ATP). The application of this therapeutic resource brings ergogenic and
      protective benefits in muscular performance. The use of LED as a light source is promising
      because of its low cost, but there are no enough studies that support this use in athletes,
      with a focus on performance improvement. In addition to the deficiency of the sample, there
      is also no consensus regarding the use of different wavelengths for LED in the literature,
      thus opening gaps for the best protocol for the application of this technique. Therefore, a
      study that evaluates the use of LED in athletes, with different wavelengths, to improve
      performance is necessary. Hypothesis: It is hypothesized that the LED application is capable
      of improving athletes performance in terms of increased fatigue resistance, increased
      strength and power, increased muscle recruitment, and optimized oxygen demand. It is also
      expected that the results generated in this study can contribute to and increase the
      resources used by physiotherapists within the clinical-sports field, contributing to the
      post-training recovery, as well as the more effective physical performance in competitive
      activities.
    

Detailed description: 
      Background: Phototherapy is a therapeutic resource of increasing use in the last decade. The
      photobiomodulatory effects are produced by sources of low-level lasers or light- emitting
      diode (LEDT), and their tissue effects are equivalent. The application of this therapeutic
      resource brings ergogenic and protective benefits in muscular performance. The use of LED as
      a light source is promising because of its low cost, but there are no enough studies that
      support this use in athletes, with a focus on performance improvement. In addition to the
      deficiency of the sample, there is also no consensus regarding the use of different
      wavelengths for LED in the literature, thus opening gaps for the best protocol for the
      application of this technique. Therefore, a study that evaluates the use of LED in athletes,
      with different wavelengths, to improve performance is necessary. Objective: To analyze the
      acute effects of the application of LED phototherapy on the strength and fatigue strength
      abilities of cycling athletes. Method: The study sample will be composed of 48 male cyclist
      athletes randomly allocated into three groups: Infrared LED Group (G-I), Red LED Group (G-V),
      Infrared plus Red Group (G-IV) and Sham Group (G-S). The athletes will be submitted to a
      battery of tests, for performance evaluation which consist of anaerobic and aerobic power and
      threshold, bioimpedance, infrared thermography, creatine kinase (CK) and blood lactate
      analysis, measurement of local muscle blood flow, Gas analysis, besides the isokinetic,
      electromyographic and biomechanical evaluations. After 24 hours of the tests, the LEDT (180
      J) will be applied three times in three differents days to the quadriceps femoris muscle
      bilaterally. The same tests will be performed 24 hours after the application of LEDT. In the
      1st and 4th week, post intervention, only the isokinetic and electromyographic evaluations
      will be performed. For analysis of the data, normality test will be used to verify the
      distribution and adequate statistical tests for the appropriate intra and intergroup
      comparisons, being considered two factors in the comparisons, time and group. A significance
      level of 5% will be adopte
    

Intervention name(s): Light-Emitting Diode Device; Sham Light-Emitting Diode Device
Intervention type(s): Device; Device
Intervention description(s): The therapy will be applied on the second, third and fourth day of collection using a 25x40 cm2 LED blanket, with an equidistant distribution, with total energy per area of 180 J bilaterally on the quadriceps femoris muscle.
All LEDs will be calibrated prior to the start of applications in the Laboratory of Photobiophysics of the Faculty of Sciences and Letters of Ribeirão Preto, University of São Paulo, in which the wavelengths will be checked, the angle of radiation, power and power density.; The Sham Light-Emitting Diode Device will be applied on the second, third and fourth day of collection using a 25x40 cm2 LED blanket, with an equidistant distribution, with total energy per area of 0 J bilaterally on the quadriceps femoris muscle. At the time of application the device will not be activated
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Athletes will be randomized allocated the following groups:
Infrared LED group (G-I; n = 12)
Red LED group (G-V; n = 12)
Infrared plus Red LED group (G-IV; n = 12)
Sham Group (G-S; n = 12)
Masking: Triple (Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Other
Keywords: Phototherapy; Athletic Performance; Muscle Strength; Fatigue