Effects of Photobiomodulation Therapy Combined With Static Magnetic Field in CrossFit® Athletes
Condition: Muscle Strength
Study type: Interventional

Summary: 
      Crossfit® is a method of strength training and fitness built on functional movements,
      constantly varied and executed at high intensity. Competitions such as the Crossfit® involve
      physically demanding activities, which in addition to being performed at high intensity also
      use great measures of aerobic capacity related with performance. These characteristics cause
      metabolic and muscular stress, as well as a decrease in physical performance. The demand for
      intensity is the cause of concern regarding the practice of Crossfit® and the risk of
      injuries. Studies using photobiomodulation therapy combined with static magnetic fields
      (PBMT/sMF) to delay fatigue and increase performance have obtained positive results in
      different types of exercise and application times. However, there are no studies
      investigating the effects of PBMT/sMF in training with similar characteristics as Crossfit®.
      Therefore, the aim of this project is to verify the effects of PBMT/sMF on performance and
      muscle recovery of Crossfit® athletes at different times of application (pre workout of the
      day [WOD] and/or post WOD) in order to determine the best way to use the therapy.
    

Detailed description: 
      To achieve the proposed objective it will be performed a randomized, crossover, triple-blind
      (volunteers, outcome assessors and therapists), placebo-controlled trial.

      Twelve volunteers will be allocated to four interventions/situation. The order of the
      interventions/situations will be randomized.

      The volunteers will be treated by a blinded therapist.

      The outcomes will be obtained at baseline (prior to WOD), and 1 hour, 24 and 48 hours after
      WOD. Except for the ratings of perceived exertion that will be obtained at baseline, after
      WOD, and 1 hour, 24 and 48 hours after WOD. In addition, for the functional analysis the data
      will be collected at baseline, after applied intervention, and 1 hour, 24 and 48 hours after
      WOD. The data will be collected by a blinded assessor.

      The WOD will be consisted in finish as quickly as possible a sequence of three exercises
      (Calories in Assault AirBike®, Hang Squat Clean and Box Jump Over), in a well-known series
      model for the athletes, without rest.

      The investigators will analyze: ratings of perceived exertion; activity of creatine kinase
      (CK); levels of the cytokine Interleukin-6 (IL-6), and maximum number of free squat reps in 1
      minute.

      Statistical analysis:

      All data will be analyzed both in their absolute values and in relation to their percentage
      variation from the values obtained in the pre-WOD (baseline) assessments. The results
      obtained will be tested for normality using the Kolmogorov-Smirnov test. If data show normal
      distribution, the ANOVA test (one or two way depending on the outcome analyzed) with post-hoc
      Bonferroni will be used. The level of statistical significance will be p<0.05.
    

Intervention name(s): Effective PBMT/sMF; Placebo PBMT/sMF
Intervention type(s): Device; Device
Intervention description(s): A cluster with 20 diodes, manufactured by Multi Radiance Medical® (Solon, OH, USA), will be used: 4 diodes of 905 nm (1.25 average power, 50 W of peak power for each diode), 8 diodes of 850 nm (40 mW of average power for each diode) and 4 diodes of 633 nm (25 mW average power for each diode). Effective PBMT/sMF will be applied in direct contact with the skin and light pressure in: 4 sites in the knee extensor/hip flexor muscles, 3 sites in the knee flexor/hip extensor muscles and 1 site in the plantar flexor muscles. The effective PBMT/sMF will be applied to both lower limbs. The dose used for applications will be approximately 270 J for knee extensors/hip flexors, 180 J for knee flexors/hip extensors, and 60 J for plantar flexors.; A cluster manufactured by Multi Radiance Medical® (Solon, OH, USA) with 20 diodes will be used: Placebo PBMT/sMF will be applied in direct contact with the skin and light pressure in: 4 sites in the knee extensor/hip flexor muscles, 3 sites in the knee flexor/hip extensor muscles and 1 site in the plantar flexor muscles. The placebo PBMT/sMF will be applied to both lower limbs. The dose used for applications will be approximately 0 J per diode. The sounds and signals emitted from the device as well as the information displayed on the screen will be identical, regardless of the type of treatment (active or placebo).
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: The volunteers will be allocated to four interventions/situation:
Effective PBMT/sMF before WOD and placebo PBMT/sMF after WOD;
Placebo PBMT/sMF before WOD and effective PBMT/sMF after WOD;
Effective PBMT/sMF before WOD and effective PBMT/sMF after WOD;
Placebo PBMT/sMF before WOD and placebo PBMT/sMF after WOD. The order of the interventions will be randomized.
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Prevention
Keywords: Photobiomodulation Therapy; Low-level Laser Therapy; Static Magnectic Fields; CrossFit®; Strength Training