title: What is the ideal dose and power output of low-level laser therapy (810 nm) on muscle performance and post-exercise recovery? Study protocol for a double-blind, randomized, placebo-controlled trial.
abstract: BACKGROUND
  Recent studies involving phototherapy applied prior to exercise have demonstrated positive results regarding the attenuation of muscle fatigue and the expression of biochemical markers associated with recovery. However, a number of factors remain unknown, such as the ideal dose and application parameters, mechanisms of action and long-term effects on muscle recovery. The aims of the proposed project are to evaluate the long-term effects of low-level laser therapy on post-exercise musculoskeletal recovery and identify the best dose andapplication power/irradiation time.
  
  
  METHODS
  A double-blind, randomized, placebo-controlled clinical trial with be conducted. After fulfilling the eligibility criteria, 28 high-performance athletes will be allocated to four groups of seven volunteers each. In phase 1, the laser power will be 200 mW and different doses will be tested: Group A (2 J), Group B (6 J), Group C (10 J) and Group D (0 J). In phase 2, the best dose obtained in phase 1 will be used with the same distribution of the volunteers, but with different powers: Group A (100 mW), Group B (200 mW), Group C (400 mW) and Group D (0 mW). The isokinetic test will be performed based on maximum voluntary contraction prior to the application of the laser and after the eccentric contraction protocol, which will also be performed using the isokinetic dynamometer. The following variables related to physical performance will be analyzed: peak torque/maximum voluntary contraction, delayed onset muscle soreness (algometer), biochemical markers of muscle damage, inflammation and oxidative stress.
  
  
  CONCLUSIONS
  Our intention, is to determine optimal laser therapy application parameters capable of slowing down the physiological muscle fatigue process, reducing injuries or micro-injuries in skeletal muscle stemming from physical exertion and accelerating post-exercise muscle recovery. We believe that, unlike drug therapy, LLLT has a biphasic dose-response pattern.
  
  
  BACKGROUND
  The protocol for this study is registered with the Protocol Registry System, ClinicalTrials.gov identifier NCT01844271.
authors.forename: Adriano Rodrigues
authors.initials: AR
authors.lastname: de Oliveira
authors.forename: Adriane Aver
authors.initials: AA
authors.lastname: Vanin
authors.forename: Thiago
authors.initials: T
authors.lastname: De Marchi
authors.forename: Fernanda Colella
authors.initials: FC
authors.lastname: Antonialli
authors.forename: Vanessa dos Santos
authors.initials: Vdos S
authors.lastname: Grandinetti
authors.forename: Paulo Roberto Vicente
authors.initials: PR
authors.lastname: de Paiva
authors.forename: Gianna Móes
authors.initials: GM
authors.lastname: Albuquerque Pontes
authors.forename: Larissa Aline
authors.initials: LA
authors.lastname: Santos
authors.forename: Ivo de Oliveira
authors.initials: Ide O
authors.lastname: Aleixo Junior
authors.forename: Paulo de Tarso Camillo
authors.initials: Pde T
authors.lastname: de Carvalho
authors.forename: Jan Magnus
authors.initials: JM
authors.lastname: Bjordal
authors.affiliation: Postgraduate Program in Biophotonics Applied to Health Sciences, Universidade Nove de Julho (UNINOVE), Rua Vergueiro 235, São Paulo, SP 01504-001, Brazil. ernesto.leal.junior@gmail.com.
authors.forename: Ernesto Cesar Pinto
authors.initials: EC
authors.lastname: Leal-Junior
mesh_terms: D015415:Biomarkers / Q000378:metabolism; D001696:Biomechanical Phenomena; D001938:Brazil; D002985:Clinical Protocols; D004311:Double-Blind Method; D015444:Exercise; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism; D028022:Low-Level Light Therapy / Q000379:methods*; D008297:Male; D009119:Muscle Contraction / Q000528:radiation effects*; D018763:Muscle Fatigue / Q000528:radiation effects*; D018482:Muscle, Skeletal / Q000378:metabolism / Q000503:physiopathology / Q000528:radiation effects*; D018384:Oxidative Stress; D011829:Radiation Dosage; D020127:Recovery of Function; D012107:Research Design; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D015415:Biomarkers; D018836:Inflammation Mediators