title: Effects of Light-Emitting Diode Therapy on Muscle Hypertrophy, Gene Expression, Performance, Damage, and Delayed-Onset Muscle Soreness: Case-control Study with a Pair of Identical Twins.
abstract: The aim of this study was to verify how a pair of monozygotic twins would respond to light-emitting diode therapy (LEDT) or placebo combined with a strength-training program during 12 weeks.
  
  
  
  This case-control study enrolled a pair of male monozygotic twins, allocated randomly to LEDT or placebo therapies. Light-emitting diode therapy or placebo was applied from a flexible light-emitting diode array (λ = 850 nm, total energy = 75 J, t = 15 seconds) to both quadriceps femoris muscles of each twin immediately after each strength training session (3 times/wk for 12 weeks) consisting of leg press and leg extension exercises with load of 80% and 50% of the 1-repetition maximum test, respectively. Muscle biopsies, magnetic resonance imaging, maximal load, and fatigue resistance tests were conducted before and after the training program to assess gene expression, muscle hypertrophy and performance, respectively. Creatine kinase levels in blood and visual analog scale assessed muscle damage and delayed-onset muscle soreness, respectively, during the training program.
  
  
  
  Compared with placebo, LEDT increased the maximal load in exercise and reduced fatigue, creatine kinase, and visual analog scale. Gene expression analyses showed decreases in markers of inflammation (interleukin 1β) and muscle atrophy (myostatin) with LEDT. Protein synthesis (mammalian target of rapamycin) and oxidative stress defense (SOD2 [mitochondrial superoxide dismutase]) were up-regulated with LEDT, together with increases in thigh muscle hypertrophy.
  
  
  
  Light-emitting diode therapy can be useful to reduce muscle damage, pain, and atrophy, as well as to increase muscle mass, recovery, and athletic performance in rehabilitation programs and sports medicine.
authors.affiliation: From the Laboratory of Electrothermophototherapy, Department of Physical Therapy (CF, NP), and Post-Graduation Program in Biotechnology (CF, EM, NP), Federal University of São Carlos; Optics Group, Physics Institute of São Carlos, University of São Paulo, São Carlos (CF, VB), São Paulo, Brazil; Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, Massachusetts (CF, MRH); Department of Physiological Sciences, Federal University of São Carlos, São Carlos (DB); Faculty of Medicine, University of São Paulo, Ribeirao Preto (JS, AA); Center for Cell Therapy and Regional Blood Center of Ribeirao Preto (JS, AA, RP); Departments of Medicine (RR) and Genetic and Evolution (AFC), Federal University of São Carlos, São Carlos; Post-Graduation Program in Bioengineering, University of São Paulo, São Carlos (VMA), São Paulo, Brazil; Department of Dermatology, Harvard Medical School, Boston (MRH); and Harvard-MIT Division of Health Sciences and Technology, Cambridge (MRH), Massachusetts.
authors.forename: Cleber
authors.initials: C
authors.lastname: Ferraresi
authors.forename: Danilo
authors.initials: D
authors.lastname: Bertucci
authors.forename: Josiane
authors.initials: J
authors.lastname: Schiavinato
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Reiff
authors.forename: Amélia
authors.initials: A
authors.lastname: Araújo
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Panepucci
authors.forename: Euclides
authors.initials: E
authors.lastname: Matheucci
authors.forename: Anderson Ferreira
authors.initials: AF
authors.lastname: Cunha
authors.forename: Vivian Maria
authors.initials: VM
authors.lastname: Arakelian
authors.forename: Michael R
authors.initials: MR
authors.lastname: Hamblin
authors.forename: Nivaldo
authors.initials: N
authors.lastname: Parizotto
authors.forename: Vanderlei
authors.initials: V
authors.lastname: Bagnato
mesh_terms: D016022:Case-Control Studies; D003402:Creatine Kinase; D015444:Exercise / Q000502:physiology*; D017079:Exercise Tolerance / Q000502:physiology; D006801:Humans; D006984:Hypertrophy / Q000097:blood / Q000473:pathology / Q000628:therapy; D053583:Interleukin-1beta / Q000097:blood; D028022:Low-Level Light Therapy / Q000379:methods*; D008297:Male; D018763:Muscle Fatigue / Q000502:physiology; D063806:Myalgia / Q000097:blood / Q000473:pathology / Q000628:therapy*; D055435:Myostatin / Q000097:blood; D052097:Quadriceps Muscle / Q000378:metabolism / Q000473:pathology; D055070:Resistance Training / Q000379:methods*; D013482:Superoxide Dismutase / Q000502:physiology; D058570:TOR Serine-Threonine Kinases / Q000502:physiology; D013848:Thigh / Q000473:pathology; D014430:Twins, Monozygotic; D015854:Up-Regulation; D055815:Young Adult; D000099156:Superoxide Dismutase 2
chemical_list: D003402:Creatine Kinase; D053583:Interleukin-1beta; D055435:Myostatin; D013482:Superoxide Dismutase; D058570:TOR Serine-Threonine Kinases; D000099156:Superoxide Dismutase 2; C525911:MSTN protein, human