title: Light-emitting diode therapy (LEDT) before matches prevents increase in creatine kinase with a light dose response in volleyball players.
abstract: Low-level laser (light) therapy (LLLT) has been applied over skeletal muscles before intense exercise (muscular pre-conditioning) in order to reduce fatigue and muscle damage (measured by creatine kinase, CK) in clinical trials. However, previous exercise protocols do not exactly simulate the real muscle demand required in sports. For this reason, the aim of this randomized and double-blind placebo-controlled trial was to investigate whether light-emitting diode therapy (LEDT) applied over the quadriceps femoris muscles, hamstrings, and triceps surae of volleyball players before official matches could prevent muscle damage (CK) with a dose response, establishing a therapeutic window. A professional male volleyball team (12 athletes) was enrolled in this study, and LEDT was applied before 4 matches during a national championship. LEDT used an array of 200 light-emitting diodes (LEDs) arranged in 25 clusters of 4 infrared LEDs (850 ± 20 nm; 130 mW) and 25 clusters of 4 red LEDs (630 ± 10 nm; 80 mW). Athletes were randomized to receive one of four different total doses over each muscle group in a double-blind protocol: 105 J (20 s), 210 J (40 s), 315 J (60 s), and placebo (no light for 30 s). CK in blood was assessed 1 h before and 24 h after each match. LEDT at 210 J avoided significant increases in CK (+10 %; P = 0.993) as well as 315 J (+31 %, P = 0.407). Placebo (0 J) allowed a significant increase in CK (+53 %; P = 0.012) as well as LEDT at 105 J (+59 %; P = 0.001). LEDT prevented significant increases of CK in blood in athletes when applied before official matches with a light dose response of 210-315 J, suggesting athletes might consider applying LEDT before competition.
authors.affiliation: Laboratory of Electrothermophototherapy, Department of Physical Therapy, Federal University of Sao Carlos, Rodovia Washington Luís, km 235, 13565-905, Sao Carlos, SP, Brazil, cleber.ferraresi@gmail.com.
authors.forename: Cleber
authors.initials: C
authors.lastname: Ferraresi
authors.forename: Ricardo Vinicius
authors.initials: RV
authors.lastname: Dos Santos
authors.forename: Guilherme
authors.initials: G
authors.lastname: Marques
authors.forename: Marcelo
authors.initials: M
authors.lastname: Zangrande
authors.forename: Roberley
authors.initials: R
authors.lastname: Leonaldo
authors.forename: Michael R
authors.initials: MR
authors.lastname: Hamblin
authors.forename: Vanderlei Salvador
authors.initials: VS
authors.lastname: Bagnato
authors.forename: Nivaldo Antonio
authors.initials: NA
authors.lastname: Parizotto
mesh_terms: D000293:Adolescent; D000328:Adult; D003402:Creatine Kinase / Q000097:blood*; D004311:Double-Blind Method; D015444:Exercise / Q000502:physiology; D006801:Humans; D008027:Light; D028022:Low-Level Light Therapy; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology; D052097:Quadriceps Muscle; D054798:Volleyball; D055815:Young Adult
chemical_list: D003402:Creatine Kinase