title: Effect of 830 nm low-level laser therapy in exercise-induced skeletal muscle fatigue in humans.
abstract: This study aimed to investigate the effect of 830 nm low-level laser therapy (LLLT) on skeletal muscle fatigue. Ten healthy male professional volleyball players entered a crossover randomized double-blinded placebo-controlled trial. Active LLLT (830 nm wavelength, 100 mW output, spot size 0.0028 cm(2), 200 s total irradiation time) or an identical placebo LLLT was delivered to four points on the biceps humeri muscle immediately before exercises. All subjects performed voluntary biceps humeri contractions with a load of 75% of the maximum voluntary contraction (MVC) force until exhaustion. After active LLLT the mean number of repetitions was significantly higher than after placebo irradiation [mean difference 4.5, standard deviation (SD) +/- 6.0, P = 0.042], the blood lactate levels increased after exercises, but there was no significant difference between the treatments. We concluded that 830 nm LLLT can delay the onset of skeletal muscle fatigue in high-intensity exercises, in spite of increased blood lactate levels.
authors.affiliation: Laboratory of Human Movement (LMH), University of Caxias do Sul, Rua Francisco Getúlio Vargas, 1130, Caxias do Sul, 95070-560, Rio Grande do Sul, Brazil. ecplealj@ucs.br
authors.forename: Ernesto Cesar Pinto
authors.initials: EC
authors.lastname: Leal Junior
authors.forename: Rodrigo Alvaro Brandão
authors.initials: RA
authors.lastname: Lopes-Martins
authors.forename: Adriane Aver
authors.initials: AA
authors.lastname: Vanin
authors.forename: Bruno Manfredini
authors.initials: BM
authors.lastname: Baroni
authors.forename: Douglas
authors.initials: D
authors.lastname: Grosselli
authors.forename: Thiago
authors.initials: T
authors.lastname: De Marchi
authors.forename: Vegard V
authors.initials: VV
authors.lastname: Iversen
authors.forename: Jan Magnus
authors.initials: JM
authors.lastname: Bjordal
mesh_terms: D000293:Adolescent; D000328:Adult; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005080:Exercise Test; D006801:Humans; D007259:Infrared Rays / Q000627:therapeutic use; D019344:Lactic Acid / Q000097:blood; D028022:Low-Level Light Therapy / Q000379:methods*; D008297:Male; D018763:Muscle Fatigue / Q000528:radiation effects*; D018482:Muscle, Skeletal / Q000502:physiology / Q000528:radiation effects; D054798:Volleyball / Q000502:physiology; D055815:Young Adult
chemical_list: D019344:Lactic Acid