title: Identifying Dosage Effect of Light-Emitting Diode Therapy on Muscular Fatigue in Quadriceps.
abstract: Hemmings, TJ, Kendall, KL, and Dobson, JL. Identifying dosage effect of light-emitting diode therapy on muscular fatigue in quadriceps. J Strength Cond Res 31(2): 395-402, 2017-The purpose of this study was to compare the effects of various dosages of light-emitting diode therapy (LEDT) on muscle fatigue while performing a single-leg extension to exhaustion. A total of 34 recreationally resistance-trained athletes between the ages of 18 and 26 participated in 4 trials. Each trial included pre-exercise/postexercise blood lactate measurements and 2 sets of 3 maximal voluntary isometric contractions (MVICs), followed by LEDT on 6 points across the superficial quadriceps. Each randomized trial consisted of a placebo, 30, 60, or 120 seconds on each point on the quadriceps. Three minutes after LEDT, the participants performed an eccentric leg extension with 120% of MVIC until fatigue. There was significant increase in the number of repetitions performed between the placebo treatment and 60 seconds (p = 0.023), as well as placebo and 120 seconds (p = 0.004) of irradiation on each point. There were no significant differences in blood lactate levels between any of the 4 trials. In conclusion, LEDT had a positive effect on performance when irradiating 6 points on the superficial quadriceps for 60 and 120 seconds before an eccentric leg extension.
authors.affiliation: Department of Health and Kinesiology, Georgia Southern University, Statesboro, Georgia.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Hemmings
authors.forename: Kristina L
authors.initials: KL
authors.lastname: Kendall
authors.forename: John L
authors.initials: JL
authors.lastname: Dobson
mesh_terms: D000293:Adolescent; D000328:Adult; D056352:Athletes; D004311:Double-Blind Method; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D007537:Isometric Contraction; D019344:Lactic Acid / Q000097:blood; D028022:Low-Level Light Therapy / Q000379:methods*; D008297:Male; D018763:Muscle Fatigue / Q000502:physiology*; D052097:Quadriceps Muscle / Q000502:physiology*; D055815:Young Adult
chemical_list: D019344:Lactic Acid