Phototherapy for Improvement of Performance and Exercise Recovery: Comparison of 3 Commercially Available Devices.
BACKGROUND
Recent studies suggest the prophylactic use of low-powered laser/light has ergogenic effects on athletic performance and postactivity recovery. Manufacturers of high-powered lasers/light devices claim that these can produce the same clinical benefits with increased power and decreased irradiation time; however, research with high-powered lasers is lacking.


OBJECTIVE
To evaluate the magnitude of observed phototherapeutic effects with 3 commercially available devices.


METHODS
Randomized double-blind placebo-controlled study.


METHODS
Laboratory.


METHODS
Forty healthy untrained male participants.


METHODS
Participants were randomized into 4 groups: placebo, high-powered continuous laser/light, low-powered continuous laser/light, or low-powered pulsed laser/light (comprising both lasers and light-emitting diodes). A single dose of 180 J or placebo was applied to the quadriceps.


METHODS
Maximum voluntary contraction, delayed-onset muscle soreness (DOMS), and creatine kinase (CK) activity from baseline to 96 hours after the eccentric exercise protocol.


RESULTS
Maximum voluntary contraction was maintained in the low-powered pulsed laser/light group compared with placebo and high-powered continuous laser/light groups in all time points (P < .05). Low-powered pulsed laser/light demonstrated less DOMS than all groups at all time points (P < .05). High-powered continuous laser/light did not demonstrate any positive effects on maximum voluntary contraction, CK activity, or DOMS compared with any group at any time point. Creatine kinase activity was decreased in low-powered pulsed laser/light compared with placebo (P < .05) and high-powered continuous laser/light (P < .05) at all time points. High-powered continuous laser/light resulted in increased CK activity compared with placebo from 1 to 24 hours (P < .05).


CONCLUSIONS
Low-powered pulsed laser/light demonstrated better results than either low-powered continuous laser/light or high-powered continuous laser/light in all outcome measures when compared with placebo. The increase in CK activity using the high-powered continuous laser/light compared with placebo warrants further research to investigate its effect on other factors related to muscle damage.
Postgraduate Program in Biotechnology, Oxidative Stress and Antioxidant Laboratory, University of Caxias do Sul, Brazil.
Thiago
T
De Marchi
Sports Medicine Institute, University of Caxias do Sul, Brazil.
Vinicius Mazzochi
VM
Schmitt
Postgraduate Program in Biotechnology, Oxidative Stress and Antioxidant Laboratory, University of Caxias do Sul, Brazil.
Carla
C
Danúbia da Silva Fabro
Postgraduate Program in Biotechnology, Oxidative Stress and Antioxidant Laboratory, University of Caxias do Sul, Brazil.
Larissa Lopes
LL
da Silva
Postgraduate Program in Biotechnology, Oxidative Stress and Antioxidant Laboratory, University of Caxias do Sul, Brazil.
Juliane
J
Sene
Sports Medicine Institute, University of Caxias do Sul, Brazil.
Olga
O
Tairova
Postgraduate Program in Biotechnology, Oxidative Stress and Antioxidant Laboratory, University of Caxias do Sul, Brazil.
Mirian
M
Salvador
D000328:Adult; D054874:Athletic Performance / Q000502:physiology; D004311:Double-Blind Method; D015444:Exercise / Q000502:physiology; D005260:Female; D006801:Humans; D007834:Lasers / Q000145:classification*; D008297:Male; D018482:Muscle, Skeletal / Q000503:physiopathology; D063806:Myalgia / Q000175:diagnosis / Q000209:etiology / Q000517:prevention & control; D010789:Phototherapy / Q000295:instrumentation / Q000379:methods; D052097:Quadriceps Muscle; D020127:Recovery of Function
high-intensity laser therapy; light-emitting diode therapy; low-level laser therapy; photobiomodulation therapy; skeletal muscle performance