Laserterapia de baixa potência no desempenho e recuperação muscular pós-exercício: potência ideal de aplicação e efeitos em exercício de curta duração

Abstract

Low-level laser therapy (LLLT) has recently been used to alleviate post-exercise muscle fatigue and enhance recovery. Positive results have been demonstrated when phototherapy is performed prior to exercise. However, certain factors, such as ideal output power and exposure time, remain unknown. A previous study by our research group demonstrated the ideal dose, but the results could be enhanced further with the determination of the ideal output power. Thus, the aim of the present study was to elaborate (Article 1) and to execute (Article 2) an LBP application protocol, evaluating the effects of laser therapy on post-exercise skeletal muscle recovery, identifying the best output power and exposure time. A randomized, placebo-controlled, double-blind, clinical trial was conducted with the voluntary participation of high-level football players. The following were the LLLT parameters: wavelength of 810 nm, dose of 10 J and output power of 0 (placebo), 100mW, 200mW or 400 mW (different groups). The quadriceps muscle was chosen for analysis and received radiance from a cluster of five diodes, distributed in two points on the vastus medialis, two points on the vastus lateralis and two points on the rectus femoris. Physical performance (peak torque/maximum voluntary contraction), delayed onset muscle soreness and biochemical markers related to muscle damage (CK and LDH), inflammation (IL-1, IL-6 and TNF-) and oxidative stress (CAT, SOD, carbonylated proteins and TBARS) were evaluated prior to isokinetic exercise as well as one minute and one, 24, 48, 72 and 96 hours after the exercise protocol. The findings revealed statistically significant differences (p < 0.05) favoring an output power of 100 mW regarding the recovery of peak strength, delayed onset muscle soreness and biochemical markers, suggesting this to be the ideal output power for the population studied.