Using a single dose of photobiomodulation (laser + LED) to improve performance of lower limbs in functional test: randomized clinical trial
Background: Photobiomodulation (PBM) improves functional performance; however, there are still doubts whether the improvement occurs immediately or late after a single dose. This study evaluated the effect of PMB by a single dose via cluster (laser+LED) on muscle fatigue recovery in young sedentary adults, both immediately and in the short term (period between 24 to 48 h) after the fatiguing event. Methods: Randomized clinical trial with 60 volunteers randomized in 5 groups (n=12 in each): control (CG); placebo (SG); PBM in knee extensor (KE_G); plantar-flexor (PF_G); knee extensor+plantar-flexor (KE+FP_G). Before the intervention (pre) a fatigue endurance test was applied, which consisted in going up and down one step until exhaustion. The number of repetitions and the time to exhaustion were recorded. Then each group received its respective intervention and immediately after that, the fatigue endurance test was reapplied (immediate post). In the period between 24 to 48 h after irradiation, a new fatigue endurance test was performed (late post). In addition to the comparative statistics, complementary metrics (minimum detectable change and effect size) were calculated. Results: Through the integrated analysis of inferential statistics and complementary metrics, it was observed that although there was no time of evaluation effect, there was a group effect. PBM improved performance in KE+FP_G and PF_G regarding CG. Conclusion: It was concluded that a single dose of PBM irradiation improves functional performance, but it is suggested that there is specificity of the irradiated muscle group, although it does not depend on the moment.