Does photobiomodulation therapy combined to static magnetic field (PBMT-sMF) promote ergogenic effects even when the exercised muscle group is not irradiated? A randomized, triple-blind, placebo-controlled trial

Abstract

Background: The direct application of photobiomodulation therapy (PBMT) using low-level laser therapy (LLLT) and light emitting diodes (LEDs) combined with a static magnetic field (sMF) (PBMT-sMF) to target tissues is shown to improve muscle performance and recovery. Studies have reported possible PBMT effects when a local distant to the target tissue is irradiated. Notably, the extent of these effects on musculoskeletal performance and the optimal site of irradiation remain unclear, although this information is clinically important since these aspects could directly affect the magnitude of the effect. Therefore, we investigated the effects of local and non-local PBMT-sMF irradiations on musculoskeletal performance and post-exercise recovery before an eccentric exercise protocol. Methods: This randomized, triple-blind (participants, therapists and assessors), placebo-controlled trial included 30 healthy male volunteers randomly assigned to the placebo, local, and non-local groups. Active or placebo PBMT-sMF was applied to 6 sites of the quadriceps muscle of both legs. An eccentric exercise protocol was used to induce fatigue. The primary outcome was peak torque assessed by maximal voluntary contraction (MVC). The secondary outcomes were delayed onset muscle soreness (DOMS) measured by visual analogue scale (VAS), muscle injury assessed by serum creatine kinase activity (CK), and blood lactate levels. Evaluations were performed before the eccentric exercise protocol (baseline), as well as immediately after and 1, 24, 48, and 72 h upon protocol completion.

Photobiomodulation and Sports: Results of a Narrative Review

“…Yet, many of these repercussions, as well as the complex clinical applications are still incompletely known. Some positive effects were also obtained by simultaneously applying PBMT and static magnetic fields, which we considered in this review [100][101][102][103].…”

Effects of Photobiomodulation in Sports Performance: A Literature Review

“…Of the five studies in which the intervention consisted of a strength test with concentric and eccentric exercises measured using an isokinetic dynamometer, four were found to show significant changes in the group in which PBMT was used compared to the placebo group. In three of them, muscle damage after exercise was reduced [11,18,19] and, in the other, fatigue and time to exhaustion were observed to decrease [14].…”

“…Machado C. et al, 2020 [18] researched whether PBMT along with a static magnetic field improved the recovery and muscle damage in thirty healthy males after an eccentric strength test measured with an isokinetic dynamometer.…”

“…However, the lessening of pain in muscles showed differences of a significant nature in those participants who received PBMT as regards the placebo group in the studies by Peserico C. et al, 2019 [15], Machado C. et al, 2020 [18] and Leal Junior E. et al, 2020 [19].…”

“…Among the two studies in which the intervention was a combination of cardiovascular and strength exercise tests, neither demonstrated the effectiveness of PBMT, applied before or after exercise, for muscle recovery in high-intensity cardiovascular exercise [6,18]. However, one of the studies showed that muscle recovery is greater after strength training in the group that received PBMT when compared to the placebo group [18].…”