Abstract
The effects of preexercise photobiomodulation therapy (PBMT) to enhance performance, accelerate recovery, and attenuate exercise-induced oxidative stress were still not fully investigated, especially in high-level athletes. The aim of this study was to evaluate the effects of PBMT (using infrared low-level laser therapy) applied before a progressive running test on functional aspects, muscle damage, and inflammatory and oxidative stress markers in high-level soccer players. A randomized, triple-blind, placebo-controlled crossover trial was performed. Twenty-two high-level male soccer players from the same team were recruited and treated with active PBMT and placebo. The order of interventions was randomized. Immediately after the application of active PBMT or placebo, the volunteers performed a standardized high-intensity progressive running test (ergospirometry test) until exhaustion. We analyzed rates of oxygen uptake (VO2 max), time until exhaustion, and aerobic and anaerobic threshold during the intense progressive running test. Creatine kinase (CK) and lactate dehydrogenase (LDH) activities, levels of interleukin-1β (IL-1-β), interleukin-6 (IL-6), and tumor necrosis factor alpha (TNF-α), levels of thiobarbituric acid (TBARS) and carbonylated proteins, and catalase (CAT) and superoxide dismutase (SOD) activities were measured before and five minutes after the end of the test. PBMT increased the VO2 max (both relative and absolute values—p < 0.0467 and p < 0.0013, respectively), time until exhaustion (p < 0.0043), time (p < 0.0007) and volume (p < 0.0355) in which anaerobic threshold happened, and volume in which aerobic threshold happened (p < 0.0068). Moreover, PBMT decreased CK (p < 0.0001) and LDH (p < 0.0001) activities. Regarding the cytokines, PBMT decreased only IL-6 (p < 0.0001). Finally, PBMT decreased TBARS (p < 0.0001) and carbonylated protein levels (p < 0.01) and increased SOD (p < 0.0001)and CAT (p < 0.0001) activities. The findings of this study demonstrate that preexercise PBMT acts on different functional aspects and biochemical markers. Moreover, preexercise PBMT seems to play an important antioxidant effect, decreasing exercise-induced oxidative stress and consequently enhancing athletic performance and improving postexercise recovery. This trial is registered with Clinicaltrials.gov NCT03803956.
Highlights
In soccer, as well as in other high-level sport activities, players experience acute muscle fatigue in the hours or even days following a single match [1, 2]
The sample size was calculated based on a previous trial conducted by our research group [34], in which the primary outcome, the photobiomodulation therapy (PBMT) device, and the standardized progressive running exercise protocol were the same employed in our study
Regarding assessment of muscle damage, the results demonstrated that active PBMT applied before the exercise protocol significantly decreased the activity of both postexercise Creatine kinase (CK) and lactate dehydrogenase (LDH) (p < 0:0001) compared to placebo PBMT
Summary
As well as in other high-level sport activities, players experience acute muscle fatigue in the hours or even days following a single match [1, 2]. Since the number of competitive matches per season is very high (up to 65 to 76 matches per season) and the time to recovery between two successive matches may be insufficient (around 72 to 96 hours), players may experience chronic fatigue [1,2,3]. The process of fatigue leads to a decline in physical performance and injury in some cases [1,2,3]; it is indispensable that athlete recovery be as fast and effective as possible [7]. The evidence about the effectiveness of some of these strategies to recovery is still conflicting [17,18,19]
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