Muscle fatigue is a potential risk factor for hamstring strain injuries in soccer players. The aim of this study was to verify the effect of photobiomodulation therapy (PBMT) on the hamstrings’ muscle fatigue of soccer players during a simulated match. Twelve male amateur soccer players (~ 25 years) participated in this randomized, crossover, double-blinded, placebo-controlled trial. The volunteers were evaluated in two sessions, with a minimum 7-day interval. At each session, volunteers received either PBMT (300 J per thigh) or placebo treatment on the hamstrings prior to the simulated soccer match. Muscle strength and functional capacity were evaluated through isokinetic dynamometry and countermovement jump (CMJ) tests, respectively, before and immediately after the simulated soccer match. Players had lower reductions on hamstring eccentric peak torque [4.85% (ES = 0.31) vs. 8.72% (ES = 0.50)], hamstring-to-quadriceps torque ratio [3.60% (ES = 0.24) vs. 7.75% (ES = 0.50)], and CMJ height [1.77% (ES = 0.09) vs. 5.47% (ES = 0.32)] when treated with PBMT compared to placebo. Magnitude-based inference supports that PBMT promoted 75%, 69%, and 53% chances for beneficial effects on hamstring eccentric peak torque, hamstring-to-quadriceps torque ratio, and CMJ height, respectively, compared to placebo treatment. In conclusion, PBMT applied before a simulated soccer match proved to be effective in attenuating the hamstrings’ muscle fatigue. These findings support PBMT as a promising tool to prevent hamstring strain injury in soccer players.
Phototherapy Muscle injury Prevention Football
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Marco Aurélio Vaz and Ernesto Cesar Pinto Leal-Junior thank CNPq-Brazil for the research productivity fellowships. Maurício Pinto Dornelles and Carolina Gassen Fritsch thank CAPES-Brazil for the scholarships.
Compliance with ethical standards
The study was previously approved by the Ethics and Research Committee of the Universidade Federal de Ciências da Saúde de Porto Alegre (no. 63299416.4.0000.5345), and all participants signed an informed consent.
Conflict of interest
Professor Ernesto Cesar Pinto Leal-Junior receives research support from Multi Radiance Medical (Solon - OH, USA) and Douglas Scott Johnson is an employee and shareholder of Multi Radiance Medical, a photobiomodulation/laser device manufacturer. They didn’t have any participation in data collection or data analysis in this study. Furthermore, Multi Radiance Medical didn’t have any participation in any aspect related to this study. The remaining authors declare that they have no conflict of interests.
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