Vol.:(0123456789) 1 3 Sport Sciences for Health https://doi.org/10.1007/s11332-018-0495-5 ORIGINAL ARTICLE Photobiomodulation therapy is beneficial in reducing muscle fatigue in Brazilian jiu-jitsu athletes and physically active men Bruno Follmer 1,2  · Rodolfo Andre Dellagrana 1  · Mateus Rossato 1,3  · Raphael Luiz Sakugawa 1  · Fernando Diefenthaeler 1 Received: 9 July 2018 / Accepted: 27 August 2018 © Springer-Verlag Italia S.r.l., part of Springer Nature 2018 Abstract Introduction Photobiomodulation therapy (PBMT) applied prior to exercise may provide ergogenic effects by delaying the onset of fatigue. The Brazilian jiu-jitsu (BJJ) is a domain combat sport in which elbow flexors’ isometric contraction is commonly performed. Purpose This study was aimed at investigating the effects of PBMT on torque parameters in groups of BJJ athletes (n = 10) and physically active men (n = 10). Methods The strength testing protocol was composed of elbow flexors’ maximal isometric voluntary contractions at 90°; treatment application (placebo or PBMT); fatigue protocol; and one elbow flexors’ maximal isometric voluntary contraction. Magnitude-based inference analyses were used to examine practical significance. Results BJJ athletes presented higher relative isometric peak torque values pre (ES = 0.92) and post (ES = 1.32) fatigue protocol than those observed in physically active men. Beneficial results were shown in the time to exhaustion (difference: 5.5 s, likely beneficial) and impulse during fatigue test (difference 271.1 N m s, possibly beneficial) for physically active men and in the impulse for BJJ athletes (difference 179.0 N m s, possibly beneficial) in favor of PBMT compared to placebo. Conclusions The PBMT was efficient in delaying the onset of fatigue regardless of the individuals’ training level and could be suggested as an ergogenic factor to improve muscle performance. Keywords Muscle strength dynamometer · Torque · Martial arts · Double-blind method · Randomized controlled trial Introduction Photobiomodulation therapy (PBMT) applied prior to resist- ance exercise may provide ergogenic effects [1], since it has been shown to improve muscle performance by delaying the onset of fatigue [2–4]. Although the mechanisms behind the positive effects of PBMT in reducing the fatigue response are unclear, some evidences indicate that PBMT effects may be exercise dependent [5]. For high intensity and/or strength exercises, PBMT seems to improve the mitochondrial activ- ity, phosphocreatine resynthesis, and lactate oxidation [6, 7]. These effects have shown improvements in isometric proto- cols to exhaustion [8–10], number of voluntary repetitions until exhaustion [3, 4, 11], and strength maintenance after fatigue protocols [2, 12]. Most of the studies involving PBMT and fatigue have assessed physically active subjects [13, 14]. However, the PBMT application in highly trained subjects (i.e., athletes of several modalities) has grown in the last years [15, 16]. * Bruno Follmer brunofollmer@hotmail.com Rodolfo Andre Dellagrana radellagrana@gmail.com Mateus Rossato rossato.mateus@gmail.com Raphael Luiz Sakugawa rlsakugawa@gmail.com Fernando Diefenthaeler fdiefenthaeler@gmail.com 1 Biomechanics Laboratory, Center of Sports, Federal University of Santa Catarina, Florianópolis, SC, Brazil 2 Rehabilitation Neuroscience Laboratory, University of Victoria, Victoria, BC, Canada 3 Laboratory of Human Performance, Faculty of Physical Education and Physiotherapy, Federal University of Amazonas, Amazonas, AM, Brazil