BackgroundPhotobiomodulation therapy (PBMT) has recently been indicated as a potential therapeutic strategy in diverse health and sports contexts. However, its efficacy on muscle performance in female futsal players remains unknown. The purpose of this study was to investigate the dose-response effect of PBMT on muscle performance in female futsal players. MethodsIn a crossover design, fifteen female futsal athletes (age: 18–30 years) were randomized to receive 1 of 4 PBMT conditions (placebo, 300, 900, and 1260 J [J]) on four occasions, separated by a 2-wk washout period. PBMT treatments were applied on the quadriceps muscle of both legs using a device containing 200 light-emitting diodes (LEDs), immediately before the following tests: countermovement jump (CMJ) (i.e., flight time as indicator of muscle power), maximum voluntary isometric contraction (MVIC) for the leg extension exercise (i.e., muscle strength), and 3 sets of repetitions-to-failure (i.e., local muscular endurance) for the 45° leg press exercise, with recording of rating of perceived exertion (RPE) after each set. The fatigue index was determined by the number of repetitions between sets 1 and 3. ResultsNo significant differences were found between the PBMT conditions for the maximum number of repetitions (p = 0.899), RPE (time p < 0.0001; interaction p = 0.653), fatigue index (p = 0.835), muscle power (p = 0.789), and isometric peak and mean torque (p = 0.776 and 0.537, respectively). ConclusionDifferent doses of acute PBMT with LEDs do not improve muscle performance (endurance, power, and strength) and RPE in female futsal players.
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