Influence of photobiomodulation on energy contribution in normoxia and hypoxia conditions in amateur runners: a single-blinded and randomized crossover pilot study.

This study aimed to investigate the influence of photobiomodulation therapy (PBMT) in hypoxia (HYP) and normoxia (NOR) on time to exhaustion and the energetic contribution of treadmill running in amateur athletes. Eleven male participants, aged between 18 and 29 years, were submitted to an incremental test to determine the iV̇O2max, and subsequently on separated days, to the PBMT application (irradiation = 720 s; wavelength = 850 nm), followed by four efforts to exhaustion, in treadmill running, under different conditions [NOR + placebo (PLA); NOR + PBMT; HYP + PLA; HYP + PBMT], in random order, to access energy contribution and maximal accumulated oxygen deficit alternative (MAODALT). Time to exhaustion and absolute aerobic contribution were lower in HYP than NOR, for both PLA and PBMT conditions (p < 0.05). In the percentage energy contribution of each metabolism during exhaustion effort, aerobic participation was lower, while MAODALT was higher in HYP than NOR, only in the PLA situation; alactic anaerobic participation was higher in HYP than NOR in the PBMT application situation (p = 0.002). The PBMT does not promote additional benefits over time to exhaustion in NOR and HYP conditions, however PBMT during exhaustive efforts in HYP results in an increase in anaerobiosis.