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This study aimed to identify the near-infrared (NIR) light emitting diode (LED) time response on isokinetic peak torque of elbow flexors. This was a prospective, randomized, single blind, pre–test post-test, and placebo-controlled crossover study. Forty-five healthy non-athletes were assigned at random to 3 groups equally: 5 minutes, 1-hour and 5-hours groups. Each group (n=15) had at the first session 890 nm wavelength NIR-LED, either in active or placebo conditions, prior to exercise that provokes fatigue (5 minutes, 1 hour, or 5 hours). After an interval of 7 days, the second NIR-LED condition was applied at the second session. The assessment of isokinetic peak torque was done at base line and post exercise in each session using isokinetic dynamometer. There was no significant difference between groups and between conditions in isokinetic peak torque (p > 0.05). Isokinetic peak torque decreased significantly post treatment compared with pretreatment (p < 0.01) in all groups, but the 5 minutes group showed the least percent of decrease. In conclusion, NIR-LED can most probably resist muscle fatigue with the parameters used in this study if it is employed 5 minutes before exercise.