The Weightlifter's Blackout is a period when all lights must be turned out or covered to prevent them being seen by the others. Also it is a temporary loss of consciousness experienced during weightlifting or another strength training activity when the breath is held [1] [2][12].
Many weightlifters at one point or another in their careers will experience the phenomenon of “blacking out." This will most likely occur in lifts where the breath is held for a longer than normal time, such as in a military press, squat clean, or squat.