The ATP-CP and glycogen-lactic acid system follow the anaerobic pathway, which means that they function in the absence of oxygen. Absence of oxygen doesn’t mean there is no oxygen available, it only means that the task was completed so fast, oxygen couldn’t reach the working muscle group. Working without oxygen means that the muscles will be able to work for a very short duration of time because there is only so much you can sustain in the absence of oxygen. Since they last for a very short period of time, obviously they can carry out really high-intensity tasks.
