Also take a look at Lactate Threshold. The point of intensity during exercise, when your body switches its source of energy from oxygen to stored sugars (glycogen). Short burst of explosive movements are anaerobic. When those short burst of exercise turn into longer, more extended exertions your body switches its energy source. That is the point of anaerobic threshold. The type of training you concentrate on (aerobic or anaerobic) will dictate how early or late the onset of the anaerobic threshold takes place.