Polarized training is a training method in which you either train at low or at high intensities, while ignoring any intensity in between. Hence the term 'polarized'. In a 3 zone training model, polarized training comes down to training in zone I and III. In a 5 zone training model, the majority of time is spent in zone 1,2 and zone 4,5. Around 80-90% of the training is done in a low intensity range, while the remaining 10-20% of training is at a high intensity【5†source】.