Training intensity and how to distribute it within the training plan is a highly debated topic in the endurance community. The success of the Dutch Olympic speed skating team at the Sochi Winter Games and a study on how they train and distribute training intensities has shed a light on how elite endurance athletes actually train.
There are two types of training models commonly used by endurance athletes, the Threshold Model and the Polarized Model. The threshold model dictates that 57% of training is at low intensity; 43% at medium intensity; and 0% at high intensity. The polarized model dictates that 80% of training is at low intensity; 0% at medium intensity; and 20% at high intensity. Both low intensity (aerobic) and high intensity training (anaerobic) are important in the development of endurance performance.
What constitutes intensity?
Training intensity can be divided into 3 zones or 5 zones and all have to do with ventilatory threshold 1 (VT1) and ventilatory threshold 2 (VT2). VT1 is the intensity at which ventilation starts to increase in a non-linear fashion and VT2 is the point at which high intensity exercise can no longer be sustained due to an accumulation of lactate.
Using blood lactate measurements, intensity can be divided into three zones: zone 1 (lactate ≤2 mMol/L), zone 2 (lactate 2-4 mMol/L) and zone 3 (lactate ≥4 mMol/L). Zone 1 is low intensity (high volume), zone two is moderate intensity (lactate threshold) and zone three is high intensity training. In the 3 zone model it is generally accepted that training in zone 1 is below VT1 and training in zone 3 is above VT2.
Intensity can also be measured in a 5 zone scale as used in endurance sports in Norway
| Intensity zone | Heart rate (%max) | Lactate (mmol.L-1) |
| 1 | 55-75 | <1.5 |
| 2 | 75-85 | 1.5-2.0 |
| 3 | 85-90 | 2.0-3.5 |
| 4 | 90-95 | 3.5-6 |
| 5 | 95-100 | 6-10 |
Essential in the 5 zone model, zone 1 and 2 in the 5 equate to zone 1 in a 3 model zone. Zone 3 in the model equates to zone 2 in the 3 model zone and zone 4 and 5 in the zone 3 in the 3 zone model. For the purpose of this article we will be using the 3 zone model.
How coaches train their elite athletes using polarized training
Polarized training method subscribes to more low intensity training with some high intensity training. The training intensity distribution recommends that about 80% of the training should be done in zone 1, about 15% to 20% in zone 3 and very little training in zone 2, <10%. It is polarized as it emphasizes less of zone 2 and more of zone 1 and zone 3.
Polarized training emphasize that endurance athletes should spend most of their training hours in the low intensity, high volume training. The idea is by staying away from moderate intensity on those low intensity days you are able to train harder on the high intensity days. Moderate training is viewed as too slow to be specific to training objectives and too high of an intensity to allow for recovery.
In a study done on the Dutch Olympic speed skating program from the last 38 years showed that the team has shifted to a more polarized training approach. They looked at Olympic medalists training programs from 1972, 1988, 1992, 2006 and 2010 and concluded that during this time period there was no increase in total net training hours, no systematic trends of on ice training hours and a decrease of inline skating training hours done during the summer training months6. The program had also won 8 gold, 5 silver and 4 bronze Olympic medals.
Looking at the training intensity during the 6 Olympic years the team spent most of their time training at low intensity, zone 1. The only exception was in 1972 where low intensity and moderate training had about similar training durations. Though trends have shown a decrease in the moderate training zone it is still slightly more than high intensity training.
More research has also looked at elite rowers, cross country skiers, cycling and endurance runners and has shown that elite athletes train very little at the moderate, lactate threshold, intensity10.
Polarized training suggests that elite endurance athletes should be doing 75%-80% of their training hours in low intensity zone and about 15%-20% at the high intensity zone. By training more in zone one it is endurance athletes can minimize over training, injuries and increase performance.
Video
Managing the distribution of training intensity: The Polarized Model
Stephen Seiler PhD Faculty of Health and Sport Science University of Agder, Kristiansand, Norway and Norwegian Olympic Federation
Dr Seiler addresses three questions on the subject of managing training distribution:
- How do elite endurance athletes actually train?
- Is this pattern based on history or physiology?
- HIT – How are intensity and accumulated duration integrated as a stimulus signal?