The list of endurance training philosophies is long. Each training theory has aspects that get good fitness and performance results, and some aspects that leave athletes with questions about their program. At the core of any training philosophy is the need to physiologically change the body from its current capacity into the capacity required for the demands of the sport. The road to this end goal is paved with different theories to peak endurance performance. One such method is the Polarized Training method.
This method separates physiological adaption into two distinct training zones. At the lower end of the training spectrum is low aerobic (endurance type) work. This is primarily beneficial for developing mitochondrial density (amongst other benefits). The other end of the polarized intensity spectrum is high intensity work, where the goal is VO2max development, or the body’s ability to use large amounts of oxygen at rapid rates. Roughly 80% of training is done in the low zones, and 20% is done in the higher zones. The studies done on this method have shown that marathon times improve without training at marathon pace. Training is done below or above marathon pace for the benefit of racing a marathon. The exact intensities, based on heart rate (HR), are 70-75% of HRmax (for low intensity training), and 90-95% HRmax (for high intensity training).
As an endurance coach I have adopted this method in my own philosophy of coaching. I do include more race specific training closer to the races, as I feel there is a need for the body to learn what racing intensity feels like. This is more in the middle of these two polarized zones, and I prefer not to spend too much time there. The benefits from using a more polarized method have been interesting for the development of my athletes. From my sports physiotherapy background, I found that it is a great method for reducing risk of overuse injuries. This is largely due to the steady increases in volume at lower intensity, along with very short blocks of high intensity intervals, again mitigating the risk of injury. I have also found these intensities to be better for recovery, with a 24-48 hour turnaround time between sessions being acceptable for the most. Structuring these into a week’s schedule is also made easier, as low intensity training can almost double up as a recovery day for some sessions.
The one negative I have encountered is that the intensity needs to be accurate. If you are too low on your low intensity, athletes tend to get slower and sluggish whereas going too fast, fatigue tends to last longer than usual. The lower intensity efforts for me are crucial, as they need to be hard enough that the system gets stressed for adaption to occur. Generally, talking pace is acceptable, but I would rather say talking uncomfortably is more suited for training adaption to occur in these low zones. I like to get these endurance runs or bike sessions done in a HR zone of 75-80%. Below this I would say is more of a recovery session than a training session.
How do you measure this? You need to have a heart rate strap. It is well known that with higher intensity training a wrist based HR monitor is not useful. These can be up to 15 beats per minute off. Another way to accurately run in this intensity is Rate of Perceived Exertion (RPE). For lower intensity runs, I would stick to 3-4/10, and for higher intensity efforts I would stick to 8-9/10. Pace is difficult to use unless you are on a treadmill or a very flat road. HR is very sensitive to external factors like sleep status, hydration and feeding status, emotional states, etc. So if you are using this model, I would stick to HR or to RPE.
One final word on training models. There is no “one-size-shoe” to fit all your needs. A good coach understands their athletes needs’ and responses to training, and will always adapt training theories (within limits) to personal athletic needs. It is of the utmost importance that the athlete understands and buys into what the program is offering. Without this there will always be setbacks and disappointments.