Power Training: How to do Polarised Training (Part 1)
For cyclists focused on training and athletic performance, polarised training is a crucial topic. Below, we provide a comprehensive guide to polarised intensity distribution and training methods:
1. What is Polarised Training?
In cycling, polarisation refers to the training intensity distribution where the vast majority of training time is spent in either low-intensity or high-intensity zones, rather than being concentrated in medium-intensity zones. This concept was most famously introduced by Stephen Seiler.
Polarised training is almost the exact opposite of the classic "threshold training" model. In the threshold training model, the vast majority of training is conducted at a medium intensity, specifically around the Maximal Lactate Steady State (MLSS), also known as the lactate threshold.
The polarised model divides training into three zones, as described below:
- The vast majority of training (about 75%) is in the low-intensity zone (Zone 1).
- A significant portion of training (about 20%) is in the high-intensity zone (Zone 3).
- Only a very small fraction of training (about 5%) is in the medium-intensity zone (Zone 2).
This model is often simplified as 80% low intensity + 20% high intensity, hence it is also commonly referred to as "80:20 training".
Definitions of the Three Training Zones
These three training zones are typically defined based on the relationship between lactate levels and power output. Below is how these zones are scientifically defined and how they correspond to the classic 7-zone model.
LT1 / VT1
- The first lactate threshold (LT1) refers to the exercise workload at which lactate levels begin to rise significantly above resting levels.
- This reflects an increasing contribution of glycolysis—the breakdown of carbohydrates—to power output.
- The first ventilatory threshold (VT1) usually occurs in a similar "zone" to LT1 and can be observed through an increase in the rider's breathing rate.
- Changes in breathing rate are related to oxygen uptake and, particularly, the exhalation of carbon dioxide (CO₂).
LT2 / FTP / CP
- The second lactate threshold (LT2) refers to the exercise workload where the rate of lactate accumulation begins to exceed the rate of lactate clearance.
- This means lactate levels will accumulate rapidly, and a steady state can no longer be maintained.
- LT2 is sometimes also referred to as the Maximal Lactate Steady State (MLSS).
- This marks the point where the aerobic energy system can no longer meet the energy demands of the exercise on its own.
- This is also the metric we typically try to estimate when performing an FTP test, although FTP almost always differs slightly from LT2.
- Critical Power (CP) is a related concept that usually sits in the same intensity zone, but in most cases, it also presents some differences from LT2 and FTP.
These thresholds are difficult to determine precisely because lactate levels constantly change with power and exercise duration, while blood lactate sampling only provides discrete measurements. Therefore, various testing protocols exist to determine these breakpoints, but none are perfect, and different protocols may yield different results.
One common method is to define:
- LT1 as the exercise load corresponding to a lactate level of 2 mmol/L.
- LT2 as the exercise load corresponding to a lactate level of 4 mmol/L.
However, in reality, the true lactate turn points might occur above or below these specific load levels.
Relationship with Traditional Training Zones
Defining training zones based on laboratory lactate or expired gas measurements is ideal. However, most people do not have access to such testing. Therefore, we can attempt to map the polarised model onto the common 6-zone or 7-zone heart rate/FTP training models.
In the 6-zone/7-zone models:
- LT2 is approximately located in the mid-to-upper part of Zone 4.
- LT1 is more difficult to pinpoint. On average, LT1 occurs at around 52% of Maximal Aerobic Power (MAP), which roughly translates to 65%–70% of FTP, or near the top of Zone 2 in the 6-zone/7-zone model.
You might also see sources suggesting LT1 is at the top of Zone 3. This is because the location of LT1 has considerable individual variation; for individuals with stronger fat oxidation capabilities, LT1 is typically higher.
If laboratory testing is unavailable, the best approach is to assume LT1 is roughly in the middle of Zone 3 within the 6-zone/7-zone model. Under these circumstances, the polarised model might look like this:
- 75% of training sessions are in Zone 1, Zone 2, and the lower part of Zone 3 (i.e., below roughly 85% FTP).
- 5% are in the upper part of Zone 3 and Zone 4.
- 10% are in Zone 5 and above.
To avoid confusion between different zone numbering systems, the three zones of the polarised model are named:
- Low Zone
- Medium Zone
- High Zone
(Rather than simply Zone 1, Zone 2, and Zone 3).
Rating of Perceived Exertion (RPE) can also be reliably used to estimate lactate threshold turn points. Checking your subjective feeling of exertion during training is highly valuable to ensure the boundaries of these training zones align with how you feel. Generally, it maps out as:
- Low Zone: RPE 1–4 / 10
- Medium Zone: RPE 5–6 / 10
- High Zone: RPE 7+ / 10
2. Why Adopt Polarised Training?
In traditional training, endurance riders and coaches typically used the "threshold model," where the vast majority of training time was scheduled around the lactate threshold. It was previously believed that because this type of training is moderately intense—challenging yet tolerable—it could generate the maximum training stress and thus stimulate the greatest training adaptations.
However, about 20 years ago, a series of observational studies on the actual training practices of elite athletes discovered a different reality. Across many endurance sports and among athletes from various countries, elite and Olympic-level competitors did not use threshold training as their primary method. Instead, they were found to dedicate a massive amount of time to low-intensity training, while also investing a significant amount of time in high-intensity training. In other words, they vastly reduced their threshold training.
A study (Stöggl & Sperlich, 2014) compared 9 weeks of polarised training with several other methods, including the threshold training model. The experiment involved 41 highly trained endurance athletes (approximately national level). The conclusions were:
- Polarised training resulted in the greatest improvement in VO₂peak, an increase of 11.7%.
- In contrast, the threshold training group saw an average decrease of 4% in their VO₂peak.
3. The Physiological Basis of Polarised Training
Here are some physiological reasons why adopting a polarised training approach might be advantageous.
1. Increasing low-intensity training develops the aerobic energy system
Low-intensity training promotes adaptations at the muscular level, including:
- Increased mitochondrial density and activity.
- Improved capillarisation.
- Enhanced fat oxidation capacity (increasing MAP).
All these adaptations help raise the lactate threshold (FTP) and can help improve aerobic capacity. The capacity of the aerobic energy system is the greatest determining factor of athletic performance in almost all endurance sports.
2. Reducing medium-intensity training allows for higher overall training volume
- By reducing medium-intensity training, polarised training allows riders to complete a higher overall training volume.
- Many aerobic training adaptations are related to training duration rather than training intensity.
Therefore, by maximizing total training time, greater aerobic adaptations can be achieved.
3. Keeping most training low-intensity improves high-intensity session quality
Keeping the intensity low for the majority of the time allows high-intensity sessions to be executed with higher quality. For example, to induce cardiovascular adaptations associated with increased aerobic capacity, we need to be able to reach and sustain near-maximum heart rates.
4. Medium-intensity zone training can create significant training stress
Training in the medium-intensity zone can be highly stressful because riders sustain elevated lactate/acidity levels for prolonged periods. There is a view that the adaptations produced by medium-intensity training are not sufficient to offset the training stress it causes. In other words, compared to low and high-intensity training, the return on investment for medium-intensity training may be lower.
5. Helps avoid non-functional overreaching and overtraining
Polarised training can prevent non-functional overreaching or overtraining by controlling the amount of high-intensity training. Concurrently, it provides ample recovery and adaptation time between key high-intensity sessions.
6. Adds variety to training
Polarised training ensures that the training regimen has variety and includes sessions of different intensities. This helps avoid training stagnation, ensuring that not all training sessions eventually become highly similar.
4. Should "Threshold Training" Be Avoided?
A common misconception regarding polarised training is that threshold training should be entirely avoided. This view stems partly from the "80:20" ratio frequently associated with polarised training.
However, doing so is unwise. If you look at studies on training intensity distribution, you will find that about 5% to 10% of training sessions fall into the medium-intensity zone. Assuming one trains once a day, this means such a session occurs roughly once every 2 to 3 weeks; if training more than once a day, the frequency is even higher. Therefore, threshold training is clearly not completely eliminated.
Reasons for incorporating threshold/medium-intensity training:
1. Improving the Lactate Threshold
Training at or slightly below the lactate threshold, especially when combined with low-cadence work, can effectively reduce reliance on glycolysis, thereby improving the lactate threshold and promoting aerobic adaptations in Type IIa muscle fibers.
During lower-intensity training, these muscle fibers might not be sufficiently recruited, especially for time-crunched riders who cannot ride for long durations. In such cases, combining this type of training with carbohydrate restriction can be particularly beneficial.
2. Enhancing Muscular Endurance
This low-cadence, medium-intensity training can also help improve muscular endurance—the point at which muscle fibers begin to fatigue. The principle is to subject the muscle fibers to higher stress for an extended period.
3. Improving Lactate Transport Capacity
Training at or slightly above the lactate threshold also appears to improve the body's ability to "shuttle" lactate—moving lactate to other parts of the body where it can be oxidized and cleared—which similarly elevates the lactate threshold. This is particularly important for explosive-style races that frequently require short, high-power outputs, as these races constantly cause lactate accumulation which must then be cleared rapidly.
4. Familiarity with Race Pace
Threshold training helps riders get accustomed to riding for long periods at intensities close to race pace. Scheduling some race-pace rides before an event is very helpful for building a rider's confidence at that intensity.
5. Acting as an Early-Season Bridge
Threshold training can also serve as a "bridge" in the early season, helping riders transition gradually from lower-intensity training to high-intensity training above the lactate threshold. This is especially true for riders just starting interval training.
5. Pyramidal Training vs. Polarised Training
In recent years, cyclists have paid increasing attention to a training intensity distribution similar to polarised training, known as "pyramidal training". Many riders wonder if pyramidal training is actually more ideal and superior to polarised training. In reality, these two intensity distributions can sometimes be the exact same training distribution.
The polarised model originally stemmed from the observations of renowned sports physiologists and researchers like Stephen Seiler. They studied the training intensities of elite athletes in sports like cycling, rowing, and cross-country skiing. In the early stages of developing the polarised training concept, researchers used what Seiler called the "session goal" approach. This method categorizes a training session as low, medium, or high intensity based on the main portion or primary objective of the session.
For instance, a session containing 4 × 8-minute intervals will still be classified as a high-intensity session, even if it contains a massive amount of low-intensity time (including warm-up, recovery between intervals, and cool-down). The reason is that the core component and main purpose of the session fall under high intensity.
Seiler and other researchers using the "session goal" method typically found that elite athletes complete 1 high-intensity session for every 4 low-intensity sessions. That equates to: 1/5 of sessions are high intensity; 80% low intensity + 20% high intensity.
However, if another method is used to analyze the same dataset—which we can call the "time in zone" method—the picture looks different. This method records the exact second-by-second time a rider spends in each training intensity zone. Today, with power meters, heart rate monitors, and smart bike computers, this recording method is very common.
When using this method, a pyramidal intensity distribution is frequently observed:
- The majority of the time is still low intensity, e.g., 60% of total time.
- A significant portion of time is at medium intensity, e.g., 30%.
- A relatively small amount of time is at high intensity, e.g., 10%.
It is important to note that both pyramidal and polarised training intensity distributions are generally discussed within the context of the aforementioned three-zone model. The dividing lines between the three zones are typically:
- LT1 / VT1
- LT2 / FTP / CP
Even within a single training zone, such as the medium-intensity zone between LT1 and LT2, there is a very large range of power output or heart rate. Riding at the bottom of this zone compared to the top yields a very distinct difference in tolerable duration, and it is arguable that the resulting training adaptations may also differ. Therefore, training intensity should be viewed as a continuous curve, rather than several highly isolated "islands".
6. Periodisation of Polarised Training
How to Periodise a Polarised Training Plan
How should the structure of a training plan change between different training phases, such as the winter off-season and the summer racing season?
This question is closely related to the previous section; different proportions of medium and high-intensity training can be scheduled at different times of the year. In fact, many observational studies have found variations in the ratio of medium to high-intensity training time during different phases of the season.
The best way to periodise a training plan is to first test to understand your own strengths and limiters. For example, you can use:
- Power profile testing
- Lab testing
Then, work backward from your goal race to determine how much time you can dedicate to training different physical capacities, such as:
- VO₂max training
- Lactate threshold training
Afterward, repeatedly test to confirm if the training is progressing in the right direction, and adjust the training plan as needed.
From a practical standpoint, when considering training periodisation, using the 6-zone or 7-zone model is extremely helpful because it allows for a more nuanced differentiation of various training intensities. In this context, the goals of a training block might include improvements in specific areas.
For example, if the focus of a training phase is to improve VO₂max, you might schedule about 20% of your sessions as Zone 5 interval training. If the goal is to improve anaerobic power, those sessions would primarily be scheduled as Zone 6 interval training.
Can You Train Multiple Goals Simultaneously?
Absolutely, as long as those training goals are compatible with one another. For example, simultaneously developing muscular endurance, lactate threshold, and VO₂max.
Thus, you can distribute roughly 20%–25% of your training sessions across these different goals. For example:
- 5% of sessions in Zone 3 — Muscular endurance
- 10% in Zone 4 — Threshold
- 10% in Zone 5 — VO₂max
However, trying to simultaneously target raising the lactate threshold and increasing anaerobic power might represent incompatible goals. The reason is that the former generally requires a reduction in lactate production, while the latter requires an increase in lactate production.
As for low-intensity zone training, it should be present in all training phases and maintained at roughly 75% of total training sessions. However, depending on the specific training phase, the overall intensity and/or duration of the sessions can vary. For instance, during the racing phase, shorter, lower-intensity sessions can be utilized.