A common phenomenon in endurance sports is that many runners spend too much time in the moderate intensity range, sometimes referred to as the “grey zone.” In this case, the workouts are neither light enough to promote recovery nor strenuous enough to stimulate significant adaptation. As a result, Training Intensity Distribution (TID) has become a central topic of discussion in endurance training. While there is strong consensus on the benefits of polarised and pyramidal training, there is no single, superior model.
The effectiveness of any intensity distribution depends on the runner’s training age, performance level, the demands of the race, and the stage of the training season. It is also important to note that both polarised and pyramidal training are widely used by runners of all levels. This reinforces the idea that sensible application, not rigid adherence to one method, is ultimately what enables long-term performance development.
What is Training Intensity Distribution (TID)?
Training intensity distribution refers to how a runner’s total training time is divided between different physiological intensity zones. It provides a structured way to measure the strain placed on the body and the resulting adaptations. In endurance running, this is often described using a three-zone model based on physiological thresholds rather than just pace. Zone 1 represents low-intensity training, below aerobic threshold, such as easy runs, long runs, and recovery training. The primary goal is to develop endurance capabilities and an aerobic foundation. Zone 2 lies between aerobic and anaerobic threshold and includes tempo and threshold training, which are designed to enhance lactate clearance and sustain race pace. Power Zone 3 is located above the anaerobic threshold. This includes high-intensity intervals and maximal oxygen uptake exercises aimed at developing maximal aerobic power and speed.
Pyramid Training (70/20/10)
Pyramid training is a widely used training intensity distribution model for endurance running. In practice, this model typically consists of approximately 70% low-intensity training, 20% moderate-intensity training, and 10% high-intensity training. The majority of the training focuses on easy running, which develops the aerobic base. A smaller but significant portion targets threshold intensity, supported by a limited number of high-intensity exercises. This structure reflects the basic principle of endurance physiology, where an aerobic base forms the foundation of performance. This allows runners to tolerate greater loads, recover more efficiently, and maintain pace over long distances.
One of the key strengths of the pyramid model is its simplicity and practicality. It is easy to understand, implement, and scale for runners of all levels. The structure is in line with traditional endurance training practices, where runners often find it psychologically comfortable and durable over long periods of time, which supports consistency. From a physiological perspective, the emphasis on high and low intensity running volumes promotes aerobic endurance, allowing runners to handle higher training loads while reducing the risk of injury and improving fatigue resistance. This makes the model suitable for long-distance running preparation and long-term development.
However, the model’s effectiveness decreases if moderate-intensity training dominates or is poorly controlled. Training in this middle range can sometimes be too taxing for full recovery, but too light to provide a strong performance stimulus, which can lead to fatigue accumulation without development. Coaches and athletes often label this pattern as so-called “junk miles,” describing situations where runners accumulate large volumes of training at intensities that fail to support effective recovery or the development of high-level performance.
Polarised Training (80/20)
The polarised training model is based on the principle of spending the majority of your training time at very low intensity, while periodically doing high intensity, and intentionally minimising the time spent in the moderate intensity zone. In practice, this typically means about 80% low intensity training, 0-5% moderate intensity, and 15-20% high intensity training. The model combines very easy running with very hard running, with little in between. The goal is to avoid the moderate intensity trap that many runners fall into in their daily training. The main idea is that the light workouts should be easy enough to support recovery and aerobic development, and the hard workouts should be challenging enough to stimulate physiological adaptations.
One of the most significant advantages of the model is the intense and simultaneous stimulus it provides to multiple physiological systems. Large amounts of low-intensity training further develop the aerobic base, while a relatively larger proportion of high-intensity training targets maximal oxygen uptake, neuromuscular strength, and peak performance. This combination can produce significant improvements in key endurance variables, especially in well-trained runners. A study comparing different training intensity distributions showed that polarised training led to greater improvements in most endurance performance variables, including maximal oxygen uptake, time to exhaustion, and increases in peak speed and power in well-trained runners (Stöggl & Sperlich, 2014).
Disagvantages
Despite its popularity, the model is not automatically better, and its proper implementation can be challenging in real-world situations. A common problem is that runners have difficulty maintaining a truly low intensity during light training. This causes training to drift back to a moderate intensity, undermining the intended structure of the model. Another consideration is the potential risk of inadequate threshold development if moderate intensity training is consistently neglected. Studies suggest that while polarised training may be better at improving VO₂ peak, especially in shorter interventions and in highly trained athletes. Its effects on other performance markers are broadly similar to those achieved with other training intensity distributions. This indicates that moderate intensity training still plays an important role in developing endurance (Silva Oliveira et al., 2024).
Should You Choose One Model or Use Both?
A common mistake in endurance training is a black-and-white mindset, where coaches and athletes feel compelled to choose one model and reject the other. Training models should be viewed as tools, chosen based on an athlete’s needs, training history, and competition demands. The level of an athlete has a strong influence on how the body responds to training. In many cases, the total amount and consistency of training are more important than the exact distribution of intensity.
This helps explain why research results are often conflicting. Some studies favour polarised training, showing greater improvements in key endurance variables such as maximal oxygen uptake (VO₂max) and top speed. While others show no significant difference between polarised and pyramided approaches when the total training load is comparable. The practical lesson for runners is not to look for a universal winner, but to understand when each pattern is most appropriate within a broader performance strategy.
This perspective is closely aligned with the principle of periodisation, which recognises that adaptation requires a changing stimulus over time. Rather than consistently using one intensity distribution, switching patterns during training phases can produce stronger long-term progress. Evidence supports this approach, as a study comparing different training structures in highly trained runners showed that both polarised and pyramidal programs improved endurance performance. But the greatest improvements occurred when athletes switched from a pyramidal distribution to a polarised distribution within the same training period (Filipas et al., 2021).
Runner’s experience level
The optimal intensity distribution also depends heavily on the athlete’s experience level and available training time. Novice runners typically respond well to almost any structured program, so the primary focus should be on consistency, gradual progression, and injury prevention rather than fine-tuning intensity distribution. Polarised training has been shown to stimulate greater training effects than threshold training in recreational runners (Muñoz et al., 2014). However, limited training time may make pyramidal training a more practical option.
Elite and highly competitive runners often rely on periodized intensity distributions, which often include polarised elements, as in modern high-performance systems such as the Norwegian model. Top marathon runners accumulate large training volumes while spending a significant amount of time training at higher speeds (Billat et al. 2001).
Are you looking for personal coaching to apply these principles to your own training? I offer online 1-1 coaching as well as a custom training plan tailored to your goals and experience level. Alternatively, you can choose a ready-made and clearly structured program from the training programs in the online store.
References:
Billat et al., (2001) Physical and Training Characteristics of Top-Class Marathon Runners, Medicine and Science in Sports and Exercise. https://pubmed.ncbi.nlm.nih.gov/11740304
Iker Muñoz et al, (2014) Does Polarized Training Improve Performance in Recreational Runners? International Journal of Sports Physiology and Performance. https://pubmed.ncbi.nlm.nih.gov/23752040.
Luca Filipas et al, (2021) Effects of 16 weeks of Pyramidal and Polarized Training Intensity Distributions in Well-Trained Endurance Runners. Scandinavian Journal of Medicine & Science in Sports. https://pubmed.ncbi.nlm.nih.gov/34792817
Thomas Stöggl and Billy Sperlich, (2014) Polarized Training has Greater Impact on Key Endurance Variables than Threshold, High Intensity, or High Volume Training. Frontiers in Physiology. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3912323.
Silva Oliveira P, Boppre G, Fonseca H. (2024) Comparison of Polarized Versus Other Types of Endurance Training Intensity Distribution on Athletes’ Endurance Performance: A Systematic Review with Meta-analysis. Sports Med. Aug;54(8):2071-2095. doi: 10.1007/s40279-024-02034-z.