Master Running with the Triphasic Model

Isabel del Barrio 6 min. of reading Running Leave a comment

While there are various models for stratifying and dividing the different training zones, they all stem from the Triphasic Model proposed by Skinner and Mc. Mellan in 1980.
One of the major challenges faced by recreational runners is a lack of understanding of how the body works and the metabolic pathways depending on the intensity of training. This refers to the different training zones.
By not knowing the objectives of each training zone and what variables are improved in each, it is difficult to achieve sustainable improvements over time.

Index

1 What is the Triphasic Model?
2 How to Apply the Triphasic Model in Running
3 Anaerobic Training in the Triphasic Model
4 Conclusions

What is the Triphasic Model?

It is the model commonly used to determine two of the most important physiological changes. Other authors have added to and/or modified it, so it’s normal to find models with 5 zones instead of 3 phases.

The triphasic model establishes 3 phases and two inflection points that determine the transition from one phase to another: The aerobic and anaerobic thresholds (ventilatory thresholds I and II).

How to Apply the Triphasic Model in Running

The ideal approach is to perform an exercise test to determine ventilatory thresholds 1 and 2 in a precise and individualized manner, along with other parameters that will help us establish our training zones.

There are various estimated and indirect formulas to establish your training zones, with the most accurate and correct being the effort test.

But to get started, you can begin with one of the most commonly used ones: The Karvonen formula.

This formula estimates based on certain variables the heart rate depending on the intensity at which we want to work. These are estimated values and an indirect formula:

Maximum Heart Rate (MHR) = 220 – Age
Heart Rate Reserve (HRR) = MHR – Resting heart rate
Target heart rate at x % intensity = (HRR) * x % + Resting

Phase I Training

Aerobic Phase.

This phase ranges from rest up to the first threshold (aerobic). The subjective perception of effort is comfortable with very controlled breathing. Here, workouts in would be conducted.

Type I muscle fibers (slow contraction) with a very aerobic character.
The main energy pathway used is the oxidative pathway of fats.
Oxygen Consumption (VO2) will gradually increase showing a growing production of energy that depends on oxygen, placing it at the transition to phase two (approximately 60-70% of Maximum Oxygen Consumption or VO2Max).

Training in this zone produces improvements in:

The capacity of type I muscle fibers.
The metabolization of fats as an energy pathway, less dependent on glycogen.

The limit of this phase corresponds to the lactic threshold and ventilatory threshold I (VT1). It is a very important inflection point since many physiological changes occur around it, such as the appearance of lactate.

Phase II Training

Aerobic-Anaerobic Phase.

With increasing intensity, other energy mechanisms begin to participate to obtain energy more quickly and thus sustain the required effort. Here, known as tempo runs at threshold are performed.

The subjective perception of effort in this zone, varies from a soft-moderate sensation to the perception of hard-intense work.
Progressively as intensity and strength requirements increase, type IIa fibers (less aerobic and fatigue sooner) will participate.

Therefore, carbohydrates begin to be needed as an energy resource and as a result of their metabolization, the lactate in the blood increases.

Training in this zone-phase produces the following improvements:

Ability to maintain a balance between lactate production and its elimination.
Aerobic Power.

Oxygen consumption continues to increase gradually, until reaching what would be the start of Phase III (80%- 90% of VO2 max).

Phase III Training

Metabolic Instability Phase.

As exercise intensity and force production increase, the end of phase II is progressively surpassed, after the maximum steady state of lactate, a new increase in pulmonary ventilation (hyperventilation) occurs again. The workouts conducted in this phase correspond to series or sprints, where we apply the highest intensity, generating a high level of lactate.

It is at this point, where the triphasic model establishes ventilatory threshold II and indicates another significant physiological change.

Thus, phase 3 would begin at the end of the maximum steady state of lactate up to exhaustion.

The predominant metabolism is glycolytic (hence, nutritional strategy is important when you are going to perform this type of training and there should be sufficient availability of muscle glycogen and ergogenic aid, such as energy gels, to avoid running out of sufficient energy).

From here on, the subjective perception of effort is very high and the sustained efforts are very short.

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Anaerobic Training in the Triphasic Model

In each of the zones described above, the body responds according to an intensity, load (external or internal). While different models exist, all authors determine each training zone based on the location of what they call a physiological milestone.

That is, to determine these ranges and zones, they use a response given by the body (heart rate, pulmonary ventilation, blood pressure, etc.)

Understanding this model will allow you to individually calculate your different training zones and plan your running sessions better.

Ideally, over time, you will learn to control and understand well how your body works. This way, you can manage not only the rhythms and heart rate but also your perception of effort.

Conclusions

The Triphasic Model simplifies the way in which we can organize our training, determining 3 zones differentiated by thresholds and metabolic instability.

In endurance sports, like running, to be able to plan, structure, improve, and avoid overtraining, it is essential to know the different training zones.

This way, you can optimize your sessions and manage training loads effectively.

References

García Pallarés, J., & Morán Navarro, R. (2012). METHODOLOGICAL PROPOSAL FOR THE TRAINING OF CARDIORESPIRATORY ENDURANCE. Journal of Sport and Health Research, 119-136.
López Chicharro, J., & Fernández vaquero, A. (1995). Exercise Physiology. Panamericana.

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