Triathlon intensity: how Joe Friel explains effort, zones, power and pace

When asked how their training is going, Friel observes that many athletes respond with hours or kilometers. Chapter 4 expands on this conversation: to understand your preparation, you also need to know how effort is distributed.

Intensity holds an important position in this edition. But the proposal isn't to indiscriminately increase effort. It's about being able to define and use it according to the purpose of each session and the demands of the competition.

Four Ways to Track Intensity

Perceived exertion allows the athlete to rate how demanding an activity is. Friel uses a numerical scale to relate sensations to effort levels. The method keeps the athlete engaged in observing their own body.

Heart rate adds a measure of the response to exercise. Power, especially in cycling, and pace, in running and swimming, provide benchmarks for the work performed and the output produced.

This information is not interchangeable in all situations. It describes different aspects of the same session. By combining them, the athlete can better understand the relationship between observed performance and perceived demand.

Why Establish Zones?

Zones organize intensity ranges to facilitate communication and planning. A guideline like "do an easy workout" becomes more specific when the athlete and coach share a common understanding of what that means.

Friel anchors the discussion on functional thresholds for heart rate, power, and pace. The chapter presents field tests and the option of lactate assessments to organize these benchmarks.

One detail is worth highlighting: the 5th edition provided describes 20-minute field tests for cycling and running, as well as a 1,000-meter or -yard test for swimming. This must be respected when identifying the content of this edition, avoiding mixing it with protocols found in other sources.

This article presents the logic behind the tests; it does not reproduce their complete instructions or the tables needed to apply them.

Individualizing Your Benchmarks

The author criticizes the reliance on age-based formulas to establish personal zones. His argument is that individual differences can make a population-based estimate unrepresentative of a particular athlete.

The text connects this point to the principle of individuality: the benchmark should aim to represent the person who will use it. The chapter also insists on the importance of collecting data under suitable and repeatable conditions.

In field tests, familiarity with the effort and pacing control influence the quality of the information. The book particularly warns about safety in cycling, where an intense effort requires attention to the surroundings.

Heart Rate and Power Zones Can Diverge

An important point in the chapter is that zones from different metrics do not need to coincide perfectly. Being in a certain heart rate zone does not necessarily mean being in the same numbered zone for power or pace.

In Friel's explanation, an athlete can develop greater speed or power for a given effort response. Performance benchmarks change throughout the preparation, while heart rate benchmarks may behave differently.

This divergence must be interpreted within the adopted system. The zone number alone doesn't resolve the analysis; you need to know which metric it refers to and how it was determined.

Threshold and Lactate in the Chapter's Rationale

Friel presents lactate testing as another way to organize intensities and describes two thresholds, identified as LT1 and LT2. The text connects these points to the transition between different effort levels.

The discussion also seeks to dispel the simplistic association between lactate and muscle soreness. For the editorial purpose of this series, what's relevant is to understand the role of these measurements in the method of organizing training.

The book's estimates and simplifications should be read within its intended scope. A complete analysis of the assessment methods would require other references; here, we are following the author's explanation.

Polarized and Pyramidal: The Race Remains the Benchmark

The chapter presents the debate on intensity distribution, including polarized and pyramidal models. Friel favors a large amount of low-intensity training, with more intense sessions organized throughout the preparation.

At the same time, he explains that race-specific intensity may require changes in this distribution. The duration of the race and the athlete's level influence the effort that will be sustained during the event.

Therefore, a preference for a certain model does not eliminate the principle of specificity. As the competition approaches, the preparation needs to address what it demands, including intermediate intensities when relevant.

Editorial example: the same course at different times

An athlete repeats a course and manages to produce more power with a similar perceived exertion. Instead of concluding that everything should remain framed within the same old ranges, they take the data to their coach for review.

The editorial example illustrates the usefulness of relating sensations, cardiac response, and performance. The chapter teaches how to give meaning to intensity so that it can be planned, monitored, and revised.

Reference: FRIEL, Joe. The Triathlete’s Training Bible. 5th ed. Ch. 4, “Training Intensity”. Summarized in our own words from the provided English edition. Protocols and tables not reproduced. Next article: goals, assessments, and preparing for a new season.

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