Eneko Llanos, Ican Mallorca Triathlon 2011.

Eneko Llanos, Ican Mallorca Triathlon 2011. (Photo: Inigo Mujika)

In the second part of the article published in the magazine Trisense I describe the main characteristics of block periodization and polarized training. You can read the first part of the article here.

In an attempt to overcome these limitations, other concepts of periodization have been developed. One of them is blocked periodization, intended for high level endurance athletes. In general terms, this alternative proposes a sequence of specialized training cycles or blocks containing highly concentrated training loads directed to stimulate a reduced number of specific qualities. In contrast with the traditional periodization model, in which several athletic qualities are developed simultaneously, block periodization promotes the consecutive development of selected specific qualities. The main characteristics of block periodization are:

High concentration of the training loads, eliciting a sufficient training stimulus for high level athletes.
Minimal amount of specific qualities developed in each block, to provide a highly concentrated training stimulus.
Consecutive development of multiple qualities, beyond those developed in each block.
Use of specialized block mesocycles of accumulation, transmutation and realization.

Moreover, the relative impact of the various combinations of training intensity and volume has been studied and debated for years by athletes, their coaches and sport scientists. Those studies have elicited two basic patterns of training load distribution: the “threshold” training model and the “polarized” training model.

The first model emerged as a result of several studies showing important performance improvements in subjects who trained at the intensity corresponding to their lactate threshold. Thus this pattern emphasizes training at lactate threshold or intensities that are very close to it. In contrast, the polarized training model emerged recently from observations of international level endurance athletes (rowers, cyclists, cross-country skiers, marathon runners). In general, these athletes carry out nearly 75-80% of their training at intensities below their lactate threshold, and the remaining 20-25% is distributed between training “at threshold” and much higher intensities (usually in the form of interval training), with a predominance of intensities above the lactate threshold. Basically, the distribution of training intensities is polarized below and above the intensity corresponding to the lactate threshold.

It is likely that the new challenge for triathlon coaches consists of dealing effectively with block periodization and the polarized training intensity distribution model. Both could well be the most appropriate tools for the design of training programs in modern triathlon.


ISSURIN, VB. (2010). New horizons for the methodology and physiology of training periodization. Sports Med 40 (3): 189-206.

SEILER, S. (2010). What is best practice for training intensity and duration distribution
in endurance athletes? Int J Sports Physiol Perform 5 (3): 276-291.

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