Some time I have the opportunity to go into letsrun, and I'm interested in reading what is written about technical arguments.
All the explanations by Antonio are very, very clear and correct. It's possible to see that he is a man used to manage technical probelms thru a deep knowledge of physiology, and of the history of methodology.
I saw a question to myself, regarding the practical use of intermittent training with my athletes.
At first, I want to say the reason because I use this type of training. This is very different from the classic "interval training", having a different effect.
The INTERMITTENT TRAINING can be used with different distances, and different goals.
For example, the theorical of preparation for soccer players, the French Gilles Cometti, spoke about an INTERMITTENT TRAINING for players, with sets of repeatitions of 30m with very short recovery (may be 5 sec., the time for turning a start again), imitating the type of effort that a player can do.
In the methodology for training swimmers, there are a lot of short interval with very short recovery (for ex., 20 x 50m at 98% of max intensity with 10 sec. recovery).
Speaking with prof. Bonifazi, a physiologist that is also the scientist checking the italian swimmers, I learnt that the effect of LONG INTERMITTENT TRAINING is the same of Long Fast Run, but the final level of lactate is lower, and the level of cortisol doesn't grow too much. The level of cortisol is the main difference. An high level of cortisol (in Italian is Cortisolo, I don't know if in English Cortisol is the correct name, but I hope that someone more expert than me can correct some mistake) provokes a state of stress making the recovery longer.
For example, for an athlete like Shaheen, if he goes for 5 km fast in training in 13:45 (2:45 per km), he reaches 12-15 mmol, and his speed per km is 90% of the final goal. Instead, if he goes for 15 x 400 in 61.0 with 20/30 sec. of recovery, the final level of lactate is lower than 10 mmol, the total amount of km is 6, and the speed is 100% of the speed of the competition. The recovery after this type of training is faster, this is not damageous for muscular fibres, and the type of physiological support is more consistant.
The point is that, if the duration of an effort is not very long in relation of the speed, you can remove the most part of the lactate in your muscles in very short time, so you can maintain low the level of Cortisol.
The new idea for increasing the Aerobic Power and creating the MAX LASS is to reach for short time high level of lactate, but not to last the same effort for long time in order to avoid the accumulation in the fibres.
Practically, is a training that can help the fibres to become more elastic from inside, provoking in short time a quick raise in the production of lactate, but not making the fibres tired because is possible to recover in very short time. This system is also called OBLA, and of course cannot replace the long continuous run, but can help a better execution of it.
I don't know if my explanation was clear, because I cannot help myself with a dictionary, but I hope that is possible to understand the mean of this training.
Regarding the practical use of it, I use the INTERMITTENT TRAINING during all the season, mostly during the Fundamental period, but also during the competition period. The system is the same : for example, if I want to prepare a race of 3 km at 7:30 (60.0 every lap), my training (INTERMITTENT) is 8 x 400 in 59.0 with 20 sec. recovery. This is the BASE of ENDURANCE for a training of SPEED ENDURANCE (for example, 8 x 400 in 55.0 with 1 min), and is the base of SPEED for a training of SPECIFIC ANAEROBIC RESISTANCE (for example, 20 x 400 in 61.0 with 1 min).
In any case, in my type of training I don't use MICROCYCLES, and every type of training can be carried out only once every two weeks.
I think that the secret is to use with continuity a mix of all the elements of the preparation. But, in my opinion, also elements very close really mean different type of stimuli.