In recent years, the term “Zone2 training” has made it into the hobby scene. What is it all about and what are the sources of error?
Training mistake made by many athletes: Zone2 training is too hard
Zone2 is a newer term for basic training in the lower endurance zone, formerly known as the basic endurance zone1 GA1. This zone can be maintained for hours and theoretically even days if the athlete is sufficiently trained and well nourished. The majority of energy production takes place under aerobic conditions. Both fat and carbohydrates are “burned” in the cellular power plants, the mitochondria, to produce energy (ATP, adenosine triphosphate) with the help of oxygen. The need for carbohydrates decreases as the level of training improves.
Zone2 training improves endurance with only moderate fatigue from training. This leaves room in the training plan for few and very hard training sessions between the relatively easy Zone2 training. The training is thus separated into two poles and called polarized training. In short, 80 percent of the training should be relaxed (ideally Zone2) training. The prerequisite for this is that the Zone2 training is really Zone2 training. This is the biggest training mistake many athletes make: Zone2 training is too hard and is not really Zone2 training.
What kind of training is Zone2 training?
Zone2 training is based on the training status and therefore the metabolism of the respective athlete. To find out the athlete’s own training zones (see table below), for example, a so-called FTP test is carried out. The FTP (functional treshold power output) is the power output that an athlete can maintain over a longer period of time, ideally 60 minutes. This power output reflects the athlete’s (energy) metabolism under stress.
1st mistake: FTP test flawed
The “inventors” of the FTP, Allen & Coggan, have specified a test protocol for determining the FTP. This provides for a total of 25 minutes (!) of all-out effort, whereby attention should be paid to a constant power output and ideally the last few minutes should even be an increase. A 20-minute period is used for the test result, from whose average performance values five percent is subtracted to calculate the FTP. However, the 20-minute period is preceded by a 5-minute all-out period. This 5-minute all-out period is ignored by many athletes or most of them do not even know that it exists. If it is omitted, higher performance values are achieved in the FTP test and the resulting zone areas are incorrectly shifted to higher watts as determined by the FTP. As a result, athletes sometimes train in zone 3 of their metabolic performance profile and not in zone 2.
The protocol is very strenuous. This test can only be tackled if you are sufficiently rested and have no energy deficiency (empty carbohydrate stores). There are now numerous shorter protocols, such as on the Zwift platform, which promise good results. I advise against these test protocols! Shorter protocols are completed at a metabolic rate that is far above the “anaerobic lactate threshold”, which distorts the results. This usually leads to an overestimation of the FTP, especially in athletes who are good at pedaling high wattages for short periods of time.
I recommend using the traditional FTP test protocol!
2nd mistake: Ignoring the duration of the effort
When training for several hours, the training zones shift! Although the FTP is indicated by a fixed power value in watts, this value represents a metabolic state in which the body is able to maintain a constant blood lactate level. With prolonged training, the body is no longer able to achieve the original metabolic state at the same watts. As a result, all training ranges measured in watts decrease. Professionals like Tadej Pogačar therefore reduce their watts with increasing time during Zone2 training. As an amateur rider, you don’t have the extensive testing options of a professional to determine the exact drop in performance. As a rule of thumb, you can adjust the power output over time to the lower Zone2 range for rides lasting several hours and to the upper Zone1 range for very long rides.
3rd mistake: Not staying in Zone2
To achieve the best training effect through Zone2 training, it is important to stay in this training zone. It’s not just the average watts achieved at the end that count – and certainly not the normalized performance. It is important to keep in mind that Zone2 training is about training the metabolism and not just power zones (see error 2). If short hard bursts are performed in Zone2 training – such as on hills – the body is forced to leave the Zone2 training metabolism and then no longer returns to this metabolic state. This has been proven several times, e.g. with breathing masks.
Group rides that result in uneven performance (e.g. due to accordion effects) and in which you occasionally push hard over small bridges etc. and tackle hills with increased effort destroy the effect of Zone2 training, even if the average watts at the end should be in Zone2.
Training zones according to Allen & Coggan:
Conclusion:
Be honest with yourself: carry out the FTP test according to the specified protocol. Reduce watts on longer rides and maintain watts from the flat on hills. Avoid short power peaks. On group rides, experienced guides and experienced cyclists are needed to adjust the pace on climbs and maintain the effort on the flat.
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Literature selection:
Van Bon, Marco & Vroemen, Guido. (2018). Power Speed Profile: Performance model for road cycling (1).
Allen, Hunter und Andrew Coggan. Wattmessung im Radsport und Triathlon. ISBN: 9783936376739. ISBN-10: 3936376735. Hamburg 2017. Spomedis
Chandel, Navdeep. Navigating Metabolism. ISBN 10: 1621821293. ISBN 13: 9781621821298 Publisher: Cold Spring Harbor Laboratory Press, 2014
https://open.spotify.com/episode/7AUm2TKSKRqd1HRm43aBHw: #318 ‒ Cycling phenom and Tour de France champion Tadej Pogačar reveals his training strategies, on-bike nutrition, and future aspirations
Coggan AR, Kohrt WM, Spina RJ, Bier DM, Holloszy JO. Endurance training decreases plasma glucose turnover and oxidation during moderate-intensity exercise in men. J Appl Physiol (1985). 1990 Mar;68(3):990-6. doi: 10.1152/jappl.1990.68.3.990. PMID: 2111314.
Klitzke Borszcz F, Ferreira Tramontin A, Pereira Costa V. Is the Functional Threshold Power Interchangeable With the Maximal Lactate Steady State in Trained Cyclists? Int J Sports Physiol Perform. 2019 Sep 1;14(8):1029-1035. doi: 10.1123/ijspp.2018-0572. PMID: 30676826.
https://www.youtube.com/watch?v=-6PDBVRkCKc: 201 – Deep dive back into Zone 2 Training | Iñigo San-Millán, Ph.D. & Peter Attia, M.D.
