During the season it is necessary to evaluate our performance in order to determine if we are achieving the expected benefits from training. In addition, knowing our physical condition allows us to better plan competitions, since we will know at what intensity we should go to achieve maximum performance. One of the most popular ways to assess physical condition is the exercise test, and although there are many important markers during this type of test (e.g., maximum oxygen consumption), the so-called anaerobic threshold or lactate threshold is one of those that has the greatest correlation with performance in endurance sports.
The lactate threshold is defined as the maximum load during an incremental test that precedes an exponential increase in lactate values, that is, just before lactate levels skyrocket. This moment would correspond to the intensity from which we obtain energy practically only from glucose through the “anaerobic” pathway, and therefore, from this intensity onwards, fatigue would arrive quickly. Although the lactate threshold is widely used in endurance athletes, its measurement requires specific tests (either in the laboratory or on the track) and blood sampling, which makes it difficult for the average athlete to use it routinely. However, and given the rise of power meters among cyclists of any level, there are field tests that can be carried out anywhere (even by the cyclist on their own) and that aim to replace these laboratory tests.
Possibly the best-known field test is the Functional Threshold Power (FTP), created by Allen and Coggan (Allen and Coggan, 2006). In brief, these authors proposed that the FTP would correspond approximately to the power that can be generated over 60 minutes, and that it would be equivalent to the lactate threshold. However, due to the physical and mental difficulty of performing a 60-minute test, FTP is normally calculated using a 20-minute test, recording the average power produced and subtracting 5% (e.g., if I am able to produce 300 W during those 20 minutes, my FTP would be 285 W).
But is FTP really a valid substitute for the lactate threshold? To answer this question, a recent study (Valenzuela et al., 2018) conducted on 20 cyclists who trained at least 4 hours per week analyzed the differences between this field test and the lactate threshold measured in an exercise test. The results showed that, in general, the power associated with FTP was the same as the power at the lactate threshold, and that both markers were almost perfectly correlated. However, in a more detailed analysis it was observed that while in higher-level cyclists there were no differences between FTP and the lactate threshold, in lower-level cyclists FTP was slightly lower than the lactate threshold.
Therefore, a 20-minute test like the FTP can be a practical and valid way to estimate the lactate threshold in cycling without the need for an exercise test, which will allow us to assess our physical condition and plan training and competitions. It is important to note, however, that to estimate the lactate threshold more accurately, the FTP (95% of the power generated in 20 minutes) seems to be valid in higher-level cyclists, but in recreational cyclists it may be better not to subtract the 5% from that power.
References
- Allen, H. and Coggan, A. (2006) Training and racing with a power meter. Boulder, CO: Velopress.
- Valenzuela, P. L. et al. (2018) ‘Is the Functional Threshold Power (FTP) a Valid Surrogate of the Lactate Threshold?’, International Journal of Sports Physiology & Performance, p. 1-. doi: 10.1123/ijspp.2015-0012.
AUTHOR
Pedro Valenzuela
Researcher in the Physiology Unit of the University of Alcalá and in the Performance Control Unit at the Sports Medicine Center (AEPSAD, CAR of Madrid).
Web: www.fissac.com
