Threshold test: why measure the anaerobic threshold?

Running, cycling, triathlon, trail running: what do endurance sports have in common? Performance and fatigue. The Training methodology  in all of these sports are very similar and improvisation should be avoided. We need to evaluate the athlete’s capacities through specific tests in order to adjust training goals according to subjective characteristics. 

What is anaerobic threshold?

The anaerobic threshold is the level of exercise intensity at which lactic acid builds up in the body faster than it can be cleared away. For this reason, it is also sometimes called the lactate threshold or lactate turn point (LT) the point at which your muscles “tip” into an intensity which cannot be sustained for long.

Why measure anaerobic threshold?

It is essential to increase anaerobic threshold if you want to go faster for longer.

You spend valuable time training with determination, passion and dedication but often do not obtain the expected results. You find your performance decreasing over time and often run out of energy during a race that was very important to you. Why?

In endurance sports such as cycling, it is fundamental to know your individual threshold ‘numbers’ if you want sustainable performance improvement. You have to know what and when to ask to your body what is required so you can achieve the best results possible and still finish strong.

Studies have proven that threshold test (or lactate test) is the most accurate way to obtain these important ‘numbers’. With this information and the correct structured training methodology you can create the most time effective, training efficient program to gain the most improvement.

The evaluation (threshold | lactate test)

The most precise and informative test that lets us fully comprehend our cardiovascular (aerobic) engine capacity and function is the threshold test through the analysis of blood lactate. Thanks to the accuracy of this evaluation the results allow for more specific ‘numbers’ to structure a personalized training plan according to specific goals and races entered.

The test is designed to identify precisely the running speed or the cycling power to be used to set training intensities: low aerobic zone, high aerobic zone, anaerobic threshold. Taking this test, makes it possible to create a graph where heart rate and blood lactate are a function of speed (in running) and power (in cycling).

The interpretation

First, let’s say that there is not an “absolute and definitive interpretation” of the values achieved since they need to be analyzed according to the races we are going to do.

To give some examples:  your body needs to be trained in different ways depending on your goal – a full marathon, a 10K race, a short or very long cycling event. Moreover, the data should be interpreted according to the level of the athlete: a good runner will run the half marathon at a speed that is close or even slightly higher than the threshold speed, whilst a beginner will choose a speed between low and high tempo.

If during a running event speed is fairly constant, the situation is different when cycling, where a number of external conditions (road inclination, draft, wind) constantly requires differences in power expression. On a race with short climbs it will be possible to overcome the threshold power for a few minutes, whilst on longer races and long climbs it would be important not to go above threshold values to avoid getting into ‘trouble’ where you can’t sustain the duration.

In fact, the concept of anaerobic threshold is related to type of metabolism activated by the body to produce energy: when intensities are below the threshold value energy is produced by a mixture of fat and sugar with an increasing contribution of the latest as the intensity increases. For that reason, it is clear that if you overestimate your capacities you can run out of energy and the consequence will be a sudden decrease of the performance.

This occurrence is described as ‘hitting the wall’ that some marathon runners face at a certain point of their race (typically above 30 km) or the hunger crisis of a cyclists on long endurance races. No matter when, the sudden decrease of performance always has the same outcome: an intensity that is too high with a consequent depletion of glucidic storage. To avoid these risks, knowing your ‘numbers’ is fundamental to plan both your training and racing.

Planning your training

The lactate test defines your capacities and provides your coach with the precise information to design a proper personalised training plan.

Let’s give some examples:  marathon runners or triathletes (1/2 Ironman or Ironman) should be trained to maximize fat utilization and to accumulate the least lactate as possible. Their performances in fact lasts some hours without significant changes in intensity. That’s why their sessions should be designed around low and medium tempo training with some progressions (fairly long) up to threshold.  This is the correct way to train muscles to use the aerobic metabolism.

The training for a 10 km or for a 50Km event will be significantly different. For these competitions it will be important to train the capacity on maintaining thresholds or above thresholds values training at those intensities. These athletes, thanks to their different physiological make-up can produce a higher level of lactate

The reference value of the anaerobic threshold (expressed in mmol) is absolutely subjective and need to be interpreted by an expert trainer. Normally, in athletes involved in long distance at a constant intensity the threshold is generally lower than 4 mmol, whilst in athletes competing for 60/90 min max or with constant intensity variation the values can be much higher.

When should a threshold test should be done?

Considering that the test provides indicators to design a personalised training program, it should be executed at least 2-3 months before competing in the races entered. During these months it will be possible to successfully compensate any lack of performance and to properly tweak the pre-competition phase. A fairly good athlete should repeat the evaluation every 3-4 months and adjust the training loads accordingly. The test should be taken in similar conditions, using the same protocol with adequate rest at least two days before.

I can’t do the test with professional supervision. What can I do?

Although it is ideal to do the tests in a controlled environment under the supervision of a professional that will subsequently analyze the results, this it is not accessible to everybody.However, there are other ways of conducting threshold tests with estimated values to analyze the relationship between power and heart rate – such as an incremental intensity test leading to exhaustion.

In this case it is the Technogym Maximal Test available on the MyCycling app. The evaluation protocol, developed by the Technogym Scientific department provides a maximal ramp test designed which is designed on the athlete’s physiological characteristics. During the warm up phase an analysis of the heart rate is done and the increments in power that occurs every minute are chosen accordingly to get to the maximal effort within 15 to 20 minutes. Then an algorithm predicts the relevant values: heart rate, cadence and power at threshold. Subsequently a training program called Technogym Neuromuscular Training is generated.

Cyclists, measure your power

A final consideration devoted to cyclists is related to the use of the relevant data obtained from the test: heart rate, lactate and power thresholds. This data allocates your individual thresholds to corresponding training zones specifically for your capacity. Power is more reliable than heart rate which has a great deal of variability and can change on a regular basis.  It is extremely beneficial to train with a power measurement system to know exactly what watts you are producing while pedaling. This is the only scientific and precise way to use at the best the data obtained from the threshold test.