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Performance Testing, Part 2: Testing VO2 max

Updated: Nov 28, 2022

Why Test?

First, let’s start on a broad scale. Why test? “Testing” is a popular word in endurance sports but can mean different things to different people. No matter the specifics, any test should help accomplish two primary objectives. First, it should give the coach/athlete an objective measure of the athlete’s current fitness level. This is pretty straightforward, but will be covered more in-depth in later posts (LT1, LT2). Second, it should objectively inform the athlete/coach not only what the fitness level is, but how that fitness level is being achieved. This part, the how, is far too often overlooked. Ironically, the how is critical for interpreting the what and then making an educated decision on how to move forward with the training program.

Just as each patient in a doctor’s office has their own health problem, each athlete has their own physiological makeup. As a patient in a doctor’s office, you would hope that the doctor would not simply prescribe you treatment because that treatment worked for other patients who had similar symptoms. Hopefully, the doctor would analyze your situation by asking questions, doing blood work, taking samples, etc, and then prescribe you a specific treatment, knowing the exact mechanisms causing your problem and the exact mechanism of the medicine. Rather than, “you have this disease and this medication should fix your disease because most people respond well to the medicine”, we have, “this is your disease, it is caused by a lack of x and too much y, so we need a medication that will specifically increase x and reduce y.” This is the precision you would expect when it comes to your health, so it should be the precision you receive in a training plan. Without creating a thorough picture of how the athlete’s fitness is composed, the coach can not give a precise “treatment” for the fitness. Without adequate testing, there would be far too much guesswork involved in prescribing a training plan.

What Protocol?

It’s important to remember that there a several ways to track most metrics, but the key to getting useful test data from any test is consistency in variables. Keeping as many variables constant as possible (heat, altitude, power meter, time of day, energy status, nutrition, etc) is necessary if you want to be able to compare one test to another. Each test has its own pros and cons and can give slightly different results. For this reason, it is best to chose a test that works well and then stick to that test over time to have comparable results.

This part of the series will focus on the actual tests you can perform to better understand the parameters that dictate performance level. We last learned about VO2 max and its implications for training and performance. Now, let’s look at how we can find VO2 max.

VO2 max - The Tests

Test 1: Lab Ramp Test

The lab ramp test is the gold standard for testing VO2 max. This test uses spirometry to measure the amount of oxygen being consumed by the athlete during exercise. By incrementally increasing exercise intensity over a relatively short period of time, a lab tech can measure the maximal amount of oxygen consumed by the athlete. Assuming a true maximum and leveling off of oxygen consumption occurs, the maximum value is then considered the VO2 max. The value will be given in milliliters of oxygen per kilogram of body weight per minute (ml/kg/min). The values will range from the 30s for low level athletes to the mid-90s for rare specimens. You can then associate this max VO2 value with a power or pace to determine the speed at VO2 (vVO2) or power at VO2 (pVO2). Of all methods, this is the most expensive and time consuming.

Test 2: Aerotune or INSCYD

Stemming from the same school as Aloïs Mader, physiologist and cycling coach Sebastien Weber developed an early software for his Pro Tour riders on Columbia HTC. With great success there followed by widespread adoption in the professional cycling world, Weber’s software (and the program of Björn Kafka, Aerotune) is now used by a large number of professional cycling teams. The program requires the athlete to do a series of time trials (10 second, 4 minute, 12 minute) and then upload their file to the program. The algorithm, fine tuned with thousands of lab tests, provides the coach/athlete with a VO2 max value, VLa max value, and a whole array of metrics usually requiring a metabolic cart to obtain. Although not 100% as accurate as lab testing, the Aerotune and INSCYD tests are within 4%. This is certainly within the acceptable range for determining what the important values are, what direction they are moving, and by how much. This method, unlike lab tests, is straight forward and can be done anywhere, anytime (inside or outside). The repeatability, lack of lactate testing, and low cost is what makes this a good option for many athletes.

Test 3: 4 minute test

The most straightforward method of testing power at VO2 max would be a 4 minute time trial. With this power number, the coach/athlete can at least estimate the power at VO2 max and track the changes over time. Done alone, however, this only provides you with one metric (power) and nothing else. If you have a power meter, you are better off doing the array of Aerotune/INCYD tests to gain more useful data from your efforts. Likewise, a VLa max on either far side of the spectrum could affect the results of this test.


Meaningful changes in the body take place relatively slowly and are too small to detect on a day to day or even week to week basis under normal conditions. The changes invoked by training depend on the type, duration, and intensity of training. They also depend on the starting level of the athlete and the quality of recovery after training. For VO2 max, changes will take place slowly and are usually not large. Therefore, at least 6-8 weeks should be given between tests. For a more thorough outline of the timeline of physiological changes induced by training, I would recommend reading Jan Olbrecht’s, The Science of Winning.

Up Next

The next post in this series will explore VLa max. What is the maximal glycolytic rate? How does it impact performance? And, most importantly, how can the coach/athlete use this value to help guide a successful training plan?

For more information on testing, coaching, or consulting, please feel free to email me at or message on Instagram (@robbie_deckard).

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