In March, I had the chance to participate in a field-based VO2max test. The objective? To evaluate physiological parameters for identifying areas that could benefit from improvement. Sporttesting operates as a mobile laboratory, conducting physical assessments directly at athletes’ training locations. For runners, this includes performing the VO2max test on a track.
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The principle of a VO2max test
The VO2max test measures a person’s maximum oxygen consumption during exertion. It’s a critical performance factor for events ranging from 3000 meters to half-marathons, and even marathons, alongside running economy and endurance.
Conducting a VO2max test is beneficial not only for tracking progress but also for determining individual pacing and training zones.
Traditionally, most VO2max tests are performed on treadmills, requiring substantial equipment. However, advancements in technology have introduced portable devices like the MetaMax 3-B-R2 from Cortex, weighing approximately 1kg, offering a more field-representative testing environment.
Treadmill running can alter one’s stride. Furthermore, the calibration of treadmill speeds is often imprecise, with each step subtly slowing the treadmill’s motors. Consequently, the speeds recorded on treadmills may not translate accurately to outdoor conditions.
I recall undergoing a VO2max test in 2014 on a treadmill. I recorded my Maximal Aerobic Speed (MAS) at 24km/h, yet in reality, I’ve never surpassed 23km/h! The experience involved excessive sweating in a poorly ventilated room, and maintaining balance at high speeds felt like a juggling act.
In contrast, conducting the test on a track with a portable device proves to be more practical and relevant. It allows for assessment under actual training conditions, making the results more applicable for future training and competitions.
The first sensations with the device
Jonas from SportTesting outfits me with the device, which is surprisingly light, weighing less than 1kg. I record my weight and measure my resting oxygen consumption for five minutes before beginning the test. Standing in shorts and a T-shirt at the tail end of winter, I can’t help but feel a bit chilly as I eagerly await the start of the test 😉
The test protocol is straightforward: I start with a 5-minute run at 10km/h, followed by an increase of 0.5km/h each minute until I reach exhaustion. Cones are placed every 50 meters to guide me, and I need to align with each cone at every beep.
Running at fundamental endurance speeds of 12km/h is familiar territory for me, so I comfortably settle into the initial 10km/h pace. However, as the speed incrementally increases, the challenge intensifies. Without a clear indication of my current pace, it’s tough to gauge exactly where I stand.
Gradually, I start to feel the burn in my legs, and I mentally push myself, aiming for just two more laps. Ultimately, I conclude the test at the 22km/h mark, a testament to my endurance and the effectiveness of the testing protocol.
What is measured during the incremental exercise test?
Throughout the test, a small turbine measures the volume and flow of inspired and expired air, rotating in one direction on inhalation and in the opposite direction on exhalation. A small sensor measures the composition of the air in carbon dioxide and oxygen and calculates the respiratory quotient.
The respiratory quotient is the ratio of the amount of CO2 expired to the amount of oxygen inspired. It varies depending on the substrates used by the body during effort and therefore whether it primarily burns lipids or glycogen. This will determine different training zones.
An optical Polar heart rate monitor on the arm, and 2 Stryd power sensors complete the measuring devices.
At the end, I have a lactate test just after the effort and then 5 minutes later. This allows us to verify if the effort was maximal and to see the lactate kinetics after the effort.
My VO2max test results
My VO2max test results are quite revealing. Starting with the lactate test, the measurement immediately post-exercise indicates a lactate concentration of 11.8mmol/L. This level significantly exceeds the 8mmol/L threshold, which is the minimum required to classify an incremental test as ‘maximal’. A result below this threshold might suggest that factors such as motivation could have adversely impacted the test’s outcome on that day.
My VO2max is recorded at 71mL/min/kg, impressively close to the 72mL/min/kg I achieved at 24 years old when I was a member of the French national team for the 1500m. Interestingly, my overall VO2max, not adjusted for weight, has actually improved, registering at 5.21mL/min compared to 5.06mL/min back in 2014. This improvement is a welcome surprise, especially considering that I now focus on marathons and trail running, training ‘only’ six times a week. This is in contrast to the more intensive training regimen of nearly ten sessions per week during my track years.
My Maximal Aerobic Speed (MAS) is currently 22km/h. This is slightly below my peak speed of 22.9km/h from my prime track years, as calculated using the CNRS/MIT performance prediction model. This decrease aligns with my current training focus, which is less oriented towards high intensity.
Additionally, my anaerobic threshold is identified at 19.2km/h, with my aerobic threshold at 15.5km/h.
Focus areas for my progress
One area where I see potential for improvement is in my low fat consumption at low intensities, particularly in terms of fundamental endurance. Over the coming weeks, this will be a key focus.
During the test, I was able to maintain the VO2max plateau – the point where VO2 levels off – for two minutes. This indicates that my anaerobic capacity is within the ‘normal’ range. This is to be expected since I haven’t engaged in lactic anaerobic track sessions for several months.
Post-test, my heart rate was monitored for five minutes. The data on my heart rate kinetics, specifically the rate at which my heart rate decreased, suggests that I have excellent recovery capabilities. This insight implies that I may not require excessively long recovery periods during training sessions.
My running economy remains fairly consistent across different paces, though there is room for improvement, particularly through strength training.
An important aspect of the test involves measuring the runner’s weight before and after the exercise to assess dehydration rate. On the day of my test, I measured my dehydration rate at 900mL/h. This measurement can also be replicated in regular training sessions, both before and after, to effectively fine-tune hydration strategies.
When to perform a VO2max test?
When should you consider undergoing a VO2max test? As illustrated by my experience, the VO2max test offers a comprehensive analysis of your physiological data, highlighting areas for improvement and guiding your training paces.
Furthermore, you can input your Maximal Aerobic Speed (MAS), anaerobic and aerobic thresholds, and fundamental endurance pace into the RunMotion Coach app. This allows you to tailor your intensity zones based on your unique profile, optimizing your training regimen.
One of the key advantages of working with a team like Sporttesting is the ability to obtain a wide range of measurements during a single test. This provides an in-depth understanding of your own physiology, facilitating precise adjustments to your training plan.
Ideally, you should conduct a VO2max test slightly after the start of the season, typically after 1 to 2 months of training when you are in good shape. This timing allows you to assess your baseline fitness and identify areas for improvement. Additionally, it’s beneficial to repeat the test a few months later to track your progress and determine whether the recommended changes have yielded positive results.
Wishing you a successful test!
Photo credits: Mathilde L’Azou