INSCYD Testing

Human performance testing without a lab, lactate, and VO2 measurements. Get an inside view into your physiology and take the guesswork out of training at home or on the road using just a power meter.

What is the best way to improve your power and performance on the bike? Is it Sweet Spot training? High volumes of long slow distance? Perhaps polarised training? The only correct answer is, it depends. But you can find out what might be the best solution for you, when you discover the building blocks of your power: VO2max and VLaMax. INSCYD testing gives you an accurate measure of both (plus much, much more), and once you know them you can have confidence in how you should be training to improve your performance and achieve your goals.

You can skip directly to one of the following sections on this page:

Why INSCYD testing, Testimonials, Metrics, How it Works, Frequently Asked Questions (FAQ), Pricing, Contact Us

Why INSCYD testing can improve performance

Performance is not random. It can be broken down into a very small number of fundamental components. In cycling, we really don't need to worry about much more than aerobic capacity (VO2max), glycolytic capacity (VLaMax), and aerodynamics. Functional Threshold Power (FTP, or the anaerobic threshold) is important, but it is to a very large extent determined by the combination of VO2max and VLaMax, so if we want to improve FTP, what we really want to be doing is improve VO2max or VLaMax. Only when we understand our own physiology and metabolic profile, can we really plan our training the most effectively. 

With the INSCYD Critical Power testing service that you can do at home or out on your normal cycling routes using only your power meter, you will get this kind of under-the-hood view of your physiology. You will get to know what your VO2max, VLaMax, Anaerobic Threshold, and Fat and Carb oxidation rates are, and your training will become much more targeted and informed, resulting in improved performance.

Not only CAN you do this testing anywhere in the world, but you literally CANNOT do this testing in almost any laboratory. Most labs will only test your VO2max and your threshold, but you will not get to know your VLaMax. Knowing both VO2max and VLaMax is essential for knowing which "knob to turn" in training. That is, should you train your VO2max, your VLaMax, try to get your threshold to a higher percentage of VO2max, or should you practise your ability to oxidise fat? 

Once you know which knob to turn, selecting the correct "training recipe" becomes if not straightforward at least significantly easier. In fact, through our testing service we will teach you what type of training is recommended for each of the physiological targets you may set for yourself after getting your test results.

Take a look at the following infographics to get some more information on the difference INSCYD testing can make:

  • FTP (Anaerobic THRESHOLD)





FTP - Critical Power testing with INSCYD


The INSCYD analysis provides a highly actionable and fascinating insight into a athlete's metabolism that results in laser focused training. At worst it is a secret weapon, and at best it will result in a quantum leap in your performance since the resulting training plan is not only tailored to your goals but to your individual metabolism.

Christian Dembowski age-group triathlete

Christian Dembowski

46, Germany

“The Power-Performance Decoder is like a remote controller, and nowadays crucial to give
us coaches an insight into the riders' actual level.“

- Kristof de Kegel, Coach of Mathieu van de Poel and Team Alpecin FENIX -

“Your really know what you need to work on if you know your VLamax“

- Dan Lorang, Coach of Jan Frodeno & Anne Haug -

“INSCYD offers us the ability to create the most accurate measures of metabolic efficiency
available today“

- Prof. Elliot Hawkes, Stanford University -

“INSCYD is the perfect solution to understand how training effects the adaptation of specific
physiological systems.““

- Dennis Sandig, German Triathlon Federation -

“With the help of the INSCYD software I have been able to cater my training to my own
unique energy systems, and tailor that plan to be efficient at the races and durations that I
want to excel at.“

- Lionel Sanders, 2nd in the IRONMAN World Championships 2017 -

“INSCYD testing especially helps my coaches to help create the best training programs for

- Primoz Roglic, Winner Vuelta d’Espagna 2019 -

“INSCYD is like a compass that guides us in the dark““

- Marco Pinotti, Head of Performance CCC Team -

“INSCYD helps me the most before the major training periods because we want to make
sure that we make the best possible training program.“

- Mathieu Heijboer, Head Coach Team JUMBO-VISMA -

Metrics - a 360-degree view of your physiology

With an INSCYD critical power test you can obtain a full metabolic and performance profile. The test result is a multi-dimensional model that includes all the relevant physiological components of performance. Your capacity to perform in any race and the way you should train to improve on that performance can be boiled down into the following metrics that you will obtain. 

1. VO2max (Aerobic Capacity)

From an 800m run to an IRONMAN triathlon, the aerobic capacity - or VO2max - is the single most important performance metric. Measuring VO2max isn't something new. But with INSCYD testing you can now see how VO2max interacts with race and training performances:

  • Explain changes in threshold power.
  • Compare the effect of high-intensity interval training over high-volume endurance training on VO2max and fitness improvements.
  • Understand the impact of VO2max on fat oxidation and carbohydrate combustion.
  • Evaluate the impact of specialized nutrition regimes to further increase VO2max.

Along with your test results, you will get information and content on different ways to improve VO2max, so that if this is your limiter, you know what training you should do to address it.

2. VLaMax (glycolytic/anaerobic capacity)

There are two sides of VLamax (glycolytic capacity). 

  • On the one hand, a high VLamax increases the power available for short efforts: a 200m swimming race, a 400m run, an attack, a sprint.
  • On the other hand, a low VLamax improves the anaerobic threshold and fat combustion and shortens recovery from hard efforts.

This means even for an Olympic distance race, you want a low VLaMax to maximise your performance. Knowing your VLaMax will be a game-changer in your training program:

  • Explain changes in anaerobic threshold power, and plan for how to best improve threshold power. 
  • Plan your personal target VLaMax based on your goal races (there will be huge differences between an Ironman athlete and a cyclocross or criterium cyclist)
  • Decide on what training will allow you to decrease/increase your VLaMax until you reach your own ideal VLaMax.
  • Tune your nutrition to further help decrease/increase VLaMax. 
  • Understand the impact of VLaMax on fat oxidation and carbohydrate combustion.

Along with your test results, you will get information and content on different ways to alter (decrease or increase) VLaMax, so that whichever way you need to take it, you know what training you should do to do so.

3. Anaerobic Threshold (MLSS)

INSCYD detects your anaerobic threshold as per the scientific definition: the maximum intensity at which lactate combustion matches lactate production. But knowing your threshold power simply isn't good enough! Only if you understand WHY it is what it is can you effectively change it. 

  • High VO2max and high VLaMax? Reduce VLaMax. 
  • Low VO2max and low VLaMax? Increase VO2max. 
  • Anything in between? INSCYD will show you the relative strenght of your VO2max/VLaMax, and make it easy for you to decide which one to tackle first, in order to improve threshold power. 

Along with your test results, you will get information and content on how best to tackle anaerobic threshold improvements in various scenarios, as described above. 

4. Fat and Carb combustion

Increasing fat oxidation and thereby sparing precious and limited glycogen is a very important part of endurance events. Especially so when we talk about half and full Ironman racing. But fat and carb combustion is highly individual - there is no certain percent of FTP at which your maximum fat oxidation occurs, and how much carbs you use at e.g. your goal race intensity is natually also very individual to you. 

Use INSCYD's accurate and validated fat and carb combustion reports to:

  • Tailor your race (and training) nutrition plans to how much carbohydrate you actually combust at your race intensity. 
  • Use your own experience of your maximum tolerance for taking on energy in races to fine-tune your pacing plan so you don't run out of fuel, and to set a benchmark for how much you should increase your tolerance to take on energy by practising it in training. 
  • Know your FatMax zone and train in it to improve your ability to oxidise fat for fuel.
  • Use nutritional strategies to improve your fat oxidation and evaluate the impact of them. 

Along with your test results, you will get information and content on different ways to use the knowledge of your fat and carb combustion rates to tailor race nutrition plans as well as to improve fat oxidation with training. 

5. Lactate accumulation and recovery

If your racing scene is high-level draft-legal triathlon or cycling disciplines with large variations in intensity (road racing, cyclocross, crit racing) then your ability to use lactate as fuel and to shuttle it is critical in your performance puzzle. These abilities are highly trainable, and INSCYD testing allows you to monitor your progress and improvements in your production and combustion of lactate. 

  • Learn exactly how quickly lactate accumulates in your blood at any given intensity. This information will inform training decisions, and potentially even race planning.
  • Learn exactly how quickly you process and get rid of lactate at any given intensity. This information will inform training decisions, and potentially even race planning.
  • Tailor your high intensity interval training to your lactate accumulation and recovery. If you want to practise your lactate shuttling abilities, then knowing your maximal lactate combustion power is critical, and the lactate accumulation/recovery chart will help you set exact power and duration targets for your intervals and recoveries to maximise their effect. 

Along with your test results, you will get information and content on how to use knowledge of your individual lactate production and combustion rates to inform race tactics and to optimise interval training. 

6. Individual Training Zones

It's about time we move on from thinking that everybody can be training various energy systems using the same generic percentages of FTP. The reality is, while you maybe should be doing VO2max intervals at 135% of FTP, your buddy might only do them at 115% of FTP, and 130% would completely burn him out.

Your results will contain training zones completely individual to you and your physiology. Whether you want to go out and do VO2max intervals or a FatMax ride, you will have an accurate power target for you to hit your training objective. 

  • Recovery
  • Endurance
  • FatMax
  • Moderate ("Medio")
  • Lactate Shuttling
  • Anaerobic Threshold
  • VO2max
  • Anaerobic / Glycolytic

Along with your test results, you will get information and content on how to use your individual training zones to the best effect. 

More than just results: You get the complete how-to-interpret-and-apply-the-results-in-practice package

Your purchase includes a complete written plus illustrated documentation, as well as 9 video lessons with all the information and practical examples you need to apply your test results in training and racing.  This information pack is included as part of all pricing tiers.

INSCYD testing boxshot

Both the written documentation and the 9 video lessons cover the following topics:

1. Choosing and prioritising training objectives

2. How to use INSCYD training zones

3. How to improve anaerobic threshold (FTP)

4. How to increase VO2max

5. How to decrease VLaMax

6. How to increase VLaMax

7. How to improve fat oxidation

8. How to create race fuelling plans

9. Advanced: Lactate accumulation and recovery

How the testing works

  • STEP 1

  • STEP 2

  • Step 3

Perform the time trials - you only need a power meter  

After you order the test, you will receive all the information required about exactly how to perform the time trials that make up the test. Note that you can do the time trials whenever you want, wherever you want, as long as you do all of them within a few days of each other. We recommend spreading out the time trials over three days, e.g. Monday, Wednesday and Friday of the same week. 

You will be doing a 20-secon sprint test, a 3-minute all-out time trial, a 6-minute all-out time trial, and a 12-minute all-out time trial. 

You send in the workout files (in fit-format), and leave the rest to us for analysing your files, selecting the right inputs, and then letting the software get to work and crunch the numbers.

INSCYD Power Performance Decoder - Testing 2
INSCYD Power Performance Decoder - Testing 4 Files
INSCYD Power Performance Decoder - Testing 1
INSCYD Power Performance Decoder - Testing 3 Zwift
INSCYD Power Performance Decoder - Results 3

Frequently Asked Questions (FAQ)

How does this service help me improve performance?

As mentioned elsewhere on this page, performance is not random. And the training that works great for one athlete, might be horrible for another athlete if they have different metabolic profiles.

For example, an athlete training for long-course non-draft triathlon that has a high VLaMax will need to lower it to improve their FTP and fat oxidation, and therefore performance in these longer races.

If this athlete tries to follow a very polarised training plan, with a large amount of low-intensity training and a few high-intensity interval sessions chances are that in those interval sessions, the athlete will go too hard and trigger a glycolytic stimulus that will keep their VLaMax high or even increase it.

What this athlete should be doing instead is to train in a less polarised manner, do more sweet spot and tempo work, ideally with low-cadence efforts, and perhaps even complement this with some fasted rides in their FatMax-zone.

That is how they will lower VLaMax, and therefore improve FTP and performance in long-distance triathlon.

Your metabolic profile may be different, but no matter what it is, you will always be able to fine-tune your training to whatever your individual case may be.

I'm not a fast cyclist or triathlete. Will I still benefit from this?

Yes! Whether you're slow or fast, the best thing you can do to get faster is to start training in a way that is well-suited for your physiology and metabolic profile.

Perhaps your profile is more of a low VO2max AND low VLaMax. The key for you then would be to increase your VO2max. If your training has been very oriented towards Sweet Spot and tempo or other "mid-zone" intensities, this is quite a common scenario.

Many athletes are constantly loading on with training stimulus designed to lower VLaMax, when it's already as low as it needs to be, and probably can be. What they need to be doing, is to work on VO2max, which can be done in a number of ways, including increasing training volume (primarily at low intensity), incorporating high-intensity intervals (e.g. VO2max intervals), a combination of the two, or a number of other potential solutions.

The point is - professional or back-of-the-packer, we all have our individual physiology, and for any of us to improve, we will always benefit from planning our training based on informed decisions on what aspect of physiology we're actually trying to target. 

How accurate is the testing and how does it compare to testing in a laboratory?

INSCYD is build bottom up from more than 150 scientific studies and on more than 30 years of sport science history and development. As an example, scientific validation of INSCYD's calculations for the anaerobic threshold shows an average tolerance of 2.5% - compared to traditional lactate threshold tests which fall in the 4-10% range.

For VO2max, the best metabolic carts, as used in high quality, human performance labs, encounter a typical error of 2-4%. INSCYD matches that accuracy.

For VLaMax, a notoriously difficult thing to measure, if you go to one of a handful of high performance laboratories in the world that can actually measure it correctly, you will get a 4-6% accurate results. INSCYD's power only protocol is not quite as good at around 10%, but considering the financial and time commitment of going to one of those labs, the 10% accuracy is clearly better value for money. 

To summarise, INSCYD's algorithms are extremely robust, and the main source of inaccuracy comes from equipment, such as a poorly calibrated power meter. Make sure that your power meter works well, has fresh batteries, and is calibrated, and the INSCYD test is generally as accurate or better than even the best laboratories for FTP and VO2max in particular.

Why should I choose this testing service rather than a laboratory test?

Very few laboratories are able to test VLaMax, and therefore, in any such laboratory you will get an incomplete picture of your metabolism. The few that do offer VLaMax testing require a significant financial and time commitment to go to and test at (unless you happen to live right next to one). 

Getting VLaMax and VO2max is essential for being able to really know which knob to turn in training, so most labs shouldn't even be on your list of options when compared to INSCYD testing. 

In addition, the parameters that can be tested in most labs (VO2max, anaerobic threshold) are usually more accurately measured by INSCYD than by the lab, so even if your only reason for doing a test is to get to know what your VO2max is, doing an INSCYD test is how you will get the most accurate estimate of it. 

Can I do the test remotely, on the trainer or on the road?

Yes you can, but you should make sure to either do all the time trials on the trainer or do all of them on the road. You don't need anyone or anything other than your power meter. We recommend you do the test on the road if you do the majority of your training outdoors (and you have a good stretch of road to test at), and vice versa on the indoor trainer if the majority of your training is done indoors.

What is the testing protocol? 

You have a few options here that you can read about in detail when you complete the order and get access to the full protocol, but the standard protocol consists of four time trials of different durations: 20 seconds, 3 minutes, 6 minutes, and 10 minutes. 

Generally, we recommend performing the three longer time trials on separate days, but to complete all within at most 5-7 days. So for example, the protocol could look as follows. 

Monday: 10 min easy, 5 min ramping up power (from Z2 to Z5) followed by 1-2 x 6-8 second sprints, 8-10 min very easy spin where the last 100 seconds are coasting (no pedaling allowed),  20-second all-out seated sprint, 15 min easy spin, 3 min all out time trial, warm-down. 

Wednesday: 10 min easy, 5 min ramping up power (from Z2 to Z5) followed by 1-2 x 6-8 second sprints, 8-10 min very easy spin, 6 min all-out time trial, warm-down.

Friday: 10 min easy, 5 min ramping up power (from Z2 to Z5) followed by 1-2 x 6-8 second sprints, 8-10 min very easy spin, 12 min all-out time trial, warm-down.

Should I do the test in the aerobars or sitting up?

The 20-second sprint test should be do sitting up, but you must remain seated.

For the other time trials, you should select the test parameters according to how you do the majority of your training. If the majority of your training is indoors and in the aerobars, then test like that. If the majority is outdoors, and sitting up, then test like that.

Can I do the test if I do not have a power meter?

No. You need a power meter, or alternatively, a very accurate indoor trainer that is still accurate during very short sprint efforts, like a 20-second sprint. The high-end indoor trainers on the market may pass this test, but most low- to mid-range trainers will not.



If you have a basic understanding of exercise physiology and metabolism and are ready to do a little work on your own to understand your results, this is an affordable option for you. 

€ 150
  • Full Metabolic Testing service and complete results report
  • Complete written documentation and 9 video lessons on interpreting your results and use them to drive training decisions

If you want to get those last few percentage points of performance (marginal gains), then a one-to-one consultation with coach Mikael allows you to apply your results to improve performance to even greater effect.

€ 250
  • Everything from STARTER and MOST RECOMMENDED
  • Private consultation (45 minutes) with coach Mikael Eriksson on the test results and using them. 

Contact Us

If you have any questions about the service or want to know if it is right for you, please contact us using the form below.