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What's Important?

Today one of the biggest issues athletes face is time. Maintaining a balance between family, work and training can be challenging. With limited time to train it is important to make the most of each swim stroke, every pedal turn, every stride and rep in the gym.

One way to determine how to train is to identify what the key performance indicators for your event are. This sounds obvious but can be overlooked. For example long distance triathlons such as Ironman events have different requirements to a 20K Time Trial

Once you identify what the requirements of your event are you can focus on what is important. To help navigate training most athletes will train using specific training zones based on some type of physiological assessments.

One of the most common cycling tests out there is the Functional Threshold Power (FTP) test. FTP is supposed to represent what a cyclist can hold for an hour long time trial. Training zones are then extrapolated from your FTP. 70% of FTP for base training, 120% of FTP for VO2max intensity, and so on.

But, determining training zones this way can present problems. For some athletes the base training zone is higher (75% of FTP) or has to be much lower (65% of FTP). Same with VO2max or high intensity intervals: for one athlete they may need to perform these intervals at 135% of FTP whereas their training buddy may need to hold 115% of FTP.

Performance is not random. It can be broken down into a small number of fundamental components. In cycling, we don’t need to worry much beyond aerobic capacity (V02max), glycolytic capacity (VLamax) and aerodynamics. FTP is important but it is to a large extent determined by the combination/interaction of V02max and VLamax. So if you truly want to improve your FTP the focus should be on improving V02max or VLamax.

But what are V02max and VLamax?


Simply put it is the maximum amount of oxygen uptake that you use during exercise. Measuring V02max is not something new, but it is often misunderstood.

From an 800m run to an Ironman triathlon, the maximum aerobic capacity or VO2max is the single most important performance metric.

Once measured V02max can be trained with specific training. With INSCYD testing you can see the impact of V02max on race and training performance:

  • Compare the effect of high-intensity interval training and long endurance workouts on VO2max and fitness improvements

  • Evaluate the impact of specialized nutrition regimes to further increase VO2max

  • Understand the impact of VO2max on fat oxidation and carbohydrate combustion

  • Explain changes in threshold power


VLamax is the maximum lactate production rate. High lactate production means high power output when sprinting.

There are two sides to VLamax:

  • 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 increases your FTP and fat combustion and shortens recovery from hard efforts.

This means that knowing what your VLamax will be a game changer for your training and performance. It will help explain:

  • Whether anaerobic capacity is a strength or a weakness based on your event

  • How best to design training to improve your FTP

  • Target training based on your goal events. i.e

    • low VLamax is desirable for Ironman races

    • a higher VLamax is desirable for crit and cyclocross racing

  • Decide training prescription based on increasing/decreasing VLamax

  • Tune nutrition to decrease increase VLAmax

  • Predict the impact of an altered anaerobic capacity on the performance before planning a training regime

Performance is predictable so once you know your V02max and even more importantly your VLamax, your training becomes clear. Both of these metrics are tied to your own personal physiology and metabolic profile.

Let’s use an example

Imagine two triathletes or cyclists, both weighing 75 kg. Both have a Functional Threshold Power (FTP) of 300W. It’s not uncommon to have two athletes with the same FTP.

Rider 1 has a VO2max of 50 ml/min/kg.

Rider 2 has a VO2max of 63 ml/min/kg.

How is this possible? We know that a high V02max is desirable so you could assume that this should mean that Rider B should have a higher FTP.

But we also know that VLamax has a role to play in how FTP is composed.

Rider 1 has a VLaMax of 0.3 mmol/l/s.

Rider 2 has a VLaMax of 0.9.

A higher VLaMax means a lower FTP! To increase their FTP Rider 2 will need to focus on reducing their VLamax

To increase their FTP Rider 1 will need to focus their training to increase VO2max

Two riders with the same FTP. But will require two completely different training solutions to improve FTP.

Changes in threshold power will be directly related to your V02max and VLamax.

If you have:

  • A high V02max and high VLamax: Train to reduce VLamax

  • A low V02max and low VLamax: Train to increase V02max

  • A low V02max and high VLamax: Training to increase V02max while decreasing VLamax

INSCYD shows you the composition of your threshold power: body composition, VO2max (aerobic capacity), VLamax (lactate production). Once you know this you can decide the training required to change it.

What's Important?

For an Ironman event above we identified sparing carbohydrates and a good fat combustion are important for race day performance.

Most race pacing strategies are set based between 70 to 78% of FTP for amatuer athletes. If you are calculating your FTP based on a standard you may be over or underestimating your true potential.

Fat and Carbohydrate combustion are highly individual and cannot be accurately identified as a set % of FTP.

INSCYD’s fat and carbohydrate combustion reports allows you to:

  • Tailor your training and race day nutrition plans by determining the actual amount of carbohydrate you combust at your race intensity

  • Train in the FatMax zone to improve your fat oxidation

  • Fine-tune pacing and racing strategies so that come race day you have your nutrition plan dialed in

  • Make informed decisions on nutrition strategies i.e. lower carb diet, nutrition periodisation

How Does Testing Work?

INSCYD allows you to create a complete 360 degree physiological metabolic profile.

Laboratory grade testing without the need to enter the lab.

Triathletes/Cyclists can test outdoors or indoors.

Follow the testing protocol on the road or on your smart trainer even in Zwift.

The testing has been validated by world tour teams such as Team CCC, SEG Racing. Jumbo Visma and Movistar also use the software.

For the Power Performance Decoder test you will complete the following:

  • 20 second all out sprint

  • 3 min all out time trial

  • 6 min all out time trial

  • 12 min all out time trial

You can do the time trials whenever you like. You can do the test all at once which takes roughly 90 mins. Or you can spread it out over a number of days. For example you may decide to do the efforts on a Monday Wednesday and Friday.

Once completed you send us the file in .fit format and we will analyse the data and get your results back to you. The results includes the most important metrics for training purposes:

  • VO2max

  • Anaerobic threshold

  • Lactate accumulation and recovery

  • Fat and carbohydrates combustion

  • Recovery

  • VLamax (or glycolytic capacity)

Individual Training Zones

One of the most important parts of the test results are individual training zones.

Results will contain training zones that are individual and unique to you based on your physiology:

  • recovery and base zones: are based on fat and carbohydrate combustion

  • FatMax Zone: is based on the fat oxidation rate

  • Anaerobic threshold/FTP: is not based on some empirical threshold concepts but on the equilibrium of lactate production and combustion

  • aerobic maximum - based on the VO2max

  • anaerobic zone - based on energy derived from the anaerobic metabolism

This allows you to make an informed decision and at least put a number behind where you currently are.

You can then make a decision on what to prioritise in training. For time strapped athletes this can help you train more efficiently

If you would like to know more about testing do get in touch. Email

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