top of page

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.