Are you still using training zones based on a percentage of FTP, Anaerobic threshold or fixed lactate concentrations? Do you get the feeling that two athletes training in the same zone don’t show the same adaptation to the same training? If this sounds familiar then it is time for a change!

With INSCYD’s new training zone builder, you can now create your own training zones based on a variety of physiological metrics. Once you’ve created a training zone, you can also see:

  • how exercising at this training zone intensity impacts the energy systems you are targeting
  • the lactate concentrations
  • the substrate utilization
  • the training stimulus
  • and many more

In the past, most coaches used old-fashioned training zones based on %FTP, fixed lactate concentrations or a percentage of personal best.
Currently, progressive coaches use training zones based on master metrics (e.g., fat burning training based on the FatMax intensity, not a percentage of FTP).
As of today, you can create personal training zones based on master metrics and see exactly what (will) happen in the athlete’s body when exercising in that training zone. How? With the new INSCYD training zone builder!


#1 Base training in cycling

Let’s start with an example that is very close to what many coaches are familiar with.

STEP 1 – With the new training zone builder, you can choose many sports. For this example, we start with cycling.

STEP 2 – After you chose the sport, you can choose the unit of intensity (reference). In cycling, most coaches express the training zone intensity in power (watt). However, in other sports this could also be speed (e.g., mph) or pace (e.g., min:sec/100m).

STEP 3 – Next, you choose the master metric. This metric is the physiological value that is used to calculate the intensity. Let’s stick with FTP or Anaerobic Threshold as the master metric, just because many of you are familiar with %FTP training zones.

STEP 4 – Once you have decided on the master metric, you can choose the target percentage and its upper and lower limit. For instance, target = 70%, lower limit = 60%, upper limit = 80%.

We’ve now built a training zone like many (cycling) coaches do. The example input is 70% of FTP [80% – 90%]. An example output could be: target = 210 watt [180 watt – 240 watt].

INSCYD Training Zone Builder - cycling
Example of how the intensity at 120% FTP has a totally different impact on 2 riders

STEP 5 – With the new INSCYD training zone builder, you can now choose additional output metrics. These metrics will make you understand the specific physiological reactions in an athlete, when exercising in a particular training zone. Here’s an example.

Maybe you are interested in how much energy your athlete burns in the training zone that we created. Maybe you also want to know where that energy comes from. You then choose the additional output metrics:

  • Energy consumption in kcal per hour
  • Carbohydrate combustion in grams per hour
  • Fat combustion in grams per hour

These additional output metrics are connected to the metabolic profile of one athlete, and are therefore highly individual. With this additional training zone information, you can now create a fueling plan that matches the training zone intensity.

You may also want to know how much this training zone triggers the aerobic energy system. You therefore add the output metric:

  • Percentage of VO2max

Let’s dive a little bit deeper into the possibilities with a running example.

#2 HIT in running

In running, the reference could be min:sec/km or mph or m/s or any other pace/speed related reference. You can even select up to 3 different reference systems, so you could have the speed in m/s and in km/h and the pace in min:sec/km. For this example, let’s choose min:sec/km.

Imagine you want a training zone that increases VLamax. Therefore we select VLamax as our master metric and use a target of 30% [25% – 35%].

We’ve now built a HIT running training zone that could have the following output: target = 4:00/km [3:45 – 4:15]

Now it’s time to add additional output metrics. Maybe you wonder what the lactate concentration will be when exercising in this training zone. You therefore add the output metric:

  • Lactate concentration

Now it’s important to understand that all outcomes apply to steady state conditions. Looking at the example, you are probably not interested in a lactate concentration after an infinite amount of time. You are more likely interested in the lactate concentration of this training zone intensity after – for instance – a 30 second interval. Or after a 200 meter interval. No problem!

STEP 6 – Simply add “time” or “distance” and “30 seconds” or “200 meters” and the training zone builder will not only show you the lactate concentration when running 4:00/km in steady state, but also after 30 seconds or 200 meters. The benefit of this feature becomes even clearer in the next swimming example.

#3 200m swimming

In the previous example, we looked at lactate concentrations as an additional output metric. We could also select lactate concentrations as our master metric.

If you are a swimming coach, you would for instance want to aim for a certain lactate concentration after a 200-meter swim. You could therefore choose the lactate concentration as the master metric, add a target value (for instance 12 mmol/l), and select distance = 200m.

INSCYD Training Zone Builder - swimming
Get detailed information about a training zone – before executing the training

As a result you get the swimming speed and/or pace that a swimmer needs to aim for to get a lactate concentration of 12 mmol/l after a 200m swim. When interested, you add output metrics that tell you something about the aerobic and anaerobic energy contribution of that effort:

  • Aerobic energy contribution (%)
  • Anaerobic energy contribution (%)

You now know the speed that elicits a certain lactate concentration after a certain distance AND you know the energy contribution for that effort.

This example shows that you can choose many metrics both as an additional output value and as an input / master metric.


We only showed a fraction of the sports, references, master metrics and additional output metrics that are available. It’s time to pick your own and try them yourself!

We encourage INSCYD users to start playing around with this new feature. Use your own training philosophy to create the most effective training zones! You can find the training zone builder in the INSCYD app.

Not an INSCYD user yet? Plan a free, completely non-committal demo of the training zone builder right now!