“While everyone is obsessed with power data, INSCYD enables me to go beyond the superficial and understand my body better.” Cyclocross professional Eli Iserbyt shares what he learned from INSCYD and how he puts this into practice.

What triggers a 6x Belgian champion, 3x European champion and 2x World champion to want to become even better?
One of my challenges is, that I have the tendency to lose a bit of fitness at the end of November, beginning of December. This is an important period in cyclocross season, so of course I want to do something about it.
Together with my coach I examined why my fitness often declines during this part of the season. What do we overlook? Is it a nutrition issue, or should we adjust the training plan? Via the Belgian Cycling federation (partner of INSCYD) I was able to do my first INSCYD test, to see whether this could answer some of our questions.
Can you share some insights of your test results with us?
While everybody is focusing on the obvious results like power, FatMax and threshold values, I actually learned the most from the carbohydrate combustion rates. This showed me that – especially in long endurance training sessions – I was not even eating half of the energy necessary. This really was an eye opener and a possible solution for my problem!

Now that I have this information, I consume more carbohydrates in training. Sometimes even up to 70 grams per hour, which is about double the amount I used to eat. As a result, I’m able to increase my endurance intensity from 180-200 watts to 190-210 watts [equals about 3.6 watt/kg].
Wout van Aert mentioned that he uses INSCYD’s VLamax metric to improve the switch between cyclocross and road season (and vice versa). Is this something you focus on as well?
Yes. My transition period usually takes about 6-8 weeks. When preparing for cyclocross season, we aim for a high VLamax. It can even be 15-20% higher than during road season.
“My VLamax fluctuates 15-20% between cyclocross- and road season” – Eli Iserbyt
I however do notice that when my VLamax is too high, it becomes more difficult to recover between races, when they follow up quickly. With INSCYD I’m able to control the VLamax within the optimal boundaries.
When increasing or decreasing your VLamax, the lactate production rates change. Do you use this information in training and racing?
The lactate production- and recovery graph was something totally new to me. This is very interesting. In racing it’s difficult to implement that information, but in training it works really well.

It for instance gave me a new view on my interval training. I’m not going to share my secret new training strategy, but I can tell you that INSCYD showed me that I’m able to increase the intensity of my intervals and spent a larger amount of time at high lactate levels, without blowing up.
Learn more about the lactate accumulation & recovery graph. Download our free whitepaper and start creating better interval training.
In these kind of training sessions, it’s very important to know my exact numbers. Otherwise, I run the risk of getting overtrained. To prevent this, I perform about 6-7 INSCYD tests per year. That’s probably more than average due to the fact that I combine 2 cycling disciplines.
There are many tests that you can use as input for the INSCYD software. Which test do you perform?
I prefer to do field testing, which is possible with the Power-Performance Decoder. It enables me to test where it matters.
I have to be honest though. At first I was skeptical: how can a field test without lactate samples be accurate? However, the results were shockingly accurate and the test was easy to perform. It’s “user friendly” because you can separate the test into multiple days. Even more important: from a result perspective, you get more out of it than with a traditional (lab)test.
Get to know more about the INSCYD results via this blog: What is INSCYD.