What INSCYD has taught you?

Fast Talk Episode 159: INSCYD and the Power of Testing Analysis, with Sebastian Weber was excellent and so insightful. @trevor and @chris, based on what Sebastian had to say how has it informed your training for your N1 events?

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Welcome to the Forum, Basil.

I have taken some of Sebastian’s suggestions and already put them into practice, with my own spin. (I often like to add my own spin, since I need to devise something that fits into my schedule and, after many years of training, I have a good feeling for what works best in the greater context of my weeks.)

One of the main points he made was to do more high-torque, low-cadence work, and I have included that in many recent rides. Not the entire ride, just portions. That has also meant getting out on the singlespeed gravel bike on rolling terrain, which can lead to a great workload over the course of two or three hours.

The other suggestion he made was to do intervals at just above threshold, which I haven’t yet formally introduced into training, but it will be an easier workout to incorporate when the time comes. I will do them as hill repeats, much like 4x8 threshold intervals, for example, just at a slightly higher power output. Those used to be a staple of my training, so I know where and how to execute these well. Familiarity with a given workout is often just as crucial as doing them in the first place, because proper execution can be tricky but goes a long way in terms of the quality of the outcome.

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Hi @basilleroux thanks for the feedback and good question!

The big thing he’s made me focus on is my VLAmax and also my function reserve capacity. Both are not good and I’m really realizing how much they are impacting me. Case in point, I’ve done two races now this year and in both races I got popped in critical moments. In both cases, my FRC/W’ hit zero right at that critical moment. Here’s the example from this weekend:

Shows me that my aerobic engine is there, but I’m not going to be successful until I have enough of a VLAmax to respond to the big moments.

This has always been the case for me (never had a great VLamax) but what I’m discovering is that with age, I’ve become a caricature of younger self. What used to be a minor weakness is now comically bad. Definitely know where I’m going to be focusing my attention for the next month.

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Hi @basilleroux! Glad to hear you enjoyed the podcast with Sebastian Weber on INSCYD. He gave Chris and Trevor a lot of great, specific advice!

Have you taken the INSCYD test or another physiological test yourself?

Hi @jana, I have done the metabolic cart type of testing a couple of times and like Trevor my issue is my FRC/W’.

One more question for @trevor is how are you preparing for these races psychologically? If I understood Sebastian correctly he said at the moment you have no chance of getting in that breakaway so what are you saying to yourself on (a) the start line and (b) when the hammer starts going down and physiologically there is not much you can do?

Keep up the great work Team. Thanks Basil

Hi @basilleroux, good question! I’m personally very outwardly focused when I’m racing at my best. I don’t try to focus on fears or concerns because I personally find focusing on them just amplifies them.

Instead my focus is on taking the actions to avoid being in a place where my current lack of a VLamax will hurt me and try to put myself in places where I can still be successful without that asset. For example, this weekend I had a race with a one minute climb where I’d be in trouble if I was at the back and someone attacked. So, I was willing to lead the field up the climb at a hard pace knowing they’d sit on my wheel and let me lead. It worked well.

Likewise, looking for moves, I tried to anticipate them and be on the right wheel when they went up the road. That way I didn’t have to be as explosive. None of our moves stuck, but I was able to be in several taking this approach.


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I wanted to share what I learned from Inscyd. I know I’m just a amateur,but the cool thing with Inscyd is that the more samples you learn about, the easier it is to see how it’ll help you improve.

Riding background
I’ve been riding about 8 years pretty regularly ~300hr a year). I’m 205cm, 93kg (~16% fat). The last couple of years I’ve plateaued at 330-350w FTP.

My test results:
VO2max: 5215 (55.6 ml/min/kg)
VLamax: 0.63
Threshold: 304 Watt (= 72.9% of VO2max)
Fatmax: 4.44 kcal/h/kg @195.0 Watt - 417 kcal/hr
Carb max: 2.2 w/kg

My goal race:
11.2mi 3500’ TT in under 1hr. PB = 1:04:02

Secondary goals: half and full Ironman… When we’re ever able to swim again.

What I learned:

  • I spent too long going easy over the winter. But I felt tired with the volume so I didn’t have it in me to try hard. This brought my FTP Waaaay to low during the winter.
  • My easy wasn’t easy enough. This would have left more in the tank to do the occasional intervals to do some intensity
  • I should be doing a LOT of high torque work. Now that I know how much I rely on my fast twitch muscles to power big efforts it explains why I have such a challenge pushing my HR up before my legs want to give out.
  • To get where I want to be ~400w FTP, threshold close to VO2max, I’m going to need to train a bit more (12-14hr / wk), more consistently, focus on VO2max in off season (which will push VLamax up), then lowering VLamax as I get closer to races
  • Nutrition: This is the big one. I’m not even close to the amount of calories I need in longer/harder training rides / races. Like… Need to get used to 100+ g carbs an hour… Vs. the 30-40 I would usually do… Which explains why I’d end my Sunday rides and have to nap all day to recover… Now I’m good to play with the kid and feel great!

Edit: Now the really interesting portion is that I did this test with a friend. He’s 6’2", 72kg and his PR on the mountain is just a couple seconds faster than me. However his Inscyd tests showed he had no room to improve his VLAmax (lower) and almost no room to improve his threshold as a % of VO2max. So his training will be drastically different than me me, but even though smaller at the same "fatmax"output he’ll be doing almost the same calorie burn as me.


I have performed 1 Inscyd test and am scheduled to perform a 2nd soon.

A thought I have rattling around my head is that many tests, Inscyd in included, require proper pacing. So you almost need to know what you can achieve prior to performing the test. If you put garbage in you get garbage out.

Whereas platform like Xert seems to fairly accurately predict efforts over FTP/Threshold.

At what point do we need to perform formal testing, versus just entering predicted data into a program like Inscyd?


Hello there!

Nice to see you in this world, hope you are well.

This is a tricky one.

I have sent xert files to clients who are about to perform Inscyd testing when I know they have an accurate signature.

When I do this…I do expect them to beat the goal in the outlined session by 10 seconds or more, or I make them do it again before I load to Inscyd.

This is a “be careful what you wish for” scenario.

I understand what you are saying. From a mathematical perspective this could work. From a people perspective I really need to know where my athlete is in their mind for pushing the wattage.

There is a learning curve to pacing yes, but in your case I think you are there. I feel that if you were doing a 12 min time trial, and has last test in mind, you could start the first few minutes on that old number and then assess what you might try on the day. This would give us great data for the Inscyd test, as well as data for your current level of motivation.

It is one thing to get the data from any testing software, but the day we take away the athlete having to perform that is a mistake.

I think you could use xert to plan what you WANT to do for the TTs, but then as I mentioned above, I would expect you to breakthrough by at least 10 seconds and show me what you have.

Then we can look at the nutrition side of things and see how the aerobic contribution is coming along to get those numbers.

Thanks Steve, I always appreciate your perspective.

I try to find the easy way out with modelling, and you flip it on it’s head and say “Prove it!”

Getting back to the idea behind this thread, my last Inscyd test taught me how to prove it to myself. I had to re-do my 12 min effort because the first one wasn’t my best effort. We can’t go that deep every day in training, but we need to be able to find that level of motivation every once in a while.

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@shawnfife you are a very intelligent athlete. Appreciated getting to know you on my forum, really glad you are here.

Always a pleasure chatting with you.

Food for thought: One thing that is nice about pacing the Inscyd test is that you don’t have to hit an exact time duration for each step. There is a range of valid durations. So if you pace for the middle of the range but can keep going, go for it! On the other hand if you fall a bit short that’s ok too. Case in point: On the 4 min step I overpaced and failed at about 3 min. But the algorithm still worked.

@SteveHerman Very well said! When I send out the protocol to athletes it always says 20-25s, 2m30 to 3m30s, 6-8m and so on…

Many will then build it to the shortest duration in software, then I have to remind them to build longer to make sure they have room for the ACTUAL max effort.

Nice post.