Classic or ilevels?

Ive been doing some reading as a complete newbie to power and just finished ssb low vol 1 and 2 and now will be moving onto mid vol. It has helped beyond what I could ask for.
Id never leave trainer road as it is now that I can confidently say

I do have a question though
If im wrong please correct me but TR is using Coggan classic levels, would it not be more beneficial to use the newer ilevels? Or is this only pertaining to TP etc? And or would it be too difficult to switch from one to another.
And like I said complete newbie here so dont shoot me if its common knowledge but could you use ilevels in TR?

1 Like

someone may be able to correct me, but I think ilevels are tied to the WKO software, so more of a proprietary thing?

yea, I kinda feel like that’s the case.

Ilevels are individual. They are based on the athletes power duration curve. If you want to use them you need wko or the algorithm to work them out and then modify your workouts/plan.

iLevels and classic level are very similar below FTP, close enough for it not to make any difference. iLevels are useful above FTP as efforts above FTP are much more individual. The generic VO2Max intervals are normally set around 120% of FTP this just is not effective for a majority, and for a number of people not even possible to complete.
As stated above they are based on the athletes PDC power duration curve. For them to be accurate the athlete needs periodically ‘feed’ the model with short, middle and long all out efforts.

Attached examples of an athletes Classic and iLevel below.



EDIT:- Oh, and levels above FTP have a duration attached to them. In WKO there is an optimised interval chart where it gives you further guidance on intervals for levels 5 - 7a (Pmax is just maximum power)


Classic levels are completely fine.

People below are correct that iLevels is from WKO and while I utilize that on the back end to provide workouts to athletes, I don’t even go into depth with them on that on a daily basis because athletes are provided “ride x watts for y duration with blah blah blah” so they don’t need to know the fine nuance between FRC/FTP and FRC, or FRC and PMAX/FRC.

If they want to geek on it that’s fine or if you’re building your own workouts you can utilize it, but those levels should be coincided with event specific goals as zone 6, 7 and 7a are realllly close together.

It’s all above threshold so it’s considered “hard” but for different durations.

If you’re new, nail the classic zones, and once you use WKO, graduate to 9 zone. It’s useful but not necessary by any means.

Hope that helps.



Thanks for the very helpful comment. It has cleared it up for sure. I am in no need of that fine nuanced data yet, lol


1 Like

My suggestion for TR’s vo2/anaerobic intervals is to find your repeatable power. When my vo2 is relatively untrained, I need to dial intensity in TR app down to 92% for 120% vo2 intervals. That turns the 120% interval into a 110% interval (120% * .92). Be careful, vo2 work should hurt so you don’t give up early and reduce intensity too much.

On the other side of the bell curve, some people can push 120% vo2 intervals up to a much higher intensity.

If you are in the middle of the bell curve, those 120% vo2 intervals will be good without any changes.


I’ve considered doing this myself from the athlete side, I think the ilevels make a lot of sense as a zone configuration. While I could update the Garmin to use them via WKO, I’ve not committed to do this since all the training plans, structured workouts, and platforms I use outside WKO are the classic zones and I wasn’t sure if there’d really be much benefit to seeing one set of zones on the screen but doing workouts not designed that particular way.

Can someone confirm “how” to apply the iLevels from WKO5? The power prescribed is exactly equal to my Power Duration Curve. Of course, I would not do repeat intervals at that level; right!? So, am I supposed to adjust the prescribed iLevels down by some “rough” percent? For instance, should I discount the 2:16 iLevel to 93% of what is prescribed? (It is odd that the iLevels chart would not do the calculation for you.)


so you might
1m15 intervals ~ 390 watts
3m intervals ~ 310 - 320 watts
and maybe 2x 7 minutes @ 278 - 280 watts or a single interval of 13:20 @ 278w

Optimised intervals give a more specific prescription

Maybe 5-6 x 3.5 minute intervals equal rest ~ 300 watts. TiZ would be 17.5 to 21 minutes


That helps! The Optimized Interval Targets chart is perfect. It does look like the “targets” in this chart are roughly 93-97% of the PDC. Conversely, the “iLevels for Cycling” chart appears to just report the PDC power output for the duration indicated; I suppose we are supposed to discount those amounts by this 93-97% multiple as well. Thank you!