Monitoring adaptation rather than training load

Hi everyone.

I moved away from a coach last season to manage my own training - mainly because I enjoy the speed of learning, development and ownership from making mistake after mistake.

I use to manage my training and I also coach a couple of others for free, to speed up my mistake based learning even faster!

Something I have noticed across the training monitoring tools is that they seem to promote and reward increasing training load with a moving average fitness score, despite the saying ‘training makes you weaker, recovery makes you stronger’. Taking rest weeks to allow for effective adaptation is super important, but this requires you to accept a decrease in fitness - which isn’t really true. Maybe instead of fitness, this should be considered ‘tolerance for training load’ or something similar.

Anyway specifically to my question - is there any software, algorithm or piece of maths, that monitors adaptation as fitness by understanding the benefit of rest following increasing training load? CTL/fitness seem quite dangerous to me…

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I think if CTL, etc were “dangerous” then we’d know by now.

I wouldn’t say that recovery weeks (not rest weeks) means a decrease in fitness. Obviously if you continue to drop training load then over time you will lose fitness.

I think you are confusing how the term fitness is used in the programs and how it’s used in general usage. uses “form” as the difference between short and long term training load (fatigue). It doesn’t matter what the absolute values of either CTL or ATL are, it’s the difference between them. So in a way it (and presumable WKO, Golden Cheetah, etc.) do what you are asking already. As with FTP there’s always the danger of hanging too much from a single metric for what is a very complicated area.

I’m not confusing them at all. The reason I believe they are dangerous, is that people chase ‘fitness’ ( or CTL (Training Peaks), which puts them off adequate rest (adaptation) periods. Someone who never schedules regular recovery will have a higher fitness or CTL than someone that does.

I know that if you understand these concepts fully you should not be chasing these scores.

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Then that’s surely a problem in either the athlete’s or coach’s understanding of periodised training.

I’m not sure if any of the programs does it but I’d like to see the ability to track “marker” or bellwether workouts over time. I noted in the “What workout” thread that my performance in Pettit over the last six months has improved markedly - slightly higher power but with a much lower HR. In fact my whole HR distribution has shifted down by 10bpm. I looked back at my history in to find the relevant fitness figures which were (apologies for poor formatting):

Month - Fitness - fatigue - form
May - 58 - 66 - -8
Sept - 78 - 82 - -4
Nov - 69 - 73 - -4

September was actually 5bpm down on May so pretty much a halfway mark. So even though my fitness was nominally down on Monday my form was the same but I still saw an improvement from seven weeks ago. I did a Ramp Test between the latter two so Monday’s workout was also at a higher FTP. (I’ve got a goal of completing Baxter all in HR Z1 - I missed it by 23 seconds last time!)

Further to this, I’d like to see something along the lines of an assessment week: a set of workouts that you’d do every three to six months that you could track. Maybe Pettit, Lamarck and Spencer.

Have always hated the term “fitness” to describe CTL! Just doesn’t align with the way that most people use the word.

At the risk of oversimplifying it, the best measure of adaptation is a fitness test. Whether an FTP test (there’s more to fitness than FTP but if you’re going to pick just one measure to track across different training phases then FTP is probably the least bad) or something more event-specific like 1 minute power, 5 minute power, 30 minute power in the TT position, etc.

And actually even if the goal was to achieve the highest CTL (not recommending this for a moment!) then experimenting with different approaches to this over a few seasons would likely lead you to conclude that regular recovery weeks enabled you to build to higher volumes in the long run even if there’s a short term dip.


Echoing @cartsman, I’ve always disliked the use of ‘fitness’, ‘form’, ‘fatigue’. My understanding is they came about because of copyrights on CTL/ATL/TSB. In my opinion CTL != ‘fitness’ as ‘fitness’ is multi-factoral (FTP, time to exhaustion@FTP, fatigue resistance, pVO2max, repeatability of efforts, etc.). Is someone with a FTP of 200w and CTL of 100 more ‘fit’ than someone with a FTP of 300w and CTL of 70? I’d bet on that 300w FTP person having better real-world ‘fitness.’

If you look at something like WKO or GoldenCheetah you can see historic trending information for 20min power, 5min power, Xmin power, W’ (anaerobic work capacity), etc. that are either taken from actual performances or modeled based on actual performances. That kind of information might be more of what you are looking for.

Don’t get me wrong, I think CTL/ATL are metrics worth tracking and are very useful. But people who are new to training or training with power and haven’t steeped themselves in it misunderstand that group of metrics and focus on them instead of looking at the big picture.


Then the “dangerous” part of the equation is the people, not the metric. But I understand, it’s much easier to manipulate and “fix” numbers than it is people.

Good luck.


We are all humans, we like to be able to measure ourselves, be it CTL, TSS, salary, ONS, etc.

I totally understand what @gloscherrybomb is worried about. I had a short period last season where I was ”hooked on” getting a high CTL. Easy to forget that it’s not the CTL that wins you races…

Continuing on what @Craig_G mentioned, the Performance Management Chart (or whatever its called outside TrainingPeaks) could, or potentially should, not be that individual. What I mean is, ones FTP should reflect the level of CTL/fitness. Sort of like a combined Performance Management Chart and Andy Coggans W/kg chart.

Hence, a rookie with an FTP of 100W would not be able to reach the same CTL/fitness as Chris Froome without producing the same numbers in real life.

  • True words whenever looking at tools and technology.

  • The tool is not to blame for how it is used. That honor belongs to we/us… the fallible humans with all the control and responsibility of the use.

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Agreed. But do keep in mind everyone is at a different level of expertise with metrics. I agree with OP and have witnessed beginner/moderates burn themselves out chasing a higher fitness number.

Sure, it’s the individual to blame. That metric should be used for ramp rates, not overall fitness.

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Neither will an Olympic/World Cup-level track rider.

If you use a screwdriver to pound in a nail, don’t expect hammer-like results.

WKO. Buy WKO5 and also buy the 3rd edition of Training and Racing with a Power Meter and read it cover to cover. And in parallel start watching the WKO webinars on YouTube. Get the right tools and learn to use them.


The absolute ftp number of 100w has nothing to do with it. It’s calculated relative to one’s ftp. Yes, a rookie would have a near impossible time reaching same ctl as froome, but a person with 100w ftp wouldn’t necessarily have a hard time.

In my opinion, the folks with a really high ctl are the ones that have platued ftp wise. The folks that are constantly getting ftp increases don’t increase ctl as fast because each jump in ftp relative to that person requires even more calories to be burned to increase ctl.

No, no my dear friend. I think you misunderstood me. What I meant was that I would like to see the PMC further developed to also incorporate ones ability as a rider (e.g. FTP). Of course both an amateur and a pro can have a CTL of 100, since its based on their individual FTP. However, what I would like to see is that a higher FTP would also generate a higher CTL. Hence a 100TSS ride for mister amateur would not “be worth” as much as for Froomy.

But then again, it would be f****** hard to sell training programs and tools to amateurs since they would only be looking at that “new performance chart” which shows them how bad they really are compared to the pros :joy:

You’re correct. I did misunderstand. Thanks for clarification :+1:

Thanks all, I’m glad that most of you understood the concern. Of course it is the person to blame, not the tool - but that is why we have the tools in the first place - to try to add structure and quantitative measures to help us avoid the errors we otherwise inevitably make as humans.

eFTP is a good marker in I might message David about a change of the term ‘fitness’, but as others have mentioned people chase CTL too. Scores of any type are very attractive metrics to chase.

you answered your own question, no? Don’t chase CTL, 100% agree, because that is not race readiness, which is what we truly want for events.

also, you nailed it, when athletes say they are losing fitness because they see CTL dropping during a rest week, it’s a mute point, right, because technically their anaerobic efforts would be higher during this portion of time but aerobic efforts harder to repeat, so we have to ask, What is Fitness?

To maybe help answer your question, just take a zoomed out, big picture look at the forest; there is no “one math” or one metric. You need to use them all in sync.

For those that might not know what you are referring to above, I wrote this article back in 2019 that talk about CTL obsession and also updated it this year to look at how driving your CTL super high can really make the PMC appear funny in re: to TSB down the road.

Good luck with your training!


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I don’t think I did answer my question. I knew from the outset that chasing CTL is not a good idea, in fact that’s my point. However I am not talking about race readiness here. That is easy to manage with freshness. What am I wondering is if there is any kind of metric or model that, unlike CTL, actually does give an indication of fitness from appropriate training load and recovery combination.

For example - someone that has accumulated huge load week on week on week and has a high CTL score, is likely less fit than someone with a lower CTL store, that has accumulated similar load over most weeks but has taken time for recovery/adaptation every 4 weeks.

It’s really not a biggie - you can educate away from a focus on fitness or CTL, but I think there is an issue with it being promoted as a ‘score’ when often chasing this has a negative impact on fitness.

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Just wanted to inject two things:

  1. gloscherrybomb is the absolute best user name on this sight by far. Wish I would have thought of a username with cherrybomb in it.

  2. Maybe CIL? Or chronic intensity load which is an indicator of the quality of training through the season = [(1000todays IF)(1-e^(-1/42)]+{yesterday’s CIL*(e^(-1/42)]