Understanding the impact of exercise on Fitness Signature

Hi, I’m new to Xert (since January 2022) and am trying to understand the impact of training and breakthroughs on my fitness signature.
I think I have an understanding of the three key measures - Peak Power, HIE and TP, and I can see the impact of my efforts and breakthroughs on those. What I don’t understand is that while my TP and HIE are increasing, my peak power shows a steady downward trend.
For info, most of my cycling (at the moment) is on Zwift using a SARIS H3 smart trainer, with probably around a quarter of my rides being Xert workouts.
Is the reduction in my PP simply due to Xert refining its estimate of PP as it learns what I’m doing, or do I need to adjust my exercise regime to improve PP as well as TP and HIE?

Someone will be along to correct me shortly i’m sure but I think it depends upon what you’re doing on Zwift. I believe the measures will naturalluy decay if you don’t try to make breakthroughs for each of the 3 metrics you measure ie; if you’re doing no max efforts then this will naturally go down.

There’s also a question about what you’re

Have a read of the above.

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Yes, as @Emmodd said above your signature will decay (depending on or decay setting).

The decay will make your signature metrics come down over time, while your training will influence it upwards.

With no decay your signature could only go up, and your signature would not account for losses in fitness.

Thanks for your replies guys!
While I understand that my signature metrics will naturally come down over time if I don’t exercise, what I don’t understand is why my TP and HIE are going UP yet my PP is coming DOWN. @Emmodd I will go and read the post you linked!

I had a breakthrough the day before starting this thread, in which my TP increased by 9W and my HIE increased by 3.2kJ. At the same time my PP reduced by 1W.

Today, I did another ride and my TP was unchanged, HIE increased by 0.4kJ, and PP increased by 4W.

So I guess what I’m looking for is an explanation of how these 3 measures relate to each other.

Thanks again !

Each signature variable is matched with a training load (low, high and peak matches TP, HIE and PP, resp.) and the system keeps track of how much strain (XSS) you put on each of these systems and accumulates them in their individual training loads. The system then looks to see how each of these change over time and adjusts each signature variable in accordance with your changing individual training loads but it will apply a decay to each in order to allow errors in your data to get flushed out. This does mean that you’ll need breakthroughs every so often. If you trust your data and won’t see many breakthroughs due to how you are riding/training, you can set the Decay Method to “No Decay” in which case the 3 signature variables will have predicted values from the system based on your training loads.

Thanks for that explanation @xertedbrain! So the training load influences which of the individual factors of my signature are affected by training. I now understand that. I have also looked back at some of the Xert videos and understand the concept of “Focus” and how it relates to training load.
Xert obviously takes these factors into account when recommending a workout. I will try to adjust my free rides in the same way.
My “Athlete type” is “Century Rider” so I hope to see increases of TP and also to a lesser extent HIE, and I should not be too concerned that my PP is likely to stay unchanged or even fall.

Thanks again

Just wanted to re-clarify things here. Your Peak Power might not actually be dropping, but you also haven’t been putting any strain (XSS) on your peak system, so it’s detraining, technically speaking.

What you can do is to sprinkle some sprints in with your weekly training. In fact we have several sprint workouts that are mostly endurance, such as ‘Adventure of a Lifetime’ or ‘The Time Is Now’. Alternatively, there are many shorter (~60min) sprint workouts, such as ‘Heroes’, ‘Dirty Little Secret’, and ‘Purple Rain’. Since Sprint workouts put strain XSS mostly on your Peak system without really touching your high system, they’re very good to include with your base work. :slight_smile:

Thanks for the advice @ManofSteele - I like the look of ‘Adventure of a Lifetime’ and ‘The Time Is Now’ as they seem to fit my desire for endurance, but they will also hit my peak system - I’ll give them a try!

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I wanted to ask about these sorts of workouts with sprints… does the xert workout player automatically switch to slope mode for the sprints? Or is it better just to do the whole thing in slope mode?

Those are MIXED MODE workouts. Use the EBC app and leave it in AUTO mode. Our app will use ERG for the majority of the workout (warmup/cooldown/endurance intervals) but will automatically switch to 4.0% slope for the sprint efforts - no need to do it manually. Can take a few sprints to get used to how your particular trainer handles the switch (some trainers are faster than others), but makes for a great workout experience that you won’t find in many other platforms.

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I downloaded the “Adventure of a Lifetime” workout to Zwift and did it last night (on ERG mode), and what a great workout it is! It has had an immediate impact (increase) on my PP.
Many thank’s for the advice and recommendation!

I noticed you are using Zwift a lot currently. Once you go outside you will probably find it easier to sprint. I certainly find it difficult to sprint on a static bike.
I wouldn’t worry to much about PP at the moment. Remember, if two variables go up the other will reduce.

Not necessarily… :slight_smile:

This is one of many things that is distinctly different about Xert. Other platforms may track ‘time in zones’ , but they fail to recognize that spending time in Z6 doesn’t only impact your ability to produce power in Z6, but those efforts also contribute to your threshold as well. In Xert, everything (short of <10s all-out sprints) goes through your low intensity system.

HIIT = training for HIE and TP.

Looking at the distribution for a HIIT workout helps clarify this. Let’s take a look at the famous Ronnestad workout (A Pain That I’m Used To, quite literally). The workout has an insane amount of high strain (for my signature, executed perfectly, 33 HIGH XSS). But the workout also includes 136 LOW XSS… that’s ~78% of the total workout XSS going to TP system.

Similarly, we can look at total training load distribution. I usually ride 6x’s a week and I’ve been doing sprints once a week, HIIT once a week, and the other 4 rides are generally sub LTP endurance rides. If we look at my total TL (~78, just over 3 stars) can be broken down into 76.3 LOW, 2.2 HIGH, 0.6 PEAK. So despite doing SIT/HIIT about 33% of my rides, my TL is almost exclusively low strain. That will change as outdoor season starts and as I begin adding more high/peak XSS from outdoor rides :slight_smile:

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Glad to see you got results but keep in mind downloading a workout as a ZWO file means losing SMART intervals and mixed mode functions present with the Xert EBC app. That allows you to exceed targets for a true test of max power and MPA drawdown.
[You can run EBC while riding in Zwift world as long as EBC has trainer control.]

You can also validate your PP at any time by riding a BT workout from the library in slope mode. Search for “breakthrough”. Shortest workout is around 30 minutes with high/peak efforts in red of less than 10 minutes.

PP can rise one of two ways –
Actual max power which you can often achieve outdoors to greater effect OR predicted sprint power which will be calculated based on how well you perform a BT workout that includes max power efforts under fatigue. By max effort I mean you spin up, likely out of the saddle, and go as hard as you can until failure (at least 5-7 secs).

I also suggest you experiment with athlete type over time whether changing the setting under Goals or selecting a different Focus Type when filtering recommended workouts.
Century Rider (or any entry in the Endurance quadrant) will lean towards endurance workouts. To mix things up consider experimenting with the other quadrants. Variety ensures you are training your low, high, and peak systems.

Reference (quadrants shown at bottom) –
Choosing your Athlete Type – Xert (baronbiosys.com)

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