Have I accidentally hacked the system?

Hello all!

I‘ve been riding my lovely indoor bike for about 2 months now. One month on Xert. Another month on a real bike outside before.
Before that, I was a couch potato.

2 months ago I started with an FTP of 150W, which I measured by doing a 20 minute test.
Today I got another breakthrough and Xert thinks I have a TP of about 240W. That seems, to be honest, ridiculous. Now granted I am MUCH fitter than I was and I have also trained my behind off over the last few months. But I feel like Xert is overestimating me a lot.

So I was thinking that I am somehow, inadvertently, cheating the algorithm by creating breakthroughs that push up my TP, even though that’s not the case.

Is that a realistic scenario? Is that something one would be able to tell from the workout files?
I have shared my last two breakthroughs below, hoping that one of you would be able to take a look at those and tell me if something fishy is going on!

Looking forward to hearing your advice!

Breakthrough 1

Breakthrough 2

Unable to view BT#1 as that crashes my XO connection.
Suggest you file a support request with support@xertonline.com to review the account.

You need weeks of viable data for your signature to get dialed in including some BT efforts.
A traditional RAMP or 20-minute FTP test doesn’t necessarily produce the same results as a BT effort to determine TP. While TP and FTP are similar in function, they aren’t calculated the same way.
My guess is there are some data points on file that need to be flagged. Xert Support can determine that and make adjustments on their end.

What is the name of the workout used for BT#2?

Reference –
Breaking Through the Xert Way! – Xert (baronbiosys.com)

Hey! Thanks for getting back to me and trying to look at the data!

The workout of BT2 is one I created myself in ROUVY in order to push myself and actually get a correct reading on my fitness curve. I did it because I expected it to be a near BT which would correct my signature down. Well it turned out to be another BT, pushing my TP and LTP up even higher.

I simply set both workouts to public and then pasted the links here. Was that the wrong way to share my workouts?

Again thank you very much! As an inexperienced cyclist I am quite confused by the data. I’ve read through all of the documentation of Xert and I‘be also read countless papers on training (I‘m a bit of a nerd in that way sometimes), but couldn’t figure out how exactly I was fooling the algorithm here…

Not sure you’ve linked the correct rides as they are only a few days apart… and ‘only’ 20w difference in TP…

Both breakthroughs look a bit short though, so you may want to do a longer one to get a better sense of threshold eg 10 min + (doesn’t need to be constant power)… or ride as long as you can at 270w and see what happens

Were they to failure? Best not to use erg mode too

Yes I did link the correct breakthroughs. Basically I was surprised that my TP went up a lot and then only a few days later it did the same. 20W seems like a lot to me.
The results I posted were pretty much to failure, yes. I‘m sure I could have done more if my life had depended on it, but I did feel very dizzy afterwards.

As the previous poster suggested I also contacted the Xert support and got the following response, which was very helpful and covers what you suggested as well:

Hi Luca,

Thanks for reaching out to us. Welcome to Xert!

Those are both certainly very hard efforts indeed - I can see your HR was elevated quite a bit. But both these BT’s seems to be legitimate to me. Unlike other platforms, which often use ‘tests’ to determine your fitness, Xert uses your second by second MPA & power data to determine your fitness signature. You can’t really ‘cheat’ the system. If you’re able to “exceed” your MPA, then your signature must be higher since, by definition, you cannot exceed your maximum power available!

Have you tried any longer BT efforts? Seems like many of your BT efforts are relatively short (<5min). Without any longer effort, the system could possible struggle to determine your TP, as extrapolating a user’s Threshold Power from their 5 min power can be problematic.

Lastly, remember that Xert’s TP is not your 60 min max average power. In Xert, it simply represents the highest power you can ride at where MPA does not decline. Most users will likely be able to sustain riding at their TP for ~40-70 minutes. Further, very few of our workouts are based on %FTP, nor do they feature long intervals at/near Threshold. Instead, we use your entire fitness signature & MPA to calculate your interval targets and SMART/dynamic intervals.

Hope this is a helpful start! Feel free to follow up with me if you have further questions/comments :slight_smile:

So I‘ll definitely try a longer effort over the next few days to see how things go. I just think those are psychologically quite hard for me. Doing 270W feels like an impossible task over an extended period of time. I can probably only really do that for 3-4 minutes. My best 4 minute power right now is 3,7W/kg which comes out to pretty much 270W exactly. And that would be me completely done afterwards. So I feel like I could only hold the 240W suggested TP for a couple of minutes longer. But who knows, I‘ll try and post the results here.
Thank you very much!

You mention training a lot more over the last few months.
What was starting status stars count and what is it now?
Do your outdoor rides include power, HR, and cadence data?

As far as generating BTs to dial in your signature, there are workouts in the library designed for this purpose. They won’t appear on suggested lists, but you can search the library for “breakthrough” and find a variety that range in difficulty and duration.
Xert - Standard BT Workout (xertonline.com) (less than 10 minutes of “hard”)
Xert - Version 2 (xertonline.com)
Xert - Version 3 (xertonline.com)
Xert - Billat style (intense shorts) (xertonline.com)

So I just looked at the first recorded activity with power data and that puts me at 1 star. That was on the 19th of August. Xert put my TP at 160W.
I am now at 2 stars with a TP of 240W.
My outdoor ride do include all of the above mentioned data since the 19 of August.

I bought my first bike approximately 2 weeks before that. So I was riding occasionally, but really doing a 5km ride was insanely hard for me. Like literally falling off the bike hard.

I think because I was still on the trial versions I wasn’t seeing all of those suggested workouts. I‘ve never used a workout from Xert since I either ride outdoors and just try to hit general power targets, or I do indoor rides with ROUVY which doesn’t allow Xert running at the same time. So with ROUVY I do the same thing. Just hitting the interval targets for an amount of time that feels really hard, but not so much that I can’t continue the ride afterwards. I usually go for 3-4 intervals in a one hour training session.

Doing longer than one hour rides indoors is kind of hard for me at the moment simply because I get bored if I‘m not „allowed“ to go all out. And I‘m trying to follow a polarised training, so going all out is not what I should be doing all the time :stuck_out_tongue:

Thanks for giving me some insights! I feel like I‘m learning a lot and while I do have a reasonably good „scientific“ background (as in having read lots of papers), I‘m simply lacking the experience both with training in general and Xert specifically.

Just so you know, riding at threshold to failure will not lead to a breakthrough - you need to ride above threshold (else MPA doesn’t decline), which is why I said 270w. Obviously doesn’t need to be that - was just illustrative… you can look up your 10 minute power (power curve) and try and beat that for 10 minutes… or do Ronnestad intervals for 10 minutes… or anything with varying intensity that brings MPA down over 10 minutes (or longer)

Okay honestly I just tried.
I can‘t do more than this. There is simply no way I‘m holding power above my TP for longer than 5 minutes. Like absolutely no way. The problem is my 5 minute power is somewhere around 260W, which I almost averaged in this try. According to Xert my 10 minute power is somewhere around 250W.

How on earth am I supposed to go to 250W but not go to 260W or even higher? Like this just seems completely impossible to me. I need to stay over 240W, because otherwise I‘ll recover my MPS, even though I‘m realistically not really recovering. But when I just go a little bit higher than my targeted power I‘ll shorten the interval to 5 minutes instead of 10…
I‘m seriously lost here.

Edit: I just tried doing it in ERG mode. No way. Like no way in hell. My TP has to be somewhere around 170 or something. Anything beyond 200 is just completely ridiculous to me for any prolonged period of time.

Okay I think I did indeed find a major flaw in the algorithm. Depending on what data points I give it the resulting TP number is drastically different. Like it’s not even close and none of the values presented are all that realistic to be honest…
See screenshots below for examples. All data I put into the system is real data that Xert has.
I understand that Xert can’t be 100% accurate. But the those power curves make me look like three completely different riders to be honest…

I think you need to reboot and rethink this.
Filling in the power curve calculator to establish a starting signature is typically used by those with years of historical data to reference.
I don’t think anyone should go from couch potato to maximal efforts to failure at short durations two months later.
As someone new to cycling you want to build base fitness first at low intensity.
How many hours/week are you currently riding?
What is the shortest ride in distance or time you typically complete?
What is the longest ride you have completed to date in distance or time?
Are any of your cycling activities being spent entirely at low intensity? I.e., spinning easy, conversational pace, never gasping for air.


Thanks for the feedback!

I currently do between 7-10 hours a week of riding. Most of it in zone1/2 (the problem is I‘m not quite sure if my power zones are correct because my TP is so high, so it might really be mostly zone 2).

I then try to do 2 high intensity sessions a week but I really have been having sore legs for the last couple of months so there have been weeks without a high intensity session in them.

This week has been somewhat crazy because I became worried that my fitness signature is wrong and is leading me to overtraining so I tried getting near BTs to bump it down but bumped it up even higher instead. Suddenly my usual recovery rides were suggested 160W average, which is sustainable for me, but not really recovery either I guess.

Shortest ride is usually about 45 minutes on the trainer on a flat course. For the one on ROUVY I use that gets me to about 20-25km, depending on how hard I was going really.

Longest ride in time would be 3 hours, but that was with my girlfriend going for a picknick out of town. I was barely doing any work (I averaged 70W during that ride even though I was doing frequent sprints to not get on her nerves riding next to her all the time and not doing anything). Longest ride in distance so far was 55km I believe. That was on a flat course though. I‘ve done some 40km rides which were a bit hilly as well, so that obviously took me a bit longer.

Pretty much all of my „performance riding“ is done indoors. When I‘m riding outdoors I‘m either riding to my girlfriend‘s apartment which is only 5km away, or I go for relatively simple/short rides. That‘s because until recently I didn’t have a smartphone mount (which I‘m using as a bike computer), so I had to navigate by having Komoot giving me directions via headphones. Didn’t feel very safe riding in a big city, not knowing where the hell I was actually going. So I stuck to indoor riding!

Winter is coming so I‘ll probably stick to mostly indoor riding and hopefully be reasonably fit once spring comes around next year to actually ride in the hills/mountains surrounding the city with moderate confidence.

Taking all that into account I did think I was training correctly (except this week really!). I‘m just a bit worried that the workout advice I get from Xert is rather detrimental because pretty much every session ends up being a high intensity one.

Sure, I can just go by heart rate and feel and ignore power zones completely, but then what’s the point of Xert really…

I hope you understand my confusion and quite frankly frustration. Right now I‘m just afraid the tool that’s supposed to keep me from overtraining is really just doing the opposite…

Two things come to mind

  1. You are very likely tired / fatigued from all the recent BT efforts - take it easy for a while and then try the longer effort again
  2. Your HIE may be low. It is towards the lower end for your sprint power, assuming that’s actually correct / max(?), according to this, and I think your ratio with this formula is also low. Usually you see low (relative) HIE in people with well developed aerobic systems, rather than relative beginners. If out, it would lead to TP being too high

Practically, you can flag the BTs that give too high a TP, and then make sure your next BT is a longer one… I think the issue is that lack of longer breakthrough. (Also try a sprint at some point to make sure PP is correct). Or the support team could fudge it for you in the meantime (by going into the BT and lowering TP and raising HIE and saving the result), but not sure how much confidence that gives

If you are new to cycling I would suggest you focus on extending the duration of your rides. Create some workouts with steady power in Z2 that you are able to hold for at least 60 min (+warm up and cooldown). Bump up the power a bit for each ride to see what you can maintain. Also, have a look at your heart rate to see if it is drifting (increasing) a lot from the first part to the second part of the ride.

If you do not have a fan, then you should probably get that.

First of all thank you very much for actually looking at this and trying to help me out here. That’s much appreciated! I think I’m someone who overthinks his hobbies and tries to be very structured and “scientific” about things. Therefore having potentially wrong data stresses me out and having people who are trying to help me fix that is incredibly reassuring!

  1. Yes I think I’m extremely tired just going by feel. I haven’t had a single day without DOMS in my legs since starting cycling. Xert does sometimes say I’m fresh though and I decided to trust the system and just went for it on those days. In the end I do like pushing myself, so that was a convenient excuse I guess.

  2. I looked at the links you posted and my data does seem very weird compared to other people’s data. The thing is when I tried fixing it by manually lowering my TP and then going for a longer breakthrough (I did an 11 minute BT yesterday averaging 220W, had my TP manually set to 200) the resulting TP does seem realistic to me, but the HIE is then completely out. Xert suddenly disregarded my shorter term power and though I had declined massively there, which is simply not the case. It almost seems as though the system won’t accept that I can’t hold a certain effort over 5 minutes but then rapidly decline after that. So it either makes me an endurance monster, or simply disregards the data points in the 2-5 minute range.

I even had the support team have a look at those last two BTs and the certainly thought they are very valid. They also said I need to go for a longer BT in the future, but I don’t see myself being able to do anything over 250W for longer than 5 minutes any time soon… :smiley:
And when taking those recent BTs out of the equation my fitness signature is also just plain wrong…

Regarding sprint power:

I did get a sprint BT last week when I was out on that long ride with my girlfriend. Basically I easily got over the 700W sprint limit without trying all that hard. My heart rate certainly shot up after the effort, but I assume I had a little bit more in me. Hard to tell with very short sprints that weren’t even designed to be all out efforts I guess.
The problem I have is, that I can’t even get close to that number on the indoor trainer. I think the best I’ve done indoors is somewhere in the 600W range. And basically what’s happening there is, that the entire bike starts hopping about in my apartment going completely crazy and I just can’t get the power down. Probably down to my technique. I assume I swing the bike about wildly when sprinting outside, which is hard to do indoors obviously.

Again thank you very much! I’ll wait and see what the support team thinks about this situation and if there’s anything I could do about this. And I’ll certainly keep this thread updated if anything changes or I find a solution. I guess I can’t be the only one having this problem!

Good advice! I have certainly been doing this and anything in the 160W range is easily sustainable for an hour. HR doesn’t really drift for those lower efforts anymore either. I had some crazy drifting when I started though, haha!

I do have a fan, although that’s probably not the best solution. I am currently using one of those hang the hose out of the window ACs in its fan only mode. So it does certainly provide a little bit of airflow, but I dedicated fan is probably better. I’m not too keen to spend another big chunk of money on a dedicated indoor cycling fan next though… :smiley:

But I guess Christmas is coming!

Indoor cycling fans are nice (Wahoo Headwind), but you can probably get something useful for $30 as well.

One other thing I just did:

I changed my starting training load to zero, since my first uploaded activity on Xert is also my first activity ever. Like my first ever endurance activity period.
That did two things:

  1. It reduced my training status down to 1 star from two stars.
  2. It’s now telling me I’m crazily stupid and overtraining like a madman. That sounds about right to be honest.

But it also did a bonus thing, which I don’t quite agree with:

It bumped up my TP even higher. Only by 5W, so it’s not too bad, but still annoying…