TP detection

I’m totally new to automatic TP detection, if i have no history, how will xert detect my TP during my first workout? With my heart rate I presume?
otherwise i don’t see how he could know if i’m in the rough or not, so the use of a cardio belt is a prerequisite to use xert?
Thanks !

It doesn’t really use Heartrate. The model (Xert) is only as good as the data you feed it. So it won’t provide a good estimation of your TP unless you provide the model proper max efforts.

It gets better the more max data you provide. There are certain “breakthrough” workouts in the library that can help you reach your max. Otherwise a 3-5min max test and 10-20min max test can provide good data for Xert to model your TP.

OK thanks,
I found “Xert Fitness Test for Breakthrough”
Do you think is it enough?
And can I make this workout with ERG mode?

when working out for a breakthrough it is best to use slope mode for the critical segments/ sections. The reason is you need to go past the point of breakthrough for the algorithm to work. Ie breakthrough plus say 10-15 seconds. Otherwise it may think it is not a true breakthrough. The essence of a breakthrough is going significantly beyond what the algorithm thinks you can do based upon your fitness signature. So in the above the sections where you see the purple MPA graph draw down, those sections should really be done is slope mode.

With no power data history to import you can alternately seed your starting fitness signature by entering 2-3 known power curve values here – Xert - Power Curve (
Then prove that signature by performing a BT workout in Slope mode as @skinner_ron suggests.
This assumes you are in a fresh state, ready to go all out on any intervals designed to drive you to failure. In the example BT workout that entails two max sprint efforts followed by a series of steps ending in an interval to failure. Right before you are about to fail, spin up, and go all out for at least 5-7 seconds.
You don’t do this under ERG control because you want to exceed targets or durations or both if you are able. ERG control would stop you from doing that.

Pretty good input from this thread so far, but thought I’d chime in as well…

In order for Xert to model your maximum potential, it does need to see some maximal effort… think of a hard effort where you feel like you can’t possibly pedal any harder. Unlike other platforms that often use some sort of standard FTP test (20 min, 8 min, ramp, etc.), Xert can determine your fitness signature from any hard/maximal effort. Could be a Zwift race, PR/KOM effort on a Strava segment, etc.

In general, it’d be good to include a few short/hard sprints with your Breakthrough workout so Xert has a good estimation of your Peak Power in addition to your Threshold Power!

1 Like

Thanks for answering, so basically on [Xert Fitness Test for Breakthrough] I need to do the 2 sprints breakthrough and the last part as much time as i can? I dont understand the last part because I will be just near breakthrough ?

Should I continue to pedal until I can’t after the last interval or should I just put more watts during the last interval and stop when they indicate it?

in the last one just go full gas and ride till you cant(empty)

1 Like

The BT workout you selected – Xert - Workout Details ( – is an example of push-over and pull-down efforts to generate BTs. See reference article below for details.

Your goal is to –

  1. Demonstrate your peak power during two short sprints; at highest watts you can possibly generate indoors, out-of-saddle max effort.
  2. Complete a series of steps that draw down MPA and end with a final interval you continue to ride as hard and as long as you can until you collapse.

In this respect target watts and duration are a guide, not a limitation. Ride the entire workout in Slope mode to ensure that.

Reference –
Breaking Through the Xert Way! – Xert (

1 Like

Well, I did the fitness test,
I thought i was going to tear everything up in the end, i kept pedaling for at least 2min after reaching my mpa, but i’m surprised to see on the graph that i only actually pedaled for a few seconds of more, as if xert had adjusted my mpa whith my 2 previous sprints…

If you don’t mind, you make the activity public & share it so we can see. You could also post the BT report in the Breakthrough Thread if you’d like!

If you did exceed your MPA during the ride and get a Breakthrough… Xert needs to apply your new signature such that your power only touches (but never exceeds) your MPA, since Power can’t ever exceed your Maximum Power Available (by definition). If that’s the case, you can open the activity, scroll to the bottom and push the ‘previous’ button, which will show the MPA data using your old/starting signature! This should align closely with what you would have seen in real-time! :slight_smile:

1 Like

That’s the answer I’ve been waiting for , Thanks!