Unlike other platforms Xert uses MPA to derive your fitness signature and power curve and does not rely on MMP sampling alone. The emphasis is on calculated values rather than power points achieved in the past. That is a fundamental difference if you are accustomed to real-world numbers to define your curve.
You can see this in action on any activity but particularly on HIT or hard workouts/rides that include periods of maximum effort under fatigue. Open the activity details and select the Power Duration tab. Note the three curves (Current Fitness Signature plus Signature and MMP for This Activity).
For more info see these posts –
- Is PP a theoretical number? - General - Xert Community Forum
- From old trainer to smart trainer. Set FTP - Training - Xert Community Forum
A quick way to validate your calculated PP is to perform (in Slope mode) a sprint workout like this one or a “fitness test” workout as described in the links above. Or a few 20-30 sec sprints outdoors.
Another option is to view details on your last BT activity, enter a higher PP value below the chart, and click Extract. Watch what happens to TP. You can also tweak HIE and enter a median value from this chart then Extract.
If you like the results, click Save which locks the signature so that future adjustments apply to that reference point signature.
An XFAI plan configured for “will likely achieve” is going to be a conservative prediction.
IME I have reached or exceeded predicted numbers prior to target date and I’m good with that.
Another factor is Xert is applying their hybrid polarized model to the forecast which does place an emphasis on more hours than you may be used to. You can tweak that by using the General Settings sliders and accumulate more strain in less hours or purposely select tempo/SS workouts on endurance days for a more time-crunched approach.