I have the Zwift Indoor Trainer, which to me is perfect (low sound, can easily adjust positions for different users). I recently switched indoor training software from TrainerRoad to Xert - I’ve tried Zwift before, but for some reason I preferred TrainerRoad.
Now in Xert, I notice my TP slowly decreasing below levels I deem reasonable given my current fitness. Apparently, I have to do breakthrough trainings to increase my TP.
My assumption is (haven’t found evidence that suggests otherwise) I can only use Erg mode with my Zwift Indoor Trainer.
(1) Is there a way to grow my TP using only Erg trainings?
(2) Is there a way to manually put a higher TP value in my profile?
Hopefully someone else with more knowledge can chime in, but for (1) - definitely yes.
You just need to do a good mix of workouts that will target that metric. What training program you have selected and what stage of it you are in will determine what workouts are recommended and what their focus will be. If you want to target TP explicitly, you might want to set up “Goal” or “Challenge” program as those will focus on raising TP x amount in y time. All other programs should also improve TP (except I think in the case where your TP is already sufficient for the final goal when it would just maintain). Some phases of different training programs will focus on different aspects of your fitness signature at different times, but all should contribute to your TP in the grand scheme.
Breakthroughs are not required to increase metrics if you are completing recommended training. They function more like a rebalancing or measurement / proof of metrics vs calculated or predicted metrics based on just training schedule / completion.
Verify what training program you have selected and what it is targeting. Then there are some possibilities for your TP metric being inaccurate or decaying too quickly. A maximum effort breakthrough is probably the easiest and best way to reset it. You can also modify in settings how fast your fitness signature will decay without appropriate training. If your TP metric is too low compared to what you can actually do, then the trainings it recommends will be too low also.
If you’re getting repeated and frequent breakthroughs it likely means your TP metric is understated, and you are only resetting it up to the effort level that you exert. If you do a 100% maximum effort then it should be set more accurately and only go up from training or maximum efforts after additional training. Are your breakthroughs resetting to the same or very close number from before decay, or are they constantly hitting new highs?
Also Xert by default initially calculates your fitness signature from the last 3 months of imported data, so if you don’t have any hard rides within that timeframe you could be looking at inaccurate numbers.
First, just to share my setup so you have some context: I use a dedicated bike on a Tacx Neo 2T with Zwift and virtual shifting. I haven’t installed the Zwift Cog, so I still have physical gears available when I want to use Mixed Mode workouts. But if/when I do structured workouts, I use ERG mode in the Xert app or I push the workout to Zwift and disable ERG mode, preferring to use virtual gears to control my efforts.
(1) Can you grow TP using only ERG?
Yes. With consistent training and a positive Improvement Rate, we expect your training load — and over time, your TP - to gradually increase. It’s usually not dramatic (often 1–2W per week with steady training), but it does add up with consistent training over time.
Breakthroughs can accelerate updates, but they’re not strictly required for progress. Also, if you’re seeing TP drift down, it could be related to Signature Decay. You might want to review that setting - many athletes (myself included) prefer using the Slow Decay setting.
(2) Can you manually adjust TP?
Yes. If you’re confident your FTP/TP should be higher:
Open a recent activity
Scroll to the bottom of the MPA chart
Manually enter the TP value you believe is correct
Save the change
Xert will recalculate all subsequent activities using the updated signature.
@ulty 's advise is spot on as well. If you’ve not really pushed yourself to the limit recently, it’s very possible & likely that your signature may be underestimated. If that’s the case, go out and do a Zwift race, or free rid and do a few max power sprints (5-10s all-out) plus a longer hard effort to failure (8-12 min or so). Either of those options should be great to help dial in your signature, if needed.
Hope this helps - and welcome again! Cheers! -Scott
Fitness signature refers to the combination of metrics that Xert tracks and calculates based on your activity data: peak power, high intensity energy, threshold power, and lower threshold power. They’re displayed on several pages within the website: all the tabs within the “my fitness” section except the calendar, your profile settings, and the power curve page.