New Zwift User

I’ve decided to use Xert to guide my winter training on Zwift as I get ready for outdoor mountain bike training. I have a Kinetic Road Machine 2.0 with the green V3 Inride sensor. Not a “smart” trainer, but I do regular spindowns and keep the tire & roller pressure consistent. I’m reasonably confident that I’m getting good power numbers (within 3%). I upload my Zwift workouts/rides/races to Strava. I’ve fed Xert my Strava training data going back to October 16th (the date that I got the trainer). I’m trying to figure out how to prime Xert with an accurate fitness signature?

Xert initially gave me a peak power (back in October) that seemed ridiculously high (1150) and arbitrary. I think that the highest watts that I’ve ever seen in a sprint is around 980 watts, and that would is very recent, as I’m in much better shape now than I was in October. Back then I would assume that it would have been in the 800s. Where would that 1150 peak power have come from? I’ve seen that I can edit the value in the advanced section of my first workout and it will cascade through a ll of my subsequent workouts. And if I edit that… I assume that I should also be changing my initial HIE? I’m also wondering about my TP. I did a Zwift FTP ramp test a couple of weeks ago which put me at 248 watts. Xert is currently putting me at 235 watts, which I assume has been extracted from my October-March Strava data, but also seems to be impacted by making any changes to peak power.

I’m loving Xert… but just wondering how to best use it moving forward… and what my fitness signature values should actually be?

Hey Casey. Welcome to Xert! Most often too high a PP can be caused by data errors that should be removed/fixed. Sometimes the algorithm detects that you’ve done a max power effort under fatigue in which case it will estimate your PP to be above the max power in the ride. But you’re right that all your numbers are related and a PP and HIE that are elevated will make your TP lower. This is why you cannot use ramp tests or other simple, single tests to understand your entire fitness profile. Other systems don’t account for how your PP or HIE influence your ability to perform. Good luck!

My history going back into October really doesn’t have any maximal efforts. I was just getting back on the bike and wasn’t doing much in the way of peak power testing. I was just trying to lose weight and bump up my FTP. I can live with my historical fitness profile being a bit wacky. What I would like to do is figure out what my current fitness signature values should be. Would it be helpful to do a test using the protocol described at the end of this article?

Unfortunately I don’t have a Garmin device, and I haven’t been able to get my Pixel 2 XL working with my ANT+ stick + OTG cable. So I’ll have to go the Zwift -> Strava -> Xert.

That should be fine. You can do a specific test or what many others do is just join a Zwift race and try and keep up with a group that’s too fast for you.

I have been using a Pixel 2 with ANT+ without issues once the ANT+ services apps are installed. I think there are three of them.
I insert a Suunto Movestick into the stubby OTG adapter that came with the phone.
I connect the Suunto/adapter into the phone, close all other apps, start the Xert app, select Record, select Scan, wait for sensors to connect (trainer and HR), then select workout/activity.
I use BLE for my Polar cadence sensor.