Xert Signature and Strava metrics

Hi. Been evaluating how useful Xert might be to managing my fitness and performance levels and am reaching the subscribe decision. I am retired and my cycling is reacreational so maybe outside Xerts main focus. I cycle quite hard - mainly 2 or 3 2-3 hr rides a week in a moderately mixed hilly area (so I do regularly get near to exhaustion on some climbs). I feel perhaps wrongly that Xert FTP252 and PP708 are a little high and HIE7.8 a little low. I say this based on my Strava maximal power curve (232 for 20 mins) and the max power reported for individual rides. Both data sets are based on around 90 rides this year using the same 4iiii power meter. I have experimented by using the sig cal to enter 3 data points from my Strava curve (at 5, 60 and 1080 secs) and it gives PP635 HIE13.6 FTP 229. I have then saved and locked these settings into an earlier ride to see if that feeds through and alters the current signature downwards, however over time the subsequent rides bring the signature back to pretty much the original place! So I guess i am left wondering if Xert is overst ating my metrics or not. I know I could have just changed the current signature but wanted to see whether my ongoing rides would simply bring it back up again which they do. I have a smart trainer but have not experimented with workouts as yet.
Thanks John

Hi John. Thanks for your detailed explanation.

Looking at your first breakthrough activity, you had locked a signature of 684, 10.6, 248. I used signature you suggested and ran an extraction. The results were 634, 15.6, 242. I resaved/locked that and watched the progression recalculation. Your Aug 16th ride seemed to need an adjustment afterwards too so I save/locked that activity.

I wouldn’t base FTP on your best 20 minute power. It can only be estimated using a all-out, fresh-to-failure, well-paced effort 20 minute test. Just finding your best 20 minute effort will most always underestimate your FTP.

Btw, kudos for looking into how to address the issues you had. Sometimes (not often fortunately … for most, never) you have to look into a ride or two and see if things can be improved. This is why we have the save/lock feature on activities.

Good luck using Xert!!

Thank you for your help Armando. Is there a way of identifying locked rides as I’m not quite sure which ones you adjusted. It was the 6 Apr I locked originally on the Strava data? Sounds like you found another later ride left locked in error overriding it?
May I ask more generally:
Am I correct that any rides prior to the most recent locked ride are excluded from the calculation process.
I realise Refresh shows the immediate effect of changes to the 3 metrics of the ride. What exactly does the Extract button do as often the refreshed figures will further change when that is activated - why?
If you extract and then leave the page without saving are all the changes / extraction undone. What happens if the saved your changes without using extract?
Sorry for the questions but you need to know rexactly how it all works if your going to intervene.
Cheers John

… Looking at my recent rides now MPA is too high. These are regular routes and I pretty much know my points of exhaustion. Maybe reset everything for a last try??

… now recalculated progression and analysed and locked sig on my 26 Aug ride which i chose because it has 2 or 3 testing gradients around 16%. I’ll see how I go from there Armando thanks :slight_smile:

John, sounds like you and I are trying to use Xert for similar purposes (improved fitness overall rather than competitive targeting). And, like you, I find myself puzzling about how to make sense of some of how Xert works. Any interest in a collaboration resulting in a document folks like us could share with other Xert users? Pretty sure Armando would welcome this.

Yes Fred the lack of documentation and explanation is an issue for me too. I guess Armando is limited in what he can do through the forum. Not sure there is much we can do apart from pointing this out.

Do join the Facebook Xert Users group as there is a lot of dialogue there. We could definitely use more user contributed content.

Ok, except hate Facebook…

Only use it for Xert. Ignore all the rest.