Completely resetting signature after big lay off

Another reset signature question I am afraid but I have searched for the answer and I cannot see a relevant comment.
I have had a bike accident and will have 6 weeks off before starting up with gentle spinning. I expect my overall recovery back to around my TP of 260 to take possible 2-3 months once I have started riding (indoors) again.

From a WKO5 perspective I am going to estimate FTP at 50% of current so that any TSS I generate is relative to my current fitness level.

How would I approach resetting TP in Xert. Would a guesstimate of 50% for PP and TP be a good start. If I leave it as is even with decay set it will take a while to drop down sufficiently that I am able to get any sort of BT and my TL will be way under what it should be.

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I’ve had this problem (and pondered it many times) before, and this was my finding:

Yes, it’s easy to reset signature when fitness is on the way up, using a breakthrough.

But when fitness is on a sharp decline (sickness, injury, holiday, life etc), the best way to rectify is to adjust the decay method to aggressive and then try for a BT ride on one of the earliest rides back.

Any time I tried manually tweaking the numbers it would lead to strange signatures in the future. But I’ll be interested to see how others approach this.

I wish xert had an option to adjust signature decay rate automatically e.g. so when ramping up in training load I want no decay (to keep interval and LTP targets realistic), but for big ramps down in training, I want closer to an aggressive (so that I can easily get a realistic breakthrough when returning to normal training).


Yeah, this is generally how I would approach this. Change Decay setting to ‘Aggressive’, then “Save”. Once that’s done, go to the last activity before the break and flag/unflag the ride. By flagging and immediately unflagging, you’re just forcing Xert to recalculate all your data from that ride using the newly selected decay type (Aggressive), which will bring your signature down a bit faster than No Decay or Optimal Decay.


Thanks Scott. I will do that . My subscription expired on May 4th which was after my accident but I will re-subscribe in a couple of weeks and do as you advise. I can see that my CTL in WKO5 has dropped from 78 to 40 already.

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You’ll see similar changes in Xert’s TL, though we don’t use a single TL constant of 42, but rather we use 3 separate TL’s (Low TL constant is 60, High/Peak TL constant is 22).

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@ManofSteele do you see any benefits to experimenting with tweaking the load constants to better match an individuals physiology? If so what’s the safest way to start playing? :slight_smile:


Some words of experience for ya: Taking forced time off the bike after an ‘incident’, I’ve been through the same thing. Twice in the last couple years.

June '19, hit by car, long list of injuries, 3 months of nothing, and almost another 3 months before I was interested in riding again. TL from 45 to 5, TP from ~200 to 135.

Jump forward to December '20, total hip replacement surgery (a result from the crash, didn’t heal well enough). Including time before the surgery, I was off the bike for almost 3 months this time.

I had worked my TL back up to ~50 before surgery, and brought my TP back up to the ~200w I was at before the crash (about the best I’ve had over the years). Again the TL dropped, down to 10 this time, and TP way down as well. I could feel it too, getting back on the bike the power was just not there. But it came back.

But, I just started working on getting BTs when I could. Doing as much polarized riding as possible. With each BT its felt ‘right’, in that I don’t think it was sandbagging me beforehand, and I don’t feel like I can do any more at the moment.

So far I’m already back up to 40 TL, and 175 TP, well ahead of where I was a year ago.

All this was with the standard Decay settings, I haven’t changed a thing on that. So basically, just get out and ride easy for awhile when you can. Then when you are medically cleared (or feeling good enough if this is all on your own), start pushing for the BTs again. And again. And again.


So inspiring, Ian. Thank you for sharing your story … and such a magnificient XPMC chart!

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Playing likely isn’t the best way to do it.

It’d likely be more efficient/systematic from our end - tracking the changes between each system’s training loads between breakthroughs, as well as looking at changes in signature parameters relative to changes in training loads. But that’s a lot of computing - and requires high-quality data for best results.

Thanks Ian, that is really helpful. Seeing your numbers climbing again must be so motivational.

Followed the advice and set my decay to aggressive. TP dropped from 260 to 195.
I set my FTP to 50% so 132w and I have done a couple of very easy rides and I suspect my current FTP is closer to 195 than 132 but I just want to stay steady and grow my TL which has dropped from 92 to 49.

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As an update I am still not sure that my signature represents my current level. FTP is ~160 now but TP is at 192 and even with aggressive decay it is going to take a long time to meet 160.
In the meantime my PP is way off what I can do currently and my TL is growing much slower than it should do as I am doing about an hours workout a day - easy stuff.

have you done a " all out" effort or break through effort recently? Without this it is really hard for the algorithm to pull out the data you need. If you have one of these activities then one thing that is interesting is to open that activity and then choose the advanced MPA chart. In there you can see a button called extract (bottom right corner). Click this and if it is possible it will extract a signature from that single ride. When you do this what do you see? is it more aligned with your expectations? If it is then you can then save this signature and it will apply going forward. However you do not have to save it this is just a gut check and will not effect your signature unless you press save and then only after you tell the system you are certain you want to do so.

Also of note in that same page view you can enter the various signature values and see how they change the MPA graph. It is a great way to learn how PP, HIE and TP interact with each other. Playing with these values on this chart does nothing to you actual signature until you ask it to save.

The key though is to go to your limits on a ride and see how MPA reacts. There is no easy way. If you did a “FTP” test that should be able to extract a signature if the efforts were long enough and after each hard effort you kept on pedalling 9ie don’t stop dead after a hard effort that messes up the algorithm).

You need to read all of John’s posts on this thread. He’s coming back from a serious crash and surgery so a BT effort is not feasible.

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That may be true, but a breakthrough is the only way Xert works. If he is spit balling a number for TP 0f 160 then he still can look at the advanced MPA and get an idea of what that looks like. If he waits for the decline in his signature it will be giving him efforts that are beyond his current fitness and ability. So it is possible to downgrade the signature in advanced MPA or maybe Scott or one of the XERT folks could reset his signature until he can do hard efforts to get a real signature.

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Thanks for your input Ron. As George says I cannot do an all out effort and even if I did it would be way off my current numbers.

That was the point of my initial post. I recognise that Xert is good at moving numbers up but does not seem to cater very well for drops in signature values.

If I had been out for 3 months I actually think that aggressive decay would be reasonably accurate. However having only had 5 weeks off and surgery it has not brought me down enough.
Perhaps @ManofSteele or the support team could look at my signature and offer suggestions on how to reset it. Ideally TP could be about 160 and PP no more than 300.
At least that way I could attempt to get BT efforts in a couple of weeks and also my TL might actually start to rise rather than drop even with doing workouts each day.

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John, I feel for you and hope that using Xert can move you in the right direction. Where you are at this moment sounds like rehab more than trying to make break throughs and for that I think you may want to look at getting @ManofSteele or @xertedbrain to tweak the system to work better for you. Good luck and above all hope you are seeing things improve.

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Made a tweak to the starting signature on your initial return to the bike - have a look at things now! Follow up with me via PM if you’d like :slight_smile:


Thanks @ManofSteele . Those numbers look realistic so I am happy.

PS I like the new options in goals. Ideal for those like me who don’t have a race target but do want to improve.