What is the highest fitness score possible on Strava?

Mine is consistently around 100, as the rides I do are consistently 100-150 relative effort.  It's to do with the effort put in compared to your FTP (or heartrate equivalent), and the time it's over.  1 hour at FTP would be 100, but Strava uses something different based on heart rate.  The fitness score decays over time, but relatively slowly (42 days I think)  The fatigue score is also based on recent relative effort, but decays more quickly (7 days I think), and form is the balance between the two.  The idea is to manage this balance.  It's explained on TrainingPeaks.

 There probably is a maximum fitness based on maintaining a high relative effort over many days. For me, a 100k in a little under 4 hours gets into the 400s for relative effort.  Getting more than 100 for an hour based on FTP does indeed suggest that the FTP is wrong, so Strava must be getting something wrong for my intensity score (too high).

I believe it's linked to your FTP and effort level, along with time spent. So if you have an FTP of 200w and do a 1hr ride at 200w, you'll get a training intensity score of 100 and I think a training load of 100. If you did the same for 2 hours it would be intensity of 100 and load of 200. And likewise a 100w ride would be intensity of 50 and load of 100. I think. And then continued efforts at a given level increases your score.

I would guess, though it is only a guess, that anything over a fitness score of 100 may mean your FTP is inaccurate, or you're putting in ridiculous hours on rides.

Edit: found this and it explains it far better. Think I'm wrong on the 100 point but you do need to be doing high load rides. And it's all relative to you anyway so one person's 100 isn't comparable to your own https://www.google.com/amp/s/science4performance.com/2019/11/04/modellin...

My highest is 104, I'll generally hit 90-100 at the end of a training block before it drops back down during recovery week and the process starts again.

Even though I'm pretty meticulous with my numbers, I've stopped worrying about it over anything other than a 1-3 month view.  Right now I've just started another training block and am at 82, lower than it was around the time I did my first imperial century.  I'm substantially faster now than I was then (averaging >30kph vs ~20kph), but my overall graph shows roughly flat since then (with some peaks and troughs, but never going too far either way).

So yeah, not entirely sure it works over the longer term.

Have a google of CTL/ATL/TSS  (Strava appear just to use Fatigue/Fitness possibly for legal reasons)
There's no real right or wrong answer to what a good figure is, but  consistantly over 100 would seem to indicate a substatial training load.
*However!* It is very much a case of garbage in, garbage out, and if your power/HR figures for maximal sustained efforts is not correctly identified, the numbers you see will be proportionally too high/low. 
 

Another runner/part time cyclist here - I usually peak about 150, ATM it's in the 130s, seldom goes below 120. Doesn't seem to mean a huge amount to me - garmin based VO2max seems better...

I'd like to see a little more of the algorithm used to calculate it to be honest.  At the moment I'm pretty much as bike-fit as I've ever been, I've done a record amount of miles this year and I'm on 47, down from a peak of 59 in late October.

It's difficult to tell but I get the distinct impression that I get more 'credit' for a three-hour tempo ride with Mrs JGV where I'm hardly out of breath, than an hour's solid Zwift workout that's building strength and ability to clear lactate and so on.  All these things are just numbers of course, and more is better but it would be good to understand what you're supposed to do or not do.

My Veloviewer score is 99.935 if anyone cares.

As others have said not sure of the accuracy, I hadn't looked at it for ages until I read this post and then pleasantly surprised to see I got a best of 98 this Sunday

I'm ignoring it.

At the start of the 1st lockdown I decided to run a minimum of 5k every day. I carried on after lockdown ended and stopped after 200 days. My fitness score dropped off during this period. Any bike ride I fitted in seemed to up the score disproportionately so I decided that either I didn't understand how it worked, or I had configured something wrong, or it just wasn't very good. Unless running every day makes your fitness worse. Anyway I'm ignoring it.

221 mid-summer 2019 (triathlete alert - it's boosted if you do some HIIT running). I have to say its poor indicator of 'fitness' though, I'm currently on 191 and not feeling very fit/fast at all.

My highest was 92 but I have no idea how it works or if it's accurate. My graph has fluctuated like coronavirus cases but I definitely didn't feel any more or less fit during this time 

I've had it in the early 90's. I think a friend once said he got up to 120 or 130?

To get these scores you generally need to be pushing hard on a regular basis (if not riding long distances). You also need to limit or at least manage your recovery time as the score drops by a couple of points approx every day you don't ride

Not sure butmine is higher than 40, and have maxed out at 79, not that at the moment, that against power, against relative effort maxed out at 60. Not sure what it means though.