Elevate/Strava - Loss of Fitness

I’ve been using the Elevate extension for Strava and while I’m not that concerned, I am a bit curious in my recent loss of fitness. I had to take 5 days completely off last week due to my wife having surgery. She’s fully recovered and I’ve been back on it since the weekend. According to Elevate my fitness level is back to 52.1 after this morning’s session. That’s equivalent to where I was over a month ago. I know I shouldn’t put too much stock in these numbers, but do you really lose that much fitness over a 5 day rest period.

For reference, I rode spruce knob -2 this morning averaging about 200 watts at 153HR. A month ago I rode Pioneer and averaged a similar power with 131 avg HR. So perhaps I have lost quite a bit of fitness over my short break. Or it’s just the accumulated fatigue of the week coming off of so much rest?
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Don’t sweat it: five days off isn’t going to set you back significantly.

FWIW, I think the maths behind the charts also takes into account how quickly you’ve accumulated the training load too, so it’s easier to lose recent rapid gains.

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As far as fitness points go, yes you lost that according to the algorithm they use. Those numbers really indicate the long term training load compared to your ability, not really a true indicator of your relative fitness on the bike compared to others or even yourself one month ago. I use another application to track similar numbers and I was sick for four days and lost about 6 points (75 - 69) over that period and subsequent “get back into it” workouts. Then that weekend I produced a lifetime best 20 minute TT power despite that number being fairly low to where it is in season for me. Even if you are more relatively fit now than you were a month ago, say a 275 FTP vs 250 prior, that number and trend line is based of your current threshold and not a base line that would see higher numbers the higher your threshold is. So you haven’t necessarily lost fitness, just your chronic training load has reduced.

Regarding the elevated HR that is likely due to the fact you really didn’t rest during that week off the bike, something these numbers do not take in to account, and you may be at an elevated level of personal stress or fatigue due to the circumstances. I highly doubt the days off the bike were restful and you probably had increased responsibilities and stresses off the bike and that can easily take a toll on your recovery and HR. You could also be getting sick, since you were likely in a hospital , my HR rises when I get sick and usually can predict it with such data. It could be several other outside factors than just your overall capacity or fitness during that workout. If you completed the intervals and the RPE was were you anticipated it to be then your fitness is fine, if it was extremely more difficult perceived then perhaps you did lose a little bit. I would stress over either of these two things for your relative fitness overall but I always recommend easing back in to it after time off like that.

It’s just some rolling average of TSS/day. You may in fact be more “fit” depending on recovery for those 5 day coming back but, yeah the number is just a way for us to measure how much load over time we are doing. For me it’s as important to use to stay away from overdoing…

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Very good points. Yes, stress load was definitely more than normal even with no training last week. Degraded sleep as well. RPE was about where I anticipated so I guess I shouldn’t worry about the HR too much.

The formula they use doesn’t remember anything. Elevate’s fitness graph is just using the CTL formula. Tomorrow’s CTL is based on nothing but today’s CTL and today’s TSS.

If you’re doing no TSS, it’s just exponential decay. In five days, you’ll lose about 11% of your CTL (1-exp(-5/42)).

You should probably think of CTL not as a fitness score, but as a measurement of training volume. If you didn’t have CTL, you might measure volume in hours or miles. Miles is an inconvenient unit because how far you go depends on so much: how fast you are, how hilly the route is, etc. Hours are independent of those things, but they don’t measure how hard you were working: 5 hours a week of Z2 is pretty different from 5 hours a week of Sweet Spot. CTL is basically “difficulty-adjusted hours”.

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I stand corrected.

I’m not sure if this applies but elevate did an update recently. After it updated I lost 20 points of fitness going back to when I started tracking. I tried to fix it and realized it’s just a number and gave up.

+1. Simple yet excellent explanation!

Agreed – it’s not called Chronic Training Load for nothing!

I ran my first ultra last year (and had my highest fitness scores on Elevate during that time). I then dropped back to around 5k 2-4 times a week, do far, far lower mileage per week than last year, yet have been setting 5k PBs ever since (including a few weeks after the ultra). I’m on course for another 5k pb tomorrow - yet Elevate says my fitness is around a third of what is was after my ultra (was 37, now 12). So while “fitness” is good for tracking hours and intensity trained, not so good for comparing different distances.

Fitness is a slightly misleading term here and not meant to be taken literally - but used because Chronic Training Load is copyrighted.

It’s worth looking at the Form line here (which is your 6 week training load less the training load over the past week) to assess your current capabilities, which has jumped up sharply, representing your longer term training, but with the deloading of training stress over the past week.

The Performance Management Chart which Elevate presents is not intended to be a literal fitness measure, but a guide as to how much training stress your body can take, based on recent training history.

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