Fitness/form for bike touring

[Gauvins]

I am winding down a tour of Lapland and was wondering about the relevance of intervals’ form indicator.

Depending on the course profile and weather, a typical daily load would be around 200.

I started the trip at a fitness of 40. (I can’t spend more than 1hr/day on the trainer), such that a few days into the tour, my form would drop to -50 or lower. Even now, after a month+ on tour, my fitness is at 100 and my form below -50.

My understanding was that one can pedal in zone 2 almost indefinitely, as long as food and water intakes are appropriate.

Perhaps educate me, or suggest tweaks to derive meaningful information. For now I look at this and don’t know what to do with these results.

[Rutger]

This kind of riding is prob an edge case for these models. That being said, what do you get when you change this to percentage of fitness?

[MedTechCD]

You can read about that here:

FITNESS PAGE - a guide to getting started

FAQ Fitness Page: My Form number is not matching how I feel This is a remark that shows up regularly on the forum and there are multiple reasons why people have difficulties understanding this. A first thing that has a pretty big impact on the numbers, is the setting of how Form is displayed. It can be displayed as an absolute difference between the Fitness and Fatigue numbers or as a percentage difference related to the actual Fitness number. If your Fitness number is 100, both settings wil…

Read the post just above also to better understand what the Fitness chart is doing.

[MedTechCD]

First of all, your numbers don’t hold up. If you did 200TSS per day for over 30 days, the Fitness number would be at least 150.

The starting point of 40 would indicate an average daily load of 40 for the last 42 days. 40 TSS in an hour is an intensity of ~63%, about half-way Z2.
On your tour, are you getting those 200 TSS from 5 hours at a similar intensity or are you doing a lot more hours at lower intensity?
Is load calculated from Power or HR?

• If Power, did you ever set your FTP correctly? And did you retest? Because 30+ days at such a load will certainly have raised your FTP. And then Load calculation is based on an FTP that is too low and that will over-estimate load.
• If HR, which method? Time in HR zones? Load from HR Time in zones is based on the average of the zone. If you constantly ride at the lower range of the zone, load will be over-estimated.

I think you are using HR Time in Zone and are riding lots of hours at the bottom of the range. That makes it sustainable but over-estimates the Load.
Compare the TRIMP number from one of your one hour trainer activities to one of your tour-rides, on a per hour base. I wouldn’t be surprised that the TRIMP/hour from your tour-ride is way lower.

[Gauvins]

Numbers are what they are. Zero days explain the difference.

Yes one hour on tour requires less work than 1 hour on a trainer.

I link to the Garmin ecosystem. I’ve had a power meter for a couple of weeks. Then relied on hr. No idea how exactly these systems talk to each other.

Just to be clear, I think Intervals is great. The fatigue/fitness metrics are useful. Forms perhaps misleading for low effort/long duration load.

[MedTechCD]

@Gauvins

No idea how exactly these systems talk to each other.

You need to get things set up correctly or the numbers will not make sense. To get a correct setup, you need some basic knowledge on how it works. Read the above linked Guide posts as a start.
It’s not like you just need to get your activities in to get a meaningful analysis. Everything regarding Load is referenced to a threshold that you have to set correctly. If it’s off the board, all Load numbers will be off the board as well.
Form is just the difference Fitness - Fatigue. Fitness is a 42day moving average of load referenced to threshold and Fatigue is a 7day moving average of load referenced to threshold. If those make sense, then Form will also make sense.
In your case something is completely off because no-one can sustain Form levels of -50 for weeks in a row.