Riding and Racing Outside in the Winter - How does TSS work when power numbers aren't included?

Ok so, imagine this: Fat bike race, Garmin power pedals, deep fresh snow quickly becomes a trampled course. Uphill riding is almost impossible. Descending is very little pedaling but extremely taxing. Heart rate is high, but power is low.

Next race: ditch clipless for flats, because, well, safety. The course is better, but the last couple of laps demand walking/running due to warming temps. My heart rate stayed maxed out since, well, running in deep snow.

I ended up stripping the power info out of the first race so as not to wreak havoc on AI FTP detection. Heart rate was used for the TSS for both races. However, since I keep uploading to Training Peaks as well, I noticed a big discrepancy in TSS. For example, Training Peaks had me at 200 hrTSS, and Trainer Road at 150 TSS based on HR.

Also, why is cadence data associated with a ride with no power meter? Where does it come from?

Just wondering how this could throw off AI FTP and adaptive training, Red Light Green Light, etc.

Thanks in advance!

Sounds like a fun kind of race – fat bikes are always a blast!

For the TSS Estimation/hrTSS discrepancy, this may be because TR and TP estimate your HR TSS differently. TR requires your maximum HR and your date of birth, while TP uses your Threshold HR.

I’d make sure the HR metrics you have plugged into both TR and TP are as accurate as you know them to be, but there still may be some differences in the TSS values you see as they aren’t calculated exactly the same way.

As for cadence, it would still make sense to see it on there for your first race with power because nearly all power meters use cadence to determine your power output in the first place. If you stripped the power data away, there should still be cadence data “leftover” that would be displayed. To get more specific, power = force x speed, so it’s not only how hard you’re pushing on the pedals but also how quickly you’re turning them (i.e., your cadence) that determines your power.

All that said, these rides and races will still impact Adaptive Training and Red Light Green Light because your training stress will still be assessed (even if the uploaded ride does not include power) and your plan adapted if necessary. AI FTP Detection, however, does ultimately rely on power data to give you accurate detections, but if these rides are only once in a while and you’re still getting plenty of other rides that do include power data, then I wouldn’t worry about a few rides that don’t have power data – AI FTP Detection should still be getting good data from you for your future detections.

Hope that helps clear things up – feel free to let me know if you have any additional questions!

Thank you! I really appreciate your detailed answer, and yes, this clears most of it up. I look forward to races w/ power as I know that will affect my FTP.

Still one last question: on the ride where I didn’t have any power meter at all, I still see a cadence average of 24 and a max of 52. These numbers don’t really make any sense, but just wondering where they come from…the only sensor I had on was a Garmin HRM Pro.Well, and the wahoo element roam tracking the ride. Does it guess at cadence because of speed? Which is 4.9mph over 2 hours for 10.5 miles. Because…well…this wasn’t a road ride! Yes, fat biking is its own special magic. So glad to have it as an option! Thanks again!

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No problem!

It does sound odd that there is cadence data on the ride(s) without a power meter… Ultimately, cadence won’t have any effect on AI FTP Detection or Adaptive Training, so it doesn’t really “matter” in that it won’t do anything negative to your plan, but it would be interesting to investigate what’s going on here.

I saw there are a few fat bike rides/races on your TR Calendar. Could you tell me the date of one of those where you didn’t have the power meter on your bike so we can take a closer look at the ride file?

Hi!

Sure, Sunday Jan 26 “Canaan Fatbike Race” didn’t have a power meter.

However…I realized I’ve often seen weird cadence numbers on my Wahoo Elemnt Roam when I’m not running a power meter. So that’s where it’s coming from. Where the Wahoo gets it from? I have no idea. I did a quick google search and didn’t find an obvious answer. I did a scroll through the settings on the unit and via the app, no place where cadence is mentioned.

But, as you say, this doesn’t really matter so…now that I know that I am just fine not worrying about it!

I am new to TR and really enjoying the platform as well as the support. Thanks so much!

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