These two pages are from the same MTB race. The first is the data from the Wahoo app before it synced with Strava…the second is what Strava interpreted it as…quite a bit different. Any ideas why?
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Wild stab in the dark, one is taking data from one pedal and simply doubling it and the other is taking data from 2 pedals and adding them together.
One includes zeroes (strava) and the other doesn’t (wahoo).
ETA: In this case, including zeroes is better (strava).
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I think it because of the way the two different apps cope with zeros in the power averaging.
Looks as though the wahoo app might ignore the zeros and Strava includes them?
Also, on the wahoo app, it’s weird that the NP is higher than the average power - this shouldn’t really happen - maybe again because the wahoo app ignores zeros?
EDIT: beaten to it - should be more concise 
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Wahoo default setting is to ignore power zeros. But you can change in settings to include zeros
IIRC the Zero setting is stored in the head unit, so wouldn’t Strava just receive the data as sent via the Wahoo device and therefore have the “same” data seen in the Wahoo app?
I think it’s not about the raw data but about the processing of it.
@craigmanning also check if your FTP is set the same in both apps
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I would think Strava would just use the data as it was given. Is there a setting in Strava to not include zeros? Anyone that has raced mtb with a power meter knows that the power numbers dont really represent the true effort. Im always amazed at how low avg power is even though you are hammering.
- Always worth checking for some data, but that won’t alter Average Power, 209w vs 172w between them. Something more than FTP is different here.
Average power gives your average power amount during the ride, expressed in watts (a measure of how much energy you are placing into the pedals.) This is inclusive of the entire ride, and Strava includes zeros (coasting).
I wonder it it’s possible that you have zeros excluded in the Wahoo app, but Strava still gets a “complete” file and then includes zeros that are lacking on the Wahoo side?
What is your setting in the Wahoo app?
Physiologically those zeros are important though. You can’t pedal at 500W for 1 min then 0W for 1 min and say average is 500W. But it’s also harder than doing 250W. Which is why normalized power was invented (weighted average power). NP is what you’re looking for.
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I agree, but since the weighted average power (which I assume is Wahoo’s unbranded version of NP and will always include zeros) didn’t match NP, I bet OP has different FTPs set as well.
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Indeed, my gut says FTP and Zeros are different here at the very least.
FTP is the same in both apps. I cant check if zeros are included without the head unit in the app and Im at work. I will look later.
So my Roam was set to not include zeros in average. Guess that explains it. Apparently that is the default setting. I only started using the Roam late last year and I don’t recall ever changing that. I know when I had the Bolt I had it set to include zeros.
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Strava includes zeroes while coasting, but it cuts out paused time. So when you’re sitting at a stop light, Strava will exclude that data. It only includes moving zeros, as far as I know.
In Wahoo you can use the App to make sure your head unit is recording Zeros. My average power on my head unit & in TrainingPeaks is always lower than my average power in Strava.
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I use Sauce plugin to get Strava/Sauce data to match other analytical tools (TP, WKO, etc).
Hi craigmanning,
The discrepancy is caused by 0W calculating.
I asked Strava and here’s the answer from them:
Another consideration is whether your device/platform uses a different method than Strava when calculating your stats. While other platforms might exclude null or 0w values in the power data, Strava does not allow you to exclude these values, and they will be included in your overall power analysis. 0w values can be a result of instances where you may not pedal when you coast downhill, for example. Null values occur when there are no power values for certain points - like if your power meter died (but not if it’s paused). Null values will be treated as 0w. One calculation isn’t necessarily correct or incorrect, but we do feel we’re using standards that most athletes would agree upon.
We understand our athletes use hundreds of different devices and apps and are doing our best to accurately analyze each file regardless of the differences in file formatting. We’re always working to improve our athletes’ experience, and we will pass this feedback along to our engineering teams.
The Strava is a central data container that I use to sync with TR and Riduck. And all those data are different to my bike computer device.
I think almost power meter ignore the 0W by default, so the answer from Strava disappointed me a lot.
Anyway, I won’t extend my Strava subscription next year.
I think this might be one for the “unpopular opinions” thread - including the zeros is the method most people agree is the most usefull. Strava is going with the mainstream view here.
If i held 300w for an hour up hill and then coasted bake down for an hour - I wouldnt say I averaged 300w for the ride - but thats the answer ignore zeros whould give.
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