I think I saw in a different thread that you are mostly a cycling guy but one question. Is there any thought to including running efficiency and decoupling using GAP instead of cycling power? I use those values with much excitement for cycling would love to see them for running. Especially with the addition of normal bands being added for fitness charts.
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That is planned. I am going to add “pace duration” and “GAP duration” curves similar to the ones for power and eventually decoupling and similar stuff using the pace info.
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Is this still planned? Would love to see it for running without having to use power!
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i believe you can now do this yourself via “computed activity fields”
check out the thread
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This is currently very important to me because I’m coaching some athletes that don’t have power. Just wanted to add my +1 as a supporter - it’s a sorely needed feature 
A reference here, although you probably already know it - The Efficiency Factor in Running | TrainingPeaks
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I have just created a custom activity field for this (GAP/HR). Other people have created several different running efficiency metrics some based on heart rate reserve. You can find all of these by clicking “Custom” under the activity timeline chart and doing search:
The calculation for this one is simple:
You need to add it to each athlete. Older activities need to be re-analysed to pickup the new field. Easy to do this from the activity list view:
Choose “Edit” and “Re-analyse”. Tick the “Keep existing intervals” box.
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Thanks @david, I’ve been playing with these (and I appreciate the new field, simple and clear). It’s just that the Power activity page is so useful, it goes beyond a flat efficiency/decoupling measure. I hope at some point we get a similar Pace page 
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Been playing around with this too. But I don’t understand why anyone would want to use HRreserve. If your resting HR is elevated, which usually isn’t a good thing, the efficiency factor would be higher…
Can someone who uses it like that explain me what the purpose is?
Are you referring to this shared field?
I think the idea is that (average HR - resting HR) better reflects the level of effort exerted on that day than simply average HR.
As for a resulting higher efficiency factor: Imagine that you match someone’s GAP and average HR but they have a lower resting HR – they required a higher increase in heart rate to achieve the same speed as you. You could say you’re more efficient.
With that said, I’d rather just follow Training Peak’s formula as it’s easier to understand and should result in less variance.
Is there one of these custom metrics using exactly the TP formula?
No, because the NGP formula TP uses is not public. See this for a more in-depth discussion:
With regards to EF, I believe David’s GAP/HR is the closest you’ll find here.
Some more info and an approximation (??) of NGP in these links:
In general, the Strava GAP model seems quite close to NGP for uphill terrain. On downhill terrain, there’s a bigger difference where Strava inflates the pace more then TP’s NGP.
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