I’m guessing I’m not the only one that has noticed there’s a regular difference between the TrainingPeaks NGP and the Strava GAP. I understand that each company has a formula it uses to calculate these and they decide what that formula is. What I don’t understand is how they are regularly so far off! For instance, I got out on two feet yesterday and ran a few intervals. There was a 1 min steady effort that differed by 1:00 min/mi on the pace (only -1 feet of elevation change). That was an extreme case, but the longer efforts (10 min, 5 min, etc.) were in the 10s/mile range different.
It seems like TrainingPeaks has been the gold standard in training analysis for quite some time, but I also feel that Strava has been investing a lot in making their product better and better. This could be a Strava PR thing, but I recall several months back they announced they were updating their GAP calculations because of all the data they’d been receiving. The TP info I can find is all from 2008, but appears to have a more scientific backing. It also appears that Strava is the one that is regularly faster than the other.
So, what does the peanut gallery think? Does anyone else notice this difference? Is one more accurate than the other?
I wouldn’t worry about GAP or NGP at all unless you train your run specifically by pacing zones. If that’s the case pick the one you use for your training evaluation vs social stats. I’ve never really noticed the TP NGP before, but the Strava GAP is usually minus a few seconds from my average pace on a route where the start/finish are in the same spot.
I only use pace zones for run training… which can be problematic mid-run, so I end up going by feel for a lot of it especially when hilly. Had mixed results with a HR monitor back in the day so just decided to drop it altogether. At this point my coach goes with TP so that’s what I compare run to run.
All that being said, I’m just wondering why there’s a large difference in the two.
As an (unpaid) Strava promoter, I am a huge fan of GAP, though it has a couple limitations:
Sometimes Strava routes/segments have GPS inaccuracies that make GAP wildly inaccurate. You’ll get used to where these are if you run the same routes and see routinely unrealistic GAP paces.
It estimates too fast (in my opinion) on steep uphills and too slow on steep downhills. A 4:30 down might be a 6 min GAP, while I’ve seen 4 min GAPs at 8:30 pace.
Other than that, I think it’s an awesome tool to equalize hilly running! My 4 mile uphill tempo GAP and my 4 mile flat tempo pace are shockingly similar (with GAP a bit faster because I think it tends to be overly optimistic).
I wouldn’t worry about GAP or NGP at all unless you train your run specifically by pacing zones. If that’s the case pick the one you use for your training evaluation vs social stats. I’ve never really noticed the TP NGP before, but the Strava GAP is usually minus a few seconds from my average pace on a route where the start/finish are in the same spot.
That makes sense because the hills make the route harder than if it was perfectly flat (which is the adjustment). Do a really hilly course and the offset can be over a minute!
Yeah I did a run last week were I was going along at 7:0X mile after mile then hit a huge hill and dropped to like an 8:30, but the GAP for the mile was the same as my other efforts on flatter terrain for the run.
So I would say there is some merit to whatever algorithm they are using.
Yeah I did a run last week were I was going along at 7:0X mile after mile then hit a huge hill and dropped to like an 8:30, but the GAP for the mile was the same as my other efforts on flatter terrain for the run.
So I would say there is some merit to whatever algorithm they are using.
Thanks for the anecdote! I’m friends with some of the employees for Strava Run, and they work really hard to make the metrics work and also to be responsive to what people ask for.
What I’m asking for next is Gender/Age-Adjusted Pace! I think it’d be great for women and masters runners to see how awesome they are relative to the lame 26-year old men.
A few things can cause the differences with the big one being differences in elevation source/correction (and noise) and then of course the actual formula for calculating NGP vs GAP.
Regardless it (NGP or GAP) is really only useful for rTSS calculations (Strava training load), comparing a flat run to a hilly run, and when reviewing a training run with intervals not run on a track. On it’s own, like any other metric, it doesn’t tell the whole story.
When talking to your friends, always use the faster number
