How would you interpret the D numbers on the intervals? Some are positive and some are negative.,
Joe Friel to my knowledge is the coach that introduced aerobic decoupling to a wider audience. There are still some 10+ year old blog posts discussing application. Originally he used it to determine when it was time to progress from early base (zone2 riding) to adding tempo and sweet spot.
I use it after taking a break. Look for decoupling to drop below 5% on 2 to 3 hour rides. Then I stop using it for anything, however I do keep reviewing it all season.
NP/HR can only give you a positive number.
I mean more the Decoupling numbers on Intervals. I don’t have a guide on how to interpret them… might have to look for this Joe Friel post @bbarrera has seen.
Sorry, really need to learn to do this stuff myself… but totally new to working with decoupling and I’m kinda just bored and looking for a new plaything with it. See the D values in the two 50min blocks, they have different values, some are - numbers.
Intervals actually breaks the intervals 50/50 so I have 4 decoupling values over the two efforts.
Interval 1
0%
1.8%
Interval 2
4.1%
-2.1%
Second interval is crazy, goes from 4.1% to minus 2.1%!
Can I read something from that?
Hmm, intervals.icu wrongly identified your long 50 minute efforts as three separate efforts? Surprised it didn’t break the second 50 minute effort into 4. That’s what I see.
Ah yes, the break in the second one is when I went through a mini roundabout… was literally just a few seconds I slowed and stopped pedalling… didn’t think it would cause any problems for it.
Use that route a lot, its excellent and flat, just has that one bit that you need to chill for. I go up and down it… so usually twice I hit that bit.
Wow that’s amazing. Was expecting a one-liner like, ‘can’t tell you anything’ go do 90min intervals (which I really didn’t want to hear).
That explains why when I was looking at the two intervals it read to me like something was wrong in interval 1, or like it was harder… penny starting to drop now on what this decoupling stuff means.
I think I’ll do what bb said earlier… maybe use it more on long steady state rides, like 3hours or so, get a feel for base fitness.
Put in some pro-volume 20 hour weeks recently, don’t hate me, hate the free time I’ve had during lockdown 
Thanks again btw, you and @bbarrera are great here, you guys could write books on this stuff.
And both names start with BB funnily enough 
@Shrike per my earlier comment I only find real value in using aerobic decoupling after coming back from an off-season break. In 2019 for several reasons I had very little or no cycling during the May-August time period. It took about 6-8 weeks for my decoupling to drop below 5% on a long tempo ride. For example:
- 2nd week: 17% decoupling on a 2 hour zone2 workout (TR’s Virginia) on trainer
- 3rd week: 4%, 7%, and 4% decouplings on 2 hour zone2 workout (TR’s Gibbs) on trainer
- 4th week recovery week for TR’s traditional base
- 5th week 3% decoupling on 2.25 hour (TR’s Warren)
- 7th week -3% decoupling outside tempo (only 1 hour tempo of good data)
- 8th week 0% decoupling on Wed night 1.5 hour zone2 group ride (off the back with another rider) and Fri afternoon 2.25 hours of outside tempo (both rides mid October and temps 90F / 32C)
This was coming back after many months off the bike, and yet the decoupling quickly dropped on 2+ hour workouts inside and outside even with warm temps and I’ll mention my ‘indoor’ trainer is in the garage and I train after work during the heat of the day.
My only advice is to a) toss out the first 20-30 minutes (warmup), and b) toss out any non-steady portions, and c) if you have a X hour event, lets say 5 hour event, then doing a longer steady ride of similar duration and looking at decoupling gives you an indication of aerobic “base fitness” for that duration. Its a simple metric and given your results so far I’d say its of limited value. On the other hand if you had >5% decoupling on 45 or 60 minute zone2 then it would say a lot more.
Hope that helps.
A common theme i see through a lot of comments in this thread is how decoupling is being used. In respect of a single workout, its just a metric and not much can be gleaned from it. It’s usefulness is in tracking it over time and seeing how it changes when you look at workouts of similiar time/intensity over a matter of weeks.
What you should start to see as your aerobic capacity grows is that decoupling is reduced for the same power target.
Hmm. that may be individual because I haven’t seen that. Here is an older post talking a bit about it:
and the pic from that post
a couple of notes:
- that is for a segment that started after a 15-25 minute warmup
- focusing on time period from November 2016 thru April 2017 my aerobic capacity increased substantially in March however I have a December 11th effort at 0.99 IF and -4.3% decoupling
Here are my two ‘worst ever decoupling’ effort on that segment, one happened just 2 days ago:
May 2020:
9.2% decoupling as part of a 3x15 tempo with bursts workout.
April 2021:
8% decoupling on a non-steady state 4x4.5 minute zone5 ‘controlled vo2max’ (not full gas) intervals.
to be honest i’m not sure what i’m meant to make of this data.
You’re comparing decoupling between rides of varying power targets and therefore getting varying decoupling results.
The portion of my comment you quoted excludes the most critical part
the majority of those are at threshold, just mentally ignore the three non-threshold (IF of 0.77, 0.73, 0.84) workouts. Therefore all but three of those rides are basically at or near FTP, and with basically no decoupling. IMHO the data tells a story.
In other words, all but three are:
- at same relative intensity
- on the same course and time is relative to the amount of headwind
- over a period of many months
- over a period of increasing aerobic capacity (late 2016 lower aerobic capacity compared to March/April 2017)
Putting decoupling into a zone bucket, workout by workout. Workouts with a low VI, say 1.05 or lower, means it was close to a ‘pure’ zone workout for that segment:
my n=1, after establishing basic aerobic fitness my decoupling is usually below 5% on zone2 / zone3 / zone4 workouts. My hypothesis for the negative numbers is that the warmup includes a hard effort a few minutes before the start of the segment, and heart rate settles down over the first few minutes of the segment.
I’ve seen similar trends on other workouts, with a longer warmup and then a long steady tempo effort.
All of that is a long winded explanation with empirical data, that I’ve found little value to using aerobic decoupling as a general purpose metric during a season and across seasons. However it does help me after an off-season break.
Your Mileage May Vary (YMMV).
On a related note have a look at the “Power vs Heart rate” chart on the /compare page. Your power vs HR curve shifting right (more watts for same HR) is a very nice indicator of improving fitness without have to do any tests. Intervals.icu does a lot of data cleanup to produce good data for that chart.
agreed thats why I called it out.
No. Its a 10.8 mile (17.4km) Strava segment that I recreated in WKO. There are a couple of ways to get to the segment, and different wind conditions, and several traffic lights and a railroad crossing, so thats why I said 15-25 minute warmup. And to be more precise, it has always taken no less than ~15 minutes to get to the start of segment and usually about 17 minutes minimum.
The chart in previous posts shows all my efforts on that one segment. Looking at VI and IF you can see for yourself there are fair number of “pure” threshold efforts (IF around 1.0 and VI <=1.02) and the resulting decoupling for ~50 minute effort is low. Now I hope we can agree that ~50 minutes is a LONG effort at threshold, and it isn’t possible to go much longer.
The last pure 10.8 mile effort on that segment was a year ago (March 31 2020) with an 18 minute warmup:
and then 51:07 at threshold, based on an 20-minute field test from 9 days earlier. So that is 100% FTP effort for 50+ minutes.
Removing the first 15 minutes, in other words making it a ~33 minute warmup:
and the decoupling drops even lower (from 3% down to -0.2%).
And I agree with you that longer, lower intensity efforts are likely best for using aerobic decoupling metric. For example doing TR’s Conness, a 165 minute (2:45:00) indoor training workout at 60-70% FTP as part of Traditional Base on Mon/Wed/Sat of the same week (Oct 2018), I had decoupling of:
- 0.3% (84F / 29C in garage)
- 0.6% (79F / 26C in garage)
- 2.8% (61F / 16C in garage)
My conclusion, after reviewing decoupling data from all rides since getting a power meter in October 2016, is that after early base I’ve seen incredible consistency in having relatively low decoupling almost regardless of temperature for efforts from long 2.5-to-4 hour zone2, ~2 hour tempo / zone3, and ~50 minute threshold zone4 efforts. One difference between the UK and Northern California - I routinely ride in 90+F / 32+C temperatures and I have acclimated to working out in warm temps. YMMV.