So I’ve been looking at efficiency factor recently since it got baked into intervals.icu (for the uninitiated it’s normalized power divided by HR). Like aerobic decoupling it appears to be a measure of aerobic fitness, if you see higher EF during a ride then you’re aerobically adapted. I’ve been looking at my pettit workouts the past 5 weeks and they’ve all been 1.4, while my sweet spot intervals tend to be around 1.6-1.7. Now if I’m understanding correctly, EF doesn’t necessarily give insight into potential changes in FTP, but just base fitness? If so, then it makes sense why my EF is so steady since I’ve maintained aerobic fitness, even if not top end stuff, all year.
Anyhow, based on search results, this isn’t something that’s been discussed around here, so maybe we can get a good chat going and others can dig into this for their own riding and their aerobic fitness assessments.
I think that is actually a bad example and article by Joe. Making any observations on improvement on two or three days of training period is obviously meaningless. Over longer period of time, say month and more, sure, you can see differences in your efficiency factor. On a day to day basis, there are so many factors, from external, like temperature, humidity, to internal - sleep quality over last night or several days, food eaten, workouts done before, etc that impact heart rate.
I would suggest reading another article by Joe, which, in my opinion, is much better representation of his knowledge on this topic.
Decoupling is a metric for seeing improvements to aerobic endurance during base. The article you linked has good information about that, and how to use on long intervals to determine when you’ve established good enough aerobic endurance to move from base to another phase of training.
EF is about how efficiently you generate aerobic power, which changes over the course of a season. Its the topic of this thread and in The Cyclist’s Training Bible there is a functional aerobic threshold test. Joe suggests doing this test every 3-4 weeks, year round. So EF is used to track aerobic fitness over a season. And in the article I linked, EF can even shed some light on short-term trends.
As Joe suggests, for aerobic fitness over an entire season you should track EF. Use decoupling during base to determine when you have established enough aerobic endurance to move into next phase of training.
I guess what I am trying to stress and where Joe is providing bad example is that using workouts within short period time cannot be used with any confidence when determining whether there are any EF changes or not. Even workouts month apart might not be providing a good picture of any improvement or lack of it due to all factors that affect HR. I would suggest that one should always try to look at a bigger picture and longer trends then pay attention to any one or few workouts.
As Seiler rightfully points out in his presentations, one workout is probably 1/300 of workouts completed over year and obviously even lesser part of work completed over few years (that take for adaptations to fully occur). We should try not to make too much of assumptions while analyzing any short term changes because it might be misleading.
Coming back to EF and decoupling, I agree that those are great tools to measure changes of performance in time and also identify performance requirements required to be successful at certain levels. There is article analyzing Will Barta’s progress to WT level and his coach states that to be successful at u23 level rider has to have ability to a) Be able maintain 4w/kg for ~4hours with HR decoupling less than 5% b) After those ~4hours still be able to punch 20mins @5.5-5.8w/kg. That really gives some perspective on how good those guys are and that’s u23, at WT level fatigue resistance will be even higher.
I’ve enjoyed looking at the EF numbers in intervals.icu as well. My EF numbers are similar to yours (1.4x for endurance rides and 1.6x for sweet spot rides). As an interesting observation from a 60 minute FTP test yesterday, my EF for the 60 minute interval was 1.45. I thought it showed that sweet spot work is also the sweet spot for power / HR efficiency whereas the relatively small increment to ride at threshold power had a pretty large increase in my HR and was less efficient.
My question regarding EF is: it is an objective number? Can we compare our EFs and brag about it?
Let´s say one cyclist “a” has a factor of 1.8, and another cyclist “b” has one of 1.4. Is “a” better than “b”?
My assumption is that this is not the case, since HR values are different for everyone. But perhaps it could work with percentage of MaxHR. i.e. 190 NP / 60% MaxHR = 317 and 200 NP/ 60%MaxHR = 333 .
EF is an individualized number, meaning the only way to brag about it is to show that yours has improved relative to you.
maybe something convoluted like ΔHR reserve / MAP in W/beat/kg could be compared between individuals? But it’s probably better just to try and improve your own relative numbers, whatever those numbers are.
Sry if I dig out this old topic (and even more so for personal advice )
Just yesterday I did a 3,5h endurance ride (70-72% ftp super steady) and I while I’m pleased with the decoupling of 0.8%, I find my ef to be pretty low with 1.32 (however I really don’t know what is “good” for an ef)
So what would that “next phase of training” be? Working on muscular endurance (e.g. with low cadence tempo work)?
It looks like you’re in pretty good shape if your decoupling is 0.8% .
Regarding EF, it’s pretty meaningless to compare between riders - it’s entirely individual. It only looks at power and HR and not at any other characteristic of the rider. A big heavy rider will likely have a higher EF than a light small rider (would expect him to have a higher FTP) but might have a much lower w/kg.
It can be useful to track improvements over the course of a year. As regards improving it, pushing your FTP up over the course of a season will likely bring up your EF. What approach to take will depend on what you’ve been doing previously. Changing stimulus can be very effective.
If you’re looking at sweetspot there’s some great information to be found here or alternatively you could try threshold work.
Actually I’m looking to enhance muscular endurance and I’m not 100% sure how to approach that. While my aerobic system seems to be fine (worked only 15 months almost exclusively on that ) , my legs feel pretty tired after 2.5h endurance
There’s a thread on here I think about Steve Neal and his philosophy of lower cadence Tempo work to augment endurance and improve muscular endurance. Have a search and see if anything comes up
In the sweetspot progression thread you’ll find different progression to boost your time in zone at sweetspot. Eg going from 4x10 mins, 2x20 4x15, 2x30 → up to 90mins for some of them I think. If you can get your muscular endurance up to that level then holding endurance pace beyond 2.5 hours will be absolutely no bother to you.
You can also join a team that has produced sweetspot workouts that you can substitute in for your TR workouts. They won’t work with adaptive training (as yet at least). I can’t remember who I should credit for producing these .
Sweetspot
Scroll down to ‘newly added’ and click ‘view all’ to see the full selection of workouts.
In fairness to TR they’ve upped their game massively in terms of progressions. You can probably find alternative workouts within their structure to maintain AT if you’re in the beta.
I was rummaging around the stats on intervals.icu, and came across efficiency factor as a metric. It’s a new one for me.
On the face of it, I think it’s a great way to measure your own progress, but it doesn’t stand up well when comparing athletes. If you’re very big and put out a lot of power (like me) then your efficiency factor is really hight (mine is between 2.2 and 2.9) but that doesn’t actually equate to being especially fast on the bike.
But of course, if your EF increases over time, you are getting more efficient and that’s great. It just isn’t worth comparing to other people unless they are of a similar age and weight.
You just need to make sure you’re comparing EF for the same sorts of rides, because HR doesn’t track linearly with power. Your EF at 90% of FTP will always be higher than your EF at 70% of FTP.
)
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(worked only 15 months almost exclusively on that 
) , my legs feel pretty tired after 2.5h endurance 
.