I tried HRV Logger and was doing 10w increments and after 6 or 7 DFA alpha 1 went a bit bellow 0.75 but i continued and it went above…
Do I need to use first value as LT1 or the value where DFA alpha 1 stabilised?
How long was each step? They should be 6-8 mins so values stabilise. Otherwise I’m not really sure as all my tests have been pretty easy to interpret and I haven’t seen this issue I’m afraid.
6min. after third measurment I increased power
Same here. My test (have to do it again) gave 145bpm and 220W, that is in my Z3 zone (low Z). But I will re-do my test this week.
Interesting thread indeed. In my shorter endurance rides, maybe I focus more on time just below LT1. But for longer endurance (3h+) I will try to ride around 185-200W. Still base period so…
Bruce Rodgers has said in his blog somewhere that 0.75 is an average of where LT1 falls, some people might find it at 0.8 say.
Ran DFA Alpha1 analysis on a lot of data over the last two years, and ended up at around 142bpm and 81% HRmax / 89% LTHR. Right at the top of my Friel Zone2-HR and about the middle of Coggan Zone3-HR.
Also, the data for inside workouts collected using Garmin 530 and Dual HRM is super clean with few if any artifacts.
Same here based on DFA alpha1, however I have no lactate data to collaborate those results.
Using percentage of FTP (which is usually based on another percentage) to deterimante zones is practical and fine for a lot of people but for some is not even close… I did a lot of lactate testing and ride analises and found that is not strange to find upper zone two to be for example 260w and FTP to be 290w…
On the other hand I currently have an athlete who cannot hold 170w without big HR drift but doing 4m intervals at 420w…
My last lactate test was end 2019 (every 3min +40w). But I think it overerstimated my LT1.
0
10min 100 1,36w/kg 110bpm 0,8mmol/L
13min 140 1,90w/kg 120bpm 0,5mmol/L
16min 180w 2,45w/kg 128bpm 0,5mmol/L
19min 220w 2,99w/kg 149bpm 1,0mmol/L
22min 260w 3,54w/kg 164bpm 2,6mmol/L
25min 300w 4,08w/kg 174bpm 9,5mmol/L
28min 340w 4,63w/kg 178bpm 10,5mmol/L (peak at 178W and 313W)
It stated my LT1 at 160bpm and 255W and my LT2 at 170bpm and 280W. So that seems very high. 280W is around my FTP but that 255W. I don’t know if it is correct. But maybe with some good testing for the dfa A1 maybe I can get a clearer result. And I am now fitter then in 2019, certainly my endurace as normally have increased to because did more volume in 2021 en 2022.
Do you use Runanalyze for analysing your files? Or what software do you use?
Having done some lactate testing myself this sounds like a recipe for inaccurate results. Also I wouldn’t necessarily think that results from a lactate test over 2 years ago are still valid.
Step duration was too short and power increments too big.
I use 5-7min for step duration and 20-25w increments.
There are a lot of methods but I found that you should look the curve and then find best method. Usually is around about 1mmol above lowest reading (not rest value)
You should be well warmed up and not be eating at least while doing the test (but I would suggest even 2hr before)
Yep - I use 6min steps, with (depending in athlete) 15-25W increments (sometimes confirmed with a MLSS test, but rarely).
The Colab notebook and similar code on my laptop. Every indoor and outdoor ride is recorded on Garmin 530 and dual HRM.
Interesting…seeing these big individual ranges makes it even harder to make sense of one’s own data interpretation…
Did you have any quick recommendations for those 2 showcases given above?
(Like more intensive/raising the roof work for number 1 and more long slow steady state endurance for number 2.)
Yes, will give a follow up with some N=1 anecdotes (maybe in the sweet spot progression thread)… 4 VO2max workouts done by now and so far happy with that experiment…
I made a test yesterday with a 6 min/step ramp and found my LT1 at 75% of max heartrate. It feels correct to me as it’s the point where breathing started to change. That’s the upper limit of endurance zone 2(out of 7) if you use heartrate.
However, the LT1 power I reached during the test is 82% ftp, in my mid-tempo zone.
My question is: Do you use the LT1 test to change your endurance zone ?
Additional info: my ftp was tested 3 weeks ago. I’m definitely slow twitch, most of my rides were done at 75% max heartrate in the past years, rarely going above. I only started doing intervals and using power zones a few months ago. Endurance zone feels really easy, more like recovery on a heart point of view.
For people using the Colab workbook, do you get the .fit file directly from your bike computer?
I downloaded mine from Garmin Connect but there didn’t seem to be any HRV data in it.
Edit: Silly me, I had HRV logging disabled.
No - dont change zones - just remember where it fell and if/when you decide to do specific sessions targeting around LT1 then you can use those numbers.
The 7 zone model is not anchored around LT1.
I did not. But I don’t really use a time in zone model to guide my training.
If it helps: prior to thinking about LT1 (and reading ISM training concepts), my training was essentially a sweetspot based model. Standard stuff where easy rides were recovery, long rides were just riding along and then sweetspot/threshold and supra threshold. Look at TR SSBMV2, general build, and that would be an approximation. My prior coach was a sweetspot / threshold guy and we were targeting 15-35 min time trials.
Incorporating LT1, I moved some of that SST/Threshold time down and some of that easy recovery time up. It would sound cooler if I added more detail and had a nice progressive overload scheme to share, but didn’t do anything fancy. Just time in and around LT1 with some harder days ( “stuff” ) thrown in, some race approximations, and accumulating as much time riding in and around LT1 as I could.
Remember to factor in duration. Yes, during that 6 min/step ramp you found a power and HR that corresponded to LT1. But you were (presumably) fairly fresh and the test didn’t take that long. So yeah, .82 IF wouldn’t be outside the realm of possibility. At the beginning of most of my LT1 rides, my power is sometimes 20W higher than previous assessment for about 20 mins or so. It then levels. If I go long enough, it falls 
(of course, right? lol)
Try this: ride at your LT1 HR (75% max) and let power just come (or go). Clamp HR and you will not hold .82 IF forever.
Agree with this. Don’t mix or try to reconcile different zone systems, you’ll be stuck on the internet too long if you do that.