Pure base = not above zone 2?
Mostly. Did only one weekly session with sprints fairly regularly. On shorter endurance rides I did a brisk initial 5min effort after reading on its effect on fatox. Apart from this no real intensity. There were a few days with fun elements though. However, nothing structured until January.
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Have you messed around with the DFAa1 in HRV logger yet? I’d be curious to see what your results are given you have actual lactate measurements.
Not with the app but with the initial Python notebook. Not really sold on it. As with everything HRV related too much noise in the data. Would like to play around with Kubios but I don’t have access to the premium version with the relevant filters. Without these there are simply to many artefacts in my data. And it’s not overly reliable in my opinion. The published papers look good but it’s always difficult when you transfer to the field. And in the end, my La measurements are so consistents that I have a lot of faith in them. Once you understand what impacts the absolute values it’s a great tool. Power, heart rate, La offers a lot. I see why the NOR triathletes get tested so much. Especially in the field.
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Gotcha, thanks for responding.
I’ve found good success using the Polar H10 and doing testing with it indoors, but I don’t have access to lactate, hence my interest in it. I can’t imagine it’s very accurate using outdoor data due to the noise.
Yes over in the Twittersphere there are comments that using it for outdoor running is a challenge whereas on a treadmill it’s fine. I’m using it a lot on my turbo and getting few, if any artefacts, using the HRV logger. The thing I am finding is that it appears to be very consistent giving me me my LT1 generally within the same 10W range… Anything outside that tends to coincide with poor sleep, fatigue or just not feeling right on the bike.
Somewhere in this blog by one of the key researchers of HRV/LT1/DFA a1 is an article on what makes Kubios the “gold standard” and what feature of the premium version is responsible for this. If I remember correctly it has something to do with artefacts removal.
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Yes, just like the python script. In the blog index there’s a comparison of Kubios vs Python Nb, and the author concludes:
- The above python implementation seems (based on very limited data) to parallel that of Kubios.
Cheers
I’ve definitely noticed recent diet can be a difference between a baseline at 1 mmol and 2 mmol. That’s why point estimates for any of the thresholds aren’t comparable.
Its also pretty clear ism is having his guys train at the very top of z2 like right at the z2/z3 border, i.e. 1 mmol above baseline. Z2 probably starts more like .3 to .5 above baseline, so theres a wide range of 30-50 watts when using those measurements for z2.
I think I’ve confused myself. To confirm, when you and others are referencing this z2/z3 border being what ISM has his athletes train endurance at, you’re referring to coggan power zones? so about 75% ftp? Or are you referring to standard 5 zone hr model? Thank you
Referring to Coggan zones.
In reality, most zone systems (be they HR or power-based) implicitly acknowledge their roots in lactate measurement. LT1 is a phenomenon that occurs in the lactate curve during various ramp tests. Because of this lineage, fitness zone systems tend to use this point as a demarcation or in some other way afford significance to it. For example, Coggan decided that right around that point (with normal distribution) he would draw a (basically) arbitrary line between to ranges of intensity.
We’ve been debating about it ever since.
ISM himself is going to do a full lab work up and skip the FTP thing. Because of the obvious desire not to do that among most amateurs, we’ve been trying to ascertain various field tests to get at this LT1 like thing, which is mostly an act of faith, since we don’t really know what to do with it once we have found it.
But there are quite a few anecdotal experiences about riders training right at it and improving.
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I see, thank you for clarifying! I’ve been wondering if my HR zone 2 rides have been too easy. Seems like they might be
Mine were in 2019. I’m one of those guys that if I “go by feel” I don’t go too hard. I tend to go too easy.
Doing long(ish) rides at .73-.78 IF is not too easy. 
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Uh oh, garmin had my last endurance ride at an IF of .61. Guess I better up the intensity
Yeah, to throw another anecdote on the pile I see my biggest improvements by a long shot when I do the majority of my endurance work around 75%.
I do find it really difficult to do outdoors though- the terrain around here means that the descents drop my IF pretty significantly if I’m trying to keep it steady on the climbs, and not being the most bike-friendly of areas to start with I’m yet to find any routes where I’m confident ripping the downhills to keep the power up. In the past the extra hours during the summer has sort of made up for it, but that’s becoming less and less sustainable as volume/fitness increases.
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This is interesting and has really got me thinking about IF for these z2 endurance rides…
I’ve done a solid block of about 3 months of mostly z2 riding with a max of 1 weekly session at 105% or so, and some weeks only z2 work. I’ve not really paid any attention to IF and just made sure I was doing 2.5-4hrs of steady pedalling and usually coming home with an NP of around 65%. Th gains have been impressive and I’ve gained around 15w at mid z2 HR compared to the end of 2020.
have done a couple of harder rides recently though - really hitting the IF 0.75 boundary for 2-3 hrs and, as others have said, its a MUCH harder ride. On a training week of 15-16hrs its going to take me a while to significantly increase the time at that IF in a way that doesn’t wipe me out. At the end of last week I was feeling good and went out with the idea of doing ‘some’ work at IF 0.75 but came home 3.5hrs later having done about 3hrs pretty constant at that intensity after feeling really good for 60 miles. I really felt it the next 3 days though!
I’m still mentally debating how much the value-fatigue ratio will work for adding this kind of work? I’m pretty much at my weekly time limit as I approach 20hrs a week though, so something needs to change though I guess 
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I would disagree. The 5 zone hr model is supposed to be: z1 < lt1, z2 @ and around lt1, z3, “threshold” middle zone, z4 @ and around lt2, z5 > lt2
ISM describes his bread and butter endurance target as a physiological point around vt1 based on his description of doing the metabolic testing. Despite what obndy says, an r of .7 is not random but a good but not great correlation between lt1 and vt1.
So his prescription is at the very top for a 5 zone hr model if you have them set properly for your hr response.
We’re agreeing. “z2 @ and around lt1”. In other words, LT1 is in some way used in zone systems that are not based on lactate. That’s my only point.
Ime, the coggan zones dont match up well with hr zones, only really z4.
In the context of my post, i was talking about top of hr zone2, or 80% of max hr.
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