You can see why I use Friel HR zones… but some use Coggan, and some use their own zones. From talking to my coach (he has over 50 athletes), HR zones can vary quite a LOT and therefore need to be individualized.
Interesting. Idk my Ftp at the moment, anywhere from 240-255 I would say…
Your LTP is 68% of your mFTP…I’m at 78%-80%.
This type of rider profiling is key IMO…
That’s not bad, though. Less than 10 watts off and it gives you an idea of where to start “looking” for your lower threshold. And that’s only from power data. I like it.
The WKO mFTP is 268-269W after a strong push for 32 minutes at 276W where I ran out of road and daylight. So it wasn’t a max effort to failure.
Xert LTP is 70% of 272 which is 'what my coach gave me for not going to failure" estimated FTP.
Tried this for the first time today. This is a transition/rest week after finishing 16 weeks of building so have been playing around with all sorts of various benchmarks/tests - I have done a ramp test, a 1hr time trial, and now this AeT all within the past 7 days.
Using this method and a cutoff of 0.75, I got a VT1 heart rate of 149.75 bpm, with a fairly wide margin of error mind you. I took the raw data that the HRV app gives you (in a CSV file in dropbox), and plotted DFA alpha1 as a function of HR, fit a linear trend line, then solved for HR value at DFA alpha1 of 0.75:
This is in keeping with the value I would use from RPE, and is also my HR that I can literally sustain for all-day bike rides (longer than 20 hours at a time). I had also done a 1-hour time trial the day before this, and this HR value for VT1 is 83% of my LTHR (based on max 1-hr HR, VT2 HR, and RPE, all of which agree to within 1bpm), and 76% of my max HR.
During the testing protocol, I noticed that changes in on bike position had a significant impact on measured DFA alpha1 (see figure below). Despite only having 1 artifact removed during the whole test, you will note that points A, B, and C below are significant outliers. Point A is when I first switched from the hoods to the drops. Point B is when I read an email on my phone.
Point C is interesting because it’s when I deliberately tried to vary my heart rate significantly by intermittently breathing very slow, then quicker than I needed.
As expected, there is poor correlation as to my power output at this threshold. Within the past week week alone, my power output during an interval at least 10 minutes long that had an average HR of 150 has been anywhere between 201w and 233w. This was true even when you removed the impact of any cardiac drift by solely focusing on intervals within the first hour of a workout, when drift was less than 1%. Major confounding variables here seem to be caffeine intake, time of day, sleep quality the night before, as well as how fatigued I am from recent workouts.
How about this ?
Of course it will work reliably all the time and produce valid data. Take a look at the power meters. That is the future of any sports data gadget. Something between meh, at least it is consistant and random number generator.
We were using noninvasive tissue lactate monitoring in pediatric ICU about 10 years ago. I don’t recall what mechanism they were using for this at the time, but I’ve always been surprised that we hadn’t seen this used in sports wearables yet.
I’m guessing this company is using some sort of electrochemical biosensor to detect lactate with their product - Biosensors based on electrochemical lactate detection: A comprehensive review - ScienceDirect
My guess is they are taking advantage of the correlation between sweat lactate levels and serum/tissue levels, and actually measuring sweat levels - https://pubs.acs.org/doi/10.1021/acssensors.1c01009
Reading through I saw this didn’t have an answer so hear are my .02
HR staying stable is more or less the oxygen required at the workload is stable and your heart is able to deliver it. Decoupling later in a ride (when it’s not the slow component) I would assume to be that your muscles are requiring more oxygen. Why would that be? I think it’s because as you fatigue you start accessing less aerobically trained motor units to provide the wattage. Less efficient = more oxygen usage.
If by fractional utilization you mean higher % of vo2max at LT1 and LT2. HR is only one variable of cardiac output. Your heart can also increase it’s stroke volume which would deliver more oxygen per pump. Also blood volume contributes to stroke volume; its one of the first things to return after time off and base training. So you could produce more watts at the same heart rate. This could mean your vo2 max has increased but its not a definite. Vo2 max is measured by how much oxygen is USED and not how much oxygen CAN be delivered. Its the reason vo2max is measured higher in XC skiing vs running, then biking, then swimming. More muscles being used means more oxygen demand. It’s like having a lambo in bumper to bumper traffic.
So when you are increasing your fractional utilization you are increasing your ability to consume that oxygen that is being delivered to your legs. That can be capillary density, thinner/longer muscle fibers?(fuzzy on that bit), type 1 fibers, or more mitochondria density.
So although heart beats and stroke volume are important, more beats or bigger strokes are pointless if oxygen utilization is unchanged.
Whoa whoa whoa!
Wait no you’re right. 
Although up till recently I wasn’t coaching for profit anyway, and never really intend on “making a living” from it. It’s a side gig/passion play, and it is fair to say I learn more than I’ve ever given here anyway.
@kurt.braeckel I have interacted with you off and on since I first joined (Fall 2018) and have not once thought your contributions were motivated by anything other than a desire to learn, inform, and participate. If you happen to pick up a few athletes along the way, awesome (coaches FTW, and coaching if you want to win lol 
)
Frankly I think that is what motivates most of us who are still around. Kudos 
To me it’s really obvious when it gets too far away from the exchange of experiences and ideas.
Thanks, that is why I’m still here. I learn a lot, and it makes researching interesting things a lot easier when there are others out there already doing and thinking about these things. There are several really, really good threads on this forum that I’ve gravitated toward. Tremendously valuable discussions go on here that have nothing to do with TR, so I’m glad they allow us to have the forum to discuss these ideas!
And disclosure: I’m still a long grandfathered paying subscriber even though I rarely use the platform anymore. Still good to be up on what goes on with it as many of my club mates use it and ask questions about it.
So this season and last I’ve been mostly spot checking lactate levels during workouts to monitor workout intensity for some key workouts. A big change for me this year is using a Cp estimate from the 3 minute all out test. It’s difficult to execute inside on rollers, but from what i understand, as long as w’ is exhausted by about 2 minutes in, power reaches a stable reading.
Also I’m using a block training method of planning my microcycles, started with z2 focus, then tempo, just finished a ss block and will move on to a vo2 block next. This is inspired by the classic data about adaptions to a new stimulus occurring within 1 to 2 weeks then stabilizing after about 6 sessions.
Progress is coming along nicely, i definitely need to work the middle zone due to my muscular phenotype. Wrestling and skiing favor glycolytic energy systems and in general mountain biking does as well.
Lactate after 95/105 sets went from 8 mmol down to 6 and lactate at 75% of my ftp estimate was still right around baseline (1.5 mmol for me).
So for my estimates of lt1, i was using point were respiratory rate goes above 15 which appears to be just the inflection point in my lactate curve. I will want to do a running assessment soon to see if my curve has changed shape since i last did one of those for running a few years ago.
15 watts below my Cp estimate seemed a really good point to use for training, it was definitely higher than a ramp would have estimated, but no workout was ever in danger of failure.
Real quick (don’t want to stray off topic) but what did you use to get CP? Two efforts? Three effort estimate? Or something based on 3 mins that I’m not familiar with?
I’ve blocked them all by not being on Twitter.
Since you did the nscyd test i thought you were familiar with the overpaced 3 minutes Cp estimate. I’ll try to say overpaced from now on instead of all-out. It’s a horrible 3 minutes, but when compared to a ramp test i recover from it much quicker.
I am familiar with that. You’re right . Cool