I’m reading Skiba’s book right now and I think he makes a terminology mistake a couple of times. He defines LT (lactate threshold) as the first threshold but sometimes he says “lactate threshold” and it seems like he’s talking about the area around FTP/CP/LT2.
He also says something that doesn’t make any sense on pg 36:
‘Some people refer to LT (GET/VT1) as anaerobic threshold (AT)’
Then he goes on to explain that the lactate threshold is not anaerobic (without oxygen), etc. It just seems like he’s trying to be academically correct here.
I think he’s wrong in a sense. People do call the 2nd threshold (CP, FTP, VT2, etc) the “lactate threshold” but they aren’t confusing it with the 1st threshold (Aet, VT1, etc).
It would have been helpful if he had not used LT but rather LT1 or aerobic threshold. It would be a lot less confusing.
Otherwise, it’s a good book so far. I recommend it for any wannabe physiology nerd. It’s also written at a fairly easy to understand level.
So I’m wondering if most people who move their curve to the right are just improving vo2max, which is why hr stays stable at either threshold. In the fitter version of you, lt1 is still x% of vo2max.
If you are truly changing the shape of your curve and increasing your fractional utilization, does that not change the hr at your thresholds? It appears very fit individuals have relatively high hr at their tested thresholds, but haven’t seen what those are as a % of hrmax. Robert has said that his hr stayed the same, but his max has significantly changed.
I’m under the impression LTHR (at least) doesn’t change much*. My N=1 and what I saw from other riders lactate numbers (from a former coach) led me to believe it does not. But I suppose there could be situations where it might? Not sure.
* much = if I go from 161bpm to 163bpm I don’t care (for example)…but maybe I should. Some ppl are discussing the change as if they’ve gone from 130bpm to 150bpm AeT HR. Something is off with way that is being communicated to me.
Also assuming you are thinking “inflection point” definition of LT1 and not some fixed value (in which case it very much might change).
Recollection is during my LT1 experiment 1 min and 5 min power didn’t move a lot. At least not any more than I’d expect from overall aerobic fitness gains. LT1 shifted right nicely. It took a specific block to bump 1 and 5 min powers.
Note I wasn’t specifically testing 5 min or looking for VO2max proxies so no real data (sorry!!)
The guest on That Triathlon show this week had a young athlete who came to him with a Vt1/LT1 of 135bpm. After an extended block of his Z2 training, it improved to 160+. He did say however that the guy had a VO2 max of 90!! He had just never trained at a low intensity.
Then there’s the question… is 5 min power still a good proxy for vo2max? As olbrecht woukd use capabilities at low intensity to define capacity, while “aerobic power” workouts were used to increase race pace, they did not increase capacity as he defined it. Seems quite counter to what many other studies show, but the takeaway message for me was that max pace is trainable relative to other metrics. Ime increasing power or pace at vo2max pulls everything else up so I’m still a bit skeptical of his notion.
He considers MET to be gold standard for determining AeT but claims this self-assessment is 95% accurate of MET results. This is the thing I was going on and on about above. Just seems to me like a way to establish a sub-threshold steady state, not necessarily approximate AeT/LT1. I think that is valuable in and of itself but not sure it is the “aerobic threshold” we all keep saying. Happy to be wrong but I’m not sure AeT HR really goes up 20bpm, etc. (see spanish U23 data above). Maybe it would right off the couch?
To do this on a trainer, I would set ERG mode to a power you think is close to your AeT. After 20 min warmup (or whatever it takes), ride for 60mins and then look at HR drift post ride. As he states, you might have to repeat if less than 5%, but it’s sub-threshold so why not. Doing an assessment like this outdoors or trying to use a “long ride” as a surrogate would be misleading/wrong, IMO. You really have to clamp power. This isn’t Friel’s “am I done with base training” thing.
edit: to your point though @redlude97 I think Skiba (and others) LT is higher than LT1. I think we have to remember his concept (not unique to him) came about prior to (and sort of competing with) the idea of MLSS.
I don’t know if this works? I know I can ride sweetspot 60min with a PW:hr less then 3. Done it on alpe du zwift…So I don’t know if this drift test is the way to go (for me).
So…Ok. let’s say my LT1 power is 220w at 140bpm. If I would ride 2.5-3h at 220w my HR should not be higher then 147bpm (5% diff. PW:hr)
Ouch. Hard ride
I read that blog post years ago, skipping to the end it states:
0–3.5 percent: The workout was within your aerobic intensity zones, but you should do the test again at a starting heart rate that is 5 beats per minute (bpm) higher.
So they suggest ratcheting up to a higher heart rate on subsequent test. Over time I’ve done it at a wide variety of durations and power, just a few examples:
3 hours at .73 IF (140bpm)
2 hours at .79 IF / 1.02 VI with 0.05% decoupling and then I ran out of road and water on a hot day (148bpm)
~1 hour at 1.00 IF / 1.00 VI with <3.5% decoupling and HRavg just below lactate threshold HR (156bpm)
Those were outside, I’ve done them inside as well. At least for me, its not the best functional measure of my aerobic fitness. Not sure what going a lot longer would accomplish, perhaps it would be interesting if I was doing full distance triathlon.
Here is a 50+ minute (51:33) threshold effort outside, about 10 days after a 20-min field test that bumped up my FTP:
That last one has 1.005 variability index and decoupling of 3.1% at a temp of 68F. Honestly I don’t think its misleading or wrong, or that I should reject the result and go inside to “clamp power” using Erg.
It is after all a Functional measure of aerobic fitness.
Make it not stochastic, temperature controlled and repeatable. Understand that it is an assessment so don’t use an old ride if you’re not confident about hydration status, sleep, stress, etc.
. But that’s ok. Overthinking too much already…will let this sink in…
