@Neil_Partridge you’ll often see people on this forum say that VO2max is not a power number. It’s a physiologic state. You can go harder than VO2max.
If you want to know what VO2max ‘feels like’, calculate your heart rate reserve by subtracting resting HR from max HR, hop on the erg on free ride, crank up the power to 280W or so & ride until your HR gets up to 95% of your HRR. Then lower power 5 watts, wait 30 seconds, re-evaluate HRR…keep doing that.
[so for me, TR thinks my FTP is about 300W, my resting hr is 45, max hr 180, I would set power to 320W & ride until my HR is 172 or 173, reduce power 5 or 10 watts, ride for 30s, re-evaluate HR, etc]
You can go on for many minutes in this fashion but power will gradually go down. Even though power varies you’re always riding VO2max. That’s what it feels like. Now, re-evaluate Pisgah (which, btw, is not a 1.0 VO2max workout. It’s 5+ so more of an intermediate VO2max workout in the pantheon of TR VO2max workouts). Is that how Pisgah felt?
I’m not really sure how a “TR VO2” workout differs from a “normal VO2” workout. But as others said, the purpose is generally to elicit a state of maximum oxygen uptake and expansion of heart stroke volume. TR has to walk a line of making the workouts ‘complete-able’ and difficult. Lots of people would see ‘maximum effort’ and go sprinting off the line on the first interval and then blow up. So sometimes they aim a bit more conservatively to hit the meat of the bell curve where an individual coach can tailor the descriptions to their athletes.
That’s because endurance adaptations are generally driven by duration as opposed to intensity. You also are sometimes fitting the endurance rides around your more intense rides. So yeah you might actually see a little more aerobic adaptations at a high Z2 vs a low Z2 but you might also perform worse in your threshold workout the next day because of it. And increased Z2 adaptations would be less than the potential gains from the threshold workout. So the preferable tradeoff is lower Z2 and then really nail the high intensity.
I guess I’d question what the point of a ‘sub max’ VO2 workout is. IMO, that’s just a hard ride that elicits a ton of fatigue but doesn’t get all the adaptations of a maximal effort VO2 workout.
In the end, VO2 just means “Volume of Oxygen” so you could say that any and all riding (or even just sitting on the couch) is a VO2 workout since you’re always consuming some volume of oxygen. But the state you are trying to elicit and gain adaptations from with these high intensity aerobic workouts is an increase in your VO2max and you won’t stretch your VO2max by going submaximally for these shorter durations.
This - forget about the power numbers and focus on cadence and pushing yourself as hard as you can for the time. Rest up and repeat. I like to do mine on the rollers without looking at power, just timed intervals.
I really bought in to that “max power” or “fish out of water” idea for a while. Going in with cadences like 110rpm and stuff.
In the end it just made me quit and hate the workouts. I now do 5x6’ or 4x8’ efforts (in erg when inside and i feel like it) and do it much more sustainable with regular cadences. Maybe just about reaching that “fish outa water” feeling in the last few minutes of the last few intervals. Rather then trying to be in that state as soon as possible.
I believe you then still get most of the adaptations of those EC-like workouts but at much lower cost. And being able to it multiple times a week without dreading them is worth it for me.
Btw, it being 5 to 8 minutes intervals it is pretty easy to adjust ERG a few watts when needed, especially between intervals. The first one to easy? Up it 5W for the next. To hard, 5-10W less.
Edit to add: I also reduced the rest intervals to just 2-3 minutes, rather then full recovery.
Keep in mind that not all VO2 Max workouts are specifically designed to increase stroke volume. This is why I wish there could be a different name for this power zone – as not all workouts have that same goal.
Traditional VO2 workouts in the 3-4 minute range are designed for this, and, therefore, adhering to a specific power target isn’t necessary. Many new athletes aren’t going to have the knowledge, drive, or discipline to pace a 4-minute interval at their true VO2 Max in resistance mode, though, so if we can dial in their power at VO2 Max, ERG mode will work well for them, and I can attest to that.
As for the other types of VO2 workouts, stroke volume isn’t the #1 goal, and, therefore, sitting at VO2 Max for 3-5 minutes isn’t necessary.
Well, let’s agree to call it “zone 5 workout” or “105-115% intervals”, and then use “VO2Max intervals” when we’re talking about them. Everybody agrees that it’s confusing, but just continues to use the same terminology… seems like insanity.
If TR is detecting your FTP and then serving you up a V02 workout where you are not even getting halfway through the first interval, I would first check for a discrepancy between your indoor and outdoor power meters.
The outdoor power meter could be pushing your detection number up relative to what your other PM reads indoor.
I have a friend that can only do low level TR workouts because his outdoor PM is hot (or the indoor one is reading low).
When I was doing these on the road without a PM, I had to deal with HR being a lagging indicator. So I’d ramp up intensity to get around 150+ bpm, then start my timer and punch it. If HR made it over my threshold before a minute or so (roughly 163bpm) and still climbing to near 170, that was a success. (Btw, I’m 50+yo, so yes, my ranges are lower than you 20yos with hummingbird hearts.)
Now I let erg do the thinking. The first 30 secs of the first interval I’m usually like “Not bad”. Once I’m on the last or second to last interval, the last minute is getting desperate. I’m just concentrating on pedaling, breathing, and using the distraction tricks in my bag to make it to the end.
So question—is it vo2 max work once I hit the watt target, or once my body is physically showing signs of being in debt? Are they both valuable workouts—zone 5 watts, and also just go at a pace you can barely hold for 3 min?
Totally agree, if the goal is not to raise VO2 then it’s not a VO2 workout. Coggan levels be damned.
But I think this was kinda my point. There isn’t really any pacing. Other than not totally blowing up in the first minute (which is as easy as “don’t do 200% ftp”) the power is totally secondary and only really matters to track progress or fatigue. You just go as hard as you can and then hold on. Power will usually naturally fall but you’re still going as hard as you can.
Yeah I can get that too. I tried to get to that without getting side tracked with why TR does it the way they do. In the end, TR has to give you a power target because the whole SW is based on it. And that might work for most people and get you most of the way there. Some people find this easier but I just find it easier to go out and go as hard as I can for 5x3 or whatever without worrying if ERG is set right
I don’t usually split hairs of tracking ‘time at VO2max’ but that will always be lower than the time in zone of the workout just cause, as you mentioned, it takes time to get to that state. But for myself, I usually target around 15-20min in the power zone (5-6x3min or 4-5x4min, etc) and I’d guess like 1/2 to 2/3 of that is around VO2max where the ‘real work’ is being done. Based on my breathing being ragged around 60-90s into the interval.
It totally depends on what you’re trying to get out of it. IMO, doing 6x3min at 110% FTP when you could have done 125% isn’t going to be that valuable for a decently trained athlete. You’ll get some exercise and be healthier for it but you’re getting most of the fatigue of the harder workout without pushing the limits required.
There are other reasons for Z5 workouts like repeatability and such that might not be pushing VO2max that are useful but not all Z5 workouts will be VO2 workouts. The key is to just know why you’re doing one over the other.
VO2 max range watts are TR-defined as 106-120%. From my calendar, my vo2 max workouts in the PL 4-5 range have been a mix of durations with watts from the low end to high end of that range. So it seems TR is trying to progress me up the duration and watts, which makes sense. Agree there is a point for the highly trained athlete that the dose is maxed.
And back to the OP, there is a learning curve to VO2 Max workouts. You never know what you can do until you try, and neither does TR. If you bail with 2 intervals left and say too much intensity, it will dial things back for you next time. If you crush all intervals and say you still could do another, it will give you more next time. At some point in the interval or set, you should be gasping for air, and your body will be begging for you to stop. Ignore this and keep pedaling. I rate them Hard if I had one more interval in the tank (prove me wrong!), and Very Hard if I think that was absolutely the last one I could complete. Max Effort is when I have to dial the watts back or cut something short/out. I’ve not finished any VO2 max and thought “Moderate”.
My mental tricks include disassociation from the discomfort “I am not my feelings. My body is a container for my feelings”, Curiosity “Maybe I can finish this interval”, Math “halfway there! 4/5th there! Another 30 secs and there’s only 1:30 left!”. I’ll visualize a race scenario, either hanging on someone’s wheel or trying to create a gap. Sometimes I’ll close my eyes and count breaths, and might stand for last few seconds. High intensity music.
Just to clarify in my OP, the main reason I stopped was it was too hard to maintain the watts well enough to prevent the ERG death spiral. I appreciate it’s supposed to feel very tough but I ended up not able to turn the pedals.
Lots of good responses above. For what it’s worth, as a reasonably strong masters rider with over 550 hours on the bike so far in 2025, having to do 3min repeats of 123% FTP would scare me. I get about half of my VO2 work in Zwift races.
I also want to add, that it matters why you are doing VO2max in the first place.
The more I’ve looked in to this the more I’ve come to this conclusion: There are basically two reasons to do VO2max sessions, because you’re looking to improve either:
Central (Cardiorespiratory) Adaptations (raise the roof)
And as far as I’ve been able to tell, the choice mostly depends on the ratio of FTP / VO2max power. If FTP/VO2max is <0.80 then it is best to seek Peripheral adaptations, if FTP/VO2max >0.85 then it is best to seek Central adapations.
Ad 1
You need to increase the body’s ability to deliver oxygen to working muscles. Increased stroke volume is an important adaptation here. Central adaptations occur when the heart is working near its maximal output (≥90% VO₂max). So you want high oxygen demand per heartbeat, sustained for 10–20 min total in a session. Best intervals are the 2.5 to 5 minute range with enough rest to repeat the cardiac efforts. You want to look to get HR > 90% halfway through the intervals. Higher cadence may help here.
Ad 2
You need to improve oxygen utilization, muscles’ ability to extract and use O₂ efficiently. You want sustained high aerobic flux in the working muscles — not necessarily max HR. Peripheral changes happen when muscle fibers experience prolonged metabolic stress just below or at VO₂max, where mitochondrial, enzymatic, and capillary adaptations are maximized. Best intervals are 5 to 8 minutes long with limited (2-3 minutes) recovery. HR rises more slowly and may only hit 90-95% at the end of the intervals.
Rule of thumb:
If your HR won’t climb high enough: Train central (shorter, harder).
If HR is easy to max but legs fail early: Train peripheral (longer, steadier).
For me, now early in base, I’m looking to target peripheral (muscular/metabolic) VO2max adaptations, and because my goals are Gran Fondo’s and multi-day endurance events this is also my overal aim for the season. Although I might still plan a central cardiorespiratory VO2max blcok when I get my FTP significantly >85% of VO2max (5min) power.
This . Then you begin to crave the way you feel after successfully completing the session (maybe an hour or two later as I’m finally pulling myself off of the ground next to the trainer, having titled my Strava for the ride with skulls and coffins). It’s almost a high. I dread the crap out of the sessions and they totally require a lot of preparation–mentally and with rest/nutrition/hydration. If you can get to the 4th set out of 5, you are there. You slam a gel, dump the rest of your water on your head, you don’t hear the music anymore, the fans aren’t providing relief, it’s the final climb of the race and you are with the lead group, why give up now? As much as they suck, the ability to dig deep both mentally and physically will help you during a race. I did Chequamegon this summer and absolutely went to the grave riding up Firetower Hill, maybe a 4-8 minute effort to move forward and not lose traction. Everyone else was walking but I kept pedaling, mouth was foaming, eyes crossed with black spots, face tingling, ears ringing. Don’t fear the sensations. Made it over the top, recover just like the rest intervals and be ready to go again when needed.
I rate them Hard if I had one more interval in the tank (prove me wrong!), and Very Hard if I think that was absolutely the last one I could complete. Max Effort is when I have to dial the watts back or cut something short/out. I’ve not finished any VO2 max and thought “Moderate”.
. Then you begin to crave the way you feel after successfully completing the session (maybe an hour or two later as I’m finally pulling myself off of the ground next to the trainer, having titled my Strava for the ride with skulls and coffins). It’s almost a high. I dread the crap out of the sessions and they totally require a lot of preparation–mentally and with rest/nutrition/hydration. If you can get to the 4th set out of 5, you are there. You slam a gel, dump the rest of your water on your head, you don’t hear the music anymore, the fans aren’t providing relief, it’s the final climb of the race and you are with the lead group, why give up now? As much as they suck, the ability to dig deep both mentally and physically will help you during a race. I did Chequamegon this summer and absolutely went to the grave riding up Firetower Hill, maybe a 4-8 minute effort to move forward and not lose traction. Everyone else was walking but I kept pedaling, mouth was foaming, eyes crossed with black spots, face tingling, ears ringing. Don’t fear the sensations. Made it over the top, recover just like the rest intervals and be ready to go again when needed.