Is my outdoor VO2max workout effective long-term?

A few months ago, I had a bad crash doing VO2max outside. So now that I’ve built back up to doing VO2max, I decided to do them on a steep hill to keep the speed down.

I wonder about opinions regarding this last workout…?

Here is the workout in the context of the entire ride:

And here are the details:

What troubles me is the cadence. The hill is steep enough (around 20% for a bit) at the start that I’m grinding away at less than 60 RPM, with high torque (over 60 for a bit) although it eases off towards the top. As a relatively weak, early 50s rider with a suspect left knee, I think this is probably not a good idea.

Although it certainly feels like a good VO2max workout, am I really getting an appropriate aerobic stimulus from this hill, or should I find my courage and go back to a flatter area where I can spin at 90+ during over-threshold efforts? I know I’ll get some good short-term gains from doing this once per week, but perhaps I’m shooting myself in the foot with this low-cadence, out of saddle grinding?

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Have you tried VO2max intervals indoors? Is your cadence low as well?

Regarding the intervals themselves, if they are meant to representative, the power is a bit low. If you do 3-minute long intervals, you should be around 120 % FTP, not 110 %.

Lastly, you mentioned you had a bad crash while doing VO2max work. It is essential to have suitable routes for each workout type. Especially hard VO2max workouts and hard, long threshold intervals require concentration just to meet your power targets. Navigating terrain and traffic can become difficult. I prefer to do such hard workouts indoors.


Thanks for the tips. Yes, I can do (and have done) them indoors, but in the summer heat/humidity, I want to exercise outdoors as much as possible. I like to do the workout as part of a longer, pleasure ride since I’m not a bike racer and performance comes second to enjoyment.


Is it optimal long-term to maximise gains? Probably not. Were you breathing hard, gasping for air? If yes, then it’s good vo2 max workout. They are rather low on power given low cadence but as long as breathing is there, do what works for you.

I’d disagree with @OreoCookie. 120% isn’t a hard and fast rule. 110% looks like it’s working for you at the moment. You seem to be hitting you heart rate goal (assuming your HR zones/max are set correctly). It looks like you start your intervals hard, which is good as it ramps your HR up quickly.

Personally, I find that returning to VO2 work the first couple of sessions I’ve no bother hitting HR goals. After a while though it gets a lot harder. You’re going to need to extend the duration of the intervals and use a higher cadence to help drive up HR. So I’d prob look for a shallower hill. If you have something between between 4% and 8% near you it would be perfect. It’d make it easier keeping your cadence up.

Strava can be handy for finding segments of suitable length.


It feels like a good VO2max workout for me at this point. Just worried that I’m missing something by not spinning at a good cadence.

I think that’s what I will do. Especially since this is gravel and if it rains it’ll be a mess.

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Buy a new larger cassette if you want more control of the cadence (I ride 32-11). Looks like a solid workout to me.

Your question made me lol. You say your a 50 something who might hurt their knees at low cadence. But you’re also a 50 something who crashed at faster speeds!! Seems like knees are a fair trade off to keep it upright! Stay safe and good luck


I have a local hill (actually a full set of hills) that is suitable for supra-threshold intervals of up to four minutes, it’s about 5% max grade. The road is quiet and was resurfaced a year or so ago so is really smooth and no potholes.

The first interval is a test to see if I’ve got the intensity right, for VO2max work I should just be on the point of quitting. I remember where I got to, then back down and repeat. If I’ve judged the first effort correctly then I’ll usually hit that spot within a second or so for the rest and don’t need to look at a head unit or think about anything but hammering that effort. Since all the intervals are pretty much same time and distance then the power is the same.

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If you are not a racer, then perhaps training is not as important. Currently, I’m not racing either, but I still want to train properly. However, if you want to hit your numbers, I think you should adapt. Whether that means choosing a more suitable route or hill or doing part of the training indoors and then have the pleasure ride outdoors, I don’t know.

Before I joined TR, I’d do hill climb repeats. Picking the right hill was essential, and I had one nearby that was quite suitable, but not perfect. There is one traffic light, for example, and the incline isn’t steady, so there is an element of pacing involved if I want to minimize times. (At the time I did not have a power meter, so that wasn’t an option either.) On the plus side, at the times I would train there was very little traffic. Evidently, rather than spend 3 minutes at a certain wattage, I’d just go up the hill as fast as I could for 3, 4, 5 times.

I am not sure whether your low cadence is the result of fatigue or unsuitable terrain, but if you have to grind just to make it up at VO2max power, your hill just might be too steep.


I actually just finished listening to this podcast from Kolie Moore today and at least his PoV is cadence is important for good VO2 work. The basic gist that I got is that the adaptations you’re after with VO2 work (primarily increased stroke volume) are best stimulated by high cadence (~110rpm) as higher cadence at the same power results in greater cardiac output and triggers the heart to adapt in more long-term helpful ways.

For anyone who really wants to dive down the rabbit hole:
Podcast link: Watts Doc #23: Training Your VO2max, and Why Not Rønnestad 30/15 Intervals - Empirical Cycling

One of the main studies he references: Cycling cadence alters exercise hemodynamics - PubMed

That said, if you’re just getting back into it, and don’t want to sweat it too much, any work that gets you breathing hard is probably good, but I would think 60rpm grinding on suspect knees is to be avoided. I’ve had a lot of knee problems myself and generally try to avoid anything above Z2 or 3 at lower than 85rpm.


Trying to understand the bad crash. Was this heading back downhill after a VO2 Max interval? Personally whenever I do VO2 work out side I pick hills in the 5-8% range.

I don’t have power outside, thus just go by RPE, and calibrate on first interval. Looking for heart rate to hit 90-92% of max after 4-5 mins.

Sounds reasonable. I might continue this a week or two, then go back to a more sensible cadence.

In the 5th interval, near the end, I went through a bad section of curving road where there is only one safe line (because of water-filled potholes). Due to fatigue and complacency (and distraction caused by passing a loose dog a bit earlier), I somehow missed the safe part of the road and got onto the loose, gravely shoulder. It was completely avoidable and unnecessary, but like @OreoCookie alluded to:

I had been through that section of road multiple times, and I knew how to do it successfully, but at max aerobic, I wasn’t thinking clearly. I came off the bike in soft dirt/gravel, and landed head/shoulder first onto a guardrail at 25mph+. The bike was fine but my helmet was trashed.

Here is what a crash looks like on my Garmin lol:

I managed to ride home at the end, with some help from some good guys, then spent 4 days in the hospital.

This road where I crashed isn’t the best for fast riding (at least for me). Thankfully, I have a safe, straight section of road (with negligible traffic) where I can get about 3 minutes, I will use that in the future (even though I am loathe to make a fool out of myself with high-intensity exercise in front of all the joggers and dog-walkers who frequent that area).


if you are training for events and other rides outside, it would probably be a good idea to still do some high intensity training outdoors while you are on rides by yourself, so that you regain that confidence to smash it when with others.

Just find a slightly shallower climb and go crush it! I agree, the cadence is a bit too low and grinding

Good luck!


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Many people do VO2max intervals on small hills. That not only reduces your speed — and hence, the minimal length of the segment, it naturally gives you recovery time when you coast down the hill. Do you have any hills like that in your vicinity?

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I’m definitely stronger/fitter this week. The workout execution was better, but I didn’t get much time in the HR zone. It still felt like a good VO2max workout though.

Tree cover messes up my GPS which turned on the auto-pause a couple times.

Garmin says my cycling VO2max is 52 for what it’s worth. I don’t know what good it does me to know that number, but yeah.

Two days ago, I climbed a hill and I may switch to that hill since it’s a bit better cadence-wise. Traffic might be a problem though. This was the hill:

Or, maybe I’ll go to the relatively flat section where I can get 3 minutes safely. But I want to do my original hill at least one more week.

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