Help with VO2 Training sessions

Hi Everyone, I have been on the Trainerroad Train for the past 10 weeks, switching from Training peaks and Zwift programing before that. Im sold on the TR methodology and have been performing better in my rides and races in just the 10 weeks then I have before using on other training sessions.

I am on week 2 of my specialty block and the VO2 sessions are kicking my a$$. Im finding it hard to complete them and have been chopping them into two sessions of 45 min in the am and pm just to get through them. Is this normal for everyone else? Im comfortable with the suffering but I want to make sure this is normal.

I usually try to take in a Gu or other source of 25-35 carbs prior to the session to eliminate any type of nutrition energy issues. Using a Wahoo Kicker on ERG mode.

This mornings session was 5 blocks of 5 min at 315 watts. My FTP is at 287 currently based on Ramp and also AI from TR. I make it through 3 blocks ok but blow up on round 4 and 5 with HRT at 177 and my Max is 182.

Any advice will be greatly appreciated.

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I wouldn’t try and game their system. Just do the workout and rate it accordingly. Otherwise the system cannot adjust.

For some riders, 120% above threshold can feel easy (high anaerobic capacity riders). For others, even 105% can feel very hard. Most of us land in the middle somewhere.


Last night I had a similar experience. The last interval my cadence sunk below 40 and I had to back pedal about 3 seconds to finish. My HR was still only 94% of max. I too was on ERG mode. I realized after I finished that I probably should have come out of ERG mode for my last interval or 2. For me it’s my legs that give out. I’ve got plenty of wind. I’m not really sure what that means though. Probably a lack of sufficient muscular endurance.

Switch off ERG!


Thanks, Not wanting to game the system. I really enjoy the fact when I see the AI doing its job and adjusting me up and down in workouts.

I just wanted to make sure Im not missing something. I guess Im in the lucky group of 105% feels hard. :slight_smile:

Or your FTP is a tad optimistic and that 105% is really 110% or more…

Or you are lucky to be in the predominantly slow twitch group and will be a good endurance athlete but not a sprinter.


Quoting to second this, TURN OFF ERG!


It may or may not directly help with the VO2max session issue, but the OP should consider how their threshold and sweet spot sessions feel. “Challenging but sustainable for a while” is about how I’d describe them. If threshold feels unsustainable, then they might consider setting their FTP a bit lower.

The other thing I’d raise is, how experienced are you (said to OP) and how experienced are you at VO2max sessions? Look, riding at or near VO2max power sucks. It hurts. You can get used to it. But if you’re a new rider, then at least part of the problem may simply be that you aren’t used to it yet. I’m not on TrainerRoad, but I understand you can select an easier session - you could consider doing this if you truly can’t manage the session recommended. I’d recommend not splitting the session up. Over time you will HTFU.

Last, and this is totally me being an internet pedant, but VO2 is simply the volume of oxygen you’re burning. It’s the amount of power your aerobic energy system is generating. For example, at rest, most people burn about 3 mL of oxygen per minute per kg body weight. VO2max is the maximum power your aerobic energy system can generate, usually measured in mL O2 per min per kg. A VO2 interval … technically doesn’t have a meaning. A VO2max interval means an interval done at or near VO2max power. Of course we all understand what you mean by VO2 interval, this is just me being me.

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Lots of great points already in this thread. A few things to add:

  1. VO2 max intervals are hard, like really, really hard. This especially holds true for longer ones like 6 x 4 min or 5 x 5min. Decrease the rest interval and they are even harder. I told one of my coaches in the past that the workout I did (5 x 5min) was “really hard” and he responded that it should “feel like death”. If you are hanging on by a thread towards the end, you did it right.

  2. ERG Mode. I strongly agree with switching it off. Even better, try and do these outside. Hold what you can and if your power starts to fade still finish the interval. Your heart rate will stay up and you are still getting the benefit from the interval as long as you keep pushing it. Don’t think of it as failing the interval, rather by finishing it you are going to get stronger and reap the benefits in future workouts. This is really critical as the magic happens late in the intervals and also during the repeats.

  3. Emotional committment. VO2 max work takes a strong physicial committment but there is also an “emotional” investment in doing them, especially doing them well. Think of them as both physical but also mental trainging sessions that are going to make you stronger. Try to come into them fueled and rested.

  4. After a VO2 block, it’s amazing how much easier Threshold starts to feel. Working extended times at Threshold has always been a challenge for me, but the times I am best at them is coming off a bunch of VO2 max work.


Thanks for everyones input.

Im not a new rider (plenty of ramp test, century gran fandos, XC MTB racing Cat 3 and just placed 3rd in hincappie gravel a few weekends ago) but I wouldn’t say I a cat A rider either. I never thought about switching off ERG mode, I will give this a go in my next session. As one described above, these are not impossible for me to complete but they are pushing the limits for sure. I just wanted to make sure everyone is feeling this way and I wasn’t missing something and pushing a lot harder than was intended.

Im fairly seasoned and training energy systems but never pushed into VO2 system training very much for cycling.

I may need to beef up my “emotional commitment” and just get them done.


Unless you’re going too hard to complete the intervals, this isn’t really possible. With ~1/3 of the interval left you should be breathing out your eyeballs and wishing for death or the interval to end, whichever comes first.

Definitely agree with the points above about turning off ERG. Erg can have it’s benefits but for many types of workouts I think it can lock you into a less than great power profile. For VO2 workouts, the power is just the driver of getting you do that state of VO2max where you’re breathing like a fish. The actual wattage number doesn’t really matter (but can be used to judge adaptations or fatigue). You will likely start high and start to taper as the interval goes on. And you will also likely have higher power at the beginning of the workout from the end.

If you have the option, these are definitely mentally easier outside. Our brains are much better at chasing a point in space than it is watching a timer. So if you have a hill or stretch of road that you know is 3,4,5 min to a certain point then it can be easier. Just be careful about being on an open road while having limited mental capacity for navigation.


Circling back.

Took some of the advice of moving these sessions to outdoors and made a huge difference. Thanks for all the help!