Zwift Build Me Up-Sunk by LOX VO2 intervals

Hi - I am into week 7 of this aged 53 and casual cyclist / spinner / my FTP is set at 260 and I found early weeks hard especially at higher cadence - then became more manageable - UNTIL last night in LOX - I could not complete the 5x3min VO2 at 300w I had to pause for 20 secs after no 4 and had to plough through number 5 at 85rpm

I didn’t quite hit highest HR and maybe was having off day but it would seem that my VO2 performance is below par - would you advise doing some extra VO2 work around the program ? Hoping someone will say no but suspect some hard work to do!

Don’t worry about always hitting the cadence targets. You won’t fail the workout and it gives you something to practice going forward.

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Hoo, I’ve got that to look forward to myself in a couple of weeks.

Zwift gives you credit for completing a workout if you successfully complete 80% of the intervals in it. So I would assume that you got credit for completing the workout. (You also need complete 80% of the workouts in a plan to get credit for the plan itself.)

I’d look at it this way: These plans work because they progressively stress various different systems within your body. Circulatory, muscular, aerobic, etc. There is no guarantee that each of these systems is going to respond and modify at the same rate as all the others. You may very well have reached a plateau in one or more of your systems (perhaps, as you suggest, your VO2 max.) But there may very well be room for growth in the other systems. IOW: Keep going.

As far as scheduling additional training to make up a potential VO2 deficit? I wouldn’t, at least while you are continuing with the BMU plan. Additional training is going to place additional stress on your body - right at the point when the intensity and volume of the workouts in the structured plan is reaching a peak. That strikes me as counterproductive. And, even if it weren’t, I think the time scale required to significantly train your VO2 max is such that the Build Me Up plan would be over before you saw significant results from attempting to increase your VO2 max.


I wouldn’t do anything extra during the programme as it’s pretty tough as it is. I’ve recently completed BMU and found LOX and 15.9 to be amongst the hardest sessions (I can’t remember which of these is more difficult). I managed to complete both workouts but I was absolutely on the ragged edge during the VO2 max intervals. I had done a few 5x5 sessions at a lower power in the weeks before I started BMU so perhaps that helped me.

Maybe the best thing to do is to think of it as an area to work on, and try both of those workouts again once you’ve finished the plan - it may be overtraining/fatigue that affected you in this case. I can’t recall any of the later sessions being similar to LOX so I don’t think you’ll be facing the same problems as you move on through. I really struggle with microburst type sessions and therefore I decided to skip Breakfast Returns. It’s an area I need to improve so hopefully I’ll be able to work up the motivation to try some of those sessions again (at some point!).


thx - I made it through 15.9 but died on Lox albeit my HR was 2 beats lower in Lox- think was probably bit tired from 1.5 hour on Sunday - todays Giza looks easier and rest tomorrow