VO2max: time in zone vs. % ftp

I have been thinking a bit about training vo2max.
How about time in zone vs. % ftp.
I find 4 min @ 120% almost impossible.

Effects of?
16 * 1 min @ 120% ftp
8 * 2 min @ 115% ftp
4 * 4 min @ 110% ftp

Thoughts? Research?

A lot of people do, it’s hard. However, there are a few key points of VO2 which might help make your intervals more “enjoyable”.

First, your personal VO2max might be anywhere from 110-130% of your FTP. TrainerRoad et al uses 120% because it’s a general average, a good place to start. Having said that, if your personal max is below 120%, say 116%, then yeah, those 4x120 intervals will have you screaming.

Second, like anything else, if this is your first foray into VO2 intervals, it’s probably not a great idea to jump right into the ‘gold standard’ 4x120 intervals; as above, they’ll have you screaming. But, like anything else, your VO2max is trainable so you have to train it, which means a lot of discomfort. I’ve read that it can take between 8-18 months of training to max out your VO2 ceiling but that your lower percentages can still be trained upward after that point. You can definitely start out doing the 110%ers to get the adaptations going but if you want to really grow your VO2, you will have to do those higher intensity intervals at some point.

Third, you are getting only half the picture by looking at only work time; you also need to consider rest time. It takes about 90 seconds for the body to drain of oxygen (unscientific layman’s terms here!), so any interval 90sec or less won’t really be working the VO2 system, even though your power meter says it is. The longer you deprive your body of working without oxygen, the longer your rest period can be – 4min on, 4min off. With the shorter intervals, say 1min, your body hasn’t entered a state of VO2 as it were (90 seconds remember), so your rest times must be super short – 1 min on, 20-30 sec off. This way you slowly drain the oxygen, so if you do 16x1min intervals, you might start doing actual VO2 work half way through. The longer intervals will give you more total time of VO2max adaptation than an equal time of shorter intervals: 4x4min@120% = 10 min @VO2; 8x2min@120% = 4 min @VO2.

I’ll also make a big assumption that you’ve tried only the 4 min 120% intervals and that you might change your view on their impossibleness after giving a block of 16x1min 120% intervals a shot. :wink:

That’s my $0.02…which might only be worth $0.01. :man_shrugging:


Thanks a lot for your answer! Given me a lot to think about

Did some reading:
Fredrik Ericsson(Swedish coach for among others Alexandra Engen) says 2-6 min intervals @ 106-120% ftp(or intervals of type 40/20). Says that max stroke volume comes after 1-2 minutes. Total 15-30 minutes. Heart rate above 90 % hrmax and for well trained athletes 95 %.

Allen & Coggan says 3-8 minutes(often lower end of that spectrum). Doesn’t give preferred % ftp but
gives examples of 6 * 3/3 min @ 117 % ftp or higher,
5 * 6/5 min @ 110-115 %, 6 * 3/5 min @ >115 %, 6 * 3/3 min@ 120 % + 4 * 2/4 min @ 135%

And Seiler seems fond of work @ 108% ftp…


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