As an example, if you had just done 5x 5 mins at 108% and were thinking about progressing to do more time at 108%, which would you choose to do? Why?
A) 5x 6 mins
B) 6x 5 mins
Both options give you another 5 mins at 108%, but they can seem like very different beasts to battle.
Fewer but longer reps, while slowly adding total time at power, is the typical approach. At least for building sustainable power.
If the goal of riding 108% ftp is to have time at vo2max breathing, then 5x6min is better than 6x5minute because the additional minute tacked on the end of the 5min rep (to make it 6min) is at vo2max breathing, whereas the initial part of your wouldbe 6th 5min rep is not at vo2max breathing because your body works up to that breathing rate throughout the rep.
I’m basically saying 5x6min gives you an additional 5mins of vo2max breathing whereas 6x5min gives you less than 5min, to what degree less, idk.
This is all theoretical about how vo2max training intervals works, but it’s directionally correct
The previous answers align with my thoughts on this but I also think this is target race/event dependent. For longer efforts - adding time makes sense and you could also shorten the rest interval. If it’s repeatability, then adding intervals would make sense too. Then you could also keep time the same and add some intensity.
Probably depends on your power curve or natural strengths/weaknesses. Had similar question last year – don’t race, only consideration was time spent at intervals vs achieved VO2max HR time. Tried various interval combinations (12x2, 6x4, 5x5, 4x8), each with highest sustainable power for that interval duration. Best bang for a buck was by far with 5x5. I am naturally inclined toward anaerobic power, i.e. with too short intervals did not reach to VO2max HR with many first intervals but with too long intervals I simply faded out, not even reaching intended HR at all.
Basically, just try it out. Also, experiment with hard starts, you’ll get intended HR zone faster and then just need to keep it up for remaining interval at lower power.
EDIT: Found old link, How To Increase VO2max As A Cyclist — High North Performance. There, variable power intervals look interesting. Haven’t tried myself, though.
Some considerations here:
I’m doing 8-min jobbers right now, last week before the workout it sounded impossible, but I hit a power PR and ended around 110%.
Ultimately I personally believe it comes down to several considerations, including how well you can execute them. Doing them in Erg with terrible form (hips bouncing, knees flailing, etc) is not my definition of success.
I would PREFER more short intervals. That’s why I would do the longer intervals instead.
Longer intervals. My knees will not allow me to accelerate too many times without becoming sore.
Agree with all of this.
Another thing to consider is the goal of the workout. You can’t add distance indefinitely without changing the workout at some point. 5 or 6 min is still in VO2 range but if you keep adding minutes you will eventually no longer be in VO2. can’t hold that intensity.
Some good information from the replies so far - thank you all.
I will work on extending interval duration for now and see how I get on.
Subsequently I will move on to a bunch of shorter, higher intensity VO2 intervals to mix things up a bit.
First 6x5 then next 5x6
Is going to either 6×5 or 5×6 not defeating the purpose of VO2max. Theoretically you can’t do those at the right intensity to do proper vo2max work.
Going longer makes it a d ifferent type of workout. In this case i would go harder instead of more.
For tempo/sweetspot/treshold i would indeed go longer intervals before going more intervals
As an overarching principle I agree that shorter VO2 Max intervals going flat out are likely to be “better” in terms of increasing VO2 Max than longer ones that blur the line into Intensive Threshold …
… but if the latter are specific to your racing/riding then that increases their appeal.
Of course, in that case the real answer is to do the full gas shorter ones in Build and the longer ones in Specialty.
