There’s not really one duration that works best, depends on people. I use intervals from 3-6min in training, usually with hard starts at high cadence.
This is the way, though I don’t use 2min intervals personally. 15-20 min is a good range for most, but you can work up to 24 or 25 min for this style. It kind of depends on the density and overall dose. So if you’re doing 1 VO2 per week, you might do 5x5. If you’re doing 3 or more and doing a big block, it’s more about the stimulus over the course of the BLOCK, and not any one workout or any one week.
Not really.
Kinda, yes. The higher cadence serves a couple of purposes:
Preserve your legs assuming you are doing a big block of these.
Speed the aerobic contribution, drive HR and Ventilation higher more quickly
(and this is the big one) a larger NUMBER of muscle contractions in the legs/lower legs which increases venous return and cardiac preload. Since your HR is limited, and your ability intake Oxygen by breathing is eventually limited during the intervals, the only choice your body has is to increase the volume of blood per heart stroke.
This interval design is intended to improve stroke volume, which is a central adaptation to VO2max.
#3 above is literally THE biggest reason you do VO2s at 110+. Doesn’t have to be 110+ but more leg speed while holding high/max effort power absolutely makes a difference and is the key difference for me when I’m prescribing “VO2max” work vs. “Max Aerobic Power” work.
“Go when ready” - me.
I tell people somewhere between 1:1 and 1:2 for work:rest. I agree that programming a 10 min rest between 5 min intervals is too long. But if you’re between interval 3 and 4 and taking 7 min is going to make that fourth 5 min interval higher quality, it’s fine. Most people know after a couple of these workouts when they’re ready to go again between intervals.
For me, when doing 5 min intervals, usually the first one I can go after 4 min but by number 4 or 5 I need like 7 min. Again, totally fine.
My 5x5mins and 4x6mins etc. have been done in a vo2max block with 8 vo2 workouts in 12 days with multiple double days, so that might explain why I like to take so long. In a 6x4min session I did 7-8min of rest, so I usually like around 2x length of work intervals.
For sure when I did 13 in 17 days (with double days) there were some longer rest intervals in there. Density works, but man… don’t try this at home LOL.
FWIW I’ve been working with another coach for the last four or five months, and we’re doing some VO2/MAP work right now. I’m doing a mix of things, some 3 min Zone 5 into 12 min SST; some 30/15s followed by 2x8 threshold+ intervals on short rest; and some more traditional 5x5.
As has always been my experience, the 5x5 more sustained zone 5 intervals get me to max ventilation and are harder by RPE, but the Ronnestads let me sit at a higher HR for longer periods. Interested to see how things progress after this cornucopia of MAP work.
FWIW, in one of Michael Rosenblat’s meta analysis of HIIT intervals (severe intensity domain intervals) suggests that the rest interval doesn’t matter much. The primary driver of adaptations is time in zone.
I also want to say that people shouldn’t be afraid to start slower than what is typically talked about. I’m 57, and started off with 5x5. I could do the workout just fine but it took a week to recover. I throttled back to 6x2min, 4x3min, 4x4min, and 5x3minute. All those workouts are much more achievable for me at 57 years old. I also switched to a mixed block as @kurt.braeckel suggested and that is working much better for me.
Even KM said in a pod that he might start off lower level athletes at 2min intervals. He also said that you’d probably get most of the adaptation out of the 2 minute intervals which I found curious. (He didn’t explain further.)
Just wanted to add that my coach had me taking 6 minutes rest at first for my 3 and 4 minute efforts, then when I went to 5 minute efforts, he said take between 8-10 minutes. He also reinforced that this was so I could get a better quality of interval completed. Hard starts to get “kinetics going” then settling in to the sustainable power at 110+ rpm.
I always thought that 1:1 work to rest for VO2’s was where it’s at, but I’ve been converted based on my recent experience in doin it the other way. Also, just did two sessions a week, 20 minutes max per session and 40 minutes a week is where I ended.
Typically for first time VO2 work (i.e. zero experience working VO2s), I use 3 or 3:30. Shorter for sure while they learn pacing max efforts (is that an oxymoron?). Second time, 3-6 is on the table.
I’ll die on my hill of “go when ready” rather than a fixed rest interval.
Interesting, you mean combining two workouts into one?
Last autumn at the end of recovery week tried combined workout Z5/4x3 + Z3/40 to wake myself up before loading block. Did not put much thought into it, just felt really good. Did not experiment further, indoor season was coming and went back to stock TR plans. Is it something that might be beneficial, when goal is not focused VO2max block but just touching VO2max weekly?
I prefer the short sharp stuff like Ronnestad’s as I don’t really have time to think about it. With longer stuff it probably tends to be a U shape, Start well, overthink and not so well then and over hard finish :-/
Hard start microbursts: 90s @ 130%, 30s rest, then 9 rounds of 30/15s (at ~120%/50%). Do 3 blocks in total.
Hard start Lisboas: 75s@125, 75s@115, 90s@105. 4-5 rounds total.
Do one of the above early in the morning, but only do 2 rounds (microbursts) or 3 rounds (Lisboas), then do a 90m endurance ride in the afternoon/evening. 2 rounds feels productive but not that fatiguing, and seems to sit well with a later ride at around 0.65 or an outdoors mtb potter. I’ve used this routine on weekends when I have a reasonable amount of free time in total, but family stuff means I don’t have a continuous 4 hour window at any point in the day.
I feel this is where most training plans (and myself as a result) get it wrong. We get stuck in a fixed-rest interval mentality. I’d probably benefit from a longer first and last rest interval, and shorter in the middle. First work set always feels extra-hard, even when properly warmed up, which can be mental, so helps to recover. This is a good reminder to myself to try a different approach!
This describes something much like the Rattlesnake series of workouts. I’ve been getting into them a bit lately. Someone on another thread said they couldn’t reach VO2 max with it, so I suppose that means raise cadence &/or the power target, or start the initial interval 15s early. When I had an injury to a wrist that was bad enough that it couldn’t painlessly hold the bar on the bumpy asphalt of my street, I couldn’t do intervals on my hill, so I emulated Rattlesnake -2 on foot.
I don’t see a lot of point to the long suprathreshold “VO2 max” workouts if I’m already doing threshold over-unders. A few months ago I did a workout that was something like 4×5’ @ 106% & my limiter was muscular fatigue, not O2 uptake. Felt like just another threshold workout.
What cadence were you doing the longer vo2 efforts at? I have always prescribed them without a set power target but with a high cadence to avoid the exact muscular fatigue issue you are describing.
Yeah I tend to be around 110-120rpm. But power can sometimes be barely 10-20w above ftp and late into the block might even be right near ftp. I don’t worry about power too much as long as I am cross eyed and breathing super hard.
I’ll be the contrarian here. Don’t neglect your weaknesses. If you’re doing two VO2 max workouts each week and you default to crazy high cadence because your leg muscles can’t deal with the increased torque required at lower cadences (at least this is what happens on ERG mode), make one workout a high cadence session and slowly, over time, try to decrease the cadence with the other workout. So if 110 is your default, make the lower cadence one 105 RPM. If you can complete it go for 100. And so on until you can complete it at 90 RPM (personally I would not go below 90 - and note that 90 isn’t low cadence, I consider it more of a baseline). It definitely won’t be overnight but building up your peripheral capabilities is important and shouldn’t be overlooked.
Just in case you’re not aware, this isn’t why people do VO2 at high cadence. In fact, based on what I’ve read here, it seems most of us feel it’s easier to do them at 90rpm.
Im a big fan of 30/30s (30 second at ~140-150% ftp / 30s endurance)
or
3min at 20min max power x however many reps (usually 5-8 reps) with 1 min off between reps at endurance. So its basically like a broken 20min max power test
Density works, but man… don’t try this at home LOL.