Hard start VO2max intervals

Thanks. I ride about 9hpw but sometimes go up to 12 and keep one heavy lift day every week.

I don’t always have the reps high on the vo2 work so I do ‘blocks’ you could say, but I do keep the 1-2 days in the weekly cycle always.

For example, I am having an easy-type week this week and I put down one 8min vo2 interval in the middle of a 3 hr endurance ride Tuesday and did a 7min interval in today’s 3hr but nothing else besides noodling on the bike path on the others.

You’re correct, higher watts definitely would have elevated HR. If I went 150% of FTP that would be 465-475w which wouldn’t be doable and would lead to either a failed workout or rapidly decreasing watts. Since it’s been at least year or more since my last short/short type workout there was some experimentation with power output.

This was also my third consecutive VO2 workout, so I was carrying fatigue into it. And my garage was around 78° ambient—not ideal. Still felt like this was a quality session.

I’ve learned that for me, a good VO2 workout is indicative of hard breathing and significant RPE. High HR usually comes with that, but today was different.

my trainer bike is an ancient fixed gear with a powermeter. 120 rpm gives me a little over 120% of FTP.

I’ll do the :30s, but cut the rest to :05 or :10 seconds of soft pedalling.

Try it like that – it will get pretty groovy after 8 x :30@ 120% on :05 or :10.

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Why not just do a 3min interval?

Depends on the purpose.

I find that I can’t muster the concentration to hold that intensity or leg speed on the trainer for more than a minute or so. After 40 years of wind trainers, computrainers, fluid trainers, smart trainers blah blah blah, my head is just kind of done with that – especially on a Tuesday night after 9-10 hours at school.

3-6min at 110% of FTP is mentally doable (but something like 3min at 110% only needs a 60-90 second recovery if I want to be in VO2 suckville and stay there for a few efforts – say, 2 sets of 4 x 3:00 on 1:00), and yes, I prefer the isopower longer interval. But, if it’s been a couple of weeks without whacking the gear around at 120rpm repeatedly, then I’ll do the very short rest :30 - :60 intervals. It’s not just hitting at/near VO2 on the efforts, it’s also about keeping in tune with different cadences and effort levels.

Fixed this for you.


You could tone down the volume and get there. 40reps is a lot at 150%. Sometimes when I have fatigue coming into the day my HR doesn’t get up there like it would had I been fresh. You may have experienced that if it was your third consecutive vo2 workout.

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Have you tried a higher power on the “off”?

Oh god no. I don’t think I could. That 20s is all about “recovery” so I can go harder on the 40s smashers.

I did create this workout which I’m looking forward to doing…this is to mimic a race scenario where you have to smash up a little climb, hold it for a while, and then coast a downhill. Something I see all the time in cyclocross racing. Very applicable to other forms of racing too I would imagine. Smash > Hold > Settle > Repeat

Overs are 20sec at 150-155% (all out, basically) and the other overs are 3min at 100-105%.

Pretty sure something like that is in the TR library, I saw it in someone’s timeline recently. Also think short power build had somehing like that, with an added sprint at the end of each block.

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That will show some… and FWIW the FasCat coaching crew uses hard start/end intervals. I call them :metal: for obvious reasons. There is an interesting blog post over there, on the topic.

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I bet you could!

I’m not into 30/30s etc but last year I did Lincoln — 88x15/15s, rest at 88%. HR and breathing never really got into VO2max territory; ‘on’ power was ~140%. Get a bit tiring at the end but it’s good fun.

Boy…3 consecutive days of VO2 work and 2 hours at .74IF (~410TSS in 4 days) has left me destroyed. I’ve never felt so trashed! I’m hopeful some adaptations will come though!


Back when I was coached and did road racing I would do something like:

5-10x30/30 (150%)
straight into a 10-30min SS (90-95%)
then right into 5-10 x30/30 again.

Sort of like a drawn out ‘hard start’ but I found it very effective. We would build reps and SS duration progression through a 3 week on 1 week down cycle. This workout was in the middle of the weekly long ride (3-4hr).

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How many 3-day blocks are you doing?

0.74IF sounds a bit hard to me after 3 days of all-out VO2 max work. My go-to easy sessions are Townsend -1 or Gabriel if I can fit in 2 hours (both 0.60 IF).

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CX officially starts in a month, but we have 3 weeks of unsanctioned (Tuesday Worlds) races starting today. So my plan was to front load last week with 3 consecutive days and then do the races the next 3 weeks as my 1 HIT day.

So I’ll only do the 3 day block once.

It’s interesting. I think the ride was actually lower in IF. NP was 230w (FTP set at 310w) but my HR was always around estimated LT1. Never felt like I was pushing hard. Regardless, I’m smoked!

Your HR can be way lower during vo2 max block as sign of fatigue. I have seen even 10 bpm lower hr for efforts around sst and threshold, even 2 weeks after block. And during Z2 rides in vo2 max block my hr is always lower than normally. Not to mention that everything feels way easier after smashing vo2. Any kind of riding feels “this is soooo easy” and you can dig yourself a hole with this (been there, done that).

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Totally good point, I am very disciplined when it comes to doing my easy rides, because I wasn’t in the past and learn the hard way. :no_mouth:

I do think that 300 TSS in three days was probably a bit too much. But experimentation is fun!

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Depends on the training experience of the athlete, the fiber type, and the life demands.

I routinely do 300+TSS weekends, with consecutive days over 150. But, I have 40 years of this behind me, have always recovered well, and don’t have to do much with my weekend afternoons other than nap.

I also have easy 30-35TSS days on Monday and Friday.

Also, not all TSS points are created equal. Zone 5 or 6 TSS is going to take more out of you than zone 2, but most of us know that by now…