Anaerobic intervals for long endurance events?

I’m about to get into my 2nd block of build and AT is scheduling anaerobic work on tuesdays and vo2max on thursdays as my main interval days (and v02max and sweet spot on the weekend, but I usually do a single long ride on Saturdays as my only weekend training). The block I just wrapped up was v02max on tues and threshold on thursdays (which made more sense to me).

My big race coming up in June is unbound gravel, so looking at a 12+ hour day with most of that at endurance pace and hopefully not much time at/above threshold. I know I get benefits from anaerobic work for shorter gravel races, but I’m really debating whether I’d be better off continuing to push threshold and vo2max since my events are so long (I’ve got leadville after unbound, so another ~9 hour race). I’m not doubting there are some benefits to the anaerobic work, but I feel like I still have a lot of work to do on my endurance at sweet spot and threshold and I’m not sure the anaerobic work is going to help as much. I’ve also considered keeping the anaerobic and subbing threshold work in for the vo2max, but that doesn’t make much sense in my head. I’ve really never trained anaerobic much since I mostly focus on long events, but maybe it would untap some increased aerobic endurance since it’s fairly untrained. Any thoughts?

I am not a coach, or a physiologist, just someone who has many years training. My best overall condition and performances have been after builds where I work on all the training zones. My experience is that you can do threshold until you are blue in the face, and you will see some minor increases in ftp and/or some increase in time in zone, but eventually you need some other forms of stress to “raise the roof” if you will. I am guessing that is what your build is doing. I would follow the plan.


I’m in the same boat. There are a few other posts asking the same question on the forum. I wish TR would address this issue. The best advice on the forum and what I’m doing is adding as much Z2 volume as I can on top of the training plan. If I could start the training plan over again I would have set it as a rolling road race rather than gravel.

Something sounds wrong to me.

I’m not on a TR plan right now, but when I was every one I did for that type of event was giving me a blend of Endurance, Sweet Spot, Threshold, and VO2. I don’t think I ever had an Anerobic or Sprint workout.

With that said, I think it’s probably just based on the type of event you choose. For those events, the recommendation I heard was Century / Gran Fondo.

other coaches may have a different perspective, but for me I don’t put a lot of value in anaerobic stuff for the type of riding I do. Anaerobic stuff will help to increase your matchbook for surges and over threshold stuff, but it’s not gonna do a ton for your aerobic endurance. If that’s your main worry, put the focus on that.

I’m actually just now on the tail end of my first anaerobic focused block since 2021 and while it’s nice that I’ve added 20w to my one minute power repeatability (450 to 470) in a few weeks, if I weren’t planning to race and trying to dig deep, I really wouldn’t even think about doing it

Every Tuesday of Rolling Road Race HV is Anaerobic.

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Sounds like it’s just a matter of choosing the wrong event type then.


If the plan is only based on event type and doesn’t look at duration, that’s certainly an opportunity for improvement. I just answered the questions they asked. Anaerobic and repeatability is very relevant for shorter gravel events where everyone is trying to rip groups apart in the first couple hours, so I get that it would be in the mix for a “generic” gravel plan. Honestly, I’m not sure why you even need a different plan for gravel compared to road racing, it’s very similar other than less recovery/Z2 with gravel. I’m going to substitute workouts to continue the focus on threshold and vo2max work. Maybe I’ll play with plan builder and see how it adjusts if I change event types.

I’ve shuffled my week around so the anaerobic ride usually ends up getting replaced with my outdoor gravel group ride. It’s fairly anaerobic, and even if it doesn’t give much structured benefit at least I’m developing race-specific skills in terms of terrain and bunch riding.

I’d try changing the event type to Century / Gran Fondo (forget the wording)

That’s what the TR team recommended for Leadville and it’s as or even more applicable for Unbound.


If I was doing a 12 hour event I would still do work in all the zones… occasionally… but my focus would be getting as much time in the saddle as possible.


I have many thoughts… :stuck_out_tongue_winking_eye:

Anaerobic and VO2 Max work will help raise your FTP…and that will raise your power levels across the board, even in Z2 where you will be spending the majority of your day at Unbound. So there is value there.


IMO, your primary focus should be on longer endurance and tempo rides. Yes, many people have been successful at events like Unbound or Leadville with only shorter, higher intensity trainer days, but that doesn’t mean it is “optimal”.

“Train like you are going to race” is a valid training concept…FWIW, I am in the same camp as I prepare for FNLD GRVL. For now, I am keeping with the Anaerobic / threshold stuff on Tues / Thursdays, but am subbing in longer endurance rides on the weekend. That is usually the Zwift BMTR Flat Century ride on Saturdays (~4 hours @ ~3 w/kg) and Goodale on Sundays (2.5 hours at ~2.5 w/kg)

IN the next week or so (weather permitting), I will begin to transition more to outside rides across the board and my Tues / Thurs rides will be more SS with spikes (fast rotating paceline rides, usually ~ 25mph) and longer weekend rides. If the trails dry out, I’ll be on my gravel bike, but if not, longer competitive group rides. Goal will be up to at least 6 hour rides comfortably before FNLD (June 10).

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They’ve addressed this repeatedly on the podcast and on the forum. Their position is that while plans do specialize, you needs contributions from all energy systems to perform. The various energy systems aren’t discrete and independent.

From an n=1 perspective, I see big benefits from doing Vo2max and Anaerobic work on my longer endurance and sweet spot efforts. In addition to building systems that can contribute to the overall load, the psychological impact of doing the more intense intervals makes the RPE of endurance and sweet spot work a little lighter.

Crux of the matter is: Trust the algorithm. If you try to second guess the TR system too much, you’re undoing the very benefits you came here for.

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Gravel doesn’t have the phenomena of the 80 mile race being over because you couldn’t match a 1-2 minute surge does it? Once your dropped on the road the race is essentially over short of a well timed train or field neutralization.

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No doubt, but I think what most people are questioning is the lack of the actual energy systems that will be used for their A event. The “endurance” rides on my current plan are only 1 hour long and are essentially recovery rides, not endurance rides.

My scheduled “work” days are currently are VO2 Max, Threshold, Anaerobic and Sweet Spot. None are longer than 2 hours. As noted, I am dumping the last 2 and subbing in longer endurance rides in their place.




Oh, well when you put it that way, I clearly see where I am wrong.

:man_shrugging:t2: :man_shrugging:t2:


I mean it sort of does more at Unbound than a road race. You may get dropped from groups over and over again though the day at the faster end. Any little climb or acceleration out of a corner can get you dropped.

I used century for my first Unbound but found it didn’t set me up well enough for the repeadet efforts at higher speeds.

I used Rolling Road Race the second year and it was exactly what I needed.

Depends on on how you approach Unbound. Are you truly looking to race it? Finish strong? Or just finish at all?

If you’re looking to actually race I’d use a plan focused on racing but add Z2 where you can.

If you are “time crunched” and only have an hour than yeah… crush the intervals. But 5 x 5 min @ 110% FTP is only going to go so far in a 12 hour event. The thing about these ultra-long events is your are testing not your FTP but rather how long you can hold a percentage of it.

I think questioning the algorithm is valid here. Even with a personal coach it is important to communicate and ask questions. Maybe some have the ability to follow blindly but personally I find buy-in best when they really believe it.

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You and I are following a somewhat similar approach. I haven’t done that BMTR ride in a while, but it’s my go-to option if I can’t ride/race outside on a Saturday. Serious tempo training for me, I think my 3 best 3:30 power records came from that ride. Super steady/smooth group. I’ve been racing the last couple saturdays, but I always try to get 100+ miles and 5+ hours on my long saturday rides. Working up to 7-8 hours. Some of that is meeting up with a group ride with some junk miles, but much of it is pretty disciplined high Z2 into Z3.