Base Phase for Ultra Endurance MTB Event

Context: Been on the platform for ~5 months and have been learning a lot. Finishing up a specialty phase leading into a 100mi gravel race in a couple weeks, and am starting to (at least I believe) see some holes in plan builder OOTB - IE lots of anaerobic work for a long (8hr) race that I will not be at the pointy end of, and will be spending nearly all of below threshold.

I’d like to be more mindful of this as I enter the training plan leading up to my big event of the year - a 100 mile MTB race happening in September (Marji Gesick for those that are familiar). This is a pretty brutal and long event, my goal for this year is in the 15-17 hr range. I’ll be using the low volume plan to allow space for outside rides and life. Currently my week is shaping up to be:

M - 1.5hr Threshold
T - off
W - 1hr VO2
T - social ride outside
F - 1hr Sweet Spot
S - 2-3 hr Z2 ride outside
S - off

My question - does it make sense to be doing V02 this early on (build, 5 months out from event), or would that time/stress be better off spent adding to my aerobic base at that stage, and then VO2 incorporated more as I enter build? I know the boxed answer would be to just trust PB and AT, but 1) I’m wondering if these longer events are a little outside it’s sweet spot (womp womp) and 2) it’s fun to tinker and understand these things in greater depth.

My thoughts as an XCM-oriented racer (not a coach, others almost certainly know more than me, etc.):

You’re far enough out from the race that you could consider spending more time working on building an aerobic base, and something like Traditional Base (particularly Parts 2 and 3 since you presumably have some base already) could be good. Then maybe take a look at the Polarized plans. Even if you don’t stay strictly Polarized in terms of TiZ, I think they give a nice foundation for 2 interval workouts a week (at MV) and the rest Z2, which I think makes it easier to fit in longer Z2 rides that can be helpful when dealing with long events like that. Certainly not the only way to do things, but it’s one approach to consider. I think when looking at longer events like that, while many can develop the fitness without long rides, having that saddle time provides some experience (even if just logistical e.g. figuring out fueling) that is valuable.


Eyeballing the schedule, I’d look at trying to get more Z2 work in.

On Friday’s, can you make the 1 hour SS ride a 90 - 120 Z2 ride instead?

What is the Thursday social ride like? Hard XC trail ride? Easy based road group ride? Based on the intensity of that ride, that may impact how you handle the VO2 and Threshold days. Assuming you can up the Z2 the rest of the week, keeping one VO2 and one Threshold day is reasonable. But if the group ride is really intense, they you may be going down the road of too much intensity and not enough easy (Z2) days.

For context, this is likely because you did the Gravel “race” event type which seems to really lean into the racing aspect whereas “gran fondo” is often more accurate with how you are planning to ride your event.

Good luck with MG. Looks so hard!

@kelseyh and @Kuttermax great thoughts - appreciate the input and suggestions. The Thursday ride is pretty chill (group dynamics and such) 90% of the time and I’m mindful of taking higher efforts into account elsewhere in the week to not bury myself. Polarized training is worth a closer look, as is a look at the week as a whole to see if there are some good windows for longer Z2 sessions during base.

Ahhh, good point! And thanks on MG, it’s a worth adversary and overall incredible event.

One misconception is that a VO2 workout is anaerobic work, it is high-end work on aerobic systems. VO2 max and Aerobic Capacity are two terms for the same measurement. Doing these workouts is designed to build your aerobic base.

For a full-day event like Marji Gesick, there will always be significant compromises from the ideal/most optimal training when you are using a low-volume plan. Think about it this way, TR is giving you a plan with 15 hours in the month for a 15-hour event. In an ideal situation, a polarized base might have you doing 2+ hours of z2 3 days a week, plus some threshold/ss workouts. With limited time subbing in an hour of z2 would just be an additional day of recovery, not base building.

Personally, I’ve had great experiences with their 3-day progression of VO2/Threshold/SS + additional volume at Z2 outside on the mountain bike. If you don’t do well with VO2, or find yourself struggling with recovery then subbing for another day of SS would be my suggestion. Mountain bike trails just don’t lend themselves to actually staying under threshold even if it is just in short accelerations up a hill or a technical section, so I found the training above threshold to be very important in race performance. My 65% target recovery ride on trails yesterday had 23 instances with 30 seconds above threshold, but only 2 seconds above z2 HR/RPE.

If you hit that week consistently I think you will find yourself in a good place with fitness for the Marji Gesick. The thing that this can’t prepare you for is how you’ll feel after 5 or 10 hours of riding trails. So I would definitely try to get some bigger back to back days on the mountain bike at some point before the race to find out how your upper body will handle it, if you have any fit issues, and to test nutrition (the gravel race will do this too).

I’m starting to wrap my head around this - thanks for underscoring that.

My original plan (using PB) for Marji was the standard SSBLV (V02, Threshold, SS) and then I had an additional day of outdoor Z2 on the weekend as I’ll have the time.

Based on some earlier advice, I went ahead and checked out the polarized plan, and the mid-volume polarized plan looks like nearly exactly what I was trying to create. Only real modification I’d be making to what PB had originally built is some reordering of my week and swapping a 1hr SS ride for a 90-120 min Endurance ride (which I’m happy to get up early and do).

I did Marji last year (before finding TR or learning anything about carbs) and I can whole heartedly attest to this :joy:. I had several 5 hour MTB rides, and one 10 hr MTB century under my belt, but the combo of race day hubbub and the intensity of the terrain (and 13k’ of climbing) had me deep deep in the hurt locker. Was able to gut out a 22hr finish but it wasn’t pretty. Hopefully Lady Luck is on my side this fall and I’m able to apply everything I’m learning and have a much improved performance.

QQ - how are you tracking this?

FWIW you can try for the short sustained interval matching, but in my experience it misses a lot of them. GoldenCheetah has the best interval detector. Or you can just eyeball it.

For example:

lots of time with power above zone2, but HR most z2 and below.

But what about sustained efforts?

just 2 short efforts detected.


detects a lot more sustained short efforts.

Hope that helps.

1 Like

I search for them through the Trainerroad workout analysis, it is a bit of a hidden feature when you look at intervals at the bottom of the workout. Instead of the summary/laps from the workout, you can search for a certain power & time combination.

1 Like