I just wrapped up Unbound XL last weekend and have done a few winter ultras. This is what I do:
- 1 VO2Max + 1 Threshold interval workouts per week during weekdays
- Lifting during weekdays
- Long endurance rides on the weekend (5h - 10h with minimal breaks)
- You can do one very long ride or two back-to-back long rides. Eg, 8h vs 4h/4h. This is all anecdotal, but I believe the single 8h is better than splitting into 4h/4h. However splitting may be necessary with scheduling.
- If splitting between two days, the closer the volume is together, the better. So a Saturday evening ride + Sunday morning ride is better than two evening rides. Anecdotal, again.
- Maybe work in some B and C events as endurance rides
- Maybe do long Z3 intervals within endurance rides
- Have at least one day completely off between big endurance rides and interval work
- 3 weekends before your event do a ride simulation shakedown that is at least 50% of the distance and mimics race conditions (eg, if the race is overnight, ride overnight)
- This rule of thumb only works up until a certain point. Maybe cap it at 24h?
- 2 weeks prior ease up on the endurance volume but keep the interval work
- 1 week prior halve the TSS of the intervals (but keep the intensity) and make sure they are finished at least 3-4 days before the event
- Do whatever pre-riding/warmup/taper-y thing you want in the days leading up to the race.
The easiest way I’ve found to program this in TR is to do a mid-volume polarized plan and then replace all the little endurance rides with one or two big endurance rides “outside” on the weekend. Also the polarized programming is experimental and sometimes can have stupidly long cooldowns–I just do 5 mins of cooldown and skip the rest. Imo, none of the TR plans are well-suited for ultra-endurance out of the box. Most of what I have is pieced together from Dylan Johnson’s videos and tips from 24h MTBers.
FWIW I’m coming from a place where I’m pretty set on endurance and my primary concern is power. You might have opposite concerns if your base is different. If you’re more concerned about endurance adaptations, I think doing a week of long distance bikepacking or an event like RAGBRAI where you are just dumping on volume day in and day out would be helpful.