How many hours of Z2 rides are you doing per week? What are you adding to those for the intensity part of the Polarized?
Right now, it’s around 4-6 hours of Zone 2 a week. Some days I do 2 hours on a day, others I just stick to 1 hour. the weekend is always a 2 hour ride on a Saturday or longer. One day of the week has been 4 x 5 VO2 intervals at 4 minutes each interval with 10 minutes of rest between. I perform those on the road bike with power at 110-120ish% of FTP depending on my energy levels that day. The one day of the week I perform intervals recently has been 30 second sprints performed 4 times with 2 minutes of rest in between repeated around 4 times per round in a workout. At the end of a Zone 2 workout I throw in a couple 30 second sprints, maybe 2-3 at the most. It’s about as structured as I get these days.
Dude. Just do it™ Sponsor yourself™ 
@FatBoySlim
Sorry to hear about your recent streak of bad luck. I think it is excellent that you do therapy to work things out. Also our souls need healing. Stay safe!
That sounds reasonable and in line with what I do: do workouts and pad them with endurance rides. Although I base my training off of a mid-volume plan. After a month-long break (my family and I went on a trip to Europe) I am currently doing a polarized block.
Personally, polarized blocks are just another tool in my tool box, and I don’t think you should be too dogmatic about it. Experiment with what works. Emphasize consistency and building habits. Stick to shared training principles like functional overload and the like.
In view of the story that you told, I’d propose four things:
- Remember that bike riding should be fun.
- A 700 km backcountry race is hard. HARD. To put it in perspective: most “normal” people think a marathon is super hard. You can finish a marathon in 4–6 hours. Your event is much, much longer. So don’t feel bad if you fail or are slower than you wished.
- Pace yourself according to your abilities. Don’t overdo it, don’t have unrealistic expectations. These ultra events are mostly competitions of people against themselves. I don’t speak from experience here, I have never done an event this long, but clearly it is hard.
- Think about ways to improve your setup that would make your life easier. An obvious one is gearing. I remember one of the winners of one of the trans-Europe ultra endurance races had a very simple 1x SRAM Apex 1 setup, and it worked for him. The highest gear was almost meaningless, the lowest gear, on the other hand, was crucially important. And it doesn’t have to be fancy equipment either. With that much stuff on your bike and your additional weight, believe in the power of levers and gear ratios. Of course, there might be other things I am missing.
The bike sounds perfect. What chain ring do you run?
Regarding pacing, power pedals are great. If you want to stay in the endurance zone, heart rate works well, too.
I have to say, I’m impressed by everyone who even attempts to finish such a race.
Also, what happened to you is really messed up.
You could consider a smaller chain ring if you felt as if you needed more gears. I have a 30-tooth chain ring on my mountain bike coupled to a 11–46 cassette. I spin out at about 36–40 km/h. So stepping down to a 32-tooth chain ring might be an option if you think you will need it. (I don’t know the terrain or if you felt like you needed one or two extra gears last year.)
Yeah, but I am going to assume this wasn’t an isolated incident. Learning from it is exactly the right way to digest this event.