It can definitely be done, but without a strong background in biking and many seasons in you it could turn out 'interesting' come race day. I have gone with this sort of approach last season and this season. With two young kids, a full time job, and lots on the weekend, getting in those long rides can be quite a challenge if you want to be 'present' for family.
I've found that I can get in a 3-4 hour ride + 30' transition run and be done around 8:30 on the weekends. Of course, this means getting up around 3:00-3:30, but it is feasible. In training for IMLP last year I only had two rides of over 4 1/2 hours and - both were midweek days I took off from work so it wouldn't effect things on the weekend with my family.
However, this training approach has a big caveat if you aren't already a pretty strong biker. As a reference, I biked 4:51 at IMMT a few years ago. In terms of structure, I break the rides up into 30-45 minute chunks with a variety of intervals at varying intensities.
A 4 hour ride could be something like:
30' warmup with as 15' easy, then 2' @70%, 1' ez, 2'@ 75%, 1' ez, 2'@ 80%, 1' ez, 2'@ 85%, 4' ez
Then for the next 3:00: 4x (5' @90%, 5' ez, 20' @ 80%, 15' @ 70%)
Finish with 30' easy
This would roughly work out to being around 10% over goal avg power. I find if I can do a whole bunch of 4 hour rides like this, then hitting IM power goals on race day is pretty easy and the run goes well.
You could also do something a bit like this with 4 hours:
Same 30' warmup as above
2:30 split up as 3x (40' at IM effort, 10' easy)
In the last hour do 3x (15' at 85%, 5' easy)
This ride has you doing some harder HIM level efforts near the end of the ride.
I always follow my long rides up with a 30' transition run with some race pace efforts or strides mixed in.
Blog:
http://262toboylstonstreet.blogspot.com/ https://twitter.com/NateThomasTri Coaching:
https://bybtricoaching.com/ - accepting athletes for 2023