My short answer is you don't. You just do your normal long runs as normal ultra training. I like to do some really slow runs with lots of walking between the running, There will be lots of walking so I like to train for that as well.
Physically I don't think you can do much more. I will certainly add more back to back long runs and more runs on tired legs to the mix. Other than that I think the battle is all in the head.
I like to do more loop type runs than normal. 10 x 1km instead of 1 x 10km for instance. I've been doing most of my runs as loops the last two months. I don't know if it really makes a difference, but if my head tells me it does that is all I want.
Thinking or feeling I am mentally prepared is a win. I am feeling like that currently and that is good. I am feeling ready to go and run round and round and round for two days.
The 471m track.
I will go and give my support at the start of the 10 day race this Saturday and the same for the start of the 6 day race next week. That is the final part of my mental preparation. Being at the track and watching the runners in the long races doing their thing. That will get me to the start of the 48 hour race on the 19th with my head exactly where and how I want it.
I will post details of my planning and prep for the run over the next few days. This is circuit running and I love it!
Happy training everyone!